The Macula Progression Study (MAPS): Repeatability of a Single, Wide-field, Swept-Source Optical Coherence Tomography Protocol

Abstract

Purpose : Commercially-available software for detecting progression with OCT do not employ a reference database with patient data repeated over short intervals to help differentiate progression from variability. We have described and validated a single wide-field swept-source optical coherence tomography (ssOCT) protocol to diagnose early glaucoma.[1] To test the feasibility of using this single scan protocol to detect the progression of glaucoma, we assessed the repeatability of its measures.

Methods : In this prospective cohort study, we included 124 eyes (124 subjects (52 healthy controls; 16 glaucoma suspects; and 56 early manifest glaucoma) with 24-2 mean deviation (MD) > -6 dB). All participants had ssOCT wide-field scans (9x12 mm, DRI-OCT, Topcon, Inc., Tokyo, Japan) and 24-2 and 10-2 visual field tests on the same day, which were repeated at least four times within an 8 week period. For quantitative analysis, we calculated the 90% limits of variability of local and global macular retinal ganglion cell plus inner plexiform layer (RGC+) and circumpapillary retinal nerve fiber layer (cpRNFL) thicknesses. Changes exceeding the upper 5% and 1% limits are deemed “possible” and “likely” progression, respectively. For qualitative analysis, two expert graders reviewed all sequential images to assess the repeatability of the single wide-field ssOCT report.

Results : The repeatability of RGC+ and cpRNFL thickness measurements was excellent (ICC= 0.96 and 0.98, respectively). The expert grader did not flag any significant changes in participants’ reports over time using the repeatability data. Figure 1 depicts an example of a patient with double arcuate scotomata affecting the macula. The wide-field reports of tests performed 4 weeks apart were very similar.

Conclusions : Given its excellent repeatability, a single wide-field ssOCT report may be useful not only to diagnose early glaucoma,[1] but also to detect early signs of structural progression.

REFERENCE
1. Hood et al., TVST 2016:5(6):4

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.