Print-Friendly
Bookmarks
bookmarks-menu

Vision - night blindness

Nyctanopia; Nyctalopia; Night blindness

Night blindness is poor vision at night or in dim light.

Considerations

Night blindness may cause problems with driving at night. People with night blindness often have trouble seeing stars on a clear night or walking through a dark room, such as a movie theater.

These problems are often worse just after a person is in a brightly lit environment. Milder cases may just have a harder time adapting to darkness.

Causes

The causes of night blindness fall into 2 categories: treatable and nontreatable.

Treatable causes:

Nontreatable causes:

  • Birth defects, particularly congenital stationary night blindness
  • Retinitis pigmentosa

Home Care

Take safety measures to prevent accidents in areas of low light. Avoid driving a car at night, unless you get your eye doctor's approval.

Vitamin A supplements may be helpful if you have a vitamin A deficiency. Ask your health care provider how much you should take, because it is possible to take too much.

When to Contact a Medical Professional

It is important to have a complete eye exam to determine the cause, which may be treatable. Call your eye doctor if symptoms of night blindness persist or significantly affect your life.

What to Expect at Your Office Visit

Your provider will examine you and your eyes. The goal of the medical exam is to determine if the problem can be corrected (for example, with new glasses or cataract removal), or if the problem is due to something that is not treatable.

The provider may ask you questions, including:

  • How severe is the night blindness?
  • When did your symptoms start?
  • Did it occur suddenly or gradually?
  • Does it happen all the time?
  • Does using corrective lenses improve night vision?
  • Have you ever had eye surgery?
  • What medicines do you use?
  • How is your diet?
  • Have you recently injured your eyes or head?
  • Do you have a family history of diabetes?
  • Do you have other vision changes?
  • What other symptoms do you have?
  • Do you have unusual stress, anxiety, or a fear of the dark?

The eye exam will include:

Other tests may be done:

References

Cao D. Color vision and night vision. In: Schachat AP, Sadda SVR, Hinton DR, Wilkinson CP, Wiedemann P, eds. Ryan's Retina. 6th ed. Philadelphia, PA: Elsevier; 2018:chap 12.

Cukras CA, Zein WM, Caruso RC, Sieving PA. Progressive and "stationary" inherited retinal degenerations. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 6.14.

Duncan JL, Pierce EA, Laster AM, et al. Inherited retinal degenerations: current landscape and knowledge gaps. Transl Vis Sci Technol. 2018;7(4):6. PMID: 30034950 pubmed.ncbi.nlm.nih.gov/30034950/.

Thurtell MJ, Tomsak RL. Visual loss. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 16.

BACK TO TOP

    • External and internal eye anatomy

      External and internal eye anatomy - illustration

      The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size. The lens then changes shape to allow the accurate focusing of light on the retina. Light excites photoreceptors that eventually, through a chemical process, transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.

      External and internal eye anatomy

      illustration

      • External and internal eye anatomy

        External and internal eye anatomy - illustration

        The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size. The lens then changes shape to allow the accurate focusing of light on the retina. Light excites photoreceptors that eventually, through a chemical process, transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.

        External and internal eye anatomy

        illustration

       

      Review Date: 8/18/2020

      Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

      The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
      adam.com

       
       
       

       

       

      A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.
      Content is best viewed in IE9 or above, Firefox and Google Chrome browser.