Night Blindness :
Nyctalopia is commonly referred to as night blindness. Nyctalopia is one of the most horrible visions in that one will find it challenging to see under extremely low lighting levels or at night. Nyctalopia is not a disease but is rather a symptom of several conditions that may affect the retina or the way somebody adapts to darkness. The most common causes of nyctalopia are deficiency of vitamin A, retinitis pigmentosa, cataract, and certain drugs. Common features are lowlight vision, enhanced sensitivity to glare from the headlight reflection, and difficulties in adaptation from bright to dim environments. Thorough diagnosis would be a more extensive eye examination, including all the visual acuity tests used combined with retinoscopy, and examination of the retina and optic nerve. The predominant cause shall determine the treatment. Vitamin A deficiency is treated by oral supplements, though surgery may be needed to cure cataract patients.