Validation of a Vision-Guided Mobility Assessment for RPE65-Associated Retinal Dystrophy

Area of Science:

• Ophthalmology
• Neurology
• Human Movement Science

Background:

• RPE65-associated retinal dystrophy (RPE65-RD) significantly impacts vision and mobility.
• Validated assessments are crucial for tracking disease progression and treatment efficacy in RPE65-RD.

Purpose of the Study:

• To validate a novel vision-guided mobility assessment for individuals with RPE65-RD.
• To establish the repeatability, convergent, discriminant, and criterion validity of the assessment.

Main Methods:

• A comparative cross-sectional study involving 29 subjects (19 with RPE65-RD, 10 controls).
• Mobility was assessed via straight-line following, maze navigation, and obstacle stepping.
• Performance metrics included time, errors, and walking speed under varying illumination.

Main Results:

• Walking speed during maze navigation effectively discriminated between RPