OFVA Eye Terms:

Strabismus-(eye misalignment) is a condition caused by a muscle imbalance that prevents the two eyes from looking at the same object together. One eye is usually directed straight ahead and the other maybe turned inward, outward, upward or downward. It can be constant or intermittent in either or both eyes.  Potential treatments for strabismus include glasses, surgery and eye exercises.


Esotropia
is a type of strabismus (eye misalignment) in which one or both eyes constantly or intermittently turn inward.

 


Exotropia
is a type of strabismus (eye misalignment) in which one or both eyes constantly or intermittently turn outward.

 


Hypertropia
is a type of strabismus (eye misalignment) in which one eye constantly or intermittently turns upward.

 


Hypotropia
is a type of strabismus (eye misalignment) in which one eye constantly or intermittently turns downward.

 

Amblyopia is a condition in which the best corrected vision in one or both eyes is decreased with no apparent eye disease. Amblyopia can be caused by strabismus, anisometropia, high astigmatism, high hyperopia, ptosis, cataract, corneal scar or other things that block or distort vision.  Although vision cannot be immediately improved with glasses alone, amblyopia can be corrected over time with glasses, patching, eye drops or other treatments.  Success is better when started before 5 years old but improvement is often possible at any age.


Lazy eye is a term some people use when talking about amblyopia, or occasionally strabismus or ptosis.


Ptosis
is a drooping upper eye lid.  Because vision is partially blocked, ptosis can cause amblyopia.  When necessary, ptosis is corrected with surgery.

 



Cataract
is a cloudiness in a part of the eye called the lens. This cloudiness scatters light as it enters the eye or keeps light from entering the eye. A cataract can prevent an eye from seeing clearly and can cause amblyopia.  If necessary, a cataract can be removed by surgery.




Astigmatism
is a type of refractive error that prevents the light rays from coming to a single focus on place at the back of the eye called the retina. Astigmatism can be corrected with glasses, contact lenses or refractive surgery.




Hyperopia (farsightedness) is a type of refractive error that is the result of the eyeball being shorter than normal. The image of near objects is focused behind the retina resulting in blurred near vision. It is commonly called farsightedness because distant images are seen more clearly. A large amount can blur images at all distances and cause amblyopia.  Hyperopia can be corrected with glasses, contact lenses or sometimes refractive surgery.

 


Myopia
(nearsightedness) is a type of refractive error that is the result of the eyeball being longer than normal. The image of distance objects is focused in front of the retina resulting in blurred distance vision. It is commonly called nearsightedness because near images are seen more clearly. Myopia can be corrected with glasses, contact lenses or refractive surgery.

 

Anisometropia is a large difference between the refractive error (need for glasses) of the two eyes.  It can be corrected with glasses, contact lenses or refractive surgery.  Anisometropia can cause amblyopia.