Multifocal exams newest options in the search for objective structural testing in glaucoma

L. Jay Katz, MD, said there is an urgent need to detect glaucomatous structural damage earlier than currently possible.

WAIKOLOA, Hawaii — Multifocal, objective assessments of retinal function may have advantages over current subjective perimetry tools in the diagnosis of glaucoma, said L. Jay Katz, MD. There is an urgent need to detect glaucomatous structural damage earlier than currently possible, Dr. Katz told attendees here at Hawaii 2005, The Royal Hawaiian Eye Meeting.

“We have all these problems with our standard visual fields in terms of test duplication being difficult, some patients not being too cooperative, and [our] not being able to interpret the data,” he said. In addition, with subjective perimetry there is a learning curve, “so with repeat testing the patients do better and better,” he said.

At present, the VERIS system (Electro-Diagnostic Inc.) and the AccuMap test (ObjectiVision) are the only two commercially available units for multifocal objective retinal testing.

The VERIS, a multifocal electroretinography test, takes about 20 minutes per patient.

The AccuMap, a multifocal visual evoked potential (VEP) test, uses checkerboard pattern stimulation with 58 test areas. It covers the central 26·, except in the nasal area where it extends to 32· to capture early nasal defects. The test takes about 30 minutes per patient, Dr. Katz said.

“Multifocal VEP is an objective method for recording visual fields, and we may start looking at it more and more in the future,” Dr. Katz said. “There appears to be reasonable agreement in at least some of the studies between VEP with standard perimetry and [Heidelberg Retina Tomograph] testing. Patient acceptance seems to be very high. They thus far seem to prefer this testing over standard perimetry.”

Dr. Katz cited the absence of a learning curve with the test as an additional positive for clinicians.

“There is a lot work that still needs to be done,” Dr. Katz said. “There has to be a better way to analyze the data, we have to have larger clinical trials and really try to see how this fits into how we evaluate patients in the future.”