Night blindness

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Last reviewed: January 2019

Last updated: December 2017

Summary

Can be caused by many disease processes, both inherited and acquired. Differentials that may cause blurred vision made worse by low light levels (e.g., cataracts, myopia, glaucoma) need to be distinguished from true night blindness.

Most commonly reported by patients with inherited retinal or choroidal dystrophies; rarely associated with an underlying malignancy.

Slit-biomicroscopy and electroretinography are often essential in narrowing the differential diagnosis.

Vitamin A deficiency can cause night blindness and is often overlooked in patients with malabsorption and malnutrition.

Vitamin A may be used to treat both genetic and acquired night blindness.

Definition

Night blindness is the inability of the eye to adapt to reduced illumination, leading to a complaint of not being able to see at night or in dim light. No standard classification system exists for night blindness. The conditions within this monograph are divided into those with an underlying genetic cause and acquired conditions (i.e., occurring secondarily to an underlying systemic disease). The inherited conditions causing night blindness affect the structures within the retina or choroid, and are referred to as retinal or choroidal dystrophies. Cochrane Eyes and Vision Group: glossary It is important to establish the difference between true night blindness, which is when the patient experiences loss of vision in a dark environment, and blurred vision made worse by low light levels, which may occur if the patient has cataracts, myopia, or glaucoma.

History and exam

Key diagnostic factors

family history of vision loss
hx of retinitis pigmentosa
congenital stationary night blindness
past medical history of vitamin A deficiency or malignancy

Full details

Other diagnostic factors

decreased visual acuity in dim light
variable pupillary responses (depending on underlying cause)
retinal vascular attenuation
visual field loss
peripheral chorioretinal degeneration
history of drugs that interfere with vitamin A metabolism

Full details

Risk factors

retinitis pigmentosa
congenital stationary night blindness
vitamin A deficiency
cancer-associated retinopathy
melanoma-associated retinopathy
gyrate atrophy
choroideremia

Full details

Diagnostic investigations

1st investigations to order

electroretinography (ERG)
slit-biomicroscopy and indirect ophthalmoscopy

Full details

Investigations to consider

serum vitamin A level

Full details

Treatment algorithm

ACUTE

genetic night blindness

acquired night blindness

Contributors

Authors VIEW ALL 

Jonathan Smith, FRCOphth, MRCP

Consultant Ophthalmologist

Sunderland Eye Infirmary

Sunderland

UK

Disclosures

JS declares that he has received travel and meeting costs from Novartis and Bayer.

Wendy Adams, MRCP, FRCOphth

Consultant Ophthalmologist

Sunderland Eye Infirmary

Sunderland

UK

Disclosures

WA declares that she has no competing interests.

Acknowledgements

The authors would like to gratefully acknowledge the assistance of Ms Karen Bradshaw. KB declares that she has no competing interests.

Peer reviewers VIEW ALL 

Makoto Nakamura, MD

Associate Professor

Department of Ophthalmology

Nagoya University Graduate School of Medicine

Nagoya

Japan

Disclosures

MN declares that he has no competing interests.

Eric Amesbury, MD

Klara Spinks Fleming Fellow

Jules Stein Eye Institute

UCLA

Los Angeles

CA

Disclosures

EA declares that he has no competing interests.

Creig S. Hoyt, MD

Emeritus Professor and Chairman

Department of Ophthalmology

University of California

San Francisco

CA

Disclosures

CSH declares that he has no competing interests.

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