[ NDSIP Home ] [ University of Nevada, Reno ] [ College of Education ] [ Contact Us ]

What Tests are Available?

If an individual has a hearing loss, and Usher syndrome is suspected, there are several tests used to determine wheter that individual has retinitis pigmentosa (RP). Some types of screening can be completed by a parent, teacher or other interested adult.

Some tests can be completed by most eye specialists during a regular exam:

Visual Field Test

Measures side vision using a machine called a Goldman Perimeter. It will indicate the field of vision (normal field=180 degrees).

Psycho-Physical Test

Indicates which colors, if any, an individual can distinguish and the amount of contrast needed to see.

Dark Adaptation Test

Determines an individual's ability to see in the dark and how long it takes to adjust to the dark.

Elctroretinogram (ERG)

The definitive test for RP, however, is the the electroretinogram (ERG), which has been found to be 95 percent accurate. The test must be administered by an opthalmologist. An ERG measures the elecricity given off by nerve impulses in the retina of the eye. The patient sits in a dark room until the eyes adjust to the darkness. One eye is then patched and the other fitted wtih a special contact lens. The test, which is painless, measures the elecrtical response of the uncovered eye as it is exposed to a flashing light.

Return to Usher Syndrome Main Menu