Eye is a very complex organ with a wonderful architecture. We can see object when light passes through the structures in the eye and produces sharp image on the retina. Lens is one of the structure that focuses light on the retina and is located near the front of the eye and is biconvex and transparent. Clouding of the normally clear and transparent lens is called cataract.
Cataract causes much more vision problem globally rather than any other eye diseasees, and the number of cataract is increasing with the aging population.
WHO/NPCB survey has shown that there is backlog of over 22 million blind eyes and 80.1% of these are blind due to cataract in India . The annual incidence of cataract blindness is about 3.8million.
Cataract is the normal part of aging, the progress of which can be accelerated by systemic diseases like diabetes etc. Cataract can also happen after an eye injury, as a result of eye disease, after use of certain medicines like steroid, alpha agonist etc. Sometimes children are born with cataract.
Cataract causes a part of the lens to becomeopaque or cloudy. Light does not pass through easily and vision becomes blurry like looking through a fogged-up window. The cloudier the lens, the worse the vision will be.Apart from cloudy vision, cataract may cause glare from the headlight of the car or lamps. It may cause difficulty in night driving. Person may complaint of double vision in one eyeor may give history of frequent change of glass prescriptions. Near vision may improve for some time.
Surgery is the main stay of treatment. It is indicated when the vision loss caused by cataract affects their quality of life or hampering their day to day activities. Diminished vision due to early cataract may be improved by simply changing eye glass prescription.
Over the period of time the cataract surgery has evolved drastically. The operation involves removing the cloudy lens from the eye and putting an artificial lens in its place. Before surgery the specialist will assess the patients eye and general health. The eye will be measured so that artificial lens can be prepared.
Various types of Intraocular lens
1. Monofocal – Set for one level of vision usually distant. It can be Rigid or Foldable.
2. Multifocal – Set for providing distant and near vision.
3. Accommodating lens- Similar to natural lens allows the eye to focus distant or near object.
4. Toric-More power in one specific region of the lens
Different surgical techniques
1 Phacoemulsification- Surgeon makes a tiny cut in the corneal periphery and insert a minute probe through a cut. The probe uses an ultrasound to break the cloudy lens into very small pieces. These are then sucked out. Foldable lens is inserted through an injector which gets unfold in the lens capsule.
2. In manual ECCE the lens is removed in one piece and no ultrasound is used to break it up. The surgeon makes a slightly large cut in the eye.
3. In ICCE both the lens and capsule are removed. The artificial lens is sewn into the eye. This procedure is much less common.
The cataract surgery may be done using traditional tool or it may beFemto laser assisted.
After the operation
For most patients, vision improves almost immediately. It may take a while for the eye to settle down completely. Eyedrops has to be instilled for 4-6 wks and accordingly glasses can be prescribed.
Sometime the cut in the eye needs stitch, but this is normally small enough to heal by itself.
Patient should avoid vigorous activities for a while but most people find they can go about their daily activities as soon as they get home.
Dr Rachana Jain
M.B.B.S., DOMS (Ophthalmology)
Fortis JK Hospital, Udaipur
