While OCT is generally disregarded as a useful diagnostic tool for glaucomatous optic neuropathy (GON) in high myopes, a recent study in the Journal of Glaucoma suggests there is enough evidence in OCT scans to make an accurate diagnosis.
The investigation included 100 eyes of 60 glaucoma patients or suspects referred for OCT scans and evaluations. Individuals had corrected spherical refractive errors worse than −6.00D and/or axial lengths ≥26.5mm. An OCT specialist judged whether the eye had GON based on OCT circle scans of the disc and cube scans centered on the macula. A glaucoma specialist made the same judgment using all available information (family history, repeat visits, intraocular pressure, 10-2 and 24-2 visual fields, OCT). The study created a reference standard based on the glaucoma specialist’s classifications. In addition, the glaucoma specialist judged whether the eyes had peripapillary atrophy, epiretinal membrane, tilted disc and a paravascular inner retinal defect.
Based on the OCT information alone, the OCT specialist correctly identified 97 out of 100 eyes. In 63% of cases, the inner circle scan alone was sufficient. For the rest, the specialist requested other scans. In addition, 81% of the total eyes had peripapillary atrophy (79%), epiretinal membrane (18%), epiretinal membrane (26%) and tilted disc (48%).
Despite the study’s findings, optimal use of OCT will depend on training to correctly read the scans, which includes taking into consideration myopia-related OCT artifacts and segmentation errors, as well as peripapillary atrophy, epiretinal membrane and tilted disc, the researchers noted.
Zane Z, Ravivarn J, Emmanouil T, et al. Optical coherence tomography can be used to assess glaucomatous optic nerve damage in most eyes with high myopia. Journal of Glaucoma. August 25, 2020. [Epub ahead of print].