Low Vision

Overview

Low vision is a level of vision loss that significantly interferes with everyday activities and cannot be fully corrected with standard glasses, contact lenses, medication, or surgery. People with low vision still have some usable sight, which sets it apart from total blindness, but tasks such as reading, recognizing faces, driving, or moving around safely become difficult.

Low vision can involve reduced sharpness of vision, loss of central or side vision, difficulty in low light, or problems with glare and contrast. It is most common in older adults because the leading causes are age-related eye diseases, but it can affect people of any age. Although the underlying loss often cannot be reversed, many people benefit greatly from low-vision aids, training, and rehabilitation that help them make the most of the vision they have and stay independent.

Symptoms

Low vision shows up as difficulty with everyday visual tasks despite wearing the best possible correction. Common experiences include:

• Trouble reading regular print, even with glasses
• Difficulty recognizing faces
• Problems seeing in dim light or adjusting between light and dark
• Blurred or hazy central vision
• Loss of side (peripheral) vision, causing bumping into objects
• Sensitivity to glare
• Difficulty judging steps, curbs, or distances

The exact pattern depends on the underlying eye condition. Any new or worsening vision loss should be evaluated promptly, because some causes are treatable if caught early.

Causes

Low vision results from eye conditions that damage parts of the visual system. The most common causes include:

• Age-related macular degeneration: loss of central vision from damage to the macula.
• Glaucoma: gradual loss of side vision from optic nerve damage.
• Diabetic retinopathy: damage to retinal blood vessels from diabetes.
• Cataracts: clouding of the lens, often treatable with surgery.
• Inherited retinal diseases: such as retinitis pigmentosa.
• Eye injury or stroke: affecting the eye or the visual pathways in the brain.

Often the loss reflects an advanced or untreatable stage of these conditions, though treating the underlying disease can sometimes slow further decline.

Risk Factors

Risk factors for low vision largely mirror those for the eye diseases that cause it, including:

• Older age
• Diabetes
• High blood pressure
• Family history of eye disease such as macular degeneration or glaucoma
• Smoking
• Previous serious eye injury or eye surgery
• Prematurity, for some childhood causes

Diagnosis

Diagnosing low vision involves confirming the level of vision loss, identifying its cause, and assessing how it affects daily life. This includes:

• Comprehensive eye examination: measuring visual sharpness, field of vision, and eye health.
• Visual field testing: to map any loss of central or peripheral vision.
• Retinal imaging: such as OCT and photographs to assess the macula, optic nerve, and retina.
• Low-vision evaluation: a specialized assessment of functional vision and the tasks a person needs help with.

This evaluation guides both treatment of the underlying condition and the choice of aids and rehabilitation.

Treatment

While the underlying loss often cannot be reversed, a great deal can be done to help people use their remaining vision and stay independent. Approaches include:

• Treating the underlying disease: for example, injections for macular degeneration, pressure-lowering treatment for glaucoma, or cataract surgery, which may improve or stabilize vision.
• Low-vision aids: magnifiers, telescopic lenses, electronic readers, and high-contrast tools.
• Technology: screen-reading software, text-to-speech, and high-magnification settings on phones and computers.
• Vision rehabilitation: training in new techniques for reading, cooking, and getting around safely.
• Environmental changes: better lighting, reduced glare, and high-contrast labeling at home.

A low-vision specialist can tailor these tools to a person's specific needs and goals.

Prevention

Many causes of low vision can be slowed or prevented with early detection and good eye and general health. Helpful steps include:

• Having regular comprehensive eye examinations, especially with age or diabetes
• Managing diabetes, blood pressure, and cholesterol
• Not smoking
• Protecting eyes from injury and ultraviolet light
• Promptly treating eye conditions such as glaucoma and diabetic retinopathy before they advance
• Reporting new vision changes early

When to See a Doctor

See an eye doctor if you notice that everyday tasks are becoming harder despite your usual glasses, or if you have gradual changes in your central or side vision. Early evaluation can identify treatable causes and connect you with low-vision services.

Seek urgent or emergency eye care for sudden vision loss, a curtain or shadow across your vision, sudden flashes with many new floaters, or sudden painless loss of vision in one eye, as these may signal a treatable emergency such as a retinal detachment or eye stroke.

Related Topics

Frequently Asked Questions

References

1. National Eye Institute (NEI). Low Vision.
2. American Academy of Ophthalmology. Low Vision.
3. MedlinePlus, U.S. National Library of Medicine. Vision impairment and blindness.
4. Centers for Disease Control and Prevention (CDC). Vision Health Initiative.