Microperimetry and Structural Risk Factors on OCT in Intermediate Age-Related Macular Degeneration

To determine the relationship between structural biomarkers on optical coherence tomography (OCT) that increases the risk of disease progression and microperimetric retinal sensitivity in patients with intermediate age-related macular degeneration (iAMD) DESIGN: Prospective cross-sectional, observational study PARTICIPANTS: Forty-five eyes of 23 patients with iAMD METHODS: Patients underwent OCT and microperimetry. OCT scans were evaluated for the risk factors intraretinal hyperreflective foci (HRF), hyporeflectivity within drusenoid lesions (HRDL), subretinal drusenoid deposits (SDD), double layer sign (DLS) and drusen volume. Microperimetric retinal sensitivity was analyzed with a 33-point grid covering the macula. With a novel method of determining what part of the retina corresponded to each microperimetry point, a Voronoi diagram was constructed, dividing the macula in cells consisting of the region nearer to each point than any other. The Voronoi diagram was superimposed on the OCT making it possible to determine the point-to-point location of the OCT risk factors. Univariable and multivariable linear mixed effects models were used for analysis MAIN OUTCOME MEASURES: Association between microperimetric retinal sensitivity and OCT risk factors at individual measuring points RESULTS: 1479 points of retinal sensitivity and corresponding structural area on OCT were included in this study. Retinal sensitivity was significantly decreased with presence of the OCT risk factors HRF, HRDL, DLS and drusen volume (all P < 0.001) when analyzed with the univariable linear mixed effects model. The multivariable model showed a significant decrease of retinal sensitivity with presence of HRF (P < 0.001), DLS (P = 0.025) and greater drusen volume (P < 0.001) CONCLUSION: Presence of HRF, DLS, and greater drusen volume, all of which increase the risk of disease progression, are significantly and independently associated with decreased microperimetric retinal sensitivity in patients with iAMD.