Multimodal structure–function mapping of retinal sensitivity loss in pachychoroid spectrum diseases

PURPOSE: Pachychoroid spectrum disease (PSD) is characterized by a thickened choroid and alterations of the retinal pigment epithelium (RPE). Although structural changes in PSD have been well described, the relationship between RPE integrity and retinal function has not been fully clarified. This study investigated the characteristics of retinal sensitivity in eyes with inactive PSD using near-infrared autofluorescence (NIRAF) and microperimetry. METHODS: Twenty-six eyes without recent exudative activity were retrospectively analyzed. Hypoautofluorescent areas on NIRAF images were manually outlined to identify regions of RPE alteration, and mean retinal sensitivity (mRS) was compared between the inside and outside of these lesions. RESULTS: Thirteen eyes showed macular neovascularization (MNV-positive), while the remaining thirteen had no MNV. In MNV-positive eyes, mRS was significantly reduced within hypoautofluorescent lesions compared with surrounding areas (26.98 ± 7.14 vs. 29.11 ± 4.53 dB, p = 0.021). In MNV-negative eyes, a similar but nonsignificant trend was observed. In an exploratory adjusted linear regression model, MNV status was associated with greater lesion-associated retinal sensitivity reduction (B coefficient = 1.55, p = 0.032). Sublesional choroidal thickness and symptom duration were not significantly associated with ΔmRS. CONCLUSION: These results suggest that NIRAF-defined RPE alterations are topographically associated with localized retinal sensitivity reduction, particularly when MNV is present. The combined use of NIRAF, microperimetry, and OCT angiography may support topographic functional assessment in PSD, although prospective validation is required.