Abstract
To compare the site-specific optical coherence tomography (OCT) biomarkers that appear prior to the formation of large hypertransmission defects (hyperTDs) with the eye-level OCT biomarkers that were shown to predict disease progression in eyes with intermediate AMD (iAMD).
Retrospective subgroup analysis of a prospective cohort study.
A prospectively enrolled cohort of eyes with iAMD, imaged with swept-source OCT (SS-OCT), was retrospectively reviewed to identify eyes that developed large hyperTDs. Large hyperTDs were defined as bright lesions with a greatest linear dimension (GLD) of ≥250 μm on an en face sub-retinal pigment epithelium (RPE) slab image created using segmentation boundaries positioned 64-400 μm below Bruch's membrane (BM). All visits prior to the formation of the large hyperTDs were retrospectively reviewed to identify the OCT biomarker at the retinal location where the initial large hyperTD formed.
82 of 171 eyes (48%) with iAMD developed at least one large hyperTD. At the first visits when the large hyperTD developed, a total of 119 large hyperTDs were detected. Hyperreflective foci (HRF) were the most frequent OCT biomarker at the sites prior to the formation of hyperTDs (88/119, 74%). Soft drusenoid lesions were the second-most frequent biomarker (77/119, 65%); however, 67 of these lesions occurred in conjunction with HRF. Calcified drusen (CaD) were present at 19 of 119 sites (16%). Of these 19 CaD lesions, 7 contained hyporeflective cores (hypoRC-CaD), and 11 were associated with HRF. Non-calcified hyporeflective core drusen (hypoRCD) were present at 16/119 (13%) sites, with three of the hypoRCD associated with HRF. Basal laminar deposits (BLamD) were present at 2 of 119 sites (2%), both of which were associated with HRF. Single cases of a vitelliform lesion and a small hyperTD were also identified prior to the large hyperTDs.
Site-specific analysis showed that HRF were the most frequent OCT biomarker at the sites prior to the formation of large hyperTDs. Soft drusenoid lesions and HRF were frequently observed together, consistent with our previous eye-level multivariable analysis, which showed that drusen volume was not independently predictive of the future formation of large hyperTDs.