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Question

Common Risks of Developing an Anomaly of Binocular Vision

Answer 1

* Anisometropia * High refractive error: >3.00 DS, >2.50DC (45% chance. If FH also, 86%) * Abnormal OMB * Positive Family History (25% chance) * Low Birth Weight/Premature

Answer 2

- Reduced Snellen and grating acuity - * Loss of contrast sensitivity * Shape distortion * Motion deficits * Crowding effect

Answer 3

o Recognised that myopia is very common in premature babies o Premature and low birth weight babies also shown to have a higher incidence of strabismus o Retinopathy of prematurity

Answer 4

* Less likely to emmetropise, so consider prescribing for refractive errors earlier * Likely to have poor accommodative response, so DO NOT reduce hypermetropic rx o Likely to benefit from bifocals or other styles of near rx

Answer 5

ideally 7 pounds and 6 ounces, or 3.3kg

Answer 6

o A full term neonate is hyperopic approx. +2.00 +/-2.00DS  Pre-term can be more variable +/-2.50DS o Infants show a high degree of astigmatism too  Majority corneal  Significant reduction occurs in the first year due to the increasing eye size and concurrent flattening of the cornea

Answer 7

o Direction o Age of which it was noticed & who noticed it o Onset – sudden or gradual o Constant or intermittent o When the squint is seen o If the angle is increased or decreased o Other features e.g., AHP o Defective ocular movement o Defective vision * Ask px about gross stereo i.e. 3D movies

Answer 8

A reduction is vision in one or both eyes, persistent after correction of refractive error. Absence of retinal pathology or any disease of the afferent visual pathways Most common cause of vision loss in children , interruption of normal visual development

Answer 9

direction, size, speed of recovery, changes at distances, with/without specs

Answer 10

direction, size, changes at distances, accommodation, with/without specs

Answer 11

 Emmetropisation: expected reduction in neonatal refractive error during normal growth o Most active phase 12-18 months o Can eradicate 3.00DS / 1.50DC

Answer 12

o Active element = visual feedback mechanism in the control of eye growth i.e., time outdoors o Passive element = growth of eye; decrease of corneal radius of curvature / increase in axial length

Answer 13

 Critical period for binocular vision 0-5 years; most plastic o Time frame in which visual deprivation results in loss of function, poor prognosis for development of binocularity and most severe visual loss plastic = The brain’s ability to re-write both structurally and functionally in response to external influences (leaves it vulnerable to amblyopia)

Answer 14

 Sensitive period 5-8 years; still vulnerable to damage and may respond to treatment

Answer 15

motor and sensory fusion

Answer 16

 To put object of attention onto each fovea – maintains it there when the object moves  Allows change of fixation from one object of attention to another  Ensures proper alignment of both eyes  Weak motor causes px inability to keep image single o Interaction between this mechanism and size of deviation determines how well a phoria is compensated

Answer 17

2. Sensory fusion o Appreciate 2 similar images and interpret as one o How the eyes perceive and how the brain utilises

Answer 18

6th Nerve (Abducens)

Answer 19

4th Nerve (Trigeminal)

Answer 20

3rd Nerve (Oculomotor)

Answer 21

elevation intorsion adduction

Answer 22

depression extorsion adduction

Answer 23

intorsion depression abduction

Answer 24

extorsion elevation abduction

Answer 25

6/90-6/60 FCPL +3.00ds

Answer 26

6/36-6/60 keeler FCPL +2.50DS stereo 600

Answer 27

6/18 cardiff acuity cards +2.00DS 210-170 stereo

Answer 28

6/12-6/9 cardiff/kays pictures/ sheridan gardiner +1.25DS 100-85 stereo

Answer 29

6/9 -6/6 snellen +0.50DS 40-30 stereo

Answer 30

 Horopter: all images constant size, viewed as single  Panums fusional area: images here as viewed in 3D; images outside space cause large disparities that cannot be fused i.e., physiological diplopia

Answer 31

 Patient should be reviewed regularly, minimum every 3 months  Age in years = review in weeks (4 years old = 4-week reviews)  VA stable 2 consecutive visits = consider tapering off/stopping occlusion  Amblyopia persist & px compliant = refraction & fundus check, increase occlusion to FT or change therapy  Amblyopia persist & px non-complaint = instruction leaflet, reward scheme, video game therapy, change regime

Answer 32

1. Under action of the primary affected muscle 2. Overaction of the contralateral synergist – Hering’s Law 3. Overaction of the ipsilateral antagonist – Sherrington’s Law 4. Inhibition palsy of the contralateral antagonist

Answer 33

describes a condition in which originally non-corresponding retinal areas of the two eyes co-operate to produce a form of binocular single vision - never as good as having normal A shift in the spatial localisation of the deviating eye occurs to counteract the effect of the ocular deviation

Answer 34

 Cortical mechanism; mental inhibition of visual sensations in one eye in favour of the other  Develops rapidly in childhood; more slowly in older children up to 10years  Suppression should only be treated if the deviation can be eliminated and strong chance of restoring BSV  Physiological = normal  Pathological = used to overcome binocular diplopia in manifest strabismus or incompatible images due to significant degree of anisometropia – central suppression develops in poorer eye

Answer 35

both foveae have common visual directions - produce a single image

Answer 36

Comitant strabismus The angle of eye deviation remains the same regardless of the direction of gaze. This is the most common type of strabismus in children. Incomitant strabismus The angle of eye deviation changes depending on the direction of gaze. This type of strabismus is often caused by limited eye movement due to neurological, mechanical, or myogenic issues.

Answer 37

 Any deviation <4 prism D cannot be seen  Small – 4-8D  Moderate – 8-16D  Large - >16D

Answer 38

measures the amount of uncorrected phoria, measured with rx done on anyone who can accommodate due to panums area the eyes can be misaligned during binocular viewing w/o diplopia,

Answer 39

anatomical causes, refractive causes, uniocular activity and trauma

Answer 40

o In compensated heterophoria, motor fusion is maintained, therefore sensory fusion and stereopsis should occur o If phoria is large or fusional reserves small – increasing degrees of decompensation of the heterophoria can occur with increase in symptoms i.e., asthenopia, headaches, intermittent diplopia o As decompensation professes, fusion may break down completely – resulting in a manifest deviation & inevitable double vision

Answer 41

1. Cosmetically unacceptable / patient would like surgery to improve alignment (surgery usually when angle >20^) 2. Strabismus has become symptomatic producing diplopia - may occur if a change to the angle of deviation causes the image to fall outside the suppression scotoma

Answer 42

o Anomalies in development of skull or orbital structures o Other non-structural conditions i.e., cerebral palsy o Any impediment to good vision (i.e., congenital cataract) is an impediment to sensory and therefore motor fusion o Downs syndrome

Answer 43

measure the full extent of the phoria, useful for small deviations, especially vertical, not suitable for accommodative deviations XOP - images crossed, base in prisms needed SOP - images uncrossed, base out prisms needed *cannot use maddox rod to prescribe prism

Answer 44

when phoria is not controlled then phoria is decompensated base out - positive fusional reserves, corrects SOP base in - negative fusional reserves, corrects XOP *distance correction and lights on done on any eye infront of px, at distance and near, target single letter, a line bigger than VA for poorer eye blur break recovery

Answer 45

frontal HA's, asthenopia, intermittent diplopia, Photophobia, Difficulty changing focus from near to distance and vice versa, Blurring of reading, Crowding of words while reading o As decompensation professes, fusion may break down completely – resulting in a manifest deviation & inevitable double vision o Frontal headaches & asthenopia = caused by EFFORT to maintain BSV (tend to occur later on in the day) o Transitory diplopia & blurred vision = caused by FAILURE to maintain BSV (noticed more when tired or unwell)

Answer 46

* Optical causes: uncorrected/under corrected refractive errors (eso = hyperopia, exo = myopia), wrong corrected refractive errors by reducing VA and dissociating the eyes, ill-fitting specs causing prismatic effect, aniseikonia o SOP in younger age groups o XOP in elderly age groups o Convergences excess SOT o Accommodation excess SOT o Ill-fitting specs – induced prismatic effect o Uncorrected spherical errors o Medical causes e.g. poor GH, head trauma, meds, alcohol, stress o Precision jobs

Answer 47

o Full correction first line of management  SOP decompensated by uncorrected hypermetropia – acts as BO  XOP decompensated by uncorrected myopia – acts as BI o Ill-fitting specs can results in a prismatic effect if the lenses are decentred and can increase the degree of phoria and make control more difficult o Orthoptic exercises for divergent/convergent insufficiencies  Decompensated XOP are easiest to treat with exercises o 20-20-20 for prolonged near work o Bifocals to relax accommodation o Prisms in elderly pxs (usually first choice) o Botox injections if prism does not work

Answer 48

o Room lights off o Maddox rod place in front of the non-fixing eye with the cylinder axes horizontal o Px fixates the spotlight with the other eye and is asked on which side they see the vertical red line o Prism is held in front of the rod with its base orientated in the direction of the line and the strength of the prism is adjusted until the line passes through the light o Repeated with the other eye and then to correct any vertical deviation o Line is seen in the opposite direction of the deviation  HYPER – line is seen below dot  HYPO – line is seen above dot  RE ESO – line is seen temporally/right  RE EXO – line is seen nasally/left * Double Maddox rod o Used to assess cyclotorsion o 2 lines are seen – red and white – and ideally they should be parallel if no deviation is present

Answer 49

o No improvement – indicates pathology o Improvement – issue with rx o Worse with pinhole – macular problem

Answer 50

based on the principle of longitudnal chromatic aberration, whereby short wavelength light (green) is refracted more than the light of longer wavelengths (red)

Answer 51

very useful for refracting young children with very active accommodation, but is useful in any pre presbyopic px's to make sure you have not given too much minus or plus

Answer 52

green duochrome to ensure circle of least confusion is on the retina

Answer 53

 The vitreous is a clear gel which fills the vitreous cavity and occupies about 80% of the volume of the globe  The vitreous consists of mostly water, as well as hyaluronic acid and a meshwork of collagen fibres

Answer 54

o Vitreous base/ora-seratta o Posterior lens capsule o Optic disc o Macula o Along the retinal vessels

Answer 55

Vitreous base is the strongest attachment. The vitreous base is a 3-4mm wide zone of vitreous which straddles the ora seratta. At the vitreous base, the collagen fibres at attached to the underlying peripheral retina.

