When someone finds it hard to get adapted to weak lighting situation then this state is medically known as nyctalopia and in general terms it is known as night blindness. Night blindness is basically inability to see properly in nighttime or in dim light. It is not a disease in itself, but somewhat it is an indication of underlying problems, particularly untreated nearsightedness. Persons who are suffering from this disorder, the pupil enlarge when there is darkness or dim light and therefore they become nearsighted at night. This particular situation is called as spherical aberration. This affects the sufferer’s vision in the night hours because of the low lighting surroundings. People suffering from night blindness can see easily and clearly in day light or in proper light but have troubles of poor vision in the nighttime. A person suffering from night blindness also has problem in moving from bright regions to dim regions rapidly, because their sight does not alter to the dim light like others' does.
If someone is suffering from nearsightedness and have not taken appropriate medication to treat this situation then it can result in night blindness after some time. If someone is suffering from myopia and also having night blindness, than situation will be worse as the pupil expand more at night time. If someone is taking medication for glaucoma treatment then it can also be responsible for causing night blindness.
There are two main types of night blindness:
Congenital stationary night blindness
This type of night blindness is mainly present from the birth and genetics is responsible for this position.
Progressive night blindness
This type of night blindness is causes because of old age and increased with growing age. This condition gets worse as age increases