The Electrophysiology and Psychophysics Service utilizes sophisticated instruments to measure functional activity of the retina and the optic nerve. These technologies are used to detect and aid in the evaluation and diagnosis of a variety of visual disorders, such as genetic conditions and toxicities affecting the eye. The visual electrophysiology tests are objective and non-invasive and are compiled using ISCEV standards. These tests can be very helpful in assessing visual functions along the visual pathway from the retina to the brain.
The services are provided to both children and adults. The following tests are available:
Electroretinogram (ERG)
- Full-field ERG: Records the summed electrical retinal responses and reflects the functional state of the photoreceptors to the inner retinal layers. Test results are useful in diagnosing several retinal diseases such as retinitis pigmentosa, Leber congenital amaurosis, congenital stationary night blindness, cone dystrophy, cone-rod dystrophy, drug toxicity, and retinal vascular disease.
- Multi-focal ERG: Allows assessment of electrical responses from different regions of the retina. These test results are useful in assessing macular and paramacular pathologies such as macular degeneration, drug toxicity (Plaquenil), and enlarged blind spot syndrome.
Visual Evoked Potentials (VEP)
Visual Evoked Potentials are used to assess the integrity and maturation of the visual systems. VEP can be used to determine the visual potential and visual acuities of infants and non-verbal adults and evaluate neurological diseases such as multiple sclerosis, optic neuritis, amblyopia, and cortical blindness. Our service provides the following tests:
- Pattern VEP: Detects lesions of the visual pathways
- Flash VEP: Determines visual potentials and visual maturation
- Sweep VEP: Assess visual acuity
- Multi-focal VEP: Assess a large number of regions within a visual field
Electrooculogram (EOG)
An electrooculogram evaluates the function of the outer retina and retinal pigment epithelium. It is useful in assessing Best's vitelliform macular dystrophy, Stargardt’s disease or fundus flavimaculatus, and dominant drusen.
Preferential Looking Test
Teller Acuity Cards are used to determine pediatric visual acuity. This test can be used for infants or pre-verbal children vision screening which is crucial to healthy visual development.