Answer 56

 Posterior hyaloid membrane separates rear of vitreous from retina  Anterior hyaloid membrane separates front of vitreous from lens

Answer 57

junction between the ciliary body at the retina

Answer 58

o Bright, thin slit beam focused on anterior vitreous (posterior lens and slightly forward) o Volk lens is not used for this o Ask patient to look up-down-straight ahead o Pigmented cells in anterior vitreous = tobacco dust = +VE shafers o Helps exclude break – only 8% eyes with breaks and shafers negative

Answer 59

 PVD occurs when the posterior vitreous separates from the retina and collapses anteriorly towards the vitreous base  This occurs due to vitreous syneresis (with age) in which the vitreous becomes more-fluid like  An opening can the develops in the posterior vitreous through which liquefied vitreous passes through causing the posterior hyaloid membrane to pull away from the retina  Spontaneous PVD is common but may also follow surgery, trauma, uveitis or laser  It may cause troublesome floaters or retinal tears which may lead to a detachment

Answer 60

o Caused by vitreous opacities such as glial tissue from the disc, condensations of collagen fibres or blood o Shadows are cast on the retina and seen as floaters

Answer 61

 PVDs are non-sight threatening and symptoms usually reside after 1-3 months  Explaining & reassuring patient  Advise px tor return if any sudden change or worsening of flashes/floaters or any visual field defect – provide a patient advice leaflet  Within 6/52 from initial symptoms – PVD has greater risk of developing into RD  Review in 6/52 from initial symptoms to ensure no RD has occurred  Very occasionally, extremely symptomatic patients may require a vitrectomy

Answer 62

 Retinal thinning associated with overlying vitreous liquefaction / abnormally strong vitreoretinal adhesion  Stress caused by vitreous is worse in these areas, so retina is more likely to tear here  Spindle shaped areas of retinal thinning; sclerosed vessels forming network of white lines  Routine prophylaxis is not justified

Answer 63

*IOP often lower by about 5mmHg * RAPD * +VE Shafers – tobacco dust/pigmented particles in anterior vitreous *Chronic detachments often have thinned retina, RPE pigmentation at the border of detached retina (high-water mark) Record: o Extent of RD o Any macular involvement o Any breaks/lattice degeneration - Pigment in the fundus – Demarcation line - operculum in vitreous

Answer 64

 Benign, idiopathic, splitting of the neurosensory retina at the level of the OPL  Relatively common – 5% population  More common in hyperopia  Non-progressive/not sight-threatening

Answer 65

 Usually no symptoms  OCT useful – has the whole retina detached as in a retinal detachment or is it just a slitting of the neurosensory retina?  No retinal break  More common inferior temporal/peripheral area – loss of visual function in this area but it is peripheral and rarely noticed  Bilateral  Dome-shaped elevation

Answer 66

 PVD  Choroidal mass – urgent referral  Retinoschisis – no referral needed/observation in community practice

Answer 67

* Refers to the separation of the neurosensory retina (NSR) from the RPE * This results in the accumulation of sub-retinal fluid (SRF) in the potential space between the NSR and RPE

Answer 68

caused by the vitreous gel in the eye remaining attached to the macula after a posterior vitreous detachment

Answer 69

goal of equalising accommodative effort in the 2 eyes and achieving the bet possible binocular refraction

Answer 70

 Increased age, common in 50+  Axial length – myopic eyes more at risk (experienced 10 yrs earlier)  Following surgery i.e. cataract  Trauma

Answer 71

 Starts with PVD, typically in older patients  Persistent vitreous traction and increasing SRF  50% result in detachments – emergency referral for prophylactic Tx  Rapidly progressive  Laser Tx is likely

Answer 72

 Starts with PVD, typically in older patients  Large break, high risk of complications, worst prognosis

Answer 73

 No PVD; typically, in young (myopic patients)  Tide mark appearance  Most likely to be asymptomatic

Answer 74

 No PVD; typically, in younger px’s  Detachment may be large, usually infero-temporal  May be due to trauma

Answer 75

 Mainly caused by fibrosis from severe diabetic retinopathy

Answer 76

Flashes/floaters usually absent because vitreoretinal traction develops insidiously, and is not associated with PVD

Answer 77

 Concave configuration, breaks absent  Retinal mobility reduced, shifting fluid absent  Highest elevation of retina occurs at sites if traction  If develops a break – assumes characteristics of RRD

Answer 78

 No breaks with shifting sub-retinal fluid  May occur due to a variety of vascular, inflammatory and neoplastic diseases  Involves the retina, RPE and choroid in which fluid leaks and accumulates under retina

Answer 79

No flashes, floaters if Vitritis, field defect may develop & progress rapidly

Answer 80

 Convex configuration, but smooth surface  Detached retina is mobile, shifts fluid  Leopard spots consisting of scattered areas of subretinal pigmented clumping may be seen after detachment has flattened

Answer 81

- Pneumatic retinopexy – gas bubble inserted in eye - Cryotherapy or laser retinopexy to create an adhesive scar; prevents vitreous fluid moving into subretinal space - Scleral buckle - vitrectomy o Remove gel & remove traction on retina o Ensure retina is back in place using cryotherapy or laser, to reattach retina to RPE o Takes some time, usually put air (lasts 1 week)/gas (short acting 2 weeks, long acting 5-8 weeks)/oil (complex detachments; can see and fly, hyperopic shift but 2nd operation to remove) to allow it time to stick properly o In this time, patient cannot see or fly o Overtime, bubble gets smaller, rounder and lower over period of time

Answer 82

Areas of peripheral whitening on the retina seen without scleral indentation. Caused by a changes in the vitreoretinal attachments which result in retinal atrophy and abnormal vitreo-retinal adhesion

Answer 83

* RD with good VA (Macula On), * Vitreous or pre-retinal haemorrhage, * Pigment in anterior vitreous, * Retinal Tear/Holes with symptoms

Answer 84

* RD with poor VA (Macula off) unless this is longstanding retinal hole/tear without symptoms. * Lattice degeneration with symptom of flashes and floaters

Answer 85

o chances are higher in myopes o Px with FH of retinal detachment o RD in other eye o Post complicated cataract surgery – with vitreous loss o Injury to eye o YAG laser capsulotomy in high risk eye (high myopes)

Answer 86

o Characterised by sharply demarcated bands of tightly patched ‘snowflakes’ that give the peripheral retina a white frost-like appearance

Answer 87

o Congenital abnormality o Small, round or oval, discrete elevated whitish lesion o Typically in the equatorial or peripheral retina o There may be associated pigmentation at its base

Answer 88

Common phenomenon caused by an aberrant zonular fibre extending posteriorly to be attached to the retina near the ora serrata, and exerts traction on the retina at its base

Answer 89

o Refers to retinal areas in which a translucent white-grey appearance can be seen by scleral indentation o Frequently seen in normal eyes and may be associated with abnormally strong attachment of the vitreous gel, though may not indicate a higher risk of retinal break

Answer 90

o Diffuse or circumscribed choroidal depigmentation, commonly associated with thinning of the overlying retina o Retinal holes developing in the atrophic retina may occasionally lead to RD

Answer 91

abnormal growth of BV

Answer 92

 DRY AMD = retinal cells die off & are not renewed (because function of RPE is reduced) o Geographic atrophy = cell death of RPE cells

Answer 93

o No signs of AMD o Small (hard) drusen <63 microns)

Answer 94

o Medium drusen 63-125 microns o Pigmentary abnormalities

Answer 95

o Large drusen >125microns o Reticular drusen o Medium drusen with pigmentary abnormalities

Answer 96

o Large drusen with pigmentary abnormalities o Reticular drusen with pigmentary abnormalities o Vitelliform lesion with significant visual loss (BVA <6/18) o Atrophy smaller than 175 microns and not involving fovea

Answer 97

o Geographical atrophy o Significant visual loss associated with  dense/confluent drusen  advanced pigmentary changes and/or atrophy  vitelliform lesion

Answer 98

o Fibrous scar o Sub-fovea; atrophy or fibrosis secondary to an RPE tear o Atrophy o Cystic degeneration o Eyes still may develop of have recurrence of late wet active AMD

Answer 99

o CNV o Ocular (fibrovascular PED / serous PED with neovascularisation o Mixed predominantly or minimally classic CNV with occult CNV) o Retinal angiomatous proliferation (RAP) o Polypoidal choroidal vasculopathy (PCV); macular neovasc, occurs more in African Americans & Asians

Answer 100

o RPE degeneration and dysfunction o Serious PED without neovascularisation

Answer 101

 Generally over 55 years old  AMD leading cause of VI  Accounts for over 5-% of those registered SI or SSI  4.8% over 60s  65-74 = 11%  12.2% over 80s  75-85 = 28%  Estimation: 670,000 people in UK = late AMD

Answer 102

* Age ^ * Race - late AMD more common in Caucasians * Gender – females > males o Greater risk possibly due to longevity * Heredity – risk of AMD is up to 3 times as high if first-degree relative has the disease * Smoking - doubles risk (2-3x) of AMD o Tar of cigarettes = hydroquinine = oxidative stress = DRY o Nicotine = induces capillary formation = WET * Hypertension & other cardio-vascular risk factors (vascular disease > ischaemia/accumulation of waste products > degeneration of RPE) * Dietary factors o Low in omega 3 & 6, vitamins, carotenoids, and minerals o High fat intake, obesity, excessive alcohol consumption o BMI of 30 = higher risk * Aspirin – evidence is limited * Females – greater risk possibly due to longevity * Cataract surgery – can speed up progression from dry to wet * No evidence for increased risk of AMD due to light exposure

Answer 103

gradual reduction (over months-yrs) bilateral changes distortion only in advanced cases

Answer 104

loss of vision more quickly unilateral/ one eye worse severe/ obvious distortion noticed

