Ophthalmology Flashcards
(139 cards)
What is glaucoma?
Optic nerve damage from rise in intraocular pressure
Glaucoma pathophysiology? Normal IOP value?
- Imbalance in aqueous humour production / drainage - usually blockage
- normal pressure 10-21 mmHg
What is the pathophysiology of open angle glaucoma?
a gradual increase in resistance within the trabecular network results in increased IOP and damage to optic nerve
open angle glaucoma RF?
- increased age
- myopia (near sighted)
- FHx
- black ethnic background
Open angle glaucoma Px?
typically asymptomatic
if symptomatic:
- tunnel vision
- halos around lights
- pain
- headaches
Open angle glaucoma screening
- strong FHx - every 2yrs from 30yo
- every 5yrs >40yo, every 2yrs >60
Open angle glaucoma Ix ?
- visual fields - tunnel vision
- fundoscopy / slit lamp - cupping of optic disc
- Goldmann applanation tonometry - checks intraocular pressure
NB can use non-contact tonometry
- puff of air, estimate IOP (raised)
Open angle glaucoma Mx?
Start when IOP >24 mmHg:
- 360-degree selective laser trabeculoplasty - involves directing a laser at trabecular network to try and improve drainage
1st line medical Tx:
- prostaglandin analogue eye drops e.g latanoprost
other topical options?
- beta blockers e.g. timolol
- carbonic anhydrase inhibitor e.g. acetazolamide
- alpha 2 agonists e.g. brimonidine
surgical option?
- trabeculectomy
What is acute angle closure glaucoma?
- complete closure of angle between the iris and cornea (e.g. due to iris bulging forward) which prevents drainage of the aqueous fluid leading to IOP and optic nerve damage
ophthalmic emergency!!!
Risk factors for acute angle closure glaucoma?
- Increasing age
- Family history
- Female (four times more likely than males)
- Chinese and East Asian ethnic origin
- Shallow anterior chamber
- hyperopia
contributory medications? TCAs, adrenergic meds and anticholinergic meds
AACG Px
- red, painful eye
- N+V
- headache
- halo around lights
- sx worse with pupil dilatation - eg will be watching TV in dark room
AACG examination findings?
- pupil sluggish + dilated
- eye hard to palpation
- reduced visual acuity
- hazy cornea (oedema)
AACG Ix
- tonometry - IOP >60
- gonioscopy - look at angle (lens on slit lamp)
AACG Mx
- lie on back w/o pillow, urgent ophthal referral
- Pilocarpine eye drops (2% for blue and 4% for brown eyes) = acts on muscarinic receptors around iris to prompt pupil constriction + ciliary muscle constriction to try and open up path for aqueous humour flow
- Acetazolamide 500 mg orally = reduces aqueous humour production
- analgesia +/- antiemetics
definitive treatment = laser iridotomy - both eyes
what is age related macular degeneration? what are the two types of ARMD?
damage to the macula with central vision loss
- most common cause of blindness in
UK
- Wet (also called neovascular), accounting for 10% of cases
- Dry (also called non-neovascular), accounting for 90% of cases
ARMD - risk factors?
Older age
Smoking
Family history
Cardiovascular disease (e.g., hypertension)
Obesity
Poor diet (low in vitamins and high in fat)
ARMD pathophysiology?
- Degeneration of retinal photoreceptors
- formation of drusen (protein and lipid deposits)
- atrophy of retinal pigment epithelium
Dry / atrophic - 90% - early
Drusen, changes in pigmentation of retinal pigment endothelium
Wet / exudative - 10% - late
choroidal neovascularisation, VEGF, oedema, rapid vision loss
ARMD Px?
- Gradual loss of central vision
- Reduced visual acuity
- Crooked or wavy appearance to straight lines (metamorphopsia)
ARMD Ix
- visual acuity: reduced
- fundoscopy: drusen, red patches in wet ARMD
- Amsler grid testing - line appears crooked
- Slit lamp - pigmentary/exudative/haemorrhagic changes
- fluorescein angiography to see neovascularisation and leakage
- optical coherence tomography (OCT) to confirm Dx and monitor
ARMD Mx
Urgent referral to ophthalmology
Dry ARMD?
- stop smoking, control BP
- zinc, vit A, C, E
Wet ARMD?
- intravitreal injection of Anti-VEGF
Diabetic retinopathy
Retinal deterioration from blood vessel damage due to high blood sugar levels
how do you classify diabetic retinopathy?
Proliferative – neovascularisation and vitreous haemorrhage
Non proliferative - micro aneurysms, retinal haemorrhages, hard exudates, blot haemorrhages
NB maculopathy exists separately and involves exudates in macula and macula oedema
Diabetic retinopathy Px
non proliferative? asymptomatic
proliferative? vitreous haemorrhage, floaters, blurred vision
Diabetic retinopathy Ix
- visual acuity
- fundoscopy
- fluroscein angiography