Ophthalmology Flashcards
accomodation
changing of lens shape to focus on near objects
uses the ciliary muscle
acuity
a measure of how well the eye sees a small or distant object
Amblyopia
decreased acuity uncorrectable by lenses, with no anatomic defect
amsler grid
test chart of intersecting lines used for screening for macular disease
- lines appear wavy, squares distorted
anisocoria
unequal pupil size
ansiometropia
different refractive errors in each eye
aphakia
the state of having no lens- e.g. removed because of cataracts
blepharitis
inflamed lids
e.g. staphs, seborrhoeic dermatitis or rosacea
burning itching red margins, scales on the lashes
Treatment- good hygiene- cotton bud and baby shampoo. children- consider oral erythromycin (blepharokeratitis)
canthus
the medial or lateral angle made by the open lids
chemosis
oedema of the conjunctiva
choroid
vascular coat between the retina and the outer scleral coat
ciliary body
portion of uvea (uveal tract) between iris and choroid
contains the ciliary procresses and ciliary muscle (for accomodation)
conjunctiva
mucous membrane on anterior sclera and posterior lid aspect
cycloplegia
ciliary muscle paralysis preventing accomodation
dacrycocystitis
inflammation of lacrimal sac
dioptre
units for measuring refractive power of lenses
ectropion
lids evert (esp. lower lid) causes eye irrititation, watering ± keratitis
associated with old age and facial palsy
plastic surgery to correct deformity
entropion
lids invert (lashes may irritate eyeball) typically due to degeneration of lower lid fascial attachements
treat with botulinum toxin and then surgery
epiphora
passive overflow of teas onto the cheek
fornix
where bulbar (scleral) and palpebral (lid) conjunctiva meet
fovea
cone rich area of macula, capable of 6/6 vision
fundus
part of the retina normally visible through the ophthalmoscope
keratoconus
cornea shaped like a cone
keratomalacia
the cornea is softened
limbus
annular border between clear cornea and opaque sclera
macula
retinal area ~5mm across, lateral to optic disc
miotic
agent causing pupil constriction (e.g. pilocarpine)
mydriatic
an agent causing pupil dilatation (e.g. tropicamide)
near point
where the eye is looking when maximally accommodated
optic cup
cup like depression in the centre of the optic disc
optic disc
part of the optic nerve seen ophthalmoscopically in the fundus
papillitis
inflammation of the optic nerve head
presbyopia
age-related reduced near-acuity from failing accommodation
pterygium
wing shaped degenerative conjunctival condition
ptosis
drooping lids
refraction
ray deviation on passing through media of different density, or determining refractive errors and correcting them with lenses
retinal detachment
sensory retina separates from the pigmented epithelial layer of retina
sclera
the whites of the eyes starting from the corneal perimeter
scotoma
a defect causing a part of the field of view to go missing
slit lamp
a device that illuminates and magnifies structures in the eye
stabismus
squint
eyes deviate
tarsorrhaphy
surgical procedure to unit upper and lower lids
tonometer
device for measuring intraocular pressure
uvea
iris, ciliary body, choroid
vitrectomy
surgical removal of the vitreous
vitreous
jelly like substance filling the globe behind the lens
Stye
Hordeolum externum
abscess or infection - usually staphylococcus in a lash follicle (also glands of Moll (sweat) or Zeis (sebum))
point outwards
apply warm compress 5-10 mins, several times a day until resolution
Residual swelling called a chalazion
Pinguecula
degenerative vascular yellow-grey on conjunctiva either side of the iris
- associated with increases in hair and skin pigment, sun-related skin damage
lagophthalmos
difficulty in lid closure
- causes exophthalmos, mechaincal impairment of lid movement, leprosy, paralysis of obicularis oculi
lubricate eyes with liquid parafin ointment
Retinoblastoma signs
stabismus and leukocoria (white pupil)
always suspect when red reflex is absent
retinoblastoma inheritance
autosomal dominance - 80% penetrance
