TAMIL NADU

We can’t afford to lose sight of this disease health & lifestyle

R.Sujatha

The study by Sankara Nethralaya has found high incidence of this disease in south Indian population

CHENNAI: An on-going survey in rural and urban Tamil Nadu by doctors in Sankara Nethralaya here as part of its glaucoma project found that the prevalence of Retinitis Pigmentosa, a disease of the retina was around two per thousand persons.

The study done by Sankara Nethralaya found that the incidence was high in the south Indian population. Doctors cite consanguineous marriages as one of the reasons. Although the disease is predominantly inherited, it can be found in persons with relatives who are not affected.

What it is

The disease, which damages the retina, commonly runs in families and gets worse with time. The symptoms often appear in childhood but it is not until adolescence that marked vision problems are experienced. As the disease progresses, peripheral vision is gradually lost and the condition may eventually lead to hazy vision.

Doctors have also noticed ‘sporadic cases’ that they attribute to gene mutation.

“Retinitis Pigmentosa comes as a package and could also be associated with other symptoms such as mental retardation, obesity, retarded growth, renal dysfunction, diabetes mellitus and polydactyly (with more digits than normal),” explained Parveen Sen, senior consultant, Vitro-retinal Department, Sankara Nethralaya. She is currently involved in studying the incidence of such a combination of symptoms.

At the Government Eye Hospital in Egmore, doctors see at least one case each month, said K. Vasantha, deputy superintendent. In the last 20 years, the number of such cases had come down following better awareness about consanguineous marriages, she said. Though researchers have identified the genes that cause the disease, there is as yet no treatment or cure.

Symptoms

The earliest and most common symptom of the disease is night blindness. People report inability to see in dim lit rooms, driving in low light, at night or in foggy conditions. Some of the affected people take a long time to adjust from light to dark. Others complain of floaters or black spots in the eye, others see flashes of light. Some complain of tunnel-like vision and lack of peripheral vision. They bump into objects and end up injuring themselves.

Treatment

There is no medication to delay the process, doctors say.

But, studies have been done abroad to find whether use of vitamin D and E and Lutein and Xanthin could prevent the progression of the disease.

Currently doctors advise genetic counselling to rule out a possibility of passing on the gene if marriage between relatives is unavoidable.

“While providing driving licence it is extremely important to insist on colour vision and visual field test. Such people who experience piped or tunnel vision cannot see the entire field. They are a danger not only to themselves but also to other road-users,” said ophthalmologist P. Kanthamani.

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