Glossary

vascular endothelial growth factor (vegf)

Vascular endothelial growth factor is a protein in the body that promotes the production of blood vessels. During conditions where a part of the body is not getting enough blood, VEGF is stimulated to form new blood vessels to bring more blood. In the eye, the release of VEGF can cause too much blood to enter the eye. This contributes to a number of diseases that may affect vision.

visual field test

A measurement of how well your central and peripheral vision are functioning. This test is used to measure how much peripheral vision you have. In the case of retinitis pigmentosa, your peripheral vision deteriorates over time. One type of field test is called automated perimetry. This test can show you how much vision you have left.

During a visual field test you will me asked to look at a central object, and detect objects (moving or still) on the edge of your vision. You may be asked to complete this test one eye at a time.

Visual acuity

A measurement of how well you see in front of you. Visual acuity of 20/20 is considered “perfect” vision. 20/20 visual acuity means you can see something 20 feet in front of you what can normally be seen at 20 feet. If you have 20/50 visual acuity, it means you need to be 20 feet away from an object that someone with perfect vision can see 50 feet away.