What are the different types of cataract?

The human lens consists of layers of protein that are laid down over time and continue to grow throughout life and at all decades from 10 to 70 years; the male lens is heavier than its female counterpart.

The layered structure of the lens is much like an onion or tree trunk, albeit clear before loss of clarity and cataract occurs. The cataract causes blurred vision, loss of contrast and can make everyday tasks such as driving difficult. This can occur at any age but is more common in people over 60 years old.

Cataract surgery removes the cloudy lens protein and replaces this with a lens implant that can correct your glasses prescription for distance and near vision.

The different layers of the lens give rise to three different types of cataract as follows:

1. Cortical cataract: This type of cataract affects the clarity of the outer layers of the lens. Very often it appears white and chalky
2. Nuclear cataract: This type of cataract affects the central nucleus of the lens and gives rise to commonly seen nuclear sclerotic cataracts. Very often it appears yellowy-brown
3. Posterior sub-capsular cataract: this type of cataract occurs at the back of the lens, before the capsule that surrounds the lens protein. This type of cataract is more common in diabetic patients

Very often a mixture of the three types of cataract is seen due to all layers of the lens being affected.