The main causes of nyctalopia include:
Nearsightedness: Also known as myopia, nearsightedness is a condition that causes bullered vision in distant objects. This is because the eyeball is too long or too curved therefore the light entering the pupil is not focused correctly causing a refractive error. This refractive error does not allow the rods to properly recept the light.
Glaucoma: Is a condition that damages your eye's optic nerve. It is mostly due to the build up of pressure in the eye. This increase in pressure (called intraocular pressure) damages the nerve that transsmits images to the brain. If the high pressure persists, glacoma may cause permanent loss of vision because the optic nerve can no longer send impulse to the brain not allowing you to see the image.
Glaucoma medications: Specific glaucoma medications can narrow your pupil allowing less light to go through your eyes. This causes not enough light to be refracted resulting in nyctalopia.
Cataracts: Cataracts are build-ups of protein in the lens of your eye making it cloudy.This results in blurried vision. There are various types of cataracts: age-related, congenital (injury, infection or poor development in the womb), secondary (as a result of another medical condition) or traumatic.
Diabetes: Diabetes is a disease that unables you to use insulin (a hormone that allows cells to turn glucose into energy) in the correct way. The high blood sugar levels in your body can damage nerves like the optic nerve causing night blindness.
Retnitis pigmentosa: This is an inherited vision disorder that causes the progressive degeneration of the retina. This causes a slow loss of vision (primarily the loss of the peripheral/side vision and lastly blindness). The rods are located in the outer region of the retina therefore they degenerate first causing nyctalopia.
Vitamin A deficiency: Vitamin A is essential for proper vision. Wihtout it, it may result in poor vision at night or in dim light (nyctalopia), severe eye dryneess and keratomalacia (cloudiness in cornea).
What are the causes of nyctalopia?