Answer 105

subretinal layer

Answer 106

drusen (hard or soft) pigmentary changes eventual development of geographic atrophy

Answer 107

med - large drusen subretinal or preretinal haemorrhage CNV PED CMO

Answer 108

Consists of a blood vessel complex that extends through Bruch membrane from the choriocapillaris into the sub-RPE (type 1) or subretinal (type 2) space * May be identifiable as a grey-green or pinkish-yellow lesion o Associated medium-large drusen are a typical finding in the same or fellow eye o Sometimes CMO

Answer 109

* Px may register as sight impaired – need referred to ophthalmologist to complete this form * Px may access low vision services and LVAs o Hand/stand magnifiers (illuminated vs non-illuminated options) o Typoscope o Use large prints/increase text size on phone o Black felt tip pens to see writing easier o Audio books and Kindles (reduce glare and can increase contrast) o Alexa/Google home – allows px to speak to device and it can call friends/family, tell the time/news etc. o Liquid level indicators, talking microwave, phone with bigger numbers etc. * Training o Eccentric viewing o Steady eye strategy * Useful websites e.g. Macular Society, RNIB, Citizens Advise, Sightline * May have to refer to the GP for psychological problems that arise e.g. depression * Stop smoking * Eat healthier, exercise, diet rich in green leafy veg and fruit – no firm evidence but no harm in doing so * Protect eyes from sunlight – tinted (absorptive) lenses o May suffer discomfort from glare

Answer 110

AREDS study 2 contain lutein and zeaxanthin #AREDS2 formula also reduced the risk of lung cancer compared to the original formula, which contained beta-carotene AREDS2 supplements help slow the progression from intermediate to late AMD.

Answer 111

Urgent referral (within week) if suspect AMD – done via Fast-track Wet AMD referral (through SCI gateway) There must be a recent history (usually < 3/12) of at least one of the following * Visual loss (VA 6/12 or worse) * Spontaneously reported distortion * Onset of missing patch/blurring of central vision * NB corrected VA must be 6/96 or better in the affected eye – if any worse than this may be no improvement with injections

Answer 112

 Side effects include bleeding in the eye, feeling as if there is something in the eye, eyes being red and irritated

Answer 113

 Light is shone at the back of the eye to destroy the abnormal BVS that cause wet AMD  May be recommended alongside eye injections if they don’t help alone  Usually needs to be repeated every few months  Side effects include temporary vision loss, and the eyes and skin being sensitive to light for a few days/weeks

Answer 114

 Most used treatment  Criteria – 6/12 or worse  Avoids the proliferation of new & unhealthy blood vessels  Visual prognosis o 25% cases VA improves o 90% VA remains stable  Ranibizumab (lucentis) – approved by NHS Scotland & NICE - £742 o Initial loading dose – 3 injections, every 4 weeks o Maintenance injections usually 1-3 months, for as long as necessary o Effective for all lesion types  New drug – Brolucizumab (Beovu) – now approved by NHS Scotland & NCE, can increase time between appointments to 12 weeks – minimize treatment burden for patients

Answer 115

o Smoking & Beta carotene – More likely to trigger lung failure o Genitourinary problems & Zinc - May cause kidney stones or UTI o Heart failure & Vitamin E – Increased risk of heart failure * Ensure the patient speaks to a doctor/pharmacist about the supplements BEFORE they are taken

Answer 116

is a retinal break that involves the fovea, most macular holes are idiopathic however it could also be due to traction between the posterior hyaloid membrane and parafovea and this occur as complication of a posterior vitreous detachment (PVD) URGENT REFERRAL (within one week) - vitrectomy usually Symptoms Metamorphopsia (distortion of central vision), central vision loss or scotoma

Answer 117

B3: management to resolution Refer to GP if suspicion of hypertension or bleeding disorder, or if condition is recurrent A1: if orbital fracture or intracranial source of haemorrhage suspected, emergency (same day) referral to A&E

Answer 118

hypertension, medications, acute or chronic cough, eye rubbing, heavy lifting, recent ocular or head trauma, bleeding or clotting abnormalities and recurrent subconjunctival haemorrhage

Answer 119

Acute haemorrhagic conjunctivitis (AHC) viral conjunctivitis (typically enterovirus; usually small multiple haemorrhages; rare) usually bilateral Retrobulbar haemorrhage Conjunctival neoplasms (e.g. lymphoma) with secondary haemorrhage Kaposi’s sarcoma (red or purple lesions under conjunctiva)

Answer 120

Pedunculated papillomas are more elevated and have a rough surface, while sessile papillomas are broad based and slightly elevated with a smooth surface. Pedunculated papillomas can look like a skin tag attached to the eyelid by a stalk

Answer 121

* Measure BP * ensure posterior borders visible to rule out intra-cranial source * If recurrent refer to GP * Reassure px * Advise condition clears within 5-10 days and return if no resolution

Answer 122

o Pinguecula (no corneal involvement) o Pannus: an immune system condition that occurs as a result of ultraviolet (UV) light damage to the side of the cornea – the clear part of the eye – that triggers the body to attempt to repair the damage by sending small blood vessels into the layers of the cornea

Answer 123

Benign wing shaped fold of fibrovascular tissue Degenerative condition usually found in Hot/High UV climates

Answer 124

* UV protection (reduce risk of progression) * photo document * cold compress when inflamed * Ocular Lubricants Refer for Surgical Excision if: o threatens visual axis o induces irregular astigmatism o is associated with chronic inflammation o is cosmetically unacceptable.

Answer 125

Yellow/White deposit on the bulbar conjunctiva due to degeneration of the collagen fibres in the conjunctival stroma, thinning of the overlying epithelium and occasional calcification

Answer 126

* Lid crusting * Purulent discharge * Conjunctival Hyperaemia * Papillary Reaction * no corneal involvement usually à if corneal, possibily gonococcal

Answer 127

* Often resolves in 5-7 days without treatment, * Bathe and clean the eyelids * Advise px it is contagious * Treatment with topical antibiotic (chloramphenicol, fusidic acid) * Cease any lens wear. * Return if symptoms persist past 7 days. * Manage to resolution * Refer – If condition persists or if there is corneal involvement

Answer 128

topical antibiotic effective against Gram –ve organisms, such as an aminoglycoside (e.g. gentamycin) or a quinolone (e.g. levofloxacin or moxifloxacin) no cls worn in this time

Answer 129

B3: management to resolution. Refer if condition fails to resolve, or if there is corneal involvement. A3: If condition fails to resolve, or if there is corneal involvement, urgent referral (within one week) to ophthalmologist

Answer 130

* Watery discharge * Conjunctival hyperaemia (may be intense), * Follicles on palpebral conjunctiva (upper and lower fornix), * Subconjunctival haemorrhages, * Corneal involvement in some cases * punctate epithelial lesions initially progressing to sub epithelial lesions which may persist for months. * Pseudo-membrane on tarsal conjunctiva (Severe) Px usually have had a cold or other upper respiratory tract infection

Answer 131

* Advise highly contagious * Self-limiting resolving in 1-2 weeks * cold compress * cease lens wear * monitor for corneal involvement or development of pseudo-membrane. * Ocular lubricants * Refer – If Corneal involvement (keratitis – severe pain / visual loss) or pseudomembranes on conjunctiva (EMERGENCY)

Answer 132

central or eccentric zone of epithelial oedema overlying stromal thickening folds in Descemet’s membrane uveitis Keratic Precipitates

Answer 133

Unilateral, * Elevated IOP, * Hyperaemia, * Corneal epithelial and/or stromal oedema, * Descemet’s folds, * Shallow or flat AC, * Mid dilated pupil with absent reactivity, * conjunctival congestion

Answer 134

HZO is when the nasociliary branch of the ophthalmic division of the trigeminal nerve is involved. It generally occurs between 60-70 however can occur at any age especially in immunocompromised patients Most people get infected with the virus varicella (chicken pox) and the virus lays dormant. However, a reactivation will lead to zoster (shingles)

Answer 135

#general * unilateral painful red vesicular rash on the forehead and upper eyelid progressing to crusting after 2- 3 weeks * resolution often involves scarring. * Periorbital oedema * lesion at side of tip of the nose (Hutchinson’s sign) * mucopurulent conjunctivitis associated with vesicles on lid margin * scleritis * Episcleritis * Keratitis (punctate epithelial, pseudodendrites, nummular, disciform, reduced sensation, endothelial changes and KP) * anterior uveitis * glaucoma * posterior uveitis * optic neuritis * optic atrophy Neurological * CN palsy * optic neuritis * encephalitis * post herpetic neuralgia fever, malaise, HA, pain and altered sensation of the forehead on one side

Answer 136

Co-management with GP if keratitis limited to epithelium. * URGENT (within one week) if deeper corneal involvement such as a disciform keratitis or neurotrophic ulcer. * EMERGENCY REFERRAL TO GP for acute skin lesion

Answer 137

(acute or recurrent epithelial HSK with no stromal involvement): alleviation or palliation; monitor closely within first 72 hours to evaluate healing, but refer urgently (within one week) to ophthalmologist if epithelium has not healed after seven days A1 (if stroma involved, or in children or contact lens wearers, or in bilateral cases): emergency (same day) referral to ophthalmologist

Answer 138

Unilateral (may be bilateral) * Pain * Burning * Photophobia, * Reduced VA * Redness Epithelial : * Punctate lesion coalescing into dendriform pattern * dendritic ulcer * Opaque cells arranged in stellate pattern progressing to liner branching ulcer associated with decreased corneal sensitivity * Geographic ulcer in late stage Stromal: * Necrotic stroma * stromal infiltrates * vascularization * scarring * keratic precipitates AC * uveitis and raised IOP

Answer 139

* Circumlimbal injection, * AC flare and cells, * Keratic Precipitates, * Pupil Miosis, * Hypopyon, * Band Keratopathy, * Fibrin in the AC, * Cells in anterior vitreous, * Peripheral anterior synechiae (PAS), * Posterior Synechiae, * Rubeosis Iridis, * Mutton fat KP, * Iris nodules. IOP – Reduced (Aqueous humour production reduced), Normal/Elevated IOP (Inflammation affect outflow pathway)

Answer 140

* Mild – VA 6/6 -6/9, Superficial circumcorneal flush, No KPs, Grade 0 -1+, Normal pupil, no posterior synechiae, no iris swelling, IOP reduced <4mmHg. * Moderate – VA 6/9 – 6/30, Deep circumcorneal flush, KPs, Grade 1+- 3+, Miotic or sluggish pupil, Mild posterior synechiae, Mild iris swelling, IOP reduced 3-6 mmHg, Anterior vitreous cells. * Severe – VA<6/30, Deep circumcorneal flush, KPs, Grade 3+-4+, sluggish or fixed pupil, Fibrous posterior synechiae, Iris crypts, IOP increased, Moderate to Severe anterior vitreous cells.

