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The Effects of Alcohol on Vision

Many people drink alcohol moderately within government guidelines on acceptable amounts. However, alcohol is a depressant that acts on the brain and central nervous system, causing a range of side effects including impaired vision.



The effects on vision can become apparent from Blood Alcohol Concentration (BAC) levels of only 0.03 percent. The effects become more pronounced as levels of intoxication increase, while prolonged drinking can lead to lasting damage. This is one reason why it is irresponsible to drive under the influence of alcohol.

  1. Visual Acuity

    • Visual acuity is a measure of the sharpness or clearness of vision. At BAC levels of only 0.03 percent, sharpness is already affected. According to the University of Texas at San Antonio Police Department, visual acuity can be reduced by up to 32 percent through consumption of alcohol.

    Depth Perception

    • Alcohol affects the muscles that control eye movements, making it increasingly difficult for both eyes to focus on the same object. This causes problems with depth perception -- the ability to judge distance and depth.

    Peripheral Vision

    • Peripheral vision is that portion of sight which lies outside the normal central gaze. Alcohol adversely affects levels of peripheral vision, causing tunnel vision. This means that it is increasingly difficult to see objects to the side of the normal field of vision.

    Resistence to Glare

    • Alcohol hampers the reaction times of pupils as light levels change suddenly. This means the eyes are unable to adapt quickly enough to compensate for differing light levels and so impairing visual clarity. For example, the oncoming headlights of a car will dazzle a driver under the influence of alcohol far more than it will a sober driver.

    Optic Neuropathy

    • Optic neuropathy is the term for damage to the optic nerve that connects the retina to the brain. In people who either smoke or drink excessively, this is called tobacco-alcohol amblyopia and can result in a range of visual impairments, including decreased peripheral vision, lower sensitivity to contrast and a more general loss of sight. Improved vision can be achieved by removing alcohol from the diet, but full recovery is rare.

    Liver Disease

    • Long-term alcohol abuse may affect liver function. In addition to breaking down alcohol in the body, the liver is responsible for converting beta-carotene, present in many foodstuffs, into vitamin A, which is essential for good visual health.

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