Visual Field Abnormality Classification System Developed for Eyes With High Myopia

Researchers developed a reproducible classification system of visual field (VF) abnormalities for non-pathological high myopia, according to a study published in Ophthalmology. This system may be able to distinguish glaucomatous from non-glaucomatous VF loss in eyes with high myopia.

Researchers recruited 825 participants with high myopia (1302 eyes, mean age 30.94±9.75 years, mean axial length (AL) 26.87±1.13 mm, mean spherical equivalent (SE) -8.61±2.10 D) from a longitudinal observational high myopia registry cohort study. They performed comprehensive eye exams and VF testing on all participants. Two trained readers graded a subset of 1000 VF images to establish both inter and intra-observer agreement. 

The researchers analyzed VF defect patterns they observed in 1893 VF tests, literature reviews, and consensus meetings and classified 4 types of VF patterns: normal, glaucoma-like defects, high myopia-related defects, and combined defects.

They found that 965 eyes (74.1%) had normal VF, while 10.8% had glaucoma-like defects, 15.0% had high myopia-related defects, and 0.1% had combined defects. Among the 142 eyes with glaucoma-like defects and combined defects, 38 were diagnosed with primary open-angle glaucoma (POAG).

Intra-observer agreement of the 2 graders was 92.5% and 91.5%, respectively, while inter-observer agreement was 89.1%. After excluding the “normal” fields from analysis, intra-observer agreement was 87.8% and 86.2%, while inter-observer agreement was 82.2%.

The team noted that glaucoma-like (n=140) and high myopia-related (n=195) VF defects were associated with older age (both P <.001) and longer AL (OR:1.65, 95% CI:1.32-2.07, P <.001 and OR:1.37, 95% CI:1.11-1.68, P =.003, respectively).

They also determined that AL had more impact on the prevalence of glaucoma-like VF defects compared with the prevalence of high myopia-related VF defects (P =.036).

Investigators note that this system allows eye care professionals “to distinguish glaucomatous VF loss from non-glaucomatous VF defects in highly myopic eyes in their clinical practice and also may facilitate comparison of findings among clinical trials and epidemiologic studies.”

Limitations of the study included possible referral bias, a small number of abnormal VF cases, and the possibility that 24-2 VF missed some peripheral rim defects.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Reference

Lin F, Chen S, Song Y, et al. Classification of visual field abnormalities in highly myopic eyes without pathological change. Ophthalmol. Published online March 11, 2022. doi:10.1016/j.ophtha.2022.03.001