I have very poor night vision. What could be the cause and how do I handle this challenge? 

Solomon

Dear Solomon,

You have not specified your age and how long you have this problem. Most common cause for night blindness is vitamin A. deficiency. This could be due to dietary deficiency. Liver disorders impair vitamin A absorption and metabolism, hence lead to vitamin A. deficiency. Zinc deficiency also manifests as night blindness. Drugs like cholestyramine used for gall bladder disorders, medications used for glaucoma, also cause night blindness.

Some individuals may have had night blindness since birth due to genetic factors.

With advancing age, there is degeneration of the lens causing it to become opaque. During this transformation, the light rays are not properly focused on retina, hence impairing sharpness of vision. The clarity of vision is further reduced during night, hence causing night blindness. Macular degeneration in the eyes also causes night blindness. Retinitis pigmentosa is a congenital defect in the photoreceptors of the retina (on which light rays are focused and they transmit signals to brain for image seen) and causes night blindness. One can suffer from night blindness due to diabetic retinopathy.

Treatment of night blindness depends on treating the cause. Conditions like cataract or retinopathy need surgical intervention. Vitamin A deficiency can be corrected by taking supplements of vitamin A. Zinc supplements are also useful. Intake of vitamin A rich vegetables and fruits like mango, carrots or green vegetables helps in preventing and treating night blindness.

Dr Rachna Pande  is a specialist in internal medicine at Ruhengeri Hospital