Glossary

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Age-related Macular Degeneration (AMD)

Macular degeneration is a condition that causes permanent loss of central (detail) vision. It is commonly called Age-related Macular Degeneration (AMD) because it is the most common cause of loss of vision in people over 50 in our country.

There are two kinds of AMD:

  • "Dry" AMD, the most common form, usually has a slow progression. Nutritional and life style changes may slow the loss of vision.
  • "Wet" AMD can result in more rapid and severe vision loss from abnormal blood vessels developing under the macula and leaking blood and fluid. Prompt treatment with lasers or injections may prevent severe vision loss.

Blurred vision

Causes both near and far to appear to be out of focus, even with glasses.

Cataracts

A cataract is a clouding of the lens that causes a loss of vision. Most cataracts are caused by aging, but they can occur at birth or following trauma or other conditions. Risk factors include long-term exposure to the sun's ultraviolet rays, smoking, and use of steroids. If the eye is healthy, cataract surgery has a high success rate in restoring normal vision.  

Charles Bonnet Syndrome (CBS)

CBS describes visual hallucinations seen when you have lost vision. Although you know that the images are not real, you may see detailed patterns of people or objects. The effects often occur during quiet times and may disappear after a year or two.

Contrast Sensitivity

Many eye conditions reduce contrast sensitivity, making it difficult to see low contrast patterns, drive at night, or recognize faces.

Depression and Anxiety

Vision loss frequently causes feelings of depression or anxiety; which can result in a spiral of reduced activity, social isolation, cognitive decline and medical complications.

Diabetic Retinopathy

This disease is caused by diabetes, and can lead to blindness if not treated. Anyone with diabetes is at risk for diabetic retinopathy. Vision loss is caused by weak vessels leaking fluid or blood, or by the growth of abnormal blood vessels. Macular edema results from fluid swelling and leads to distorted vision. Unhealthy new blood vessels, called neovascularization, can grow and bleed into the clear, jelly-like vitreous that fills most of the eyeball, causing dark spots and strands in your vision. These blood vessels can form scars that cause retinal detachments and serious vision loss or blindness. Diabetic retinopathy is treated by injections, laser, or surgery. Vision loss from diabetic retinopathy may be prevented by watching and controlling your blood sugar, taking care of yourself, and seeing an eye doctor at least once a year.  

Glaucoma

Glaucoma causes progressive loss of sight by damaging the optic nerve. Increased eye pressure and insufficient blood flow to the optic nerve causes visual field defects and loss of peripheral vision. More than 2.2 million Americans age 40 or older have glaucoma. Risk factors include age, being black or Hispanic, being very nearsighted (myopic), having a positive family history, history of high eye pressure, thin corneas, history of eye injury or eye surgery, long term use of steroids, and having diabetes or high blood pressure. Glaucoma is usually treated with eye drops to lower eye pressure, laser, and/or glaucoma surgery. Regular examinations and early glaucoma treatment is important to preserve eyesight.  

Hazy vision

Causes the sensation of a film or glare that extends over the entire viewing field, causing difficulty seeing low contrast print. 

Legal Blindness

Statutory (Legal) Blindness in the United States was defined by the Social Security Administration in 1935 to be best corrected vision of 20/200 or less in the better eye, or visual fields constricted to no greater than 20 degrees. With the use of new charts and visual field instrumentation, the definition has been interpreted as corrected visual acuity any worse than 20/100. Humphrey Field Analyzers can be used for visual field determination using the 10dB stimulus.

The World Health Organization describes visual impairment as normal, near-normal, moderate, severe, profound, near-total, or total visual impairment. According to these definitions, low vision ranges between 20/70 and 20/400, and blindness ranges from 20/500 to no light perception.

These definitions are used for diagnosis codes for insurance billing or to determine funding eligibility and tax exemptions.

Light sensitivity

Produces a washed out image and/or glare disability that can cause discomfort and interfere with driving.

Loss of central vision

The loss of central vision creates a blurred or blind spot, making it difficult to read, recognize faces and distinguish details.

Loss of peripheral vision

The inability to see things to one side or both sides, causing difficult mobility and a slow reading speed.

Night blindness

This results in inability to see outside at night or in dimly lighted area such as movie theaters or restaurants.

Poor stereo acuity

Loss of depth perception leads to risk of falls and difficulty pouring liquids.

Poor color vision

Difficulty distinguishing different shades of colors.

Retinal Detachment

The retinal may separate from its underlying layer and result in total impairment in the detached area. It may be caused by a retinal hole, eye trauma, infection, high myopia, blood vessel disturbance or a tumor. Early diagnosis and surgical reattachment may restore vision.  

Retinitis Pigmentosa (RP)

RP is an inherited disease that gradually destroys night vision, severely reduces side vision, and may result in total impairment. 

Retinopathy of Prematurity (ROP)

ROP may occur in infants born prematurely and is caused by high oxygen levels in incubators during the neonatal period. 

Traumatic Brain Injury

Vision can be lost or damaged as a result of head injuries, brain damage and stroke.

Vision related symptoms of brain injuries

Brain injury can cause a host of symptoms relating to vision, including reduced visual acuity, visual field, poor contrast sensitivity, blurred vision, eye misalignment, poor depth perception, glare sensitivity, confusion when performing visual tasks, difficulty reading, double vision, headaches, dizziness, abnormal body posture, and balance problems.