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Night Blindness

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Night blindness also known as nyctalopia is one type of vision problem wherein the individual’s vision is diminished during night time or in low light. It’s actually a symptom that could arise from an underlying complication in the eyes or a primary health disorder.


Symptoms associated with night blindness

The vision of the individual during day time differs a lot from that at night. Due to reduced vision at night or in dimness, the person faces problem in travelling in dark or driving during night. For example, there could be a momentary blinding effect if a vehicle coming from ahead flashes light, followed by a short episode of darkness or you can simply find it a big task to navigate as you can sense blurriness and unclear things before you.


Causes of night blindness

The rod cells (photoreceptive) of the retina are responsible for vision in low light. Night blindness occurs when these cells degenerate due to a medical condition, deficiency or trauma.

Common causes for night blindness are: 

  • Vitamin A deficiency
  • Untreated short sightedness
  • Cataract
  • Glaucoma and side effect of glaucoma medicines


Congenital causes of night blindness are:

Congenital stationary night blindness (choroideremia) is a genetic condition that affects only males i.e. they suffer from night blindness. Women do not show the symptoms but carry the defective gene.

Secondly, retinitis pigmentosa is also a congenital defect that expresses night blindness. It can be detected during childhood itself. Usher syndrome is another genetic condition where individuals have night blindness accompanied by hearing inability and retinitis pigmentosa.

Old people are more likely to suffer from night blindness. Other risk factors include diabetes and problems in liver, pancreas and intestine.


Diagnosis of night blindness

Your doctor will focus on finding out the cause of night blindness. For this you need to present detailed history of your medical condition, surgery, eye health/complications and the medicines you are taking.

Your diet will be evaluated thoroughly to figure out deficiency in vitamin A. Blood test for vitamin A would be conducted to confirm deficiency.

Your doctor will analyse the symptoms and conduct a comprehensive eye exam which includes visual acuity tests, slit lamp examination, refraction test and retinal evaluation.

Electroretinogram and visual field testing might further be conducted depending upon the results of the preliminary tests.


Treatment of night blindness

Night blindness can be corrected or improved once the underlying disorder in the eye is treated. Surgery is usually performed on cataract and glaucoma. Vitamin A supplements might be prescribed to you along with a nutritional plan for improving your vision at night.

Similarly, corrective eye glasses or lens would be given to control myopia. If medicines have led to night blindness, then they might be stopped or the dosing might be altered.

It is important to note that congenital night blindness cannot be treated. Such people or children undergo special sessions which help them to cope with the problem in order to ensure physical safety.


Safety guidelines for night blindness

Your doctor would certainly advise you to avoid driving at night and you must follow this. Night shift drivers must get their eyes screened to avert dangers while driving in low light.

If you are not confident of stepping out alone due to reduced visibility then do not hesitate to ask for a company.

Written by: healthplus24.com team
Date last updated: August 20, 2014

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