The Electrophysiology and Vision Functions Clinic is directed by Wayne Verdon O.D., Ph.D. Dr. Verdon received his optometry degree from the University of Wales Institute of Science and Technology (now Cardiff University, U.K.). He received a Ph.D. in Vision Science at the University of California, Berkeley. Dr. Verdon is the former director of the Visual Physiology Laboratory at the Jules Stein Eye Institute, UCLA Department of Ophthalmology. He is the immediate past-Chair of the Clinical Electrophysiology Diplomate Committee of the American Academy of Optometry, and is a member of the International Society for Clinical Electrophysiology of Vision.


The Electrophysiology and Vision Functions Clinic is at the forefront where vision science, research, and clinical knowledge meet. It is one of the primary referral centers in Northern California for specialized vision testing. Performing non-invasive tests which typically can not be found in general eye care practices.

This clinic investigates:

  • the function of rods, cones and other cells in the retina
  • macular cone function,
  • retinal pigment epithelial dysfunction,
  • visual pathway disorders (which may be associated with tumors or early optic nerve dysfunction),
  • color vision problems,
  • Goldmann visual fields
  • night vision problems
  • vision loss of unknown etiology


The majority of patients are referred by eye care providers (ophthalmologists and optometrists). However, referrals are not needed for individuals to be evaluated in VFC. Patients may call to make their own appointment at (510) 643-0134.

The most common reasons for evaluation are:

  • Signs or symptoms of a known ocular disease
  • Vision loss of unknown etiology (such as reduced visual acuity, visual field loss, or a change in color vision)
  • Color vision evaluation for vocational purposes
  • Determination of possible progressive visual field loss or ERG reduction

Clinical Visual Electrophysiology

Clinical visual electrophysiology tests are performed in accordance with standards set by the International Society for Clinical Electrophysiology of Vision (ISCEV).

The following clinical electrophysiology tests are available:

  • ERG (Electroretinogram)
  • mfERG (Multifocal ERG)
  • PERG (Pattern ERG)
  • VEP (aka VER, Visual Evoked Potential or Response)
  • Sweep VEP

In addition we offer:

  • Dark Adaptation (full curve or final thresholds)
  • Goldmann Visual Fields
  • Contrast Sensitivity (Pelli-Robson)
  • Glare testing (Berkeley Glare Tester, or Brightness Acuity Tester)
  • Color Vision

Results and interpretation are provided in a report.

Many tests can be conducted on babies and children. Please contact Dr. Verdon with questions or concerns about youngsters.

Conditions Commonly Referred

We offer diagnostic work-ups, second opinions and monitoring for many conditions including:

  • Retinitis pigmentosa, Usher syndrome
  • Cone-rod dystrophy
  • Cone-dystrophy
  • Stargardt disease
  • Best disease
  • Achromatopsia (rod monochromacy, blue-cone monochromacy)
  • Nystagmus
  • Congenital Stationary Night Blindness (CSNB)
  • Pigmentary retinopathy (dystrophy versus inflammatory)
  • Juvenile X-linked retinoschisis
  • Hereditary Dominant Optic Atrophy
  • Leber Congenital Amaurosis (LCA)
  • Malingering
  • Optic neuropathy, optic neuritis

Color Vision Testing for Vocational Purposes

The Electrophysiology and Vision Functions Clinic specializes in color vision testing for vocational purposes. A few professions that require color vision assessment include:

  • Federal Aviation Authority
  • Maritime Industries, Coast Guard
  • Police and Fire Departments
  • Military Academies
  • FBI, CIA, Border Patrol
  • American Gem Society

Color tests that are available include the hard to find Farnsworth Lantern Test (FALANT). Others include the Farnsworth-Munsell 100 hue test, D-15, Ishihara, Dvorine, AOC 1965 plates, Hardy-Rand-Rittler (HRR) plates, the anomaloscope and many others.

Farnsworth Lantern Test (FALANT)

The Farnsworth Lantern Test is a device that presents pairs of colored lights. The observer is required to name the colors of the lights. The lights are designed to simulate small signal lights seen at a distance. The Lantern is viewed at 8 feet in a normally lit room. The colors can be red, green or white, presented two at a time, one above the other. The observer names the top color first, then the bottom color. The colors can be presented in any combination, including the same color on top and bottom. See the pictures. Initially, nine pairs of colors are presented. If any errors are made in color naming, the first 9 presentations are discarded and used as practice. Another 18 pairs of lights are presented and typically more than 2 errors mean that the test is failed.

The Anomaloscope

The anomaloscope is the gold standard device used to determine the precise type of inherited X-linked red-green color vision defect that an observer has. Inherited red-green color vision defects can be deuteranomalous, protanomalous, deuteranopic or protanopic. The observer looks down a tube and adjusts the intensity of a 'sodium yellow' wavelength until it appears identical to a mixture of two other wavelengths.


Electrophysiology and Vision Functions Clinic
School of Optometry
University of California
Berkeley CA 94720-2020
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Tel: (510) 643-0134
Fax: (510) 642-8012