Evaluation of Reticular Pseudodrusen by Polarization-Sensitive Optical Coherence Tomography: Case Report

Introduction: Reticular pseudodrusen (RPD) are an important clinical biomarker associated with progression to late age-related macular degeneration (AMD). We report polarization-sensitive optical coherence tomography (PS-OCT) findings in a case of RPD and evaluate the entropy characteristics of these lesions. Case Presentation: A 73-year-old man presented for evaluation of retinal angiomatous proliferation in his right eye. The left eye demonstrated multiple round, white-yellowish macular lesions consistent with RPD. Optical coherence tomography (OCT) angiography showed no macular neovascularization in the left eye. Swept-source (SS-OCT) revealed hyperreflective, spike-like deposits between the photoreceptor outer segments (PROSs) and the retinal pigment epithelium. Corresponding PS-OCT B-scans demonstrated moderately elevated polarimetric entropy values at the same locations. En face images reconstructed from the PROS layer showed circular RPD-like lesions on SS-OCT, which precisely matched high-entropy areas on PS-OCT. Merged en face maps confirmed one-to-one correspondence between RPD and regions of increased entropy. Conclusion: PS-OCT successfully visualized RPD as moderately high-entropy lesions in the PROS layer, suggesting that these deposits are composed of non-retinal pigment epithelium material, such as lipids or inflammatory cells. These findings indicate that PS-OCT may serve as a useful complementary modality for detecting RPD and may enhance current imaging strategies for assessing RPD and monitoring AMD progression.