Answer 141

* Grade 0 - No Flare / No Cells * Grade 1+ -Faint Flare (Barely detectable)/5-10 Cells in view * Grade 2+ - Moderate Flare (Iris and Lens still clear) / 10 - 20 Cells in view * Grade 3+ - Marked Flare (Iris and Lens Hazy) / 20 – 50 Cells in view * Grade 4+ - Intense flare (coagulated aqueous, fibrin visible) / 50+ Cells in view

Answer 142

Caused by denaturation of protein fibrils within the lens due to oxidative stress, increasing age and metabolic disturbance

Answer 143

* Poorer Diet * Low socio-economic status * Age * Smoking * Larger Lens * Higher Ambient Temperature Signs: * Yellowish hue * Myopic Shift

Answer 144

Cortical – Appearance of spokes * Sunlight (UVB) * Lens size * Age * Diabetes * Smoking * Female * Non-Caucasian Signs: * Increased astigmatism * Monocular Diplopia

Answer 145

Posterior Sub-capsular – abnormal epithelial cells and granular material at posterior pole due to swelling and breakdown of lens fibres * Diabetes * High Myopia * Steroids * Age * Male * Thyroid Hormone Use Signs: Rapidly progressing loss of visual acuity.

Answer 146

9. Day case procedure 10. Local anaesthetic drops and possibly intra-cameral (into AC) injection 11. Small incisions made in the cornea (1-3mm in size) 12. Viscoelastic substance injected to maintain shape and pressure in eye 13. Capsulorrhexis – round incision made in the anterior capsular bag to get access to the cataract 14. Hydrodissection – fluid injected between the capsule and cataract to separate them 15. Phacoemulsification - high frequency ultrasound device which breaks the cataract up into 2-4 small pieces which are then suctioned out 16. A folded artificial intraocular lens (IOL) is then inserted (via the small incision) and placed into the capsular bag 17. Stitches are rarely required due to it being keyhole surgery

Answer 147

1 in 10,000 - loss of eye 1 in 1000 endophthalmitis (a very serious complication) 1 in 100 will have a more serious complication resulting in a poor outcome 1 in 300 persistent corneal oedema 1 in 50 cystoid macular oedema 95% of patients have a straightforward operation

Answer 148

Corneal oedema o Raised IOP o Uveitis o Cystoid macular oedema o Periocular Bruising, o Wound leak, o Wound burn, o Hyphaema

Answer 149

Drainage – through the puncta, through canaliculi, into lacrimal sac to the nose. Pumped into there from lid action and gravity feed to lower punctum

Answer 150

A disorder of the tear film due to tear deficiency or excessive evaporation, which causes damage to the interpalpebral ocular surface and is associated with symptoms of ocular discomfort.

Answer 151

- lipid layer - aqueous layer -mucus layer

Answer 152

Reduces water evaporation from the aqueous layer Secreted by: Meibomian gland, glands of Zeiss, glands of Moll.

Answer 153

carries nutrients and oxygen to the eye and carries away waste. Hydrates the cornea and prevents it from drying out. Secreted by: Main lacrimal gland for reflex secretion, Basal secretion by accessory lacrimal glands of Krause and Wolfring

Answer 154

Trap debris and epithelial cells, which are then removed through blinking. Also allows for tear stability and adheres to the epithelial corneal cells and conjunctival goblet cells

Answer 155

o 35mm x 5mm strip of paper is inserted into the temporal side of the eyelid o Assess tear production o A normal tear film should produce a wetting length of > 15mm in 5 mins

Answer 156

o Less invasive than Schirmer o Phenol red is pH sensitive and changes from yellow to red when wetted by tears, due to the alkaline nature of tears (pH 7.4) o Thread is placed in the eye for 15s – colour of thread is then measured o Wetting lengths should normally be between 9mm and 20mm, values less than this have been shown to correlate with subjective symptoms of dryness

Answer 157

o G1: >0.3mm o G2: 0.2 mm o G3: <0.1mm

Answer 158

is a weak acid. It doesn’t stain, it fluoresces in the presence of more alkaline fluid (such as mix of tear fluid and aqueous humor) and ‘stains’ corneal epithelial cells by pooling in areas of dead or shedded cells. It fluoresces at 525- 530nm (use yellow filter).

Answer 159

stains membrane degenerate and dead cells. viewed in white light. o In dry eyes, the nasal conjunctiva stains more than the temporal and the cornea stains less the conjunctiva. Observe 1 eye at a time (use red filter) Lissamine is better for conjunctiva instead of NaFl

Answer 160

hordeloum chalazion molloscum contagiosum xanthelasma papilloma basal cell carcinoma squamous cell carcinoma malignant melanoma epidermoid cyst cyst of moll

Answer 161

1. tear nutrients (e.g. oxygen and electrolyte supply to the cornea) and antibacterial agents (i.e. lysozyme produced by the major and accessory lacrimal glands). 2. moist conditions on the eye surface (evaporation reduces surface temperature) 3. the mechanical flushing action of tear movement Aqueous deficiencies may be partial or absolute but invariably produce marked symptoms of soreness or burning. The osmolarity of the aqueous increases in dry eye and the resulting hypertonicity leads to ocular damage.

Answer 162

The forces associated with lid-globe contact during blinking is important for mucus distribution. Restricted lid movement can lead to serious tear deficiency and exposure keratitis

Answer 163

An irregular corneal epithelium (due to corneal lesions or keratoconus) can produce a thin and unstable tear film.

Answer 164

* Carbomers (GelTears, Viscotears) – semi-solid formulations of high molecular weight. o Drop frequency reduced from 20x to 4x o reduces natural elimination of tears o retention time is 7x longer o protective during sleep o high viscosity can cause blurring * Hypermellose – traditional choice of treatment for tear deficiency. Requires frequent instillation * Liquid Paraffin (Hycosan Night) – lubricates eye surface in case of recurrent corneal erosion. May cause blurry vision * Macrogels (Systane) – uses pH sensitive component to become more viscous in the eye * Paraffin (Ointment) – bland ointment are semisolid preparation of petrolatum and mineral oil and lanolin. Melt in eye and retained. Only use at night * Sodium Hyaluronate (Hysosan) – Viscoelastic high molecular weight polymer, increases goblet cell density and reduces inflammation of ocular surface. Improves tear stability and wettability. * Diet – Omega 3/6, fatty acids. * Ocular Environment – central heating, air humidifier

Answer 165

Sjögren Syndrome (SSDE)  Associated with systemic disease e.g. RA, lupus etc. Non-Sjögren Syndrome (NSDE)  Intrinsic  Lacrimal gland deficiency  Inflammation of infiltration of lacrimal gland  Lacrimal gland obstruction  Hyposecretory states i.e. reflex afferent block or secretomotor block (parasympathetic damage)

Answer 166

Bacterial infection of lacrimal sac – secondary to blockage on the nasolacrimal duct

Answer 167

Symptoms * Sudden onset * Pain * tender swelling of lacrimal sac * epiphora * fever Signs * Red, tender swelling centred over lacrimal sac and extending around the orbit * Purulent discharge from the puncta when pressure applied * frequent conjunctivitis and pre-septal cellulitis

Answer 168

ALL Children EMERGENCY REFERRAL, Severe case if px is systematically unwell, cases which do not respond to anti-biotics for 7 days Urgent referral, mild cases responsive to systemic antibiotics – monitor for blockage of duct. Manage to resolution

Answer 169

* Tape the lid to the skin of the cheek for temporary relief * Epilation of lashes can be done where Trichiasis is localised * therapeutic CL to protect cornea * Ocular lubricants Refer – Initial management followed by routine referral for surgery

Answer 170

College Management Guidelines – Mild cases require no treatment, tape lid at night to avoid corneal exposure, ocular lubricant Refer–Severe cases requiring surgery

Answer 171

* Epilation of lashes * therapeutic CL for temporary relief, * Ocular lubricant * lid hygiene for associated blepharitis Refer – Routine referral for electrolysis, cryotherapy, argon laser photocoagulation, lid surgery if secondary to entropion

Answer 172

sterile chronic inflammation from a blocked gland

Answer 173

Symptoms * painless lid lump, usually single, may be recurrent, may rupture, * sometime blurred vision from induced astigmatism Signs * Well defined, 2-8mm nodule in tarsal plate * lid eversion may show external conjunctival granuloma * associated blepharitis * induced astigmatism

Answer 174

Acute bacterial infection of the lash follicle and its associated gland of zeiss or moll

Answer 175

Acute bacterial infection of the Meibomian gland, usually staphylococcal: can develop into chalazion if untreated.

