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Causes of Low Vision - Types of Eye Conditions and Diseases

The following causes of vision loss are defined in general terms. The characteristics described below will vary based on the individual.

Albinism

Lack of pigment either in just the eyes or in the eyes, skin, and hair. Patients have decreased visual acuity (due to macular hypoplasia), nystagmus, and are typically photophobic. Patients often hold reading material close to their eyes.

Cataracts

Opacification of the intraocular lens. Patients have problems with glare, blurred vision, poor contrast, and color perception. Cataracts can often be removed, and an implant put in place to help improve or restore vision. If a cataract is removed with no implant, the patient is aphakic and will generally require strong glasses or contact lenses in order to see, and will need UV absorbing tints.

Find out more information about Cataracts (doc)

Corneal Disease/ Opacity

May be a congenital (present at birth) condition, or a scar from trauma or infection. Results in variable vision, contrast perception, and glare sensitivity.

Diabetic Retinopathy

Major cause of vision loss in the U.S. Characteristics may include: variable acuity, distortion, and patients may see floaters or spots in their vision. Two major stages of disease: background and proliferative. In background retinopathy, vision is usually unaffected, except maybe by macular edema (swelling) or by changes in refractive error that occur with fluctuating blood sugars. Diabetes affects the small blood vessels of the body, of which there are many in the eye and makes these vessels leaky. Leaky vessels result in not enough blood and nutrients passing to the end of the vessel course. This results in new vessel growth to nourish the deprived area. New vessels often break and bleed. Treatment of this new vessel growth (neovascularization) is with a laser. Laser treatment may cause visual field loss. New vessels may also tug on the retina and cause it to detach or they may break and bleed causing a large hemorrhage that disrupts vision severely.

Find out more information about Diabetes (doc)

Glaucoma

A condition where the fluid that nourishes the cornea (aqueous humor) is either over-produced or does not drain appropriately. Fluid build-up causes an increase in pressure which results in damage to the optic nerve resulting in changes in visual field and contrast. There are medications that can treat glaucoma, but it must be diagnosed early and the medications taken faithfully to help prevent loss. New surgical procedures are being developed to help treat glaucoma.

Glaucoma Information Sheet (doc)

Keratoconus

Condition resulting in corneal thinning and scarring, and irregular astigmatism. Decreased vision may occur secondary to irregular astigmatism; this is often correctable in the earliest stages, but may progress to such a point that patients require rigid contact lenses or a corneal transplant.

Macular Disease (Age Related Macular Degeneration (AMD), Best's, Stargardt's)

These diseases affect the central area of vision, which is responsible for our sharp detailed vision and our colored vision. All result in variable loss of central vision, image distortion, contrast problems, and diminished color vision. Patients will never be completely blind, because their peripheral vision remains normal. Main complaints are problems reading and difficulties recognizing faces. AMD affects the elderly; since this segment of the population is increasing, the frequency of this condition is increasing. Other condition have their onset in late teens to early adult years.

AMD Information Sheet (doc)

Nystagmus

Is an involuntary movement of one or both eyes. Sometimes called shaking or jerking of eyes. Is associated with numerous eye or neurological conditions.

Optic Neuropathy

Refers to loss of optic nerve function. Patients have loss of central vision, field loss, and color vision abnormalities. There are many causes of Optic Neuropathy such as hereditary, vascular, or inflammatory.

Retinal Detachment

Refers to elevation of sensory retina from its underlying pigmented layer. Depending on location, severity, and length of time retina has been detached, vision loss can vary. Retinal Detachment may be due to diabetic retinopathy, traction, trauma, high myopia or as a complication of ocular surgery.

Retinitis Pigmentosa

Disease that affects the pigmented layer of the retina and where the photoreceptors (rods and cones) degenerate. Characteristic vision loss includes field constriction, night-blindness. Can occur as part of systemic diseases or syndromes.

Stroke/ Brain Injury

Patients may suffer from hemifield (loss of usable field of vision) defects that can involve or spare the central vision. Patients may also have problems with eye movements or visual-motor integration.