Slit-lamp exam
Slit-lamp exam
Visual field test
Visual field test
Cataract - close-up of the eye
Cataract - close-up of the eye

Vision abnormalities

Definition:
Blurred vision is the loss of visual acuity (sharpness of vision) resulting in a loss of ability to see small details. For the most severe form of visual loss, see also blindness. Blind spots (scotomas) are dark "holes" in the visual field in which nothing can be seen.

Alternative Names:
Vision Impairment; Diminished eyesight; Decreased vision; Impaired vision; Blurred vision

Considerations:

Loss of visual acuity, changes in vision, blurriness, or dimness of vision should always be urgently evaluated by a medical profesional. Changes may represent primary eye disease, aging, eye trauma, or a generalized (systemic) illness.

Whatever the cause, visual changes should never be ignored. Decreased vision is a significant threat to the quality of life. Professional help is always indicated, but which professional to see is often a question.

Here are some tips:

  • An optician dispenses glasses and does not diagnose eye problems.
  • An optometrist is a state-licensed health care professional who performs eye examinations and may diagnose and treat eye problems. They prescribe eyeglasses, contact lenses, low vision aids, and vision therapy. In some states they are licensed to prescribe medicines in the form of eye drops to treat eye diseases.
  • An ophthalmologist is a physician -- a medical doctor (MD) or doctor of osteopathy (DO) -- who specializes in the diagnosis and medical and surgical treatment of diseases of the eye and systemic diseases which involve the eyes. They may also provide routine vision care services, such as prescribing eyeglasses and contact lenses.
  • Sometimes an eye problem is part of a general health problem. In these situations, your primary care provider should also be involved.
Common Causes:
  • presbyopia, the difficulty focusing at near which is a normal part of aging
  • cataracts (common in the elderly)
  • glaucoma
  • complications of diabetes (the most common cause of blindness in the United States)
  • macular degeneration is a common cause of loss of central vision in the elderly
  • eye infection, inflammation, or injury
    • infections of the cornea that cause scarring, distortion, or perforation
      • Trachoma, an infection common in many undeveloped areas in the world, is among the most frequent causes of blindness in the world
    • infections of the retina with viruses, fungi, or parasites -- seen with increasing frequency in AIDS patents in the past, but now much less common with modern drug therapy
  • floaters (tiny particles) drifting across the eye
    • usually are harmless and require no treatment
  • fatigue and prolonged exposure to the outdoors (temporary and reversible blurring of vision)
  • drugs (blurring, spots, and halos)
    • anticholinergics
    • antihistamines
    • clomiphene
    • chloroquine
    • cycloplegic
    • digitalis derivatives (temporary)
    • ethambutol
    • guanethidine
    • indomethacin
    • methanol toxicity (permanent)
    • phenothiazines
    • phenylbutazone
    • quinine sulfate
    • reserpine
    • thiazide diuretics
  • migraineheadaches (spots of light, halos, or zigzag patterns are common preliminary symptoms)
    • ophthalmic migraine may occur where only the visual symptoms occur, without headache
  • congenital disorders
  • heritable disorders
Home Care:
Safety measures may be necessary to help a person with visual loss. For example, it may be helpful to increase the amount of light in a room or arrange a home to remove hazards. For patients with permanently decreased vision, assistance from a specialist at a low vision clinic may offer guidance.
Call your health care provider if:
  • any sudden visual changes occur
  • there is partial or complete blindness in one or both eyes
  • there is trouble seeing objects to either side (decreased peripheral vision), or if halos are seen around lights
  • blind spots or areas of distorted vision (metamorphopsia) suddenly appear
  • a person has unusual difficulty seeing at night
Usually, the question is not whether to see a health professional, but which one to see. Finding the appropriate health professional on the first attempt will save time and money. These examples may help:
  • For decreased vision in a child, see an optometrist or an ophthalmologist.
  • For sudden blindness in one eye or both eyes, see an ophthalmologist immediately.
  • For eye pain or halos around lights, see an ophthalmologist.
  • For gradual loss of visual acuity in an adult who wears glasses, see an ophthalmologist or optometrist.
  • For gradual blurring of vision in an older person, not helped by moving closer or farther away, see an ophthalmologist.
  • For a middle aged person who sees far objects best and near objects not very well, see an optometrist or ophthalmologist.
  • For visual changes that occur while taking medication, see the prescribing doctor.
  • For decreased vision in one eye with a "shadow" in the visual field, see an ophthalmologist immediately.
What to expect at your health care provider's office:
The medical history will be obtained and a physical examination performed.

Medical history questions documenting the vision abnormalities in detail may include:
  • Time pattern
    • When did this begin?
    • Did it occur suddenly or gradually?
    • Does it occur only occasionally? How often?
    • How long does it last?
    • When does it occur? Evening? Morning?
  • Quality
    • Is the vision blurred or is there double vision?
    • Are there blind spots?
    • Are there areas that look black and missing?
    • Is side vision missing?
    • Are halos (circles of light) seen around shiny objects or lights?
    • Are flashing lights or zigzag lines seen?
    • Is extreme sensitivity to light present?
    • Do stationary things seem to be moving?
    • Are colors missing?
    • Is it difficult to differentiate colors?
    • Is there pain?
    • Is there drainage from the eye(s)?
    • Are the eyes crossed?
    • Does one of the eyes "drift"? Do both?
  • Location
    • Is the problem in one eye or both eyes?
  • Aggravating factors
    • Have you had any of the following in the last few weeks to months?
  • Relieving factors
    • Is your vision better after you rest?
    • Is it better with corrective lenses?
  • Other
  • Additional important information
    • What medications are being taken?
    • Is there a family history of diabetes?
    • Have you had a previous head injury?
    • Do you have any allergies?
    • Has there been a loss of eyelashes?
    • Is there a family history of eye disease?
The physical examination will include an eye examination. The health care provider will check vision, eye movements, pupils, back of the eye, and eye pressure when indicated. An overall medical evaluation will be done if indicated.

Diagnostic tests that may be performed include: Intervention:
Surgery will be recommended for some conditions (such as cataracts or muscle problems). Diabetics must control their blood-sugar level. Other treatments depend on the cause.

After seeing your health care provider:
If a diagnosis was made by your health care provider related to vision abnormalities, you may want to note that diagnosis in your personal medical record.

Review Date: 2/17/2002
Reviewed By: Edward B. Feinberg, M.D., M.P.H., Department of Ophthalmology, Boston University School of Medicine, Boston, MA. Review provided by VeriMed Healthcare Network.
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