Answer 176

Symptoms * Tender lump in eyelid * Epiphora * Local redness of eye and lid Signs External – tender inflamed swelling on the lid margin, may point anterior through skin, multiple abscesses involved entire eyelid Internal – tender inflamed swelling within the tarsal plate that’s more painful than stye. May point anteriorly through skin or posteriorly through conjunctiva

Answer 177

* most resolve spontaneously or discharge by resolution * remove lash from infected follicle, * manage associated blepharitis with lid hygiene * return if persist or worsen * topical antibiotics - when copious discharge Refer – In cases which do not discharge ( more with internal hordeolum) - severe or recurrent then management w systemic braod spectrum antibiotic like amoxicillin

Answer 178

Bacterial infection of tissues lying anterior to the orbital septum common in infants under the age of 10 Caused by Staphylococcal, Streptococcal

Answer 179

Bacterial infection of the tissues lying posterior to the orbital septum (within the orbit) severe and life threatening

Answer 180

* Proptosis * Restriction of EOM * pain with eye movement * reduced VA * reduced CV * RAPD present * pyrexia - fever -malaise -unilateral swelling of conj and lids

Answer 181

aphakia cornea with high DC keratoconus post graft surgery more stable vision more durable cls - up to 1 yr * High o2 permeability * Doesn’t dry out tear film due to 0% water content * Resistant to protein deposits

Answer 182

* Poloxamine – Removes lipids and environmental debris * Hydroxyalkyl phosphonate – Removes protein deposits * Boric Acid – eliminates bacteria and fungi * Sodium Borate – anti-fungal and Balances pH for natural lens wear, to match the tearfilm: 6.6 – 7.8. * Sodium Chloride - Maintains similar tonicity to the tearfilm to avoid discomfort and conjunctival hyperaemia * Hydroxypropylmethyl cellulose – Conditions and lubricates the lens surface * Chlorhexidine Gluconate - Disinfectant * Polyaminopropyl biguanide – Disinfectant and preservative

Answer 183

7. Soak lenses in solution for 4 hours or overnight in an empty lens case 8. Wash your hands 9. After soaking, rub both sides of the lens with 4 drops of the cleaner solution in the palm of your hand for 20 seconds. 10. Rinse using the solution for approximately 5 seconds to remove loosened surface deposits 11. Insert lenses 12. Discard solution 90 days after opening

Answer 184

Boston Advance Cleaner (Step 1) * Alkyl ether sulfate – surfactant to remove contaminants from the lens surface * Ethoxylated alkyl phenol – alcohol to remove bacteria from the lens surface * Quarternary phospholipids, Titanium Dioxide & Silica Gel – Aids to physically scrub off proteins and deposits when rubbing Boston Advance Conditioning Solution (Step 2) * Wetting and cushioning agents: o Cellulosic Viscosifier o Polyvinyl Alcohol o Polyethylene Glycol * Preserved with: o Chlorhexidine Gluconate o Polyaminopropyl biguanide o Edetate Disodium

Answer 185

7. Wash your hands 8. Rub both sides of the lenses carefully with 4 drops of cleaner (Step 1) in the palm of your hand for 20 seconds 9. Rinse both sides of the lens with a saline solution 10. Soak your lenses for 4 hours with the conditioning solution (step 2) 11. Add a drop of conditioner to the lens for extra cushioning and insert into your eye. 12. Rinse your lens case with a sterile disinfecting solution and then wipe dry with a clean tissue. Avoid air-drying.

Answer 186

fit on flattest K (round to 0.05mm) (plus lenses tend to drop a little, consider fitting 0.05mm steeper)

Answer 187

use formula: BOZR=FlatK - (FlatK-SteepK)/3

Answer 188

 HVID dictates the total size of the lens  TD ~ 1.5 – 2mm smaller than HVID o HVID generally 11-12mm  Generally, 9.30 and 9.80 TDs available  VVID gives us indication of the fit o Lid attached; minus lens more likely to lid attach as it is thicker in the periphery o Interpalpebral  Higher powers require greater td for stability

Answer 189

 BOZD = area with Rx (periphery of lens is for stabilisation)  BOZD must be > pupil size in scotopic (dim light) to ensure pupil is smaller than BOZD in all lighting conditions  If pupil > BOZD = issue with flare / haloes around lights  High myopes may need larger BOZDs to avoid flare

Answer 190

 Nafl = central touch, large area of edge lift  Flat fit creates a negative tear lens, resulting in plus over Rx

Answer 191

 Nafl = central pooling (smaller area of pooling = steeper lens)  Steep fit creates a positive tear lens resulting in a negative over Rx

Answer 192

0.25DS over Rx = 0.05 BOZR change Increase in diameter by 0.5 = flatten BC by 0.05 Increased diameter = increased sag Because cornea is aspheric, increasing diameter = steepening lens, therefore you need to flatten it to keep Rx same

Answer 193

fluorosilicone acrylate Silicone is softer so scratches more easily, hence modern RGPs are only on 1–2-year replacement schedules. The addition of fluoropolymers to silicone acrylate increases the wettability & less susceptible to protein deposition

Answer 194

* Usually ranges from 8.50-10.50mm * Ideally approx. 2mm smaller than HVID measurement * Influenced by the pupil size as it must be larger than the pupil in low illumination o If not px may experience halos at night/dark conditions * Higher powered lenses are better suited to larger TD so they are more stable * Altering the TD does not influence the NaFl pattern to a great degree on aspheric lenses

Answer 195

the measurement of horizontal movement on lens excursion Lag is important to measure when fitting contact lenses to assess how well the lens moves with the eye when it looks away from the primary gaze Lag is the difference in distance between the lens edge and the limbus when looking in different directions. For example, if the distance from the lens edge to the limbus is 1.5 mm when looking straight ahead, but 2.5 mm when looking up, the lag is +1.0 mm

Answer 196

* Hydrophillic polymer (Main material used is Poly-HEMA). * The oxygen permeability depends on the water content, the higher the water content the more oxygen that can pass through the lens. Advantages of Hydrogel: * Thinner lenses * Better initial comfort Disadvantages of Hydrogel: * Low oxygen permeability * Higher risk of eye infections and hypoxia-related issues * Not ideal for overnight wear

Answer 197

* Allows 5x times more oxygen to pass through than hydrogels. * The oxygen permeability depends on the amount of silicone used, not the water content Advantages of Silicone Hydrogel: * High oxygen permeability * Extended wear and longer wear times available * Easier to handle as generally thickness aids sturdiness and enhances durability Disadvantages of Silicone Hydrogel: * Tend to be more expensive

Answer 198

o 160Dk/t o 48% water content o No UV protection o Modulus 0.75 o Monthly/EW (i.e. can sleep in lenses) silicone hydrogel o BC 8.6mm, Dia. 14.0mm o Power ranges  -0.25 to -6.00 (0.25)  -6.50 to -12.00 (0.50)  +0.25 to +6.00 (0.25)  +6.50 to 8.00 (0.50) o Extended range  -12.50 to -20.00 (0.50)  +8.50 to +15.00 (0.50) o Stock in store  +/-0.25 to +/-6.00  -6.50 to -17.00 (0.50)  +7.50 and +8.00 o Also have toric, toric XR (which has an extended range for sphere and cyl powers) and multifocal options

Answer 199

> +/-4.00 K= F/((1-dF)) K = new CL power F = spec power d = BVD (in metres)

Answer 200

lens name manufacturer BOZR/TD/rx, e.g. Bioinfinity coopervision 8.4/14.2/-3.00DS

Answer 201

 Flat fit = steepen by increasing TD or reducing BOZR  Steep fit = flatten by decreasing TD or increasing BOZR

Answer 202

to make sure the optic zone radius covers the pupil at all times. If pupil size bigger than measured then distortion seen

Answer 203

Horizontal visible iris diameter (HVID) is of value to the soft lens fitting and will act as a determinant of total diameter. The HVID must be at least mm less than the TD of the lens to be fitted

Answer 204

spherical +8.00 -12.00DS toric +8.00 --10.00DS, 2.25DC is the highest water content 54% Dk 80 0.4 modulus

Answer 205

+8.00 -12.00 -2.25DC Dk 90 51% water content at core

Answer 206

+20 -20DS, highest cyl 5.75DC Dk 128 48% water content

Answer 207

1/dist(m) = D 1/0.5m = 2.00D

Answer 208

* The UK Health and Safety Executive (HSE) law states that employers must arrange an eye test for display screen equipment (DSE) users if they ask for one, as well as pay for it, and pay for glasses if an employee needs them only for DSE use o If an ordinary prescription is suitable, employers do not have to pay for glasses o In some cases an employer may choose to contribute towards specs which are not solely for DSE use, but this is entirely at the employer’s discretion

Answer 209

o The px is under no obligation to reveal any clinical information to his employer, though failure to do so may become an employment issue o Under DSE regulations, the employer only requires a very small amount of info  Confirmation that a test was performed  Whether or not the px requires no specs, their own specs or special VDU spectacles  The date of the next suggested examination

Answer 210

o In good daylight, must be able to read the registration plate  At a distance of 20m with letters and numbers on a car registered since 1st September 2001  At a distance of 20m with letters and numbers on a car registered before 1st September 2001 o VA must be at least Snellen 6/12 (logMAR 0.5) with both eyes open or only eye if monocular (with or without correction) o A VF of at least 120 degrees on the horizontal using a target equivalent to the white Goldmann III4e setting e.g. Estermann field test  There should be no significant defect in the binocular field that encroaches within 20 degrees of the fixation above or below the horizontal meridian  The false-positive score must be no more than 20% o Bioptic telescope devices are not accepted by the DVLA for driving

Answer 211

bus and lorry license o Require a higher standard of VA than group 1 o VA (using corrective lenses where needed) of at least  Snellen 6/7.5 in the better eye  Snellen 6/60 in the poorer eye o If glasses are worn to meet the minimum standards, they should have a corrective power not exceeding +8.00 in any meridian of either lens VFs:  An uninterrupted measurement of at least 160 degrees on the horizontal plane. VF (with at least 70 either side of fixation) and 30 above and below fixation  No defect should be present within a radius of the central 30 degrees o No other impairment of visual function, including no glare sensitivity, CS or impairment of twilight vision

Answer 212

* You should advise the px that they have a legal responsibility to notify the DVLA and provide them with further information on how to contact them * You should advise the px that you have a duty to notify the DVLA yourself if you think the px will not or cannot do so, and if there is any concern for the safety of the px and/or wider public * You should also consider whether you need to notify other healthcare professionals e.g. GPs who can also discuss this with the px * If driving is relevant to the px’s occupation, you should advise them to inform their employer * You should put any advice in writing and keep a clear record of your actions including any correspondence * If you have followed the above steps, but still consider that the px will not inform the DVLA, you should o First, inform the px that you intend to notify the DVLA and you have a duty to cooperate fully with the DVLA and provide all relevant information as requested o Notify the DVLA and provide all relevant information that is requested o Consider whether you need to notify other healthcare professionals e.g. GP o Keep a record of your actions and any advice given o DVLA make the final decision whether or not to revoke the px’s licence

