WEDNESDAY, Dec. 1 (HealthDay News) -- A test that measures the function of nerve cells in the retina may detect glaucoma at an early stage and help doctors evaluate the effectiveness of treatments, a new study has found.

Diagnosing glaucoma as early as possible -- before it destroys the optic nerve -- is key to preventing vision loss, according to the researchers, from the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine.

The test, known as a pattern electroretinogram optimized for glaucoma screening, measures the electrical activity of the retina as a person looks at an alternating pattern of black and white lines.

The test can detect dysfunction and abnormal changes in retinal ganglion cells (RGCs) that appear early in the glaucoma process, the researchers said, making it potentially valuable as a non-invasive method of detection.

Studying 47 people with glaucoma who had surgery because their intraocular pressure could not be controlled by medications, the researchers said the test was able to show reversal of RGC dysfunction and reduced intraocular pressure after the operations.

However, larger studies are needed to confirm the results, study co-leader Mitra Sehi said in a news release from the American Academy of Ophthalmology.

More information

The U.S. National Eye Institute has more about glaucoma.