Disorders of vision Flashcards
What are the risk factors for cataracts?
- diabetes
- age
- smoking
- steroid use
What happens to the eye in cataracts?
there is protein aggregation leads to lens opacification. This means that light is scattered as it enters
What are the signs and symptoms of cataracts?
- gradual painless vision loss
- glare (lights appear brighter)
- haloes
- myopic shift (increased short sightedness)
- loss of red reflex
When and how is cataracts managed?
No set point so when the patient feels it is interfering with their life
- Phacoemulsification (anterior capsule, nucleus and cortex removed and a prosthetic one inserted that is supported by posterior capsule)
What are the complications of cataract surgery?
- posterior capsule opacification
- posterior capsule rupture leading to vitreous prolapse and retinal detachment
Compare the pathophysiology of open and closed angle glaucoma
open: open irido-corneal angle but a blockage in the trabecular meshwork leading to reduced flow
closed: blocked irido-corneal angle with the lens pushed against the iris
What are the risk factors for open angle glaucoma
- Afro Caribbean
- family history
- myopes
What is the symptom of open angle glaucoma?
gradual, painless, peripheral vision loss
How would you investigate open angle glaucoma and what are the results?
- Raised IOP
- visual field defect
- optic disc cupping, pallor and bayoneting of vessels
Aside from primary idiopathic open angle glaucoma, what else can cause it?
- steroids
- neovascularisation in the drainage angle
- pigment deposits
- pseudoproliferative deposits (dandruff like material)
What are the risk factors/ causes of closed angle gluacoma?
- age (lens grows so pushes the iris forward and narrows the angle)
- hypermetropes (naturally narrow angle)
- asian
- pupil dilation (iris pushed forward)
- alpha agonists, antimuscarinics, TCAs
What are the symptoms or closed angle glaucoma and what does the eye look like?
Acutely painful eye with blurring and loss of vision
+/- coloured haloes around lights
+/- nausea and vomiting
Eye: fixed oval mid-dilated pupil, red, hazy cornea
What is the definitive management of closed angle glaucoma and how is it managed in the mean time?
Laser iridotomy
Pilocarpine topical drops
Acetazolamide
Analgesia and antiemetics
What topical drops are used in the management of open angle glaucoma? How do they work?
- Latanoprost: prostaglandin analogue that increases uveoscleral flow
- Timolol: b-blocker that reduced aqueous production by the ciliary body
- Pilocarpine: miotic that contracts the ciliary muscle and opens the trabecular meshwork
What are some general side effects of topical drops used in glaucoma?
- red eye
- dry eye
- irritation
- can get systemic absorption (timolol is CI in asthma, latanoprost in CI in pregnancy)
- allergic reaction to preservative used
What are the risk factors for ARMD?
CVS risk factors: smoking, diabetes, obesity
What are the signs and symptoms of ARMD? What are some specific ones to dry and wet?
- Painless central vision loss
- difficulty adapting from light to dark
- inability to discern colour shades
Dry: vision loss is especially to small print
Wet: sudden onset, straight lines appear curvy
How does dry ARMD appear on fundoscopy?
Drusen (yellow deposits)
Macula scar (thick yellow patch)
Hypo/ hyperpigmentation of the peripheral retina
How does wet ARMD appear on fundoscopy?
Neovascularisation with haemorrhages
What is the management of wet ARMD?
Anti-VEGF
What is the inheritance pattern of retinitis pigmentosa?
x- linked recessive
What are the symptoms of retinitis pigmentosa?
Peripheral vision loss - tunnel vision
Night blindness
What is seen on fundoscopy of retinitis pigmentosa?
Black spicules on the peripheral retina and a waxy looking disc
What is a retinoblastoma and what are the examination findings?
Cancer originating from the retinal cells seen in children typically about 18 months
- Leukocoria (whitening of the eye) leading to loss of red reflex
- Strabismus
- Eye watering
