Nearly half of patients with glaucoma-related mild central visual loss had defects in the far peripheral inferotemporal visual field, often in the form of temporal wedge or sector defects correlated with damage to the superior nasal optic disc nerve fiber bundles.
“We believe finding visual loss in the far peripheral field with OCT correlation could affect treatment decisions for glaucoma patients,” Michael Wall, MD, from the departments of ophthalmology and neurology at University of Iowa, College of Medicine, Iowa, and colleagues wrote in their study.
The study comprised 27 patients with mild visual loss due to glaucoma. The researchers designed a static automated perimetry test of the full visual field using Open Perimetry Interface (OPI). This test was used to determine if perimetric nerve fiber bundle defects existing outside 30 degrees correlate with areas of OCT retinal nerve fiber layer thinning in this population.
Wall and colleagues observed discrete temporal wedge defects on the OPI peripheral size V test in seven patients and more extensive inferior temporal loss including the temporal wedge defect region in six patients.
Additionally, they found two patients with thinning of the superior nasal disc without a visual field defect.
OCT data correlated best with the peripheral V test for eight patients, and the central 30-2 visual field tests correlated best for eight patients. The remaining patients’ central and peripheral tests correlated equally with OCT data.
“Since the presence and extent of visual field loss is an important factor in how aggressive treatment should be for glaucoma, finding a temporal sector defect with a normal or near normal central field would suggest more aggressive treatment could be warranted,” the researchers concluded. “Also, the presence of this nerve fiber bundle defect is useful for following patients as it may expand or deepen, suggesting more aggressive therapy is indicated.” – by Talitha Bennett
Disclosures: The authors report no relevant financial disclosures. The study was supported by a VA Merit Review Grant and an unrestricted grant to the Department of Ophthalmology from Research to Prevent Blindness, New York.