Photoreceptors integrity as surrogate of retinal sensitivity in chronic central serous chorioretinopathy: a multimodal imaging study

PURPOSE: To assess the correlation between photoreceptor mosaic integrity in chronic central serous chorioretinopathy (cCSCR) and multiple morpho-functional parameters, including photoreceptor density (PD), normalized reflectivity of photoreceptor layers (NR-PRL), normalized reflectivity of the retinal pigment epithelium (NR-RPE), choriocapillaris vascular perfusion density (CC-VPD), and retinal sensitivity (RS). METHODS: This observational cross-sectional study was conducted between June 2023 and September 2024. Patients with cCSCR and healthy controls underwent imaging with Spectralis High Magnification Module (HMM), structural OCT, and OCT-Angiography in the macular area. Regions of interest were selected and topographically superimposed across modalities. Retinal sensitivity was assessed using fundus microperimetry with a 4-2-1 automated staircase strategy. RESULTS: Mean photoreceptor density was significantly lower in cCSCR eyes than in healthy controls (6617.8 vs. 11162.3 cells/mm², p = 0.0004). Mean NR-PRL was 0.6 in cCSCR and 0.9 in controls (p = 0.0074), while NR-RPE was also significantly reduced in cCSCR (p = 0.0465). Mean CC-VPD was 41.8% in cCSCR compared with 63.7% in controls (p = 0.0011). Mean retinal sensitivity was significantly decreased in cCSCR (10.74 ± 3.90 dB) versus controls (19.39 ± 3.90 dB; p = 0.0001) and strongly correlated with photoreceptor density. A strong correlation between NR-PRL and NR-RPE was observed in both controls (r = 0.883, p = 0.014) and cCSCR eyes (r = 0.884, p = 0.015). CONCLUSIONS: Photoreceptor mosaic integrity significantly correlates with retinal sensitivity in cCSCR. HMM represents a reliable and accessible in vivo tool for quantifying photoreceptor loss and its functional impact.