Longitudinal quantitative evaluation of outer retinal lesions in acute posterior multifocal placoid pigment epitheliopathy using optical coherence tomography

Purpose: To quantify the external limiting membrane (ELM) disruption and photoreceptor volume changes in eyes with acute posterior multifocal placoid pigment epitheliopathy (APMPPE) using Spectral Domain Optical Coherence Tomography (SD-OCT) at the acute and resolution phases. Methods: Retrospective study of 10 eyes of 5 patients with APMPPE. Intact ELM and the Bruch's membrane were manually traced using ImageJ software and their lengths from each scan of the Spectral Domain Optical Coherence Tomography macular volume were summed. The ratio of intact ELM length/Bruch's membrane length was calculated. Also, two-dimensional areas of specific regions of interest were demarcated between the intact ELM and Bruch's Membrane in every cross-sectional B-scan. Total volume of photoreceptors was calculated by multiplying the total area by the distance between B-scans. Results: There was a statistically significant increase in ELM/Bruch's membrane ratio (P value = 0.022), mean photoreceptors volume (P value = 0.028), and a significant linear positive correlation between change of intact ELM/Bruch's membrane ratio and percent change of photoreceptor volume (r = 0.927, P value = 0.001) when comparing baseline and final follow-up visit, independent of total follow-up length. Conclusion: Using Spectral Domain-Optical Coherence Tomography, we showed that quantitative evaluation of ELM disruption and the volume of photoreceptor recovery can help us to follow the clinical course of APMPPE.