ophthalmology Flashcards
what is retinitis pigmentosa
inherited condition causing retinal degeneration. most common
primarily affects the peripheral retina
presentation retinitis pigmentosa
tunnel vision
night blindness often initial sign
fundoscopy of retinitis pigmentosa
black bone spicule-shaped pigmentation in the peripheral retina, mottling of the retinal pigment epithelium
(looks like black bits around the edges)
what nerve is affected in loss of corneal reflex
CN V1 (trigeminal)
- ophthalmic branch
CN III (oculomotor) palsy
ptosis
‘down and out’ eye
dilated, fixed pupil
as III controls MR, IO, SR, I
CN IV (trochlear) palsy
defective downward gaze → vertical diplopia
as IV controls SO
CN VI (abducens) palsy
defective abduction → horizontal diplopia
eye deviates inwards
as VI controls LR
what is glaucoma
optic nerve damage caused by a significant increase in intraocular pressure
what is acute angle-closure glaucoma
iris bulges forward + seals off trabecular meshwork from anterior chamber preventing the aqueous humour from being able to drain
-> continual build up of pressure in eye (particularly in posterior chamber which in turn worsens angle closure)
risk factors for acute angle-closure glaucoma
chinese/east-asian
increased age
female
FHx
shallow anterior chambre
pupil dilation
catacracts
hypermetropia (long sited)
meds that can increase risk of acute angle-closure glaucoma
adrenergic e.g. noradrenaline
anticholinergic e.g. oxybutynin
tricyclic antidepressants
presentation of acute angle-closure glaucoma
severely painful red eye
blurred vision
halos around lights
assoc headache, N&V
clinical examination in acute angle-closure glaucoma
red eye
hazy cornea
teary
fixed, dilated pupil
decreased visual acuity
firm eyeball on palpation
tx acute angle-closure glaucoma
same day ophthalmology assessment - med emergency as can lose vision
lie px back - no pillow
PILOCARPINE eye drops (causes pupil to contract)
acetazolamide 500mg oral (decreases production of aqueous humour), can be given IV
definative tx = Laser peripheral iridotomy
what is open angle glaucoma
where there is a gradual increase in resistance through the trabecular meshwork making it more diff for aqueous humour to flow through + exit eye
slow + chronic onset
RFs open angle glaucoma
age
FHx
black
nearsighted (myopia)
presentation open angle glaucoma
asx for a long time
ofen found at routine screening in eye checks
affects peripheral vision first -> tunnel vision
pain, headaches, blurred, halos
ix of intraocular pressure
goldmann applanation tonometry GS
non-contact tonometry
mx open angle glaucoma
Latanoprost - prostaglandin analogue eye drops
- increase uveoscleral outflow
- increases eyelash length
B-blocker eye drops - timolol
- reduces aqueous production
- CI asthma, heart block
SEs of prostaglandin analogue eye drops e.g. latanoprost
eyelash growth
eyelid pigmentation
iris pigmentation (browning)
most common cause of blindness in UK
age-related macular degeneration
findings assoc w age-related macular degeneration
drusen seen in fundoscopy (paler dots) - espesh around macular in DRY
neovascularisation in WET
atrophy of retinal pigment epithelium
degeneration of photoreceptors
what happens in wet age-related macular degeneration
neovascularisation
dev of new vessels growing from the choroid layer of macular into the retina. These can leak -> oedema -> vision loss
RFs age-related macular degeneration
age
smoking
white or chinese
FHx
CVD