Focal OCT defects are predictors for future glaucoma progression in the same region

Abstract

Purpose : To test the hypothesis that the presence of focal glaucomatous structural defects (i.e., a defect only in one hemi-retina) predicts further progression in the same region.

Methods : We created a database of all Humphrey visual field tests (VF) and Cirrus optical coherence tomography (OCT) scans of the disc and macular (Carl Zeiss) from glaucoma patients seen between 02/01/2020 and 05/10/2022. Overall, 78,298 VF and 49,559 OCT scans from 11,234 eyes (6,495 patients) were collected. We included only those eyes with same-day 24-2 VF and OCT exams on at least five visits, a minimum of 5 years follow-up, and a superior OR inferior glaucomatous structural defect, as defined by the Columbia University OCT-based method (CU-method) of RNFL defect with corresponding ganglion cell layer (GCL) loss.^1,2 Progression was defined as a hemi-retinal RNFL rate of change (ROC) worse than -1 µm/year and a corresponding GCL ROC worse than -0.5 µm/year using the commercially available Forum Structure-Function guided progression analysis (GPA, Carl Zeiss).³

Results : 98 eyes (83 patients, follow-up duration [Median, range]: 6.7, 5.1-11.3 years; visits: 5.5, 5-14) had inferior (n=66) OR superior (n=32) RNFL and commensurate GCL defects (Fig. 1). A total of 57 eyes (58%) progressed. 50/57 (87.7%) progressed in the same hemiretina as the original defect. 33/57 (57.9%) developed a defect in the opposite, previously normal, hemiretina. 26 of these 33 eyes (78.8%), also had structural progression in the same hemiretina as the original defect (P=0.004). The probability of developing a new defect was not significantly different based on whether the original defect was in the superior or inferior hemiretina (P = 0.142).

Conclusions : Glaucomatous structural damage is more likely to progress within an already damaged region than in a previously healthy region. In eyes with an existing structural defect, a new structural defect is typically accompanied by progression of the initial defect. An isolated OCT defect is a surrogate for future glaucoma progression in the same region.
References: Liebmann et al, JOG 2022; 2. Hood et al. PRER, 2022; 3. Hammel et al AJO 2017

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.