CATARACTS are a common problem in Lesotho, with up to 500 or more cataract operations being performed yearly around the Kingdom.
What is a cataract?
A cataract is cloudiness/whitening (opacity) in the eye’s lens that impairs vision.
Cataracts produce a progressive, painless loss of vision by blocking the light that reaches the eye lens and distorts the light being focused on the retina.
It is like a paper that has been put in front of your eye that causes you not to be able to see clearly.
What causes cataracts is usually not known, although they sometimes result from exposure to X-rays or strong sunlight, inflammatory eye diseases, certain drugs, or complications of other diseases such as diabetes.
They are more common in older people but babies can be born with cataracts.
Because all light entering the eye must pass through the lens, any part of the lens that blocks, distorts, or diffuses light can cause poor vision.
How much vision deteriorates depends on where the cataract is and how dense (mature) it is.
In bright light, the pupil constricts, narrowing the cone of light entering the eye, so that it cannot easily pass around the cataract.
Thus, bright lights are especially disturbing to many people with cataracts, who see halos around lights, glare, and scattering of light.
Such problems are particularly troubling when a person moves from a dark to a bright-lit space or tries to read with a bright lamp.
A cataract at the back of the lens particularly interferes with vision in bright light.
It affects vision more than other cataracts because the opacity is at the point where light rays cross.
Surprisingly, a cataract in the central part of the lens may improve vision at first.
The cataract causes light to be refocused, improving vision for objects close to the eye.
Older people, who generally have trouble seeing things that are close, may discover that they can read again without glasses, a phenomenon often described as gaining second sight.
Although cataracts usually are not painful, rarely they cause swelling in the lens and increased pressure in the eye (glaucoma), which can be painful.
Diagnosis and treatment
A doctor can see a cataract while examining the eye with an ophthalmoscope (an instrument used to view the inside of the eye).
Using an instrument called a slit lamp, a doctor can see the exact location of the cataract and the extent of its opacity.
Usually, people who have a cataract can determine when to have it surgically removed.
When people feel unsafe, uncomfortable, or unable to perform daily tasks, they may be ready for surgery. There is no advantage in having surgery before then.
Before surgery a person with a cataract can try other measures such as getting eye-glasses and contact lenses which may improve vision.
Wearing sunglasses in bright light and using lamps that provide reflected lighting rather than direct lighting decrease glare and aid vision.
Cataract surgery, which can be performed on a person of any age, usually does not require general anaesthesia or an overnight hospital stay.
During the operation, the lens is removed, and usually a new plastic or silicone lens is inserted. This artificial lens is called a lens implant.
Without a lens implant, people usually need a contact lens.
If they cannot wear a contact lens, they can try eyeglasses, which are very thick and tend to distort vision.
Cataract surgery is common and usually safe.
Rarely, after the operation, a person may develop an infection or a bleeding in the eye, which can lead to a serious loss of vision.
Older people in particular should make arrangements in advance to get extra help at home for a few days after surgery. For a few weeks after surgery, eye drops or ointment is used to prevent infection, reduce inflammation, and promote healing.
To protect the eye from injury, the person wears glasses or a metal shield until healing is complete, usually after a few weeks.