Opthalmology

Question 1

what is the macula?

Answer 1

it is the part of the eye that is involved in central vision (i.e. seeing what is directly in front of you)

Question 2

what is the foveola centralis?

Answer 2

small depression within the neurosensory retina where visual acuity is the highest.

located within the macula

Question 3

What are the types of AMD?

Answer 3

wet and dry

dry: takes years, due to deposition of various metabolites; 90% cases - more common

wet: takes weeks to months, due to neovascularisation growing into subretinal space

Question 4

causes of pre-senile cataract

Answer 4

steroids (dose and duration dependent)
uveitis (for which steroids are often needed)
DM
high myopia
significant trauma

can also occur in association with Down syndrome and retinitis pigmentosa

Question 5

what is myopia?

Answer 5

nearsightedness

(struggle seeing what is in the distance)

Question 6

What are the three main chambers in the eye?

Answer 6

In the anterior segment of the eye
- anterior chamber is form the cornea to the iris
- posterior chamber is the small space between the iris and the lens

in the posterior segment of the eye:
- the vitreous chamber is the space behind the lens

Question 7

what are the chambers of the eye filled with?

Answer 7

the chambers in the anterior segment of the eye (ant and post chamber) are filled with aqueous humour

the vitreous chamber in the posterior segment of the eye is filled with vitreous humour

Question 8

describe the journey of aqueous humour in the eye

Answer 8

• produced by the ciliary body
• enters the posterior chamber
• moves to the anterior chamber through a small gap between the iris and lens
• is taken up via the trabecular meshwork
• enters the canal of Schlemm
• is drained into the aqueous veins which are part of the episcleral venous system

Question 9

Mx of acute closed angle glaucoma

Answer 9

• IV acetazolamide to drop the IOP.
• Also topical agents (eyedrops) to lower the IOP: prostaglandin analogues and if not contraindicated, beta-blocker eyedrops.
• IV mannitol is occasionally required to lower IOP.
• topical steroids if eye inflammed in acute glacuoma
• pilocarpine drops are given to cause miosis (constricted pupils), which helps to unblock the closed drainage angle
• Either that day or after several days, laser peripheral iridotomy to both eyes (as if the acute glaucoma attack occurred in one eye, the other eye is likely to be vulnerable to an attack in future) -> iridotomy should prevent any future attack or recurrence of acute glaucoma

Question 10

What is mydriasis?

Answer 10

fixed mid dilated pupil

Question 11

what is miosis

Question 12

O/E findings in acute angle closure glaucoma

Answer 12

• fixed mid dilated pupil (i.e. mydriasis)
• general corneal haze (rather than specific infiltrates)
• the eye feels rock hard when (gently) palpated, and if measured, intraocular pressure will be markedly raised