Glossary of Eye and Vision Terms

Nearsightedness (Myopia)

Myopia is when your distance vision is blurry. Near vision is often good. This condition usually begins between the ages of 6 to 21 and may gradually worsen after 30. Contact lenses or glasses are often prescribed.

Farsightedness (Hyperopia)

Hyperopia is when your near vision is strained. Distance vision is often very good. This condition causes your eyes to overwork for reading and other close work. Usual symptoms are headaches and eyestrain. Contact lenses or glasses are often prescribed.


Astigmatism is when you have a misshapen cornea or lens. This very common condition causes the eye to focus light differently up and down than across. Symptoms include headaches, eyestrain and squinting. Astigmatism usually occurs in conjunction with myopia or hyperopia. Contact lenses or glasses are often prescribed.


Presbyopia is a reduction of focusing ability for anything closer than an arm’s length. This causes blurring and eyestrain. Presbyopia usually begins in the late 30’s and worsens with age. Bi-focals or reading glasses are often prescribed.


Incorrectly called “lazy eye,” amblyopia causes an eye to turn in or “cross.” This eye is not able to see 20/20 even with the best corrective lenses. Amblyopia can only be diagnosed by a complete eye examination. Vision therapy is sometimes needed along with glasses, and many cases cannot be helped if they are detected too late. Ideally, children should have a comprehensive eye exam at age 3 or 4 to screen for this condition. They can be checked earlier if parents are suspicious of an abnormality or if there is a family history of amblyopia.


Glaucoma is an eye disease in which the internal pressure of your eye rises so high that the optic nerve is damaged. Glaucoma is one of the leading causes of blindness in the U.S.

The exact cause of glaucoma is not known. For some reason, the passages that normally allow fluid within your eye to drain out become clogged or blocked. This results in fluid building up within the eye and increasing pressure on the optic nerve. The pressure can easily damage nerve fibers and blood vessels. An injury, infection, or tumor in or around the eye can also cause the pressure to rise.

Glaucoma is usually effectively treated with prescription eye drops and medicines. In some cases, surgery may be required. The goal of any treatment is to prevent loss of vision by lowering the pressure in the eye.


When the normally clear lens within your eye becomes cloudy or opaque, it is called a cataract. Cataracts vary from extremely small areas of cloudiness to large opaque areas that cause a noticeable loss of vision. Cataracts most often develop in persons over the age of 55, but they are occasionally found in younger people, including newborns.

If a cataract develops to the point that your daily activities are affected, you will be referred to an eye surgeon who may recommend the surgical removal of the cataract. The surgery can generally be done under a local or topical anesthesia. Using a small incision, the surgeon will remove the clouded lens with ultrasound and, in most cases, replace it with an intraocular lens implant. A medication is placed in the eye after surgery and the eye may be patched for a short period of time.

Macular Degeneration

Macular degeneration is an eye disease that occurs when there are changes to the macula—the small portion of the retina that is located on the inside back layer of the eye. It reduces central vision and makes seeing details for close work, like reading or sewing, difficult or impossible.

There several types of macular degeneration. In the “dry” type, the tissue of the macula becomes thin and stops functioning properly. This is thought to occur as part of the aging process and vision loss is usually gradual. “Wet” macular degeneration is less common and results when fluids leak from newly formed blood vessels under the macula and blur central vision. Vision loss from the “wet” form can be rapid and severe. There is no cure for macular degeneration, but there are some treatments that may delay its progression or even improve vision.


Diabetes and Your Vision

Diabetes and its complications can cause changes in nearsightedness, changes in farsightedness and premature presbyopia. It can also result in cataracts, glaucoma, strabismus (a lack of eye alignment) and decreased corneal sensitivity. Visual symptoms of diabetes include fluctuating or blurring of vision, occasional double vision, night vision problems and flashes and floaters within the eyes. Sometimes early signs of diabetes are detected in a thorough optometric examination.

The most serious eye problem associated with diabetes is diabetic retinopathy. Diabetic retinopathy is a weakening or swelling of the tiny blood vessels in the retina of your eye, resulting in blood leakage, the growth of new blood vessels and other changes. If diabetic retinopathy is left untreated, blindness can result.

In a routine eye examination, your optometrist can diagnose potential vision threatening changes in your eye that can be treated to prevent blindness. However, once damage has occurred, the effects are usually permanent. It is important to control your diabetes as much as possible to minimize your risk of developing retinopathy. Annual eye exams are a must for diabetics.

Dry Eye

The tears your eyes normally produce are necessary for overall eye health and clear vision. Dry eye occurs when your eyes do not produce enough tears or produce tears that do not have proper chemical composition. Dry eye symptoms can result from the normal aging process, exposure to environmental conditions, problems with normal blinking or from medications such as antihistamines, oral contraceptives, or antidepressants. Dry eye can also indicate general health problems or can result from chemical or thermal burns to the eye.

Dry eye cannot be cured, but measures can be taken so your eyes remain healthy and comfortable. The most frequent treatment is the use of artificial tears or tear substitutes. For more severe dry eye, ointment can be used. In some cases, small plugs may be inserted in the eyes’ tear drainage canals to slow the outflow of tears. Often, prescription drugs can be used to stimulate the tear glands to produce more moisture and comfort. Drs. Luthi & Rosentreter stay abreast of the current treatments for dry eye and are successful in treating this bothersome and common disorder.

Spots, Floaters, and Flashes

Spots (often called floaters) are small, semi-transparent particles within the gel fluid of the eye that become noticeable when they move within the line of sight. Some floaters may appear as a strand or could have a cobweb appearance. They may appear with flashes of light.

While some spots are normal, they can be a sign of a more serious problem and should be checked immediately by your optometrist.

Red Eyes

Red eyes can be the result of infections, allergies, inflammation or environmental irritants. Your eyes should be examined promptly to determine the source and the appropriate treatment.


A progressive thinning of one’s cornea resulting in a cone shaped and irregular corneal surface, giving the individual blurry and distorted vision. Usually this condition is best treated with special contact lenses that provide better vision compared to glasses. Many specialty lenses are available including the hybrid technology by Synergeyes–Clearkone contact lens, which is a rigid lens enveloped in a soft material. This gives the vision of a rigid lens but also the comfort of a soft lens! At times, surgical treatment for keratoconous is needed.