Ophthalmology Flashcards
Increased UV exposure is a risk factor for what 3 eye conditions
- Cataracts
- Pterygium
- Cancers of the eyelid (commonly BCC)
What is tropicamide used for
Pupil dilation (e.g. before fundoscopy of slit lamp examination)
How many layers does the cornea have
5
How can you distinguish between episcleritis and scleritis
- Episcleritis blood vessels will blanch with admission of phenlephrine/cotton bud
- Episcleritis engorged vessels in cone/wedge shape (thin towards pupil) that can be moved - superficial veins
- Actuity unaffected in episcleritis
- Scleritis is associated with underlying chronic disease, can be sight treatening as needs urgert referal if posterior scerlitis/if necrotising changes present
- Scleritis is painful with eye movement as extraocular muscles insert into sclera
Phenylephrine uses and mechanism of action
Symphatomimetic, acts on alpha1 ADRs
dilates eyes (also used as decongestant & to relieve heamorroid for vasocontrictive action via vasocontriction mediated by a1 activation, increases BP)
Proliferative diabetic retinopathy is a risk factor for what cause of sudden painless vision loss
Vitreous heamorrage (over 50% of vireous heamorage is caused by proliferative diabetic retinopathy as the new blood vessels grow into the vitreous, are weak and prine to shearing - presenting as floaters)
Characteristic of grade 4 hypertensive retinopathy
Papiloedema
Cotton wool exudates and flame heamoorrages indicate what grade of hypertensive retinopathy
Grade 3
What type of organism can cause infections/corneal ulcers in contact lense wearers
Protozoa - acanthamoebae (common in soil and even tap water)
Four features of horners syndrome
LOSS OF SYMPATHETIC TRUNK
- Miosis
- Anhydrosis
- Ptosis
- Enopthalomos
Feature that would indicate congenital horners syndrome
Heterochromia of eyes
Name two types of carbonic anhydrase drops that can be used in treatment of acute closed angle and open angle glaucoma
Acetozolamide
Dorzolamide
What is a relative afferent pupillary defect
If you don’t know this look it up, it’s conceptual
What is a Marcus Gunn pupil
Pupil with a RAPD (abnormal direct and consensual response to light shining in it due to defect in the afferent - optic nerve to pretectal nucleas bilateral innervation of edinger westphal - pathway of the light reflex)
What is an Argyll - Robinson pupil and in what conditions is it found
aka postitues pupil - accomdates but doesn’t react
small pupil, accomodates, no light response
syphillis and diabetes mellitus