WHAT CAUSES NYCTALOPIA (NIGHT BLINDNESS)?

Many people believe it’s typically dark at night, making it understandable that they don’t see well in those conditions (night blindness). This leads us to the inquiry: Can we see at night?

CAN WE SEE AT NIGHT?

The response is YES!
For effective vision in low light or nighttime, the eyes must adjust correctly. The initial adjustment involves the pupils. In dark or dim environments, the pupils dilate, allowing more light to enter the eye. This light then passes through several critical stages to reach the retina.

The retina is the light-sensitive layer located at the back of the eye. It contains photoreceptor cells called rods and cones. Cone cells are responsible for color vision, helping us see during daylight or in bright surroundings. Rod cells provide vision in black and white, enabling us to see in the dark. Therefore, night vision is primarily black and white.

REASONS FOR NYCTALOPIA (NIGHT BLINDNESS)

A decrease in night vision or complete night blindness can occur when the rods malfunction, usually due to an eye injury, condition, or disease. Poor night vision may be a temporary side effect of another health issue or a natural part of aging. It can also occur with conditions affecting how light enters the eyes. The transparent tissues at the front of the eyes are essential for light passage; if they are not transparent or don’t allow light to pass through them correctly, less light reaches the retinas, causing difficulty seeing in low light.

EYE CONDITIONS THAT CAN LEAD TO NIGHT BLINDNESS

Night blindness is primarily a sign of an underlying eye condition related to retinal health, but it can also arise from severe or worsening nearsightedness or vitamin A deficiency.

I: Nearsightedness (myopia) occurs when distant objects appear unclear. If you struggle to see clearly in daylight or need a new prescription, your low-light vision will also share that blurriness.

II: A lack of vitamin A is among the most prevalent causes of night blindness. An inadequate level of vitamin A disrupts the production of rhodopsin, the vital pigment needed for night vision. Night blindness is often an early indication of vitamin A deficiency.

III: Congenital issues affecting the eye’s pigmentation can impair night vision or lead to total night blindness. Usher Syndrome is a common congenital disorder linked to night blindness.

IV: Cataracts tend to develop with age as the proteins in the eye lens begin to crystallize and harden. They impair visual clarity, resulting in blurriness, glare, and halos around bright lights. Reduced night vision and increased challenges while driving at night generally indicate the onset of cataracts.

V: Retinitis pigmentosa is a retinal condition characterized by dark pigment accumulation in the retina, causing rod cells to deteriorate. This condition hampers low-light vision and may lead to tunnel vision and eventually complete vision loss.

VI: Glaucoma occurs when eye pressure increases, leading to progressive damage to the optic nerve. This condition affects vision both during the day and at night, first impacting peripheral vision and then central vision.

VII: Refractive surgeries can alter the cornea shape to enhance vision and affect how light enters the eye. This change may result in glare and halos around street and car lights, impacting nighttime vision

VIII: Macular degeneration is a retinal illness affecting retinal health, causing blind spots and image distortions in daytime and nighttime vision.

IX: Diabetes can alter the shape of the eye lenses and damage the eye’s blood vessels, resulting in diabetic retinopathy. One of the initial symptoms of diabetic retinopathy is poor night vision.

We will pause here, and in our next post, we will explore the signs, treatments, and prevention of night blindness.

Pritoize your eyes with us at TREE TOP VISION EYE CENTER (TREVEC), the best eye clinic in Utako, Abuja.

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