Visit 1 Flashcards
Under what principle does keratometry work
Keratometry works on the principle of recording the image size reflected from a known-sized object.
Given the object size and distance from image to object, the radius of curvature of the cornea can be calculated.
indications for keratometry
Contact lens assessments
o provide baseline and aftercare examinations values of corneal curvature and any induced changes
o determining side of astigmatic surface
RGP lens fitting
NITBUT
o Distorted mires can indicate poor tear quality
Monitoring corneal pathology
where is the astigmatism here
8.00/7.40
-2.00/-3.00 x 180
o Sphere power is located at the axis (-2 @ 180)
o The sum of sphere & cyl is located at 90 from axis (-5 at 90)
o 3D of corneal astigmatism
Types of astigmatism
WTR – vertical meridian stays close to 90 & is steepest (steepest = smallest), flattest at 180
o Smallest number is the vertical
o +ve cyl at 90
o -ve cyl 180
o More common
ATR – horizontal stays close to 180 & is steepest, flattest at 90
o Smallest number is the horizontal
o +ve cyl at 180
o -ve cyl at 90
Oblique – principles not at 180 & 90 - 130-160, 120-150
Irregular – principle meridians not separated by 90
Automatic Keratometry
Two position instruments
Use servomotors to drive the doubling device until alignment can be assessed optically using light-emitting and detecting diodes
The machine prints out 3 measures
Phi 2.4 = central 2.4mm corneal diameter (we use)
Phi 3.3 = central 3.3mm corneal diameter
Comparison of the 2 above gives an indication of corneal shape
Bausch and Lomb advantages and disadvantages
Measures the 2 meridians at the same time and contains 2 prisms which are adjusted independently
o One position– double images produced side by side at 90 deg from each other
o Variable doubling – object size remains constant, which allows for measurement of TBUT
o Fixed mires
cannot check for irregular astigmatism
Javal Schowitz advantages and disadvantages
o Two position - requires rotation about axis to measure each of the principle meridians
o Fixed doubling – the distance between the mires are varied mechanically, when these are lined up, Ks are taken from scale along each meridian in 2 stages. This system only works at certain distance from eye
o Variable mires
- used for irregular astigmatism
-more accurate as longer working distance
keratometry common errors
o Failing to maintain mire image focus when attempting superimposition of the mire image
o Not ensuring the px keeps their head against the headrest
o Forgetting to focus the eyepiece
o Not centring the mire image (in centre of cornea)
o Forgetting to calibrate the instrument regularly
4.1.2 positioning tolerances
o Heights – within +/-1.00mm of the order
o Horizontal position of the fitting point – within +/-1.00mm
o Alignment marking tilt – no more than 2 degrees from horizontal
- BS EN ISO 21987:2017
o Effective from 30th September 2017
o BS = British Standards
o EN = European Nations
ISO = International Organisation for Standardisation (worldwide federation of national standards bodies)
prism in varifocals
There is always prism at the prism reference point due to prism thinning; mainly for cosmetic purposes to ensure same level of thickness in lens despite reading addition
To check for prism in varifocals
o Measure both lenses at prism reference point
o If there is a difference, then this residual prism gives prism in specs
o Examples
3BD RE 3BD LE cancels out = no residual
3BD RE none LE = residual prism of 3BD
o Plus lenses – base up prism should be removed to reduce thickness, therefore if + lens, the prism should be BASE DOWN for prism thinning
o Minus lens – base up prism for thinning
focimeter measures what
the lens’s back vertex power
prism tolerances - british standards
1^ vertical
o Generally 1.5-2.5^
Distance vision - up to 10^ base out, 4^ base in
Near vision – up to 7^ base out, 7^ base in
prism equation
- P = prism P=CF
- C = decentration (cm)
- F = power (D)
What is meant by the terms wettability and modulus? What part do they play in contact lens selection and fitting?
Wettability refers to how easily a liquid spreads over the surface of a contact lens
Modulus is a measure of how a material will deform and strain when put under pressure. SiHy has a higher modulus than hydrogel lenses (so hydrogel more comfortable)
SiHy VS Hydrogel lenses
Hydrogels have a greater water content and lower modulus so they are more comfortable
Silicone Hydrogels have high oxygen permeability
Silicone hydrogel lenses have a lower risk of dehydrating during the day because of their lower water content
difference between DK/t and DK
Dk/t
Oxygen transmissibility, which is a measure of how much oxygen can pass through a contact lens in air.
