High myopia may be a significant risk factor for visual field (VF) defects, according to a study. In a retrospective, observational series, Kyoko Ohno Matsui and colleagues in Tokyo reviewed the medical records of 492 eyes of 308 patients with high myopia (myopic refractive error > 8.00 D or axial length ≥26.5 mm). Follow-up of five or more years was reviewed. The VFs were measured by kinetic perimetry, and were quantified in 100 sectors within the V4 isopter. Eyes with a loss of 10% or more of the sectors were categorized as having significant VF defects, and a further loss of 10% or more during follow-up was considered significant progression. Eyes with any kind of myopic macular or peripheral lesions that could cause VF defects were excluded from the study. The researchers found that significant VF defects were newly developed in 13.2% of the eyes during a mean follow-up of 11.6 ± 5.5 years. Myopic eyes with an oval optic disc had significantly higher VF defects than myopic eyes with a round optic disc. Among the eyes with significant VF defect, the temporal VF defects were seen in 61.5% of the eyes with round discs, in 75.0% of eyes with vertically oval discs, and in 68.2% of the eyes with obliquely oval discs. During a mean follow-up of 10.2 ± 3.4 years, 73.8% of the eyes showed significant VF defect progression. An abrupt change of the scleral curvature was the only factor significantly linked to VF defect progression. The combination of stretching and distortion of the optic nerve fibers resulting from an abrupt change of scleral curvature might be factors that lead to optic nerve fiber damage in highly myopic eyes, the group said. They suggested that eyes with high myopia be examined for VF defect at least once annually. The study is published in the American Journal of Ophthalmology.