Assessing Glaucoma Severity and Progression in Individuals with Asymmetric Axial Length: An Intrapatient Comparative Study.

ABSTRACT

PURPOSE: To investigate whether a difference exists in intereye glaucoma severity and progression in patients with asymmetric axial length. DESIGN: Long-term observational study. PARTICIPANTS: Patients older than 20 years with a diagnosis of glaucoma at Seoul National University Hospital, Seoul, Korea, between 2010 and 2020. METHODS: Patients with a diagnosis of glaucoma in both eyes with an axial length difference of more than 1.0 mm were included. Each individual's eyes were classified into longer eye and shorter eye, and the baseline and follow-up clinical data were analyzed using the paired T-test and McNemar test. MAIN OUTCOME MEASURES: Differences in clinical characteristics in patients with asymmetric axial length. RESULTS: A total of 190 eyes of 95 patients with glaucoma with asymmetric axial length were included in the study. The patients' mean age was 51.2 ± 12.3 years, and the mean follow-up period was 10.1 ± 3.9 years. No difference was found in baseline intraocular pressure (IOP) or central corneal thickness between longer eyes and shorter eyes. Among the baseline disc parameters, ovality index, ß-zone and γ-zone parapapillary atrophy (PPA) area were larger (P < 0.001) in the longer eyes. In the baseline OCT data, the retinal nerve fiber layer (RNFL) thickness (P = 0.009) and ganglion cell-inner plexiform layer (GCIPL) thickness (P < 0.001) were thinner in the longer eyes. According to a baseline visual field (VF) test, the mean deviation and VF index (VFI) values were significantly lower (P < 0.001, P = 0.034) in the longer eyes. Based on an analysis of glaucoma progression, the rate of change of superior GCIPL (longer eyes, -0.65 µm/year; shorter eyes, -0.40 µm/year), mean deviation (longer eyes, -0.40 dB/year; shorter eyes, -0.21 dB/year), and VFI (longer eyes, -0.92%/year; shorter eyes, -0.46%/year) were larger (P = 0.006, P = 0.005, P < 0.001) in the longer eyes. Additionally, the greater the difference in IOP fluctuation, the greater the difference in the rate of change between mean deviation and VFI. CONCLUSIONS: When an axial length difference of more than 1.0 mm was present, glaucoma tended to be more severe and to progress faster in the longer eyes. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.