Dk
Oxygen permeability, which is a measure of how easily oxygen can diffuse through a contact lens material
toric contact lenses methods of stabilisation
truncation - section of lens removed at bottom to align w lower lid margin- should help w orientation and stabilisation , usually done on a lens that also has a prism ballast
prism ballast - prism at the bottom of the lens - w gravity the lens stays w the prism at the bottom
peri ballast - lens thinned down superiorly (thickness at inferior ) so uses thickness differences as the stabilizing component, creates a base down prism effect
double slab off - thin zone superiorly and inferiorly, the lid forces (upper and lower) maintain orientation
dynamic stabilization
toric back surface
linarial material, water content, Dk/t, Dk/ modulus
material stenfilcon A
Water content 54%
Dk/t 100
Dk (how permeable a lens is to o2) 80
modulus 0.4 MPa
minimum amount of O2 for a cl
24: Minimum recommended central oxygen transmissibility level
33: Minimum recommended peripheral oxygen transmissibility level to avoid swelling³
DPA (1998) was superseded by the DPA (2018)
what is now included in the law?
New regulations which supplement the EUs General Data Protection Regulat
The new regulates collection, storage and use of personal data more strictly
Under DPA 2018 – right to find out what information the government and organisations store about you, including the right to:
Be informed about how data is being uses
Access to personal data
Have incorrect data updated/correct personal data
Have data erased i.e. the right to be forgotten/prevent further processing
Stop or restrict processing of your data
Data portability
Object to how your data is processed in certain circumstances
what does GDPR inlcude
EU regulations relating to the collecting and processing of data
Indication for consent must be unambiguous – tick box
Broader definition of personal data
Includes any potential identifiers, also identification number, location data & IP address
Higher bar for lawful processing
Must fall within 1 or more of the 6 permitted legal justifications
More rights for individuals
Right to be informed, access, rectify and erase data
Restrict processing
Not to be subjected to automated decision making and profiling
Notify of data breaches
Report a breach to information commissioner’s (ICO) office if high risk to individual within 72 hours of breach & notify individual
Penalties to hold businesses more accountable
GDPR regulates data processors and controllers
Data processing: any action performed on that data e.g. collecting, recording, storing, erasing (third party that processes personal data on behalf of the controller)
Data controller – person who decides why/how personal data is processed (any employer/employee)
Stricter rules for sharing data outside the EU
Potential penalties for non-compliance
for DR when is anti vegf done and when is photocoagulation done
DR treatment for maculopathy – anti VEGF. Laser for preventative
precision one lens technology
PRECISION1® was born from the Water Gradient Technology of DAILIES TOTAL1®, but offered at an affordable price
my day lens technology
Aquaform® Technology, which provides a unique balance of high oxygen permeability, high water content and optimum modulus for a soft and flexible lens
opteyes lens technology
aquaform technology
abberation neutrailsing technology
soft MPS ingredients
- Polyhexanide (PHMB) – disinfectant / preservative
- Sodium hyaluronate – helps stabilise tear film, reduce friction between lens and ocular surface
- Sodium chloride – tonicity, maintains ideal CL salt solution of 0.9% (too low – cornea swells, too high, cornea drys)
- Sodium phosphates – buffer to ensure neutral pH to match tear film
- Poloxamer – surfactant used to clean lenses
- EDTA – chelating agent, prevents lens deposits (i.e. calcium) / enhances action of preservatives
RGP choice in my store and why
ICON most similar to bausch and lomb materials
ICON material
Fluorosilicone acrylate?
it has a hydrophillic coating which helps with wetability and lubricity
hydrogen peroxide 1 step- coopervision
Lenses into baskets, rinse each lens in the holder for 5 seconds with peroxide solution, fill the lens case up with solution to the marked line, place lens holder inside of case and close cap, solution will bubble – ensure lenses upright and fully immersed. Allow lenses to soak for at least 6 hours.
to insert lenses need to rinse with saline first
hydrogen peroxide 2 step
- Wash your hands
- Rub both sides of the lenses carefully with 4 drops of cleaner (Step 1) in the palm
of your hand for 20 seconds - Rinse both sides of the lens with a saline solution
- Soak your lenses for 4 hours with the conditioning solution (step 2)
- Add a drop of conditioner to the lens for extra cushioning and insert into your
eye. - Rinse your lens case with a sterile disinfecting solution and then wipe dry with a clean tissue. Avoid air-drying.
