Other Eye Conditions Associated with Blindness and Low Vision

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Use our glossary as a quick reference to learn about different eye conditions and common terms used when describing them. The glossary is alphabetized to make it easier for you to find the information you need.

A – B – C – D – E – F – G – H – I – J – K – L – M – N – O – P – Q – R – S – T – U – V – W – X – Y – Z

A

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

Color Blindness

A vision problem in which a person has difficulty distinguishing specific colors—most commonly red and green, but sometimes blue and green or blue and yellow. Color blindness is not a form of blindness but rather a deficiency in color perception. It usually affects both eyes and is much more common in males than females. There is no treatment or cure for this problem, but a color-blind person can learn to adapt in various ways. For example, a color-blind driver can remember that the light positioned at the top of a traffic light is red. It is beneficial to diagnose color blindness in children at an early age so that steps can be taken to avoid learning problems related to color perception.

Corneal Disease

Disease or disorder that affects the cornea, the clear, curved surface that covers the front of the eye. The effects of corneal disease vary. Some corneal conditions cause few, if any, vision problems. For example, infections of the cornea can often be treated with antibiotics. However, if the cornea becomes cloudy, light cannot penetrate the eye to reach the retina, and severe low vision, or even blindness, may result. Corneal dystrophies are usually inherited conditions in which one or more parts of the cornea lose their clarity due to a buildup of cloudy material. Keratoconus is the most common corneal dystrophy in the United States. When corneal disease causes the cornea to become permanently clouded or scarred, doctors may be able to restore vision with a corneal transplant—surgical replacement of the old cornea with a new one.

Suggested resource: http://www.nei.nih.gov/health/cornealdisease/

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/

D

De Morsier’s Syndrome

A rare disorder present at birth, in which the optic nerve is underdeveloped, the pituitary gland does not function properly, and often a portion of brain tissue is not formed. De Morsier’s Syndrome, also known as septo-optic dysplasia, may cause blindness in one or both eyes and is often accompanied by nystagmus and other symptoms. Some children with De Morsier’s Syndrome have normal intelligence, while others may be developmentally delayed, have learning disabilities, or have cognitive impairments. Some symptoms of this disorder can be treated, but low vision usually cannot be corrected. Visual devices, such as a magnifier or a computer designed for low-vision users, may benefit some people with De Morsier’s Syndrome.

Diabetic Retinopathy

Eye condition that results from the damaging effect of diabetes on the circulatory system of the retina. The longer someone has had diabetes, the greater the person’s likelihood of developing diabetic retinopathy. Changes in the retina’s tiny blood vessels can lead to low vision. People with diabetes should have routine eye examinations to diagnose and treat diabetes-related problems as soon as possible. Maintaining strict control of blood sugar levels helps to prevent diabetic retinopathy. Surgical and laser treatments can help many people affected by this condition.

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.

K

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.

Laurence-Moon Syndrome

Previously diagnosed as “Laurence-Moon-Bardet-Biedl syndrome,” this is now differentiated as “Laurence-Moon syndrome” or “Bardet-Biedl syndrome,” both rare genetic disorders with overlapping characteristics.

Laurence-Moon is a syndrome (set of related attributes) caused by a genetic mutation and characterized by the eye condition known as retinitis pigmentosa (RP) in addition to a variety of features that may include speech delay, learning disability, short stature, kidney disease, type 2 diabetes, polydactyly (extra fingers), obesity, weakness of the legs, and reproductive issues (including small male genitalia).

We will focus on the eye condition associated with Laurence-Moon syndrome, retinitis pigmentosa. Click here for more information on Laurence-Moon Syndrome.

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

Low Vision

Vision loss may be severe enough to impede a person’s ability to carry on everyday activities but still allows some functionally useful sight. Macular degeneration, cataracts, glaucoma, or other eye conditions or diseases may cause low vision. Low vision may range from moderate impairment to near-total blindness. Eyeglasses, contact lenses, or surgery cannot fully correct it. However, a person with low vision may benefit from various available optical devices, such as electronic magnifying glasses or eyeglass-mounted telescopes. In addition, special software developed for computer users with low vision can display type in large size or read text aloud.

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.

N

Neurological visual impairment (NVI)

See cortical visual impairment.

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.

Retrolental Fibroplasia

See retinopathy of prematurity.

Rod-Cone Dystrophy

See Cone-rod dystrophy.

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.

Septo-Optic Dysplasia (SOD)

See De Morsier’s Syndrome.

T

Trachoma

Contagious eye infection, caused by bacteria, affects the eyelid and cornea. Trachoma can lead to scarring and blindness if not treated. The infection is spread by contact with discharge from the eyes or nose of infected persons and transmitted by certain flies. Trachoma is rare in the United States, but it affects millions of people worldwide, many of them children. Antibiotics are generally an effective treatment for trachoma, especially if used early in the infection. In some instances, eyelid surgery may be needed. Click here for more information about Trachoma.

Suggested resource: www.trachoma.org

U

Usher Syndrome

An inherited condition that causes partial or total hearing loss accompanied by gradual vision loss resulting from retinitis pigmentosa. Some people with Usher Syndrome also have problems with balance. There is no cure for the condition. However, early diagnosis makes it possible to help people with Usher Syndrome by providing hearing aids, training in sign language and lip reading, devices for low vision, and counseling for preparing for the future. Click here for more information about Usher Syndrome.

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

V

Vitelliform Macular Dystrophy

See Best’s Disease.

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