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Definition
Night blindness means having difficulty seeing in the dark or in low light. One of the most common issues with night blindness is difficulty driving in the evening or at night.
The Retina of the Eye
2008 Nucleus Medical Art, Inc.
Causes
There are several common causes of night blindness:
- Lack of vitamin A, which can cause a disorder of the retina and make the eyes very dry
- Cataracts , which are cloudy areas in the lens of the eye
- Some forms of retinal degeneration, such as retinitis pigmentosa
- Trouble adjusting from low levels of light to high levels of light
- Certain medications
- Birth defects
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition. Some risk factors for night blindness include:
- Age: elderly people are more likely to have cataracts
- Genetics: retinitis pigmentosa
- Diet: people who dont eat enough sources of vitamin A, such as green leafy vegetables, eggs, and whole milk products(vitamin A deficiency is very rare in the US, but still occurs in certain less developed countries)
- Disorders that affect the ability of the body to absorb vitamin A:
- Liver disorders
- Surgery on the pancreas or liver
- Intestinal conditions
- Bowel surgery for obesity
Symptoms
Symptoms are difficulty or inability to see in low light or darkness. While driving, this may also occur a few seconds after the bright headlights of an oncoming car have passed.
Diagnosis A doctor will give you a medical examination to determine the cause of your night blindness. Some of the things a doctor might do are: Ask detailed questions about your experience of night blindnessTest the levels of vitamin A in your bloodGive you an eye exam Ask about your medical history, including: DietMedicationsUse of corrective lensesFamily history of diabetes Treatment Depending on the reason for your night blindness, treatment will address the specific cause. Treatments generally include: Taking vitamin A supplementsHaving cataracts removedLow-vision aids PreventionIf you experience night blindness, it is important to take safety precautions, like not driving in the evening or at night. Also, eating a diet with adequate amounts of vitamin A may help prevent night blindness. RESOURCES: National Eye InstituteUS National Institutes of Healthhttp://www.nei.nih.gov Retina Internationalhttp://www.retina-international.org CANADIAN RESOURCES: Canadian Ophthalmological Societyhttp://www.eyesite.ca University of Ottawa Eye Institutehttp://www.eyeinstitute.net/main.html References: Beers, MH, Fletcher AJ, Jones TV, et al. The Merck Manual of Medical Information: Second Home Edition. 2003. Merck Research Laboratories: Whitehouse Station, NJ.
Herse P: Retinitis pigmentosa: visual function and multidisciplinary management. Clin Exp Iptom . 2005; 88:5: 335-350. Visionnight blindness. Medline Plus. US National Library of Medicine and the National Institutes of Health website. Available at http://www.nlm.nih.gov/medlineplus/ency/article/003039.htm . Accessed on August 21, 2005. Last reviewed January 2008 by Christopher Cheyer, MDPlease be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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