RB gene is present in everyone - normally suppressor gene or anti-oncogene
Associations with retinoblastoma
5% occur with pineal or other tumour (trilateral retinoblastoma)
secondary malignancy- osteosarcoma and rhabdomyosarcoma - main cause of death
Treatment of retinoblastoma
enucleation (eye removal) - traditional. Large tumours, long standing retinal detachment and optic nerve invasion or extrascleral extension
chemotherapy - useful in bilateral tumours
external beam radiotherapy
ophthalmic plaque brachytherapy - focal and shielded radiation
cryotherapy and transpupillary thermotherapy- control of small selected small tumours
ophthalmic shingles
pain and neuralgia V1 distribution
blistering inflammed rash
treat with oral antivirals within 72 hours of rash onset
orbital cellulitis
infection of soft tissues posterior to orbital septum
spread from paranasal sinus infection (eyelid, dental injury/infection or external ocular infection
- inflammation in orbit, fever, id swelling, decreased eye mobility±diplopia. May have chemosis and proptosis
Associated complications of orbital cellulitis
subperiosteal and orbital abscess
extra-orbitalextension
visual loss from optic neuritis/ central retinal vein or artery occlusion
intra-cranial involvement –> meningitis, brain abscess, thrombosis in dural or cavernous sinus
Treatment of orbital cellulitis
CT, ENT & ophthalpic opinion
Antibiotics
rule out underlying rhabdomyosarcoma, grave’s disease or cavernous sinus thrombosis
Preseptal (periorbital) cellulitis
infection of soft tissues anterior to the orbital septum
commonly caused by sinusitis or facial skin lesions - insect bites, trauma
characterised by acute erythematous swelling of the eyelid.
no- painful eye movements, diplopia or visual impairment
Rx- empirical treatment of cellulitis e.g. amoxicillian 1g TDS 7-10days
Convergent squint
esotropia
commonest in children
may have no cause or due to hypermetropia
strabismic amblyopia the brain supresses the deviated image, visual pathway does not develop normally
divergent squint
exotropia
occurs in older children
often intermittend
Non-paralytic squints
usually start in childhood
may be constant or not
Diagnosis of squint
- corneal reflection - reflection from bright light is asymmetrical if squint present
- cover test - movement of uncovered eye to ttake up fixation as the other eye is covered= manifest squint
latent squint = movement of the covered eye as cover is removed
Management of squint
3 O’s
O - optical - assessment, spectacles
O - orthoptic - patch the good eye
O - operation - resection and recession of rectus muscles
Paralytic squints
diplopia most on looking in the direction of pull of the paralysed muscle
separation of two images is greatest when the image from the paralysed eye is furthest from the midline and faintest
third nerve palsy
occulomotor
ptosis, proptosis (reduced recti tone), fixed pupil dilatation
eye looks out and down
Causes- cavernous sinus lesions, superior orbital fissure syndrome, DM, posterior communicating artery aneurysm
fourth nerve palsy
trochlear
diplopia
ocular torticollis - patient holds head tilted
eye looks upward, in adduction and can’t look down and in (superior oblique paralysed)
causes - trauma, tumour, idiopathic
Sixth nerve palsy
abducens
diplopia in horizontal plane
medial deviation. cannot move laterally from the mid line
lateral rectus is paralysed
Causes- tumour causing increasing ICP, basal skull trauma, MS
Horner’s syndrome
disruption in sympathetic fibres
pupil is miotic (smaller)
no dilatation in the dark and partial ptosis
unilateral facial anhydrosis = lesion proximal to carotid plexus
Causes of Horners syndrome
- posterior inferior cerebellar artery or basilar artery occlusion
- multiple sclerosis
- cavernous sinus thrombosis
- pancoast tumous
- hypothalamic lesions
- cervical adenopathy
- mediastinal masses
- pontine syringomyelia
- Klumpke’s palsy
- aortic anuerysm
Subconjunctival haemorrhage
harmless but alarming
pool of blood behind the conjunctiva
- check BP
