Glaucoma trials help in understanding visual field loss

Douglas Gaasterland, MD, who reviewed the results of three clinical trials, emphasized that clinicians need to obtain more than one visual field test at baseline. In addition, in patients with apparent deterioration in the visual field during follow-up, the loss must be confirmed. Confirmed visual field deterioration may later "recover," but is likely to relapse, said Dr. Gaasterland, who is in private practice in Chevy Chase, MD.

In the Ocular Hypertension Treatment Study (OHTS), in which 1,636 patients were enrolled, participants had normal threshold 30-2 visual fields on at least two baseline visual field tests; 125 developed glaucomatous optic neuropathy during the first 6.5 years of the study. Of the 20,597 visual field tests conducted during this time, 1,006 were repeated because of defects (n = 758) or they were not reliable (n = 258). Of 708 with an abnormal but reliable field, 703 were retested, 99 defects were replicated, 604 were not confirmed. Of these 467 were normal, 112 were borderline, and 25 could not be replicated, Dr. Gaasterland explained at the annual meeting of the Association for Research in Vision and Ophthalmology.

"The visual field defect score and the mean deviation provided similar results. Clinicians should just use the mean deviation," advised Dr. Gaasterland.