Answer 213

* Cataract o Often safe to drive and may not need to notify the DVLA (even if bilateral) o More prone to suffering glare/halos when driving at night * Monocular vision o Driver must meet the same VA and VF standards as binocular drivers o Only for those who fail to meet these requirements are required to notify the DVLA * VF defects o Bilateral glaucoma/retinopathy/retinitis pigmentosa and other VF defects that cause partial or complete homonymous hemianopia/quadrantopia or complete bitemporal hemianopia MUST notify the DVLA * Diplopia o Must not drive and must notify the DVLA – DVLA will review request for group 1 licences if corrected with glasses/patch/prism * Nyctalopia o Must not drive and must notify the DVLA (both groups) * Blepharospasm o Must not drive and must notify the DVLA (both groups) * Colour blindness o May drive and need not notify the DVLA (both groups) * Nystagmus o DVLA not need be notified providing the vision standards for driving are achieve and providing any associated medical condition is declared

Answer 214

o R = PLUS o D = Minus

Answer 215

Aspherics: o Thinner, Flatter, Lighter o Eliminates spherical aberrations, as causes all light that hits the lens surface to converge onto one focal point o Better Cosmetic Appearance due to flatter front surface o Reduces centre thickness for High Plus and Edge thickness for High Minus o Better optics in patients >+7.00D Disadvantages of Aspherics: * No useable zone in periphery * Distorted vision is notorious in minus lenses à the only real use for a minus aspheric is to reduce edge thickness

Answer 216

Prism Thinning: Incorporated vertical prism to reduce the thickness and weight of the lens * R+L Lens feel equal, no relative prismatic effect * Base down prism is applied to reduce central thickness of the lens

Answer 217

Anti-Reflective Coating: Decreases surface reflections inside the lens by phasing the reflected rays into ½ their wavelengths, causing destructive interference. Multiple coatings are applied for different wavelengths. Ultimately this improves the optical performance and removes glare for the patient. o Advantages of MAR: § Improved visual performance § Reduced Glare § Increased Contrast § Improved Cosmesis § Mandatory for High Index o Disadvantages of MAR: § Easily smeared due to hydrophobic coating § Expensive due to vacuum coating process § Prone to chemical damage from everyday products (e.g. hairspray)

Answer 218

Blocks UVA & UVB rays up to 400 nanometers. Good for patients with cataracts & AMD.

Answer 219

Frame PD – Px PD / 2 = X (in) This is important as if the lens is not decentred in to fit the Px’s PD, a prismatic effect will be induced

Answer 220

o 1.6 'T&L 25’: 20% thinner than a standard lens (2.50 to 4.00) o 1.67 'T&L 35’: 33% thinner (4.00 to 6.00) o 1.74 'T&L 50’: 42% thinner (6.00 +) On all thin lenses an anti-reflection coating is recommended as high-index lenses refract the light at a quicker rate and therefore create more reflections

Answer 221

o Colour is produced by dye moulding. o Manufactured in blocks and cut into sheets to cut the frame shape out of. o Has reinforced sides. o Finished in lacquer to improve scratch resistance. o Reshapes at 60oC. o Px may have allergies

Answer 222

o Produced by injection moulding, dying and lacquer o Stronger than Cellulose Acetate o Greater elasticity and more flexible than Cellulose Acetate o Greater resistance to ageing o Lighter o Reshapes at 70oC o Hypoallergenic

Answer 223

o Primarily used for safety eyewear (the one piece and side shields). o Can be soft or high impact resistant.

Answer 224

where the effective optical aperture is smaller than the frame aperture o Used to reduce weight and thickness of high powered lenses, poor cosmetic appearance and reduced FoV (especially for +ve lenses) rarely used due to availability of high index materials o Standard lenticular, blended lenticular o Made from plastic eg bifocals

Answer 225

Photochromic – AgCl and CuCl added to glass at manufacture, uv exposure causes chloride to undergo oxidation to chlorine and silver ions reduced to form atoms presence of CuCl in low UV allows reverse reaction o Photochromic – Plastic – spiroxazines – molecule that rotates to form a shape reducing light transmission combination of several spiroxazines each with different transmission and temperature dependencies combined to form a photochromic lens. o Photochromic performance – Temp dependent (darker and faster in cold), Enhanced by MAR (increased UV transmission)

Answer 226

 Soft designs = long progression lengths, more gradual astigmatic gradient in lens periphery, but have smaller stable reading area and distortions in the distance o Easier to get used to – less of a change per 1mm when looking down o More intermediate area o E.g., Admin worker  Hard = wider stable reading area, wider progression and distortion free distance area; however, the distortions are more severe as they are crammed into smaller area o E.g., driver

Answer 227

o ABBE number = measurement of the materials dispersion of light o Chromatic aberration = white light splits into its colour components as the lens is unable to bring various wavelengths to the same focal point o High abbe = desirable = low dispersion  As refractive index increases density and amount of aberration increases and weight decreases (plastic) or increases (glass)

Answer 228

o Advantages  Refractive index (N=1.523) is higher than that of CR39, so lenses are thinner  Lenses are abrasion resistant  Good constringence (V or Abbe number of 59) * the higher the V value the lower the material’s dispersion of transverse chromatic aberration (less likely to disperse white light into ROYGBIV)  Good transmission – 92% in uncoated state o Disadvantages  Poor impact resistance and shatters into sharp shards when broken  Density high so lenses will generally be heavier than CR39

Answer 229

o Advantages  Low density and lenses are therefore lighter than crown  Good transmission – 92% in uncoated state  Good constringence (V values of 58/59)  Impact resistance better than crown and then lens does not splinter when broken  UV protection good (around 350nm) since UV absorbers are incorporated into the lens as standard o Disadvantages  Lower refractive index (n=1.498) than crown, so are thicker than crown lenses  Abrasion resistance is poor, unless a hard coat is added

Answer 230

o Advantages  Primarily impact resistance or ‘increased robustness’, making it ideal for sports and industrial purposes  Becoming more popular for children and general-purpose specs  Good UVC protection (cut off 400nm)  Higher RI than CR39, so very light o Disadvantages  Abrasion resistance is poor, so are coated with silicone-based polymers – this reduces impact resistance slightly, but the material still maintains its ‘increased robustness’ standard  Cannot be easily tinted

Answer 231

The total power of a lens is a sum of the front and back surface of the lens F1 + F2 =FT e.g. +4 + +2 = +6.00 D +7 + -1 = +6.00D

Answer 232

o Must assess the suitability of chosen appliance o Must provide the most suitable ocular and housing type o Must ensure the finished product complies with the px’s requirements and relevant standards  Cannot repair safety specs (not even change a screw) – needs to be sent back to the manufacturer for them to carry out safety checks  Can only really carry out adjustments A visual task analysis

Answer 233

 VDU users are entitled to a free sight test paid for by their employer if they are having difficulty carrying out display screen work.  If glasses are required specifically for VDU only then the employer must provide those for free (basic cost of lens & frame). This is specified by the Health & Safety Regulations (1992).  The AOP recommends the following standards for a VDU operator: o Ability to read N6 at the range of 33 – 70cm, with adequate VA for any required task at a greater distance o Good binocular vision or well-established monocular vision o Normal NPC o Clear ocular media

Answer 234

 Polycarb shouldn’t be cleaned with acetone or methyl chloride; should avoid extreme heat – not suitable for chemical engineers  Consider glass if molten metal

Answer 235

o Must maintain the safety appliance in good working order o Must report loss or damage of the appliance o Must use the appliance as instructed

Answer 236

o Must assess the risks to workers o Must supply an appropriate safety appliance o Must maintain, repair and replace safety appliances as appropriate o Must provide areas of safe storage when not in use o Must advise employees regarding correct use of safety appliances and their limitations

Answer 237

* BS 2092 has been superseded by EN 166, 167 and 168 * These new European standards give four levels of impact resistance (see table in notes ) * Lenses are referred to as ‘oculars’ and frames as ‘housings’ * Each feature is represented by a specific symbol marked on the ocular or housing * The order in which the markings appear is standardised * These can be found in EN 166 and the College occupational optometry module 6

Answer 238

o 1 ʹ Optical Class Rx +/- 0.06 o 2 ʹ Optical Class Rx +/- 0.12 o 3 ʹ Optical Class Rx + 0.12 (Specs and Goggles Only) o 3 ʹ Optical Class Rx -0.25 (Specs and Goggles Only) o S ʹ Increased robustness (toughened or thickened CR39) o F ʹ Low energy impact (Polycarbonate and Trivex) o B ʹ Medium energy impact (Goggles and Faceshields Only) o A ʹ High energy impact (Faceshields Only) o 9 ʹ Non-adherence of molten metal/ hot solids (Goggles and Faceshields Only) o N ʹ Resistance to fogging o K ʹ Resistance to surface damage (damage by fine particles)

Answer 239

Frame Marking ʹ o F ʹ Low energy impact (polycarb lenses) o B ʹ Medium energy impact (Goggles and Faceshields Only) o A ʹ High energy impact (Faceshields Only) o 3 ʹ Liquid droplets / splashes (Goggles and Faceshields Only) o 4 ʹ Large dust particles (Goggles Only) o 5 ʹ Gas and fine dust particles (Goggles Only) o 8 ʹ Short circuit electric arc (Faceshields Only) o 9 ʹ Molten metals / hot solids (Goggles and Faceshields Only)

Answer 240

* Scale Number (filters only) * Manufacturer’s Mark * Optical Class (1 (is the best),2 or 3) * Mechanical Strength (A, B, F, S) * Fields of Use (9 Molten metal/hot solids) * Scratch Resistance (K) * Fogging Resistance (N) * Radiant Heat * CE mark

Answer 241

It causes burning of the cornea Symptoms o Will not be obvious immediately, although will be several hours after the exposure, 6-12 hours latency period o 1. Painful o 2. Sensitive to light o 3. Watering o 4. Become increasingly difficult to open the eyes due to spasm of the eyelids muscle o FB sensation, blurring of vision, redness, associated skin burns from UV exposure

Answer 242

* If there is no improvement after 30 mins of treatment, contact A&E * Treatment o Cold compresses o Local anaesthetic can be instilled to help with the pain o Drops and lubricating ointment o If pain becomes unbearable to take painkillers – as you would for a headache o Symptoms last 6-24 hours usually completely cleared by 48 hours

Answer 243

usually due to blunt force resulting in whitening and opacification of retinal area (pseudo-cherry red spot)

Answer 244

1. Wash out the eye IMMEDIATELY: normal saline or head under a cold water tap/bucket (eyes open) 2. After 1 litre of irrigation (15-30 mins), review pain levels 3. Instil topical anaesthesia if pain level if high 4. Evert the lid and clear the eye of debris 5. sweep with cotton bud 6. Wait 1 minute, measure pH of tear meniscus (lower lid) – pH 7-8 acceptable 7. Continue irrigation if necessary, repeat pH every 5-10 minutes 8. Admit to hospital

Answer 245

Where the prescriptions between R&L are different (1.50/2.00DS/DC) Simple o One eye is emmetropic and the other is either myopic or hyperopic Compound o Both eyes are either hyperopic or myopic and one eye has a higher refractive error than the other Mixed (antimetropia) o One eye is myopic and the other is hyperopic

Answer 246

For patients with anisometropia of more than 2, they may experience a difference in the size and shape of visual images and magnification: Aniseikonia.

Answer 247

Anisometropia becomes problematic when the difference is >2.00D. When looking away from the optical centre of the lens (e.g. looking down to read), issues can include: * Blurred Vision * Double Vision * Unable to tolerate reading for long periods as a result of >1D of VDPE

Answer 248

Because for each dioptre difference in power between the eyes, there is 1 dioptre of vertical differential prismatic effect at the near visual point (10mm below, 2mm in from the optical centre). According to British standards, patients can tolerate 1 dioptre of VDPE, but the tolerance is much greater horizontally (10 BO – 4 BI at dist, 7 BO – 7 BI at near) Actual Vertical Prism Reserves range between 2-4PD

Answer 249

* Visual discomfort * Visual distortion * Difficulty with stereopsis/BV. * Dizziness, H/A, Nausea.

Answer 250

* Aspheric Lens to the Most Positive Powered Eye. The retinal image size is reduced as the aspheric surface is approx. 2.00D flatter. Thinner lenses change lens shape - less maginfication - changes retinal image size * Iseikonic lens to the Least Positive Eye. The thickness is increased by increasing the base curve (to approx 8.00D) to increase the spectacle magnification of the least positive eye.

Answer 251

* Usually not an issue with SV lenses as the px will simply move their head in order to look through the optical centres (OC) o There is no prismatic effect at the OCs * However, if must be considered in the cases where the px has no choice but to look away from the OCs of the lenses, as the near visual points (NVP) do not coincide with the OCs e.g. bifocals and varifocals * Prism will be induced according to Prentice Rule: P = cF o c = decentration in cm o F = power in DS o Assume NVP is 10mm below the OC when calculating at near * A positive lens exerts base out prism * A negative lens exerts base in prism * If the lens power for each eye is different, there will be a differential vertical prism at near o Vertical prismatic power difference = difference in dioptric power between the 2 lenses in the vertical meridian (i.e. 90) o A max of 1-2 vertical differential prism may be tolerated (<1 unlikely to give rise to symptoms) * Image is always shifted towards the apex of the prism o All lenses that aren’t plano, have the potential to create prism

Answer 252

Spectacle Magnification = Shape Factor x Power Factor Shape Factor: a ratio of surface curvatures that describe the shape of the lens and typically ranges from values of -2 to +2 Power Factor: The dioptric power of the lens considering the power and vertex distance of the lens.

Answer 253

give the px two pairs for different distances, as the optical centres will be set for viewing that particular distance. Ultimately this eliminates vertical differential prismatic power. Advise the px to tilt their head downward when reading in order to view through the optical centre of the lens – however this is only successful for quick reading, as may give px neck pain due to the uncomfortable head position.

Answer 254

* Slab off near-portion for the most negative eye as it induces the most base down prism - balances eyes o Most ideal for minus lenses as the base up prism induced by the slab-off neutralises the base down prism of the main lens) (minimum slab off available – 2 dioptres base down) o The most negative eye induces the largest amount of base down prism which can be removed by slabbing-off. o The slab-off line should be set at the lower limbus. When minus lenses are slabbed off base down prism is removed. When positive lenses are slabbed off base up prism is added. BIF -thinning doesn't change anything, problem is looking into near add From pre reg academy* P=cf =0.01x-2.25 (difference betwen R and L eye) axis needs to be taken into consideration, if axis is at 180 it can be ignored, need to tranpose the LE to get axis at 180) =2.25D Base down RE, how much prism is reduced when they are looking (avergae person can only cope with 1D of vertical prism). Slab off prism could used in reading portion - induces base up prism, adds prism in the near add in the RE Slab on is base down slab off prism is base down opposite if plus precription, for the opposite eye as well

Answer 255

o Larger segment given to the most positive eye. It works on the principle that a larger segment will induce the most base down prism Formula used: Segment radius (cm) x near add = amount of relative vertical prism overcome o Most ideal for Positive lenses: the base down prism induced in the segment eliminates the base up of the distance power in the main lens) o Only successful in round segs. o To find out how much difference in size to give: Difference in seg diameters (mm) = 20 x differential prism / Add Pre reg academy* Different Segments induced different prism R seg the OC are where the radius of the segments are, would use different sizes. Bigger seg in the most plus so in the LE R seg induces prism the other way round, different segment sizes (For normal px's we Usually do R seg for plus rx D seg minus, less jump since the prisms cancel out, D seg prism is at the top of the segment)

Answer 256

Franklin Split can be used instead - 2 lenses that are held together by a frame - can put OC where needed for each lens most do E seg instead

Answer 257

SV - different retinal image sizes BIF - differential prism

Answer 258

Is the prismatic effect induced by the combination of the bifocal type and the power of the distance lens rx in the reading position

Answer 259

* Need to specify fitting cross position in both eyes (PDs/OCs) * Horizontal centration = monocular PDs * Monocular vertical centration = distance above or below HCL * Do not necessarily get image jump with varis, but will still suffer image displacement due to vertical differential prism – tend to cope with this gradual introduction of prism better o Therefore in anisometropia pxs it is better to dispense a varifocal lens with a short corridor o This will reduce the amount the px has to look down the lens, and hopefully minimise the amount of vertical prism induced by looking away from the OC

Answer 260

Position OCs 5mm below the pupil centre (a standard practice) which allows the px to read with the visual axis not too far away from the OCs For each mm decentration downwards, the Pantoscopic tilt will need to be increased 2 degrees

Answer 261

 A prism wedge is added to the back of the most minus/least plus eye  Base up to correct base down effect – neutralising effect at near  Prism is effectively removed from the reading portion of the lens, resulting in a horizontal visible edge across the front surface  The line coincides with the top part of the segment  Can be done with varifocals too  Reverse slab-off (short-cut technique to create lens)

Answer 262

 Prism x 2 = difference in segment diameter x add  The larger round segment has its optical centre lower down and therefore introduces more base down prism then does the smaller segment  The larger segment is used to neutralise the vertical differential prism by adding prism to one lens  Myopic anisometropia – the lesser myopic eye will need the larger segment  Hyperopic anisometropia – the higher powered lens introduces more base up prismatic effect at the NVP, so this lens will need the larger base down effect of the larger segment  Not usually done as it is not very cosmetically appealing  The base down effect of a round segment is exaggerated by a negative distance lens – hyperopes are better served by a down curve round segment  Myopes benefit from a D shaped or executive in which the near optical centre is better controlled (reduced jump)

Answer 263

FOV: 89 Mag: 0.76

Answer 264

* FOV: 116 * Mag: 0.76

Answer 265

o 1+ = 1-2mm o 2+ = 2-3mm o 3+ = >3mm

Answer 266

o 1+ = 1/8 to ¼ of total area o 2+ = ¼ to ½ of total area o 3+ = ½ or more of the total area

Answer 267

near response only checked if direct response is abnormal

Answer 268

Sluggish response / slight dilation = partial RAPD

Answer 269

Nerve that carries information towards the central nervous system

Answer 270

Nerve that carries information away from the central nervous system

Answer 271

* Pupil size is mainly determined by the contraction & relaxation of the sphincter muscle. Þ It is a thin circumferential ring of smooth muscle fibres * The sphincter muscle responds to signals from the short ciliary nerve Þ This constricts the pupil * The sphincter muscle is innervated by cholinergic parasympathetic fibres (rest and digest)

Answer 272

* The dilator muscle has a secondary effect on pupil size * The dilator muscle responds to signals coming from the long ciliary nerve Þ This dilates the pupil * The dilator muscle is innervated by adrenergic sympathetic fibres The Sphincter & Dilator muscles are antagonistic muscles

Answer 273

1. The sphincter muscle relaxes Þ The sphincter muscle has the biggest effect on pupil size 2. The dilator muscle contracts

Answer 274

1. The sphincter muscle contracts The sphincter muscle has the biggest effect on pupil size 2. The dilator muscle relaxes

Answer 275

problem anywhere in nerve pathway

Answer 276

but no consensual = problem with efferent pathway of consensual eye

Answer 277

 Swinging flashlight – RAPD Which indicates:  RAPD indicates - gross retinal abnormality (VA 6/60 or worse) in one eye or asymmetric, impaired optic nerve function, asymmetric chiasmal compression  Correlated with abnormal vision  Eye with RAPD will dilate when light is shone as ability to perceive bright light is diminished

Answer 278

 Difference of >0.4mm  25% of normal have this in dim light, 10% in bright light  If anisocoria present – size difference must be measured in bright & dim light  If difference remains constant = likely to be normal o 20% of population have physiological anisocoria  Difference greatest in dim light o Possibly normal o Possible problem with dilation of smaller pupil o Suggests lesion affecting sympathetic innervation of dilator  Difference largest in bright light o Possible problem with constriction of larger pupil = REFER o Suggests a lesion affecting parasympathetic innervation of sphincter o Abnormal eye movements suggest preganglionic lesions; normal eye movements suggest post ganglionic lesion  Pathological Anisocoria = defect in the efferent (motor) pathway

