A cataract is a clouding or opacity of the natural lens of the eye that causes visual impairment. The natural lens is located behind the iris, or “coloured part” of the eye and opacity in the lens causes images to appear hazy or blurred. The symptoms include:

■ Blurred vision;

■ Seeing as though through a cobweb, or having a film over the eye;

■ Frequent changing of glasses prescriptions, or seeing better without glasses;

■ Rings or halos around lights;

■ Severe decrease in vision with glare or bright lights in the eye;

■ As the cataract progresses, it interferes with daily activities; and

■ Altered colour vision.

Since most cataracts are part of the normal ageing process, they cannot be reversed. There is no medication or eyedrops or diet that will make cataracts go away. The only and most effective treatment is an operation to remove the cloudy lens. In the past, eye specialists often waited till the cataract became “ripe” and vision was very poor before suggesting one had the cataract removed. Now, with modern surgery, the operation is usually done as soon as one&’s eyesight interferes with one&’s daily life and ability to read, to work. However, once diagnosed with a cataract, your ophthalmologist needs to monitor your vision regularly for any changes and make decisions for surgery. The clinical tests include: Visual acuity — when vision cannot be corrected to a reasonable level through refraction to perform normal activities, surgery is recommended; Slit-lamp biomicroscopy — this examination enables the surgeon to look at the cataract&’s location, type, grade and density in order to correlate with the degree of visual loss; Direct and indirect ophthalmoscopy — dilating drops are placed in the eye to allow the doctor a direct view of the back of the eye (optic nerve and retina). This is important to assess the optic nerve head, retinal blood circulation and any other abnormalities that may indicate surgery or afford an assessment of visual recovery; and Applanation tonometry — this is done to rule out glaucoma.

Of the three types of cataract operations, Phacoemulsification/Phaco with IOL implantation is the most advanced technique where ultrasonic energy is used through a fine probe to emulsify the cataract and remove it. This method ensures quicker healing due to a small cut/incision, the eye remains relatively quiet, the recovery period is very short and normal day-to-day habits can be resumed quickly. The second eye can be operated on as soon as the first eye settles down. In diabetic patients, the second eye may be operated on after a gap of three weeks. The lens implanted cannot correct vision for both distance and close-up, so one will require glasses for reading and close work. But with multifocal lens implantation, glasses are not required in a majority of cases. After a Phaco operation, one needs to not sleep on the operated side; not shower for one week; not lift heavy objects for three weeks, avoid playing with small children and avoid dust and smoke and do not rub the operated eye.

 The writer is senior consultant eye sergeon and fellow, LV Prasad Eye Institute, Hyderabad.