Perg

PERG

The pattern electroretinogram is a test that measures electrical responses from the retina when a person looks at a changing pattern, such as alternating black-and-white checks. It focuses on signals produced by the retinal ganglion cells, which are the neurons that carry visual information from the eye to the brain. During the test, small electrodes are placed near the eye while the person views the pattern on a screen, and the electrical activity is recorded and averaged to reveal consistent responses. Because it measures function rather than structure, this test can detect dysfunction in the visual pathway before visible damage appears on imaging. Clinicians commonly use it to evaluate early glaucoma, optic nerve problems, and other conditions that affect the ganglion cells. It can also help track disease progression and assess whether treatments are preserving or improving retinal function. The test is noninvasive but requires the patient to fixate steadily and cooperate, so results can be affected by poor attention or eye movement. Interpreting the waveforms needs specialized training and sometimes comparison with age-matched normal values. When used alongside imaging and clinical exams, this measurement provides valuable functional information to guide diagnosis and care.