Characterization of Visual Function, Interocular Variability and Progression Using Static Perimetry-Derived Metrics...

Area of Science:

• Ophthalmology
• Genetics
• Visual Neuroscience

Background:

• Retinitis pigmentosa (RP) is a group of inherited retinal diseases.
• Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene are a common cause of X-linked RP.
• Understanding visual function, variability, and progression in RPGR-associated RP is crucial for patient management and therapeutic development.

Purpose of the Study:

• To characterize bilateral visual function in subjects with RPGR gene mutations.
• To assess interocular variability and progression using static perimetry-derived metrics.
• To provide prognostic information for patients with RPGR-associated RP.

Main Methods:

• Prospective longitudinal observational study of 47 genetically confirmed subjects.
• Assessment of visual function using ETDRS charts, Pelli-Robson charts, and Octopus 900 static perimetry with a 185-point grid.
• Generation of 3D hill-of-vision models and analysis of volumetric metrics (VTotal, V30, V5) and mean sensitivity; interocular differences assessed using Bland-Altman method.

Main Results:

• Good baseline interocular symmetry observed (1% for VTotal, 8% for V30).
• Subject percentage interocular difference (SPID) varied (16% for VTotal, 17% for V30).
• Interocular symmetry in progression was notable (73% for VTotal, 64% for V30); an overall annual decline of 6% was observed.

Conclusions:

• Generally good interocular symmetry in visual function exists in RPGR-associated RP, with some inter-subject variability.
• Findings support patient selection for clinical trials and provide prognostic guidance for clinicians.
• Volumetric and pointwise metrics from static perimetry are valuable for characterizing disease progression.