Other Eye Conditions Associated with Blindness and Low Vision

Use our glossary as a quick reference to learn about different eye conditions and common terms used when describing them not in our other sections. The glossary is alphabetized to make it easier for you to find the information you need.

– C – D – H– K – L – M – N – P– R – S – T – U – V

C

Chorioretinal Atrophy

Chorioretinal atrophy is, as the name implies, a degeneration or atrophy of the retina. It affects males more than females. It is an autosomal dominant disorder caused by mutations in the CRB1 gene.

Choroidal Neovascularization

Choroidal neovascularization refers to new and abnormal blood vessels that grow, multiply, and develop into a cluster beneath the macula. The macula is the part of the retina that provides the clearest central vision.

Choroideremia

Choroideremia is a rare disorder that causes progressive loss of the choroid, a critical layer under the retina responsible for some of its blood supply. It is an inherited disorder that generally affects males only. It commonly begins as night blindness in childhood and gradually advances to increasing low vision. Most people with this disorder can retain good vision until age 40 or 50. There is no treatment for choroideremia, but people with the disorder may find it helpful to use optical, electronic, or computer-based devices for low vision.

Suggested resource: Choroideremia Research Foundation

Cortical visual impairment

Visual impairment is caused by damage to those parts of the brain related to vision. Although the eye is normal, the brain cannot properly process the information it receives. The degree of low vision may be mild or severe and can vary greatly, even daily. Also known as cerebral visual impairment, cortical visual impairment (CVI) may be temporary or permanent. People with cortical visual impairment have difficulty using what their eye sees. For example, they may have trouble recognizing faces, interpreting drawings, perceiving depth, or distinguishing between background and foreground. Children with cortical visual impairment can often see better when told in advance what to look for. Cortical visual impairment is also known as neurological visual impairment (NVI).

tech.aph.org/cvi/

H

Hemianopia

Blindness affects half of the field of vision. Hemianopia, also known as hemianopsia, may be caused by various medical conditions but usually results from a stroke or brain injury. It may affect the visual field’s right or left side and is usually permanent. Hemianopia can produce various effects, from minor to severe. For example, a person may be able to see only to one side when looking ahead, or objects that the person sees may differ in clarity or brightness. Such low vision can make it difficult to perform daily tasks, from reading to crossing streets. There is no specific treatment for hemianopia, but low-vision rehabilitation specialists can help people learn to make the most of their sight. In addition, some people with hemianopia benefit from using magnifiers or special prism lenses.

Hyperopia

This common vision problem, also known as farsightedness, occurs when light rays enter the eye focus behind the retina, not directly on it. People with hyperopia can usually see distant objects well, but close objects appear blurry. Hyperopia may cause eyestrain or headaches, especially with reading. Eyeglasses or contact lenses can correct hyperopia. Laser vision correction is sometimes possible for people who do not want to wear glasses or contact lenses.

L

Late-Onset Retinal Degeneration (L-ORD)

A genetic retinal disorder. Onset typically occurs in a person’s fifth to sixth decade. Symptoms include night blindness, progressing to severe central and peripheral degeneration with choroidal neovascularization and chorioretinal atrophy. Because it is late onset, it is often mistaken for regular macular degeneration. Note, however, that this disorder, in its severest state, affects both central and peripheral vision and thus leads to total blindness, unlike some more common macular disorders. Laurence-Moon-Bardet-Biedl Syndrome is Rare an inherited disorder affecting many parts of the body. People with this condition have retinitis pigmentosa accompanied by mental retardation, paralysis of the legs, and various other symptoms.

Leber’s Congenital Amaurosis

Leber’s congenital amaurosis is an Inherited condition, probably caused by retina degeneration, in which an infant is born blind or develops severe vision loss soon after birth. Children with Leber’s congenital amaurosis typically have nystagmus, and some have mental retardation and hearing disorders. At present, there is no treatment for this condition. Click here for more information on Leber’s Congenital Amaurosis.

