Eye Conditions Glossary

Eye Conditions Glossary


Ambylopia occurs in children when one eye has better vision than the other. If left untreated, the child’s vision does not develop correctly and the brain eventually ignores signals from the bad eye. This causes the vision to become worse, and eventually can result in permanent vision loss in one eye.


Blepharitis is a chronic inflammation of the eyelid margin, which can cause itching, scaling, irritation, and in some cases redness of the eye. The two most common types of blepharitis are seborrheic blepharitis and ulcerative blepharitis. Seborrheic blepharitis is a skin condition and is often accompanied by dandruff or by patches of dry, scaly skin on the scalp, eyebrows, forehead, nose, or behind the ear. Ulcerative blepharitis is caused by bacteria and is more severe. Hard crusty material is present around the eyelashes. When these crusts are removed they can leave small ulcers that can bleed, ooze or cause permanent scarring which may make the eyelashes grow back in the wrong direction or not at all.


Cataract is a clouding of the lens in the eye. This condition is extremely common, affecting more than half of all Americans age 65 and over and may be corrected through surgery.

Chalazion :

A chalazion is a cyst on the eyelid. It occurs when the opening of a Meibomian gland becomes plugged and oily material produced by the gland cannot drain properly. This causes an inflammatory reaction, and a lump on the eyelid results. It may disappear in time, or it may remain and enlarge. A chalazion can be annoying and uncomfortable, especially if it is large, but it is usually not serious.

Color Blindness:

Color Blindness is when there is an absence or malfunction of certain color-sensitive cells in the retina. It often makes differentiating between colors, such as red, green, blue or mixtures of these colors difficult.

Conjunctivitis (Pink Eye):

Conjunctiva is a thin membrane which covers the white of the eye (the sclera) and lines the insides of the eyelids. Conjunctivitis, also known as pink eye, is an inflammation of the conjunctiva. The tiny blood vessels dilate, giving the eye a pink or red appearance.

Corneal Abrasions:

The cornea is the clear front covering of the eye. It is very sensitive and delicate tissue. The outermost layer of the cornea is called the corneal epithelium. A scratch or injury to the surface of the cornea is called a corneal abrasion or erosion. This is often painful. The cornea can be injured by excessive rubbing of the eye, by a damaged contact lens, by a fingernail, or by any other material that comes in contact with the eye.

Corneal Ulcers:

Corneal Ulcers are open sores on the cornea, often caused by infections.

Dry Eye Syndrome (DES):

Your eye is normally coated at all times with a thin film of tears. This is an important part of the physiology of the eye and is necessary for health, comfort and clear vision. Dry eye occurs when not enough tears are produced, or when the chemistry of tears is changed.

Diabetic Retinopathy:

Diabetic Retinopathy is a progressive condition occurring in some individuals who suffer from diabetes. It affects the small blood vessels in the retina. In the early stage, the tiny blood vessels in the eye weaken and develop small bulges that may burst and leak into the retina. As the condition progresses, new abnormal blood vessels grow on the surface of the retina that can break easily causing bleeding into the eye and clouding vision.

Floaters and Flashers:

Floaters and flashers are common symptoms described most frequently as spots, bugs or cobwebs moving through the field of vision. Although annoying, they are not serious and in many circumstances gradually become less noticeable.


Glaucoma is a common eye condition that develops when too much fluid pressure builds inside the eye. This increased pressure can damage the optic nerve. Without treatment, Glaucoma can cause permanent blindness. It is typically hereditary and may not show up until later in life.

Ocular Migraine:

An Ocular Migraine occurs when there is a sudden tightening (or constriction) of blood vessels in the eye, reducing the flow of blood. An Ocular Migraine causes temporary vision loss or distortion in one eye, and is usually accompanied or followed by a headache. Most Ocular Migraines last less than five minutes.

Photophobia (Light Sensitivity):

Photophobia, or light sensitivity, is an intolerance to light. With photophobia, any type of light, such as sunlight, fluorescent light or incandescent light can be bothersome. In some cases, only bright light is irritating, while in more extreme cases, any light can cause discomfort.

Ptosis (Droopy eyelids):

Ptosis, or droopy eyelids, is a condition where one or both of the upper eyelids may not be able to be raised completely.


A pterygium is a fleshy triangular tissue that grows over the cornea, usually on the inner corner of the eye. A Pterygium may grow large enough to interfere with vision and/or may alter the shape of the cornea.

Macular Degeneration:

Macular Degeneration occurs when the macula, the small central portion of the retina, deteriorates. This process often occurs over a period of time, and is the leading cause of vision loss in individuals over 60.

Retinal Detachment:

Retinal Detachment is a very serious condition that occurs when the retina pulls away from its supporting tissue. This is often caused by injury, high levels of nearsightedness or diabetic retinopathy and can cause permanent vision loss if it is not repaired quickly.

Retinal Vein Occlusion or Retinal Vein Blockage:

Retinal Vein Occlusion or Retinal Vein Blockage occurs when the veins carrying blood from the retina back to the heart are blocked. A Retinal Vein Occlusion or Retinal Vein Blockage can cause leaking of the blood and vision loss.

Retinitis Pigmentosa (RP):

Retinitis Pigmentosa (RP) is a rare, inherited disease where the light sensitive cells of the retina slowly and progressively deteriorate, eventually causing blindness.

Strabismus (Crossed Eyes):

Strabismus, or Crossed Eyes, occurs when both eyes do not move together to gaze at an object and instead one eye may look in or out, or turn up or down. This condition varies in severity. In some cases, surgery is required to correct.


Uveitis is when any part of the uvea, or middle layers of the eye, becomes inflamed. The Uvea includes the iris, a thin membrane containing many blood vessels, called the choroids, and the part of the eye that joins these together, called the ciliary body.