Shining light on night blindness

What are the dangers for those experiencing night blindness?

Night blindness is especially problematic and dangerous when driving. Your eyes cannot adjust between darkness and the headlights of oncoming vehicles, other cars may appear out of focus, and your depth perception becomes impaired, which makes it difficult to judge distances.

Night blindness also may affect your sight at home by making it hard for your vision to quickly adjust to a dark room after turning off the lights. “This can cause people to bump into furniture or trip and suffer an injury,” says Dr. Isabel Deakins, an optometrist with Harvard-affiliated Massachusetts Eye and Ear.

What happens in the eye to create night blindness?

The ability to see in low-light conditions involves two structures in the eye: the retina and the iris.

The retina, located in the back of the eye, contains two types of light-detecting cells called cones and rods. The cones handle color vision and fine details while the rods manage vision in dim light.

The iris is the colored part of your eye. It contains สมัครสมาชิก UFABET วันนี้ รับเครดิตฟรีทุกวัน muscles that widen or narrow the opening of your pupil to adjust how much light can enter your eyes.

If your irises don’t properly react, the pupils can dilate and let in too much light, which causes light sensitivity and makes it hard to see in bright light. Or your pupils may remain too small and not allow in enough light, making it tough to see in low light.

What causes night blindness?

Night blindness is not a disease but a symptom of other conditions. “It’s like having a bruise on your body. Something else causes it,” says Dr. Deakins.

Several conditions can cause night blindness. For instance, medications, such as antidepressants, antihistamines, and antipsychotics, can affect pupil size and how much light enters the eye.

Eye conditions that can cause night blindness include:

• glaucoma, a disease that damages the eye’s optic nerves and blood vessels
• cataracts, cloudy areas in the lens that distort or block the passage of light through the lens
• dry eye syndrome.