episcleritis
inflammation below conjunctiva
often seen with an inflammatory nodule
sclera look blue below a focal, cone shaped wedge of engorged vessels
eye aches duly
Rx- symptomatic relief - artificial tears , topical or systemic NSAIDs
scleritis
generalised inflammation of sclera with oedema of conjunctiva , scleral thinning and vasculitic changes
associated with systemic disease
constnat severe dull ache boring into eye
may present with headache and photophobia
may be necrotising
Uveitis
pigmented part of the eye- iris, ciliiary body, choroid
anterior - iris & ciliary body
posterior - choroid
intermediate - vitreous
Anterior uveitis
ank spon, sarcoid, behçets, IBD, reactive arthritis, herpes, TB
Presentation - red eye, pain, blurred vision and photophobia
increased lacrimation
treat cause
acute closed angle glaucoma
angle of anterior chamber narrows acutely causing sudden rise in intraocular pressure >30mmHg
pupil becomes fixed and dilated- axonal death occurs
raised intraocular pressure makes the eye feel hard
Presentation of acute closed angle glaucoma
generally unwell with N&V
headache and painful eye- blurred vision, haloes around lights at night
Treatment of acute closed angle glaucoma
b-blockers tried pilocarpine IV acetazolamide analgesia and antiemetics peripheral iridectomy once IOP is controlled
Complications of acute closed angle glaucoma
visual loss
central retinal artery or vein occlusions
repeated episodes
Conjunctivitis
red and inflammed conjunctiva
hyperaemic vessels may move over sclera
eyes itch, burn and lacrimate
often bilateral with discharge sticking lids together
non-infective causes of conjunctivitis
allergic conjunctivitis toxic autoimmune neoplastic contact lenses - reaction to foreign substance
infective causes of conjunctivitis
non-herpetic viral - serous discharge
bacterial
Treatment of bacterial conjunctivitis
if sexual disease, contact lens wearer or immunocompromised
chloramphenicol or fusidic acid drops
Anterior ischaemic optic neuropathy
most common cause of optic neuropathy in older patients
optic nerve is damaged if vascular supply to optic nerve is blocked by inflammation or atheroma
Retinal vein occlusion
incidence increases with age
2nd most common cause of blindness from retinal vascular disease
Accosicaed with aterioscleroisis, high BP, DM and polycythemia
Rx- intravitreal anti-VEGF therapy, dexamethosone implants
Vitreous heamorrhage
arise from retinal neovascularisation, retinal tears, retinal detachment or trauma
small extravasation of blood produce vitreous floaters
Check - acuity, pupil reaction, fundi
normally spontaneously resolves
may need vitrectomy in dense haemorrhage
Optic neuritis
subacute loss of vision
unilateral loss of acuity occurs over hours or days
colour vision is affected- red desaturation
painful eye movements
full recovery over 2-6 weeks
45-80% develop MS in the next 15 years
other causes- syphilis, leber’s optic atrophy, DM, vitamin deficiency
Rx- methylprednisolone IV 72hrs then prednisolone PO for 11 days
Wet age related macular degeneration
exudative
pathologic choroidal neovascular membranes develop under the retina
- leak fluid and blood causing a central disciform scar
vision deteriorates rapidly - distortion is key
fluid exudation, localised detachment of pigment
Treatment- smoking cessation, diet rich in green leafy veg, VEGF inhibitors- bevacizumab, laser photocoagulopathy, photodyamic therapy, intravitreal steroids
Dry age related macular degeneration
non-exudative
much slower - over decades, progressive visual loss
aetiology not well known
dursen –> optic nerve head axonal degeneration (leads to intracellular mitochondrial calcification- some axons then rupture –> calcium deposition in the extracellular space)
optic disc is made irregular and lumpy by these deposits
optic cup is absent
abnormal branching vessel patterns
Chronic simple open-angle glaucoma
optic nueropathy with death of many retinal ganglion cells and their optic nerve axons
IOP may be raised but this isn’t part of the definition
asymptomatic until visual fields are badly impaired
Diagnosis of chronic simple open-angle glaucoma
IOP measurement using tonometry Central corneal thickness measurement Peripheral anterior chamber configuration and depth assessments using gonioscopy visual field measurement optic nerve assessment
High risk for chronic simple open-angle glaucoma
need screening
>35 \+ve family history esp. siblings African-Carribean myopia diabetic/thyroid eye disease
Drug treatment for chronic simple open-angle glaucoma
aim to reduce production of aqueous or increase uveoscleral outflow
- prostaglandin analogues- latanoprost
- B-Blockers - timolol or betaxol
- a-adrenergic agonists - brimonidine, apraclondine
- carbonic anydrase inhibitors - dorzolamide& brinzolamide
- miotics - pilocarpine
sympathomimetic dipiverfrine
-fixed dose combination drops
laser therapy or surgery
Risk factors for cataracts
age related
genetic
occur early in DM
associated wtih smoking, alcohol excess, sunlight exposure, trauma, radiotherapy, HIV+ve
Nuclear cataracts
change the lens refractive index and dulls colours
Cortical cataracts
spoke like wedge shaped opacities
milder effects on vision
Posterior subcapsular cataracts
typically progress faster and cause glare from sunlight and lights when driing at night
Presentation of cataracts
blurred vision
unilateral cataracts often unnoticed
loss of stereopsis - affects distance judgement
bilateral cataracts cause painless loss of vision ± mononuclear diplopia
Post-op complications of cataract surgery
posterior capsule thickening
astigmatism becomes more noticeable
Retinal detachment
types
- Rhegmatogenous retinal detachment - fluid passes into vitreous space- caused by trauma
- Exudative retinal detachment - no trauma
- Tractional retinal detachments - pulling on retina. more common in myopic eyes
Presentation of retinal detachment
4 F’s
- Floaters
- Flashes
- Field Loss
- Fall in acuity- painless, curtain falling over the vision
Management of retinal detachment
nurse -flat or 30 degree up head tilt (inferior)
laser photocoagulation therapy
vitrectomy and gas tamponade with scleral silicone implants
cryotherapy or laser coagulation to secure the retina
Structural eye changes in DM
ocular ischaemia causes new blood vessels forming on the iris (rubeosis) - may block the drainage of aqueous fluid
- acceleration of age-related cataract formation
Pathogenesis
Eye in DM
microangiopathy in capillaries causes:
- vascular occlusion causes ischaemia ± new vessel formation - potential to bleed
- vascular leakage- pericytes lost, capillaries bulge- oedema and hard exudates–> flame shaped haemorrhages
Classification of eye disease in DM
Non-proliferative diabetic retinoapthy - mild, moderate or severe depending on degree of ischaemia
proliferative diabetic retinopathy- fine new vessles appear on the optic disc, retina and can cause vitreous haemorrhage
Maculopathy - leakage of vessels close to the macula causing oedema can can significantly threaten vision
Papilloedema
swelling of the optic disc caused by raised ICP
always bilateral, but not necessarily symmetrical
presentation- symptoms of raised ICP
Ramsay Hunt Syndrome
herpes zoster oticus
herpes zoster infection of the facial nerve
often in the elderly, severe otalgia precedes VII CN palsy
zoster vesicles appear around the ear, in the deep meatus ± soft palate and tongue
Vertigo, tinnitus or deafness
Rx- aciclovir + prednisolone
Corneal abrasion
intense pain
local anaesthetic, stain with fluroescein
should start healing within 48hrs- re-examine after 24hrs
Eye burns
treat chemical burns promptly
instil anaesthetic drops every 2 mins until pt comfortable
bathe eye in copious clean water
late sequelae - corneal scarring, opacification and lid damage
Foreign bodies in the eye
cause- chemosis, subconjunctival bleeding, irregular pupils, iris prolapse, hypaema, vitreous haemorrhage, retinal tears
X-ray orbit, orbital USS
removal of superficial FBs may be remove dwtih a triangle of clean card- chloramphenicol drops after
