Vision - night blindness

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Alternative names
Nyctanopia; Nyctalopia; Night blindness

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

Considerations
Night blindness can cause problems with driving in the evening or at night. Consult your health care provider or eye doctor.

Common Causes

• cataracts (usually in older persons)
  
• retinitis pigmentosa (may be the first sign of the disease in a young person)
  
• poor adaptation to darkness (not caused by any disease)
  o often accompanied by myopia (nearsightedness)
  
• vitamin A deficiency
  
• certain drugs can cause night blindness
  
• birth defect

Home Care
Necessary safety precautions should be taken. Avoid driving a car at night. Vitamin A supplements may prove helpful.

Call your health care provider if

• there is severe, persistent, and significantly impaired lifestyle
  
• if the symptoms are persistent

What to expect at your health care provider’s office

The goal of the medical exam will be to determine if the problem is due to a correctable cause, such as need for new glasses or cataract removal or whether the problem is something more severe.

The medical history will be obtained and a physical examination performed.

Medical history questions documenting night blindness in detail may include:

• time pattern
  o When did this begin?
  o Did it occur suddenly or gradually?
  o Is the night blindness constant or occasional?
  
• quality
  o How severe is the night blindness?
  o Is vision impaired in dimly-lit rooms?
  
• aggravating factors
  o Is myopia (nearsightedness) also a problem?
  o Do you have a fear of the dark?
  o Are you under any unusual stress or anxiety?
  
• relieving factors
  o Are corrective lenses needed?
  o Does use of corrective lenses improve night vision?
  
• other
  o What other symptoms are present?
  o Have you noticed changes in daytime vision?
  o Do you have light sensitivity (photophobia)?
  o Do you have a difficulty seeing colors?
  o Do you have cataracts?
  
• additional important information
  o What medications are being used?
  o Do you use “street drugs”?
  o Have you had any recent head or eye injuries?
  o Do you have a family history of diabetes?
  o Do you have a birth defect?
  o Do you have a healthy diet?

The physical examination may include an eye examination. A slit lamp examination may be performed as a diagnostic test.

Cataract removal should be discussed as an option when appropriate.

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