Three-dimensional Hill of Vision of Retinal Sensitivity in X-linked Retinitis Pigmentosa Participants under Scotopic and Mesopic Conditions.

Purpose: To evaluate the utility of three-dimensional hill of vision (HOV) analysis in assessing retinal sensitivity in X-linked retinitis pigmentosa (XLRP) patients under scotopic cyan, scotopic red, and mesopic microperimetry conditions.

Methods: Baseline microperimetry data from 31 eyes of 16 XLRP patients enrolled in the Horizon study were analyzed. HOVs were generated using Thin Plate Spline interpolation. Grid volumes of the central 20 degrees (V20) were compared between lighting conditions using the Wilcoxon Signed-Rank test with Bonferroni correction. Central and global deficits were evaluated across age groups and genotypes.

Results: The mesopic group showed the highest mean V20 (1.3 dB-Sr), followed by scotopic red (0.6 dB-Sr) and scotopic cyan (0.5 dB-Sr). Significant differences were found between mesopic and both scotopic conditions (p<0.01), but not between scotopic conditions (p=0.26). Central and global deficits were more prevalent under scotopic conditions and increased with age.

Conclusion: HOV analysis provides a comprehensive assessment of retinal sensitivity in XLRP, enabling detection of localized changes and quantification of sensitivity gradients. This volumetric approach offers advantages over traditional methods for diagnosis, monitoring progression, and evaluating treatment response.