The chief symptom of night blindness is an inability to see in environments with little light. The condition is not always expressed as complete blindness, but may also include diminished vision in these conditions. Other visual symptoms of night blindness can include lessened peripheral vision, poor contrast vision, and near-sightedness. Dry eyes can also occur in some cases. Night blindness may also serve as a symptom for certain underlying conditions.
Difficulty visually adapting to the dark defines most cases and most symptoms of night blindness. An individual with night blindness, for example, would likely have a great deal of difficulty navigating a barely-lit room. Moving about during the night would also present problems, which might make certain activities such as night driving problematic. In some cases, objects might simply appear more blurry than usual, but in more extreme cases an individual would not be able to distinguish any objects in a dark area. Symptoms will gradually worsen over time in some forms of night blindness.
While poor night vision is the primary indicator, other symptoms of night blindness may sometimes manifest. Blurred vision could extend to overall vision. In fact, near-sightedness — or the inability to see clearly from a distance — and night blindness are often linked. Additionally, afflicted individuals often complain of dry eyes as one of the symptoms of night blindness.
The parts of the eyes that allows sight in bad light are damaged in most cases of night blindness. Such destruction may cause a number of other visual problems that act as symptoms of night blindness. One major culprit in night blindness, for example, is the loss of peripheral vision. This involves the ability to see from the sides of the eye. Visual adjustment to different light contrasts is also diminished, which may cause delayed visual adjustments in different environments.
Night blindness often results from genetic abnormalities or a nutritional deficiency, and therefore may serve as a key symptom of such disorders. The former cause is likely if symptoms have been present since childhood. Most pre-existing conditions are genetically linked, resulting from conditions like an X-linked congenital abnormality. A depleted amount of Vitamin A may account for nutrient-related deficits, and this depletion could result from disorders affecting the liver or the intestines. Other proposed origins for night blindness include cataracts and eye injuries.
Treatments of night blindness are sparse. For conditions related to nutritional depletion, vitamin supplements could help correct the problem. Surgery may prove useful for correcting cataracts or injuries. Otherwise, the best course of action for individuals with this condition is to use caution in poorly lit areas.