Night Blindness

Raheleh Najafi

Night blindness (formally known as nyctalopia) is the inability to see well at night or in dim lighting. While this condition is not considered a disease itself, it often acts as a symptom of underlying issues (usually to do with the retina) and can be an indication for many to get an updated eye exam.

Now you might be wondering what night blindness actually is. Throughout your lifetime your eye is forced to adapt constantly. Every time you move from one room to another or transition from inside a building to outside, your eye has to adapt to this change in light. Night blindness is what happens when your eye loses its ability to adapt on its own, resulting in blurry and contorted vision.

Figure 1: https://www.shutterstock.com/video/clip-10618865-blurred-background-dotonbori-canalosakajapan

It’s important to note that there’s no need for alarm if you suspect you have night blindness. Contrary to its name, night blindness only adversely affects a person’s temporary ability to see in different lighting and does not actually cause complete blindness. It simply takes longer for a person’s eyes to adapt to different light settings when they suffer from night blindness.

Figure 2: https://www.researchgate.net/figure/The-effect-of-night-blindness_fig1_283882292

The American Academy of Ophthalmology has developed a guide of questions for those wondering if they have night blindness. If any of the following situations apply to you, it’s critical to have your eyesight checked and bring up these concerns with your optometrist:

1. Is moving around the house in dim lighting a challenge?

2. Is driving at night increasingly difficult? Is it tricky to recognize faces in dim light?

3. Does it take an abnormally long time to adjust to a light room after being in the dark?

4. Does it take a long time to see in a darkened room after being in the light?

Possible symptoms of night blindness may include headaches, severe eye pain, nausea, vomiting, cloudy vision, light sensitivity and difficulty when seeing distance. The combination of symptoms experienced with night blindness can often reveal the underlying illness of the eye.

The most common underlying conditions consist of:

• Glaucoma, this is where damage has been made to the optic nerve which connects the eye to the brain, causing an abundance of pressure in the eye and impairing vision.

• Cataracts, which occur when the lens of the eye becomes cloudy, often happens due to aging when proteins in the lens break down.

• Nearsightedness, also known as myopia, is the inability to see objects in the distance accurately. This occurs when the eye grows too long and no longer focuses light correctly.

• Lastly, a vitamin A or retinol deficiency can cause night blindness as it’s an essential nutrient for vision. This is because it makes up a protein that absorbs light in the retina and supports eye functioning.

Figure 3: https://www.naturaleyecare.com/blog/poor-night-vision-night-blind/

Depending on the reason behind the night blindness occurrence, treatment varies. Some patients may be required to wear specific types of glasses or contact lenses, to correct vision and take preventive caution against ultraviolet light that can worsen the condition.

Other patients, specifically those suffering from night blindness rooted in a lack of vitamin A, treatment may involve adding more vitamins to one’s diet through certain foods or prescribed pills.

Finally, in extremely severe cases, eye surgery may be a recommended option. Most commonly LASIK surgery is used to change the shape of the cornea. While LASIK surgery isn’t a direct treatment for night blindness itself, if the underlying problem of the eye is nearsightedness LASIK surgery is used to correct the major disease of the eye which results in all associated symptoms also being reduced, including night blindness. An eye that has a cataract would need to be removed of the crystalline lens completely and replaced with an intraocular lens and a patient with glaucoma would undergo treatment involving the release of pressure in the eye.

---

References

Boyd, K. (2017, March 18). Shedding light on night blindness. American Academy of

Ophthalmology. Retrieved from https://www.aao.org/eye-health/news/shedding-light-on-night-blindness.

Disha_Eye_Hospital. (2019, August 7). Everything that you need to know about night

blindness: Causes, symptoms and diagnosis. Disha Eye Care. Retrieved from https://www.dishaeye.org/blog/everything-need-know-night-blindness-causes-symptoms-diagnosis/.

Night vision. Vision Eye Institute. (2021, June 15). Retrieved n.d., from

https://visioneyeinstitute.com.au/eyematters/night-vision/.