Blind World Magazine

Tunnel Vision.
One may lose side vision and only see an object from the middle.

November 19, 2005.
Monitor Online.

Metusela Mugumya, 46, has suffered an eye problem for about three years. It started with his failure to drive easily at night because he could barely see beyond specific points. As a result, there were minor accidents before he stopped driving. Even while on busy streets, he always collided with people or knocked poles, as a result of poor vision.

Apparently, he barely sees a thing at night, dusk or in dark places. If he must, he uses a torch. Earlier diagnoses from various eye doctors revealed that his case was not medical. However, it was later discovered that he had a very low field of vision at five degrees compared to the normal 360. This is a pigment growing on the part of the eye called the retina, a condition called Retinitis Pigmentosa. According to Dr Cillasy Tumwesigye, an ophthalmologist at House of Optics on Luwum Street, the disease is a genetic disease, not acquired but inherited, characterised by difficulty in seeing at night.

According to an online eye dictionary, the disease is “Any of several hereditary progressive degenerative diseases of the eye marked by night blindness in the early stages, atrophy and pigment changes in the retina, constriction of the visual field, and eventual blindness”.

“The patients lose their peripheral vision – their vision is limited to just a specific point. One may lose side vision and may only see an object from the middle. Gradually, the central vision also becomes poor. Once this starts, it ends in more reduced night vision,” Tumwesigye says.

Due to inflammation of the retina, an abnormal pigment develops on the retina, causing poor peripheral vision. This is because the pigment that grows affects the blood vessels and the optic nerve, which in turn affects the flow of blood in the retina.

“The retina is like a film which covers pictures, the cons help you to see at day time, while the rods (cells which radiate vision at night) help one to see at night, but they get affected,” he says.

Tumwesigye says that it is an inherited disease hailing from one of a parent’s line or generation. It exists in two different conditions.

From the recessive autosomal pattern of inheritance, the combination of genes transmitted by crossing two individuals, is minor. Thus the dominant gene overshadows the recessive gene. This means that throughout generations, the gene may occur once in a while. “With the autosomal recessive inheritance, the disease usually occurs early in life,” he says.

According to him, this is the condition Mugumya suffers from. He also argues that some children and youths with poor vision may be suffering from the disease and may eventually go blind.

Meanwhile, with the autosomal dominant inheritance, where the genes are dominant, there is gradual loss of sight at the old age.


Usually, vitamin A is prescribed to a patient although it is said there is no definite cure for the disease. “Vitamin A improves some functions in the retina although it is not a sure treatment in itself for the disease. There is progressively no known cure for the disease,” Tumwesigye says. Other drugs may also be prescribed just to improve vision but there is no absolute treatment.

Usually, while it is anticipated that there is absolute treatment for the disease, majority reports say that the treatment is just to suspend or halt the condition, but it does not eradicate the disease.

According to an online medical geography centre, “There is currently no medical treatment for Retinitis Pigmentosa and glaucoma retinitis pigmentosa although scientists continue to investigate possible treatments. Future treatment may involve retinal transplants, artificial complications retinitis pigmentosa research, retinitis pigmentosa retinal implants [1], gene therapy, stem cells, nutritional supplements, and/or drug therapies”.

Tumwesigye says that individuals must be helped to adjust to their conditions through counselling, vision training and using of certain gadgets to help movement and vocational training to adjust to their conditions.

He argues that poor vision can directly affect one’s performance on certain jobs, so it is best that they are trained early with other skills, which may not be affected as much by poor sight.

He also argues that such cases would be solved by genetic counselling for individual knowledge of their genetics before marriage. However most individuals barely consider the concept let alone have the money to meet the costs.

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