Suggested resources:
Foundation for Retinal Research

M

Macular Telangiectasia

Macular telangiectasia (MacTel) is an eye condition that affects the macula, the part of the retina responsible for central vision, by causing small blood vessels to swell, leading to vision loss. It affects about 2 million people worldwide and has two main types: Type 1, which typically affects one eye in young men, and Type 2, which occurs in middle-aged individuals and can cause blood vessel leakage, bleeding, and scarring. Symptoms include distorted vision, central vision problems, increased light sensitivity, and blurriness, though it does not affect peripheral vision. Diagnosis involves a dilated eye exam to detect abnormal blood vessels, crystal deposits, or pigment changes in the macula. There is currently no definitive treatment.

Myopia

This condition, commonly known as nearsightedness, occurs when light rays enter the eye focus in front of the retina, not directly on it. People with myopia can usually see close objects well, but objects in the distance—such as highway signs or writing on a chalkboard—appear blurred. People with this condition may squint to see distant objects and experience eyestrain or, sometimes, headaches. Eyeglasses or contact lenses can correct myopia. Surgery is another alternative.

Neuromyelitis optica (NMO)

Neuromyelitis optica (NMO), also known as Devic’s disease, is an autoimmune disorder in which immune system cells and antibodies mistakenly attack and destroy myelin cells in the optic nerves (neuritis) and the spinal cord (myelitis). NMO leads to the loss of myelin, a fatty substance that surrounds nerve fibers and helps nerve signals move from cell to cell. The syndrome can cause blindness in one or both eyes and can be followed by varying degrees of paralysis in the arms and legs. Most individuals with the syndrome experience clusters of attacks months or years apart, followed by partial recovery during periods of remission. The onset of NMO varies from childhood to adulthood, with two peaks, one in childhood and the other in adults in their 40s. The syndrome is sometimes confused with multiple sclerosis (MS) because both can cause optic neuritis and myelitis attacks.

P

Presbyopia

The eye’s gradually decreasing ability to focus on nearby objects. Presbyopia is a normal part of aging and affects virtually everyone, usually becoming noticeable after age 40. People with presbyopia typically hold reading materials at arm’s length to bring the words into focus. They may experience headaches or eyestrain while reading, viewing a computer screen, or doing close work. Presbyopia can be corrected with reading glasses, bifocal or variable focus, or contact lenses. Using bright, direct light when reading is also helpful.

Suggested resources:

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R

Retinal Detachment

Separation of the retina from the underlying supportive tissues. Retinal detachment may result from injury, disease, or other causes. A person with retinal detachment usually does not experience pain, but may see floaters (see floaters and spots) or bright flashes of light, may have blurred vision or may see a shadow or curtain over part of the field of vision. Retinal detachment requires prompt medical attention to prevent permanent vision loss. There are several methods of treatment for retinal detachment, including laser surgery.

Suggested Resources:

Detached Retina – American Academy of Ophthalmology

Retinal Detachment | National Eye Institute

S

Scotoma

Gap or blind spot in the field of vision that may result from damage to the retina. How much a scotoma impairs sight depends on whether it affects central or peripheral vision. Common causes of scotoma include macular degeneration, glaucoma, and optic nerve inflammation. People who experience significant low vision because of scotomas may benefit from using magnifiers, bright lighting, and large-print reading materials.

U

Uveitis

Inflammation inside the eye affects the structures that provide most of the blood supply to the retina. Uveitis may affect one or both eyes. The condition may be associated with an underlying disease or have other causes, but in many cases, it affects people who are otherwise healthy. People with uveitis typically experience redness of the eye, blurred vision, and light sensitivity. They may also feel pain and see floaters (see floaters and spots). If not properly treated, uveitis can lead to scarring and vision loss. Treatment depends on which eye structures are affected and whether there is an underlying disease. Eye drops and other medications are commonly prescribed to reduce inflammation.

Suggested resource: www.uveitis.org

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