Structure function relationship of paracentral visual field impairment in myopic patients with primary open-angle glaucoma.

PURPOSE: To evaluate whether paracentral visual field (VF) impairment in patients with glaucoma and concomitant myopia is attributable to myopic maculopathy or papillomacular bundle impairment. METHODS: Patients diagnosed with primary open-angle glaucoma (POAG) who were able to complete both 24 − 2 and 10 − 2 Swedish Interactive Threshold Algorithm (SITA) standard testing on the Humphrey visual field analyzer (HFA) were included. Myopia was defined as an ocular axial length (AL) of 25 mm or greater. VF regions were classified using a structure-function relationship map developed at our facility, and total deviation (TD) values in each region were compared between myopic and non-myopic groups using generalized estimating equations (GEE). RESULTS: A total of 179 eyes from 128 patients were included in the study. AL of the eyes was 25.50 ± 2.00 mm. The myopic group comprised 103 eyes, and the non-myopic group had 76 eyes. No significant difference was found between the two groups on HFA 24 − 2, but on HFA 10 − 2, the non-myopic group had significantly lower TD values in the upper VF area (–17.94 ± 10.8 dB vs. − 13.98 ± 10.36 dB, p = 0.013), while the myopic group had significantly lower TD values in the cecocentral VF area (–4.90 ± 5.55 dB vs. − 7.42 ± 7.91 dB, p = 0.017). Nonlinear relationships suggesting optic neuropathy were observed between corresponding TD values and retinal nerve fiber layer thicknesses in the three VF regions. CONCLUSIONS: The papillomacular bundle is likely to be impaired in POAG with an AL ≥ 25 mm.