Any opacity in the lens or its capsule is called a cataract. However cataract is the opacity in lens preventing clear image formation on retina.
The WHO/NPCB (National Programme for Control of Blindness) survey has shown that there is a backlog of over 22 million blind eyes (12 million blind people) in India, and 80.1% of these are blind due to cataract. The annual incidence of cataract blindness is about 3.8 million.
Etiology of cataract
- Systemic diseases: Diabetes Mellitus, Galactosaemia, Hypoparathyroidism etc
- Drug: Steroid
- Toxic agents: Copper, Cigarette smoking etc
- Complicated cataract: (Cataract due other ocular disease ) Iridocyclitis, Retinitis pigmentosa etc
- Electric shock
- Blurring of vision/ diminution of vision
- White or grayish opacity
- Frequent changes of glass
- Difficulty in bright light
- Difficulty in night vision
- Coloured haloes
- Loss of contrast sensitivity
- Myopic shift( increase of minus power in aged person)
There is no medical treatment for cataract. Though, surgery (Cataract extraction & Intraocular lens implantation) is the only treatment, but in initial stages, refraction and adjustment of illumination helps.
Types of Surgery
Phacoemulsification with foldable IOL ( Intra Ocular Lens) implantation is the choice of surgery. Manual small incision cataract surgery is also very popular surgery in India .
Laser Cataract Surgery: Femtosecond Laser is used to perform few steps of surgery in phacoemulsification.