Cataract & Dry Eye - Pathophysiology & Treatment

Question 1

What causes cataract (cloudiness of the eye)?

Answer 1

With ageing, glutathione levels decrease (which is responsible for protecting the eye from reactive O2 species).
Antioxidants that capture these reactive O2 species also decrease.
These hence cause cloudiness in the eye.

Question 2

What is the only treatment available for cataract?

Answer 2

Lens of the eye has to be taken out & replaced by an artificial one.

Question 3

What happens in the lens of the eye during cataract?

Answer 3

Crystalline proteins in the lens are denatured from oxidative stress & an imbalance of electrolytes.

Question 4

What post-operative complications can arise from cataract?

Answer 4

1. Endophthalmitis - infection of the eye due to surgery

2. Cystoid macular oedema - inflammation of the eye rather than infection

Question 5

What is dry eye disease (DED)?

Answer 5

Irregularities in the tear producing glands in the eye layers, causing different types of dry eyes.

Question 6

What are the 2 classifications of DED?

Answer 6

1. Tear-deficient

2. Poor quality tears that are evaporative

Question 7

What are the functions of the different layers of the eye?

Answer 7

Mucin layer: anchors tears to the surface of the eye
Aqueous layer: has nutrients dissolved in it
Lipid layer: protects tears from evaporating and having dry eyes

Question 8

What is the management of DED?

Answer 8

1. Ocular lubricants (e.g. Hypermellose)
2. Combination of mucolytics (e.g. hypermellose & acyctylcysteine)
3. Eye ointments containing paraffin, which lubricate the eye surface
4. Ciclosporin eye drops
5. NaCl 0.9% as ‘comfort drops’ for contact lens wearers