Nyctalopia
People with night blindness have poor vision at night or in dimly lit environments. ‘Blindness’ does not mean that they can’t see at all – vision is only impaired by darkness.
What Is Night Blindness?
Night blindness, also known as nyctalopia, is a condition that makes it difficult or impossible to see in low light or darkness. It can occur when the eyes have trouble adjusting to changes in brightness or detecting light.
A person will mostly notably experience night blindness while driving because of the intermittent brightness of car headlights or roadside lighting. Transitioning from a bright outdoor environment into a dimly lit restaurant or shaded house, also presents visual restrictions for people people with this condition.
What Are The Symptoms?
Symptoms include:
- Difficulty adjusting to dim light
- Blurry or cloudy vision in low light
- Sensitivity to light
- Seeing glare or halos around lights
- Difficulty seeing distant objects in low light
- Inability to see stars in the night sky
- Total loss of vision when entering a dark room (lasting more than a few minutes)
- Trouble seeing objects or faces in low light conditions
What Causes Night Blindness?
Refractive errors
Nearsightedness (myopia) and astigmatism can cause night blindness because they affect how light focuses on the retina.
Vitamin A deficiency
A lack of vitamin A, which is essential for healthy eyes, can cause night blindness.
Eye diseases
Conditions like retinitis pigmentosa, which damages the retina’s cells, can cause night blindness.
Optic nerve issues
Problems with the optic nerve, which connects the eyes to the brain, can cause night blindness.
Cataracts
Cataracts can cause night blindness.
Glaucoma
Glaucoma can cause night blindness.
Laser vision correction surgery
Laser vision correction surgery can cause night blindness.
Genetic retinal diseases
Rare genetic retinal diseases like cone-rod dystrophy, retinitis pigmentosa, or congenital stationary night blindness (CSNB) can cause night blindness.
Medications
Certain drugs, like isotretinoin, can cause night blindness.
Birth defects
Birth defects, especially congenital stationary night blindness, can cause night blindness.
Older people are more likely to develop night blindness because they are more at risk of developing cataracts, than children or young adults.
How Is it Treated?
The treatment for night blindness depends on the underlying cause:
- Refractive errors: Corrective lenses, such as glasses or contacts, can help.
- Vitamin A deficiency: Increasing vitamin A intake can help improve vision. Vitamin A is found in foods like collard greens, spinach, milk, and eggs.
- Cataracts: Cataract surgery can replace a clouded lens with a clear, artificial one.
- Glaucoma: Medications can help manage glaucoma and slow the progression of night blindness.
- Retinal disease: Treatment depends on the type of disease and will require additional investigation by a retina specialist.
If night blindness symptoms are mild, it may not require treatment. Regular eye check-ups are important for monitoring and addressing the condition.