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Key Causes and Symptoms of Night Blindness

Nyctalopia (night blindness) might make it difficult for the eyes to see in dark places and adjust to sudden changes between bright light and darkness. Night blindness is a symptom of other conditions and is not a disease alone. A wide range of conditions may affect different parts of the eyes and trigger nyctalopia. However, most of the causes are treatable. Below are the common symptoms and causes to be aware of.

Key Causes and Symptoms of Night Blindness

What does night blindness look like?
While night blindness is a symptom of other conditions, many wonder what it looks or feels like. This curiosity could help one better understand it and seek appropriate healthcare.

There are two primary ways that night blindness can occur:

  • Lack of light making it to the retinas:  In this scenario, the objects one sees are darker, harder to focus, and blurry. The complication occurs because of issues affecting various structures in the eyes that should typically be clear when the irises do not widen as they should in dim light or because of health conditions that affect the retinas.
  • Retinal cells that do not react to light in the right manner:  The retinas are light sensors with cells that detect incoming light and convert it into electrical signals, then transmit it to the brain. However, some conditions may lead to burning out the retinas, which could mean the cells react poorly to incoming light or do not respond.

Symptoms

  • Trouble moving around the house at night, even with small night lights
  • Driving difficulty at night
  • Difficulty recognizing people’s faces in darkened settings, like movie theaters
  • Taking a long time to adjust in a darkened room

Causes
Various conditions might lead to night blindness. A few common causes include:

Cataracts
The eye’s lens is typically clear and acts like a camera lens. It focuses as it passes to the back of the eye. However, as a person ages, the proteins in the lens behind it break down, making it less flexible and more tedious to focus on nearby objects. With time, this lens turns cloudy, and one may see objects that appear blurry at all distances and even have trouble seeing at night or in dim light. This condition is known as a cataract.

Nearsightedness
Individuals can see because the front portion of the eye bends light and focuses it on the retina. This is situated inside the back surface of the eye. However, nearsightedness might affect one when there is a mismatch between the eye’s focusing power and length. The light rays are focused in front of the retina rather than directly on it. As a result, what one sees is blurry, with other symptoms including night blindness.

Vitamin A deficiency
Vitamin A plays a vital role in various systems of the body, including to maintain healthy vision. The body cannot make vitamin A on its own, so one must acquire it through the food they eat. So, if one does not get sufficient vitamin A, they may experience a deficiency.
Furthermore, a poor meal regime that lacks vitamin A or various disorders may result in the lack of specific pigments for the retinas to work correctly, leading to symptoms like night blindness. The eyes also require vitamin A to produce moisture to keep the corneas well lubricated. Its lack thereof may dry up the corneas, cause them to get damaged, and lead to blindness.

Glaucoma
Glaucoma is a general term that describes a group of eye disorders that damage the optic nerve. It is a common form of optic nerve damage leading to vision loss. Those with glaucoma have developed optic nerve damage from fluid buildup in the eye’s front part. The additional fluid applies pressure on the eye and gradually damages the optic nerve. This is known as intraocular pressure (IOP) or eye pressure. However, the condition might occur in people with regular eye pressure. If untreated, glaucoma or poorly managed glaucoma may result in permanent and irreversible vision loss and blindness.

Retinitis pigmentosa (RP)
Retinitis pigmentosa (RP) is a term for a group of eye diseases that may lead to the loss of sight or symptoms like night blindness. A doctor may find these diseases have specific changes in common when they look at the retina, such as a bundle of tissue at the back of the eye.
An individual with RP will experience a lack of function of cells in the retina called photoreceptors. The retina has two types of cells that gather light – rods and cones. The first are located around the outer ring of the retina and are active in dim light. Most types of this rare disease affect the rods first, causing one’s night vision and peripheral vision to diminish. The cones are usually in the center of your retina, enabling one to see color and fine detail, which is gradually lost.

Keratoconus
The cornea is the clear outer lens of the eye with a dome shape. However, if one develops conditions like keratoconus, the structure might get compromised and turn weak. As a result, the cornea may not hold its round shape and bulge outward. Changes to the cornea might make it challenging for the eye to focus without appropriate management methods, such as wearing glasses or contact lenses. One of the most common symptoms of keratoconus is night blindness. Other signs may include blurry vision, triple ghost images, and light streaks.

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