CNV lesion OCT segmentation in a clinical trial of wet AMD

Abstract

Purpose : In neovascular/wet age-related macular degeneration (AMD), choroidal neovascularization (CNV) components develop both below (Type 1 lesion) and above (Type 2 lesion) the retinal pigment epithelium (RPE). In large AMD trials, optical coherence tomography (OCT) results are usually reported by mean thickness of the center subfield (from internal limiting membrane to RPE), which ignores Type 1 CNV components and measures any exudative intra/subretinal fluid and Type 2 CNV together with the retina. We examine the course of change in retina and CNV subcomponents by segmentation of OCT images from eyes with AMD and any association of these with visual acuity (VA) over time.

Methods : In a phase 1 open-label clinical trial (PAN-01-101[DB1] ) investigating a topical ocular anti-VEGF therapy with negative[DB2] treatment results, 10 subjects with previously-untreated AMD were followed with spectral domain (SD)-OCT and best-corrected VA out to 12 weeks post baseline. Type 1 and 2 lesion compartment volumes and retina thickness were assessed using custom OCT segmentation in the Excelsior application. Pearson correlations between OCT subcomponent volumes and center subfield thickness were analyzed for relationship to VA outcomes.

Results : Baseline mean VA was 60.5 letters (SD 5.8) and mean VA at 12 weeks was 62.2 (SD 10.5). Worse VA at baseline was highly correlated to VA improvement at study end (R = 0.76). VA at baseline was negatively associated with larger CNV subcomponent volumes. Greater intra/subretinal fluid was associated with better concurrent vision at baseline (R = 0.54); however, this may be spurious, as greater intra/subretinal fluid was weakly associated with worse concurrent vision at both other timepoints (R = -0.26, -0.15). Final VA at 12 weeks had the strongest negative correlation with Type 2 CNV volume at baseline (R = -0.41). The mean center subfield thickness had similar correlation with concurrent VA at baseline (R = -0.51) as well as negative correlation between baseline thickness and VA at 12 weeks (R = -0.47).

Conclusions : In untreated AMD, concurrent VA and change in VA are typically associated with change of various lesion component volume. In this AMD cohort, Type 2 CNV volume at baseline appeared to have the strongest significance for VA at 12 weeks, and this component also was negatively correlated with concurrent VA. OCT center subfield thickness had similar correlation with VA.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.