Cataracts and Glaucoma

Question 1

What is a cataract?

Answer 1

A painless opacification of the natural crystalline lens of the eye

Question 2

What are the three forms of cataracts?

Answer 2

Nuclear sclerosis, lens becomes yellow/brown (most common)
Cortical
Posterior subscapular - related to previous uveitis or corticosteroid use

Question 3

What are the examination findings in cataracts?

Answer 3

There will be greying of the pupil under pen torch and a reduced red reflex with direct opthalmoscope

Question 4

What treatment can be offered for cataracts?

Answer 4

Myopic glasses can be used as the cataract changes the refractive index of the lens
When this no longer works then surgery can be used, cataract removed by phakoemilsification and implantation of an artificial intraocular lens

Question 5

What are some operative complications of cataract surgery?

Answer 5

Damage to the corneal endothelium
Rupture of the posterior capsule, leading to vitreous loss
Loss of lens fragments into the vitreous
Suprachoroidal haemorrhage

Question 6

What are some postoperative complications of cataract surgery?

Answer 6

Iris prolapse
Bacterial endopthalmitis
Posterior capsular opacification (corrected by laser)

Question 7

What is glaucoma?

Answer 7

Glaucoma is characterised by increased intraocular pressure resulting in optic disc cupping and visual field loss

Question 8

What is primary closed angle glaucoma?

Answer 8

This is when the angle between the iris and the cornea is reduced resulting in decreased drainage of aqeuous humour. This leads to a build up in intraocular pressure and damage to the optic nerves

Question 9

What pressure is considered raised intra ocular pressure?

Answer 9

> 21mmHg

Question 10

What is primary open angle glaucoma?

Answer 10

Syndrome in which there is raised intra ocular pressure, pathological cupping of the optic disc, field loss and open drainage angle

Question 11

What are the two theories of IOP affecting eyesight?

Answer 11

One theory is that the pressure causes direct damage to the nerve
The other theory is that compression of the micro circulation leads to ischaemia of the nerves

Question 12

How does primary open angle glaucoma typically present?

Answer 12

It typically presents late on in the disease because early disease is asymptomatic and will only present with field loss later on.

Question 13

What can cause false positives when measuring intraocular pressure?

Answer 13

Increased or decreased thickness of the cornea

Question 14

How does glaucoma progress?

Answer 14

It begins with loss of nasal and temporal vision and will progress to cause loss of peripheral vision until only central vision remains. Once visual field is loss there is no way of getting it back.

Question 15

What is the medical treatment of glaucoma?

Answer 15

Mainly treated with beta blockers (timilol) and prostaglandin analogues (lantoprost) to decrease secretions of aqueous humour. Can also be treated with systemic medications such as acetazolamide and mannitol

Question 16

What is the surgical treatment for glaucoma?

Answer 16

For closed angle glaucoma and iridotomy (hole through iris) can allow fluid to drain from the posterior to anterior chamber. Trabeculectomy is an option which involves making a fistula through the sclera to the sub conjunctival space for excess humour to drain to.
Drainage tubes can be used in severe cases