Answer 279

 Anisocoria greater is dark conditions (affected pupil cannot dilate)  Affects sympathetic nerve supply  Signs: miotic pupil, ptosis, sweating down one side of face (hemifacial anhidrosis), reduced IOP on effected side The pupil in the affected eye also dilates more slowly or less than the other pupil in response to light  Cause: commonly lung tumour  Management: urgent referral / record if longstanding  Diagnosis is usually confirmed pharmacologically using apraclonidine drop

Answer 280

 Common in young woman & usually unilateral  Anisocoria greater in light conditions (affected pupil cannot constrict)  Affects parasympathetic nerve supply  Symptoms: reading problems & glare/photophobia  Signs: dilated pupil with poor/tonic reaction to light – restricts better when accommodating  Cause: damage to the post-ganglionic supply to the ciliary ganglion & sphincter pupillae or viral infection  Management: Urgent referral to check for underlying cause o Pilocarpine check test: disease/dilated eye constricts more than the other after pilocarpine instillation as the sphincter becomes very sensitive in the defect eye & absorbs more

Answer 281

 Very rare  Signs: Bilateral miosed & irregular pupils; dilate poorly in darkness  Accommodative (normal response to near) but not reactive to light (light/near dissociation)  Cause: neurosyphilis / lesions in the rostral midbrain/ long term DM/ alcoholism

Answer 282

 Pupil may be dilated (compressive cause) or normal (if caused by diabetes)  Other signs include ptosis, eye down & out (horizontal & vertical diplopia)  Cause: Aneurysm of the posterior communicating artery (PCA) or diabetes  If diabetic CN3 > pupil sparing as DM is vascular (= no aneurysm compressing pupillary fibres)  Management: emergency referral to exclude aneurysm

Answer 283

 Sympathetic innervation = dilation = dilator pupillae  Sends signals from Edinger Westphal nuclei to both pupils via the ciliary ganglion & then CN3 (oculomotor nerve)  Efferent defects are due to damage to the efferent innervation of the pupil and will result in unequal pupil size (anisocoria)  If affected; anisocoria seen; no RAPD o Congenital (causes heterochromia also) – reassure & record o Horner’s syndrome o Holmes Aidie Pupil o Intraocular surgery o Trauma o Uveitis o Acute angle-closure glaucoma o Tumours of iris or ciliary body o Anterior segment neovasc

Answer 284

 Parasympathetic innervation = pupillary constriction = sphincter pupillae  Signals - pupil -> Edinger Westphal nuclei via the optic nerve  If affected – reduction in pupillary response to light, may only be detectable by swinging flashlight  RAPD present - no anisocoria  Most caused by lesions in the retina & optic nerve i.e., o AION o Glaucoma o Optic Neuritis o Toxic Optic Neuropathy o CRAO / CRVO o Extensive retinal detachment

Answer 285

* Prior to the Ciliary Ganglion Causing: Þ Absent accommodation Þ Fixed/Dilated pupils Þ Paresis of some of the EOMs * Post the Ciliary Ganglion Þ Post Ciliary Ganglion damage is known as Adie’s Tonic Pupil

Answer 286

Setup * Angle: 45 ° * Slit: 1-2mm in width * Filter: None * Magnification: 16-25x * Illumination: medium Observation * Detect and examine corneal structures and defects * Higher magnification preferred to evaluate both depth and extent of corneal scarring or foreign bodies.

Answer 287

Bring SL in set up position * Angle: 60° * Position of the illumination arm 30°; Position of observation arm 30°; Angle of illuminator to microscope must be equal and opposite. * Slit: width 4mm * Filter: Start with no filter * Magnification: 16x-40x * Illumination: medium to maximum Observation * To visualize the integrity of the tear film (lipid layer), corneal and lens surfaces * To visualize the endothelium 4. Start with lower magnification (10X to 16X). 5. Direct a relatively narrow beam onto the cornea 6. Switch to the highest magnification available Þ Endothelium is best viewed using only one ocular. *Focus on tear film and locate the bright corneal reflection/Purkinje image * Under specular reflection anterior corneal surface appears as white uniform surface and corneal endothelium takes on a mosaic pattern

Answer 288

Can be used in addition to the Cobalt blue filter to enhance contrast.

Answer 289

Enhances the contrast of blood vessels on the corneas of contact lens wearers and haemorrhages seen under the conjunctiva

Answer 290

Setup * Angle: 45°. * Widest beam. * Diffusing filter. * Magnification: 10-16x * Illumination: medium to high. Observation * Observe: eyelids, lashes, conjunctiva, sclera, pattern of redness, iris, pupil, gross pathology, and media opacities

Answer 291

Set-Up * Angle: 45 ° * Slit: width minimum 0.01mm * Filter: no filter * Magnification: 25-16x * Illumination: medium Observation * Used to localise: Nerve fibres, Blood vessels, Infiltrates, Cataracts, AC depth. * To discover thickening, thinning, and distortions in the corneal contour. * To determine the depth of foreign bodies or opacities in the corneal substance. (a percentage of the total corneal thickness) * To see a wide slice of stroma. (The angle between the microscope and illuminating arm can be increased.)

Answer 292

The beam is focused in an area adjacent to ocular tissue to be observed. * Angle: Variable * Slit: Parallelepiped o Iris: maximum height o Retina: Pupil size * Filter: Start with no filter * Magnification: 10-16x * Illumination: Maximum DECOUPLED Observation * Used most often in searching for Keratic precipitates and other debris on corneal endothelium. * The crystalline lens can also be retro illuminated for viewing of water clefts and vacuoles of anterior lens and posterior subcapsular cataract

Answer 293

The beam is focused in an area adjacent to ocular tissue to be observed. * Angle: o Observer central to area of interest o Illumination angle 45 deg nasally * Slit: Parallelepiped * Filter: Start with no filter * Magnification: 16x * Illumination: Maximum DECOUPLED Observations * Infiltrations, small scars, corneal vessels, micro cysts, vacuoles * Feature on the cornea is viewed against a dark background

Answer 294

Cataracts are formed when the clear lens inside the eye becomes progressively more cloudy or misty, which can mean vision is not quite as sharp. This is a slow gradual process that usually happens to most people as we get older. The early stages of a cataract do not necessarily affect your sight. If the cataract begins to affect your daily life, a 15 minute surgery can be conducted to change the lens in your eye to a clearer artificial lens in order to improve your vision.

Answer 295

these are collagen fibres These can appear to float in front of your vision. It usually occurs due to a jelly inside of your eye starting to become a little-more liquid like with age, so sometimes the number of floaters increases as you get older. However, a sudden and dramatic increase in floaters can be a sign of problem inside the eye, so you should always see an optometrist if this should occur.

Answer 296

PVD is a common condition that occurs in about 75% of people over the age of 65. As we get older the jelly like substance in the eye called the vitreous shrinks and becomes more liquid. As is it shrinks it collapses away from the light sensitive layer of the eye called the retina. some people may notice symptoms such as floaters or flashing lights as a result, but it does not in itself lead to visual loss. However, if the floaters suddenly increase and are accompanied by flashing lights or a shadow in your vision, you must visit your optometrist immediate as this can indicate something more serious called a retinal detachment. However, this is a rare complication.

Answer 297

is a common condition that may be caused because your eye doesn’t produce enough tears or because the tears evaporate too quickly. Dry eye can make your eye feel scratchy or irritated. In severe cases, it may temporarily make your vision blurry. Its uncomfortable but rarely causes serious eye damage and is easily treatable / manageable.

Answer 298

Blepharitis is an inflammation of your eyelids. It can make eyelids red and itchy and can also lead to burning, soreness or stinging in your eyes. It is a chronic condition and can be uncomfortable but rarely causes serious eye damage and is easily treatable / manageable.

Answer 299

o Alteration in epithelium of advancing lid margin due to friction during lid movement across the lens surface o Tear film thickness insufficient to separate lid and ocular surface

Answer 300

chloramphenicol 0.5% 4x a day for 5 days Dexamethason 4x a day for 28 days

Answer 301

flat fit – will have a negative tear film then it would have a plus over refraction

Answer 302

Boston EO and Boston XO material which is Fluoro silicone acrylate Dk XO=200, Range 6/EO=58 -25.00 to +25.00D in.025 increments Fit on flattest K Outside the range (- 11.00 to +16.00D) ICON back surface design can be applied Larger lens diameters usually deliver better lens stability and centration, so 9.80mm diameter lenses will be supplied unless otherwise stated or requested by the practitioner - comes in 9.3 to 9.8 Base curves 7.00-9.00mm in 0.05mm increments

Answer 303

Silicone acrylate - more prone to lens flexure Flurosilicone acrylate- better wetability, fewer deposits, but can be britte if too thin

Answer 304

Polarized lenses block horizontal light waves, including some blue light wavelengths, but they don't block 100% of blue and green light between 400 and 550 nanometers.

Answer 305

offers larger intermediate and near reading areas super soft design

Answer 306

distortion extends to distance area which affects peripheral vision px will have to move their head more for when viewing objects in periphery larger intermediate zone narrower reading area good for 1st time presbyopes (especially VDU)

Answer 307

larger distance area, narrow intermedaite corridor and wider reading area aberrational astigmatism confined to limit nasal and temporal areas distance virtually abberation free good for prev bifocal wearers

Answer 308

Generally every 2 yrs

Answer 309

A9KG Each letter and numbers shows meeting standard - resistant to head etc

Answer 310

quarter of a wavelength thick half a wavelength out of sync - cancels the wavelength out

Answer 311

reticular drusen are above RPE and more yellowish and in a network pattern and are more often extend to periphery than normal drusen

Answer 312

Vitelliform lesions are beneath the macula and are round yellowish and tend to be isolate. Tend to be more symmetical between the eyes Can be treated with antiVEGF