Boston 2 Step Cleaning and Conditioning System
Ingredients:
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
* Quaternary phosopholipids, Titanium Dioxide and silica gel – aids to physically
scrub off proteins and deposits when rubbing
Boston Advance Conditioning Solution (Step 2)
wetting and cushioning agents:
* cellulosic viscosifier
* polyvinyl alcohol
* polyethylene glycol
RGP MPS ingredients
- Polyhexanide – disinfectant/preservative
- EDTA – chelating agent
- Sodium phosphates - buffer
- Poloxamer – surfactant, clean lenses
- Sodium chloride – tonicity
minimum 4 hours soak
what to do when cls is too loose
steepen the base curve
what to do when cls is too tight
flatten the base curve
severe VF defects
Homonymous hemianopia – stroke
Bitemporal hemianopia – pituitary tumour
Tunnel vision - Retinitis pigmentosa
Severe AMD
normal blood pressure levels
normal blood pressure is between 90/60 mmHg and 120/80 mmHg
normal glucose levels
4–7 mmol/L before eating
pituitary tumour causes which VF defect
bitemporal hemaniopia
severe VF defects
- Central scotoma e.g. AMD
- Monocular visual loss e.g. CRAO or CRVO, RD, optic neuritis or atrophy or end stage glaucoma
- Homonymous hemianopia e.g. middle cerebral artery occlusion
- Homonymous inferior quadrantopia e.g. parietal stroke or tumour
- Homonymous superior quadrantopia e.g. temporal stroke or tumour
- Homonymous hemianopia with macular sparring e.g. posterior cerebral artery occlusion
- Enlarged blind spots – due to papilloedema as well as glaucoma
different targets for VFs machine
Central target: Yellow light in the bowl’s centre
* Small diamond: For patients who cannot see the central target such as those
with macular degeneration. The patient looks into the centre of the four lights
* Large diamond: For patients who cannot see the above two
insulin meds effect
Insulin - may cause hypoglycaemia which causes dizzy spells; in rare cases may cause presbyopia when first starting treatment due to shifting fluids which affect the lens; generally stabilises
o Novorapid – ingredient insulin aspart, fast-acting and works rapidly to normalise blood sugar levels, begins working after 10-20mins, lasts 3-5 hours
o Levemir – ingredient insulin detemir long acting, subcutaneous injection only, up to 24-hour duration of action
Metformin and Gliclazide side effects
Metformin (biguanide) (T2) – dry eye and increase risk of angle closure
Gliclazide – lens changes, refractive error shifts
AOP - what does it do
offers indemnity insurance for optometrists and dispensing opticians that covers claims arising from allegations of negligence
GOC
- Regulator for the optical professions in the UK
- Responsible for setting standards for optoms, DOs, optical students and optical businesses
- This is set out in the Standards Framework, which makes clear that the standards should always be the first point of reference to registrants
Medical act
Act of parliament which governs the control of medicines for human use and veterinary use, which includes the manufacture and supply of medications
Regulates use & supply of drugs/what diagnostic drugs are available, PoM/P/GSL, IP vs Entry
Entry lvl optoms, sell/supply the following
o All GSL/P meds provided it is the course of professional practice
what does the opticians act do?
Legislation compiled by parliament which gives the GOC the powers to make orders, rules and regulations in relevant areas
The sections include: GOC, registration and training of opticians, fitness to practice, proceedings and appears, restrictions
We have do heath check as well as refraction
NTG risk factors
o Increasing age
o Gender – some studies have found F>M
o Family history
o Ethnicity
Japanese > Europeans or North American Caucasians
o CCT lower in NTG than POAG
o Abnormal vasoregulation
Migraine
Raynaud phenomenon
Systemic hypotension
Diabetes, carotid insufficiency, HBP and hypercoagulability
o Obstructive sleep apnoea syndrome
o Myopia
o Thyroid disease may be more common
what does the cyclodiode laser do
destroy some of the ciliary body - reduced aqueous humour prodcued
process of GOC compliant
trabeculectomy
new passage for drainage
flap created in sclera (BLEB)
SLT - selective laser trabecultoplasaty
Laser energy is applied to the drainage tissue in front of the eye (the trabecular meshwork)
MIGS- istent
inserting two
tiny hollow metal tubes (stents) into the trabecular meshwork in the eye - for drainage
ahmed valve
a small device that’s implanted in the eye during glaucoma surgery to regulate aqueous flow and reduce intraocular pressure (IOP)
POAG risk factors
- Affects 1-2% of the white population of the UK > 4, increasing to 4-5% in > 80s
- Second most common cause of irreversible blindness in the UK (approx. 10% of blind registrations)
- Incidence: M=F
- Risk factors
o High IOP or OHT (asymmetry of 4mmHg also significant)
o Increasing age
o Ethnicity
Black > white (also Latinos, but this is < Afro-Caribbean)
Black pxs are 4x more likely to develop it
o Family history
4x more likely if a sibling has it
2x more likely is a parent has it
o Thinner central corneal thickness
o Suspicious optic nerve appearance
Large optic disc with increase cupping
o High myopia
o Diabetes
o Vascular disease e.g. HBP, migraine and poor ocular perfusion
o Eye surgery or injury
o Long term use of steroids (eye drops, pills, inhalers and creams) and the contraceptive pill
common combination glaucoma drop
simbrinza
(bromindine and brindolamide)
DR risk factors
o Diabetes duration (most important risk factor)
DR rarely develops within 5 years of onset or before puberty
Duration is a stronger predictor for proliferative disease than for maculopathy
o Poor diabetic control
Type 1 appear to obtain greater benefit from good control than type 2
The higher a person’s blood sugar level, the greater the risk of developing DR
o HBP
Very common in type 2
CVD and previous stroke are also predictive of HBP
o Nephropathy
Associated with worsening of DR
o Gestational diabetes
Pregnant women with gestational diabetes are at a higher risk of developing DR at a rapid rate
o Other factors
Smoking
Obesity
Cataract surgery
Hyperlipidaemia
Anaemia
AMD Risk factors
o Increasing age (>60)
o Ethnicity
More common in Caucasians than Black or African-Americans
o Family history
3-4x more likely with 1st degree relative
o Smoking
Doubles the risk
o Uncontrolled HBP and high cholesterol
o Dietary factors
High fat and alcohol intake and obesity increases the risk
o Sunlight exposure
o Other factors
Cataract surgery
Blue iris colour
Female gender (may be due to the fact that women live longer)
Cataract Risk factors
o Increasing age (common in > 60s)
o Family history
o Smoking
o Heavy alcohol use
o Obesity
o HBP
o Too much sun exposure (UVB)
o Ethnicity – Caucasians > Afro-Caribbean > Asians > Europeans
o Long-term corticosteroid use
o Diabetes
catarct management
- Myopic shift can be easily fixed with updating px refraction
o This may help at the start, but may come a time when a stronger rx may not help improve VA - Optimisation of reading light
o Bright reading lamp over left shoulder - Reduction of glare (px may experience this at night, and see halos around lights)
o Brimmed hat
o Anti-reflection coating/MAR - UV protection
o Reactions, sunglasses and polarising lenses (cut down glare even more) - Stop smoking
o This will reduce the rate at which the cataract develops, possible referral to GP or pharmacist for cessation info
cataract operation procedure
Phacoemulsification is the current technique which uses ultrasound technology
Corneal incision is made, the top of the capsule is removed (capsulorrhexis), phaco of the lens nucleus where lens is broke down into small pieces and removed, irrigation and aspiration, insertion of IOL into capsular bag
Monofocals and torics are available on NHS
grampian
⦁ In 2010, a clinical accord was agreed between GPs, ophthalmologists and optoms to enable optoms to undertake the management and treatment of the pxs with:
⦁ Anterior uveitis
⦁ HSK
⦁ Marginal keratitis
⦁ Corneal FB, which requires removal with a needle and/or alger brush
⦁ To undertake this extra service, community optoms have to undertake accredited training and following strict protocols
⦁ Community optoms receive an additional fee for carrying out these services
Grampian eye health network – allows optoms to undertake management of anterior uveitis, HSK, marginal keratitis, corneal FB with removal – community optoms need to undertake strict training and follow guidelines
LENS
⦁ The LENS scheme was introduced in Lanarkshire in 2010 with the purpose of attempting to reduce demand in the Ophthalmology Acute Eye Casualty Clinic
⦁ The scheme involves pxs receiving treatment for a number of conditions and follow-up appointments with their community optom, who have undergone robust training
⦁ This means pxs can be seen in the community rather than being referred to secondary care e.g. red/sore eyes, reduced vision etc.
⦁ Px satisfaction rates for the service have been high
⦁ Optoms provide this service under the current GOD supplementary fee structure
access to low potency steroids & aciclovir
ayrshire and arran
⦁ Post-operative cataract assessment
⦁ Pxs who have received uncomplicated cataract surgery are assessed 4-6 weeks post-op by their local optom
⦁ This apt. is arranged prior to the px being discharged from HES and helps to up skill optoms
⦁ One-stop cataract facility (SCI gateway)
⦁ If px wants cataract surgery and optom feels they require it, optom can refer HES for ‘one-stop’ service appointment
⦁ Forward referral form to GP, hospital and px – px is given info booklet about appointment details
⦁ Px sees ophthalmologist and px told risks/complications
⦁ If px happy with this, then no initial consultation is required from the ophthalmologist and surgery can take place
⦁ Two-stop cataract facility
⦁ Px gets initial appointment to check if they want cataract surgery by consultant
⦁ Biometry, HBP and fundus/OCT is carried out at this first apt too
⦁ If they are happy to have surgery then this takes place at the 2nd visit
⦁ Low Vision services
⦁ Optometry practices provide LV services/assessments and aids to pxs funded by the NHS board
⦁ Hospital Contact lenses
⦁ Complex fitting, therapeutic and cosmetic CLs are fitted in the community
SCI gateway
⦁ National system that integrates primary and secondary care systems using familiar yet highly secure internet technology
⦁ Gives options for specific referrals
⦁ General
⦁ Glaucoma
⦁ Orthoptics
⦁ Cataract
⦁ Wet AMD
⦁ Can refer to primary care (GPs) or secondary care (HES)
what is the data protection act?
protect person data stored about individuals on computers/paper filling systems
1. Data must be secure
2. Must be used in a way that is adequate, relevant, and not excessive
3. Kept for no longer than necessary
4. Data stored must be kept accurate & up-to-date
5. Data obtained and processed lawfully
6. Processed within data subject rights
7. Must be obtained and specified for lawful purposes
8. Not transferred to countries without adequate data protection laws
explain diabetes
This is a conditions where the amount of sugar (glucose) in the blood is too high because the body can’t use it properly. This is usually caused by your body not having enough insulin or having poor insulin which does not work properly. Insulin is the chemical that helps your body absorb sugar
mental capacity act
England & wales legislation – applies to everyone involved in the care, treatment and support of people aged 16 or over who are unable to make some or all decisions themselves
Scotlands equivalent is adults within capacity
o Any action must benefit the px and be necessary
o Wishes of person considered
o Options should be least restrictive
o Other relevant people must be consulted before decision is made
o Person must be encouraged to use skills and develop new skills where possible
- Prostaglandin analogue
e.g. Latanoprost (Xalatan)
Increase uveoscleral outflow by ciliary muscle relaxation
- Beta-blocker
e.g. timolol,
Decrease aqueous production
- Carbonic anhydrase inhibito
- Carbonic anhydrase inhibitor e.g. brizonolamide (azopt)
Decrease aqueous production
- Alpha 2 agonist
- Alpha 2 agonist e.g. brimonidine tartrate (alphagan)
Decrease production & increase outflow
PACG risk factors
Race – far eastern and Indian Asians
Refraction – hypermetropic
Short axial length – narrow AC
Age >40 – AC becomes narrow as lens becomes thicker
Gender – females
Family history – genetic factors are important but poorly defined
HBP explanation to px
High blood pressure (hypertension) is a condition where the pressure of the blood inside the arteries is higher than it should be, and so the heart has to work harder than normal to pump blood around the body
The consequences of uncontrolled HBP can be severe i.e. loss of vision due to a blockage in the blood supply to the retina or optic nerve, loss of peripheral vision due to stroke or episodes of vision loss which come and go.
The condition can be improved by lifestyle changes such as improving diet, avoiding excess alcohol consumption, stopping smoking and increasing exercise, as well as medications such as beta-blockers, calcium channel blockers and vaso-dilators.
HBP meds and side effects
Beta blocker - Propranolol = dry eye
ACE inhibitors - Lisinopril & ramipril = may cause ciliary body oedema which leads to reduced accommodation and angle closure
Calcium channel blockers – losartan
implementing GDPR
Consent to store data must be unambiguous – tick box for consent on arrival
As px’s have the right to decide how their info is controlled – ask about contact preferences on arrival
Confirm details on arrival as we have an obligation to ensure data is accurate and correct
Pxs have right to access their own info so can book time out of diary to discuss records as it must be in a test room, not shop floor; also gives evidence that you have spent time with px
implementing data protection act
Hidden information cannot be accessed without specific knowledge e.g. password
No information should be left visible to the public i.e. screens turned off/no paperwork
Regular testing of technology instore
Test room only accessible by optoms – log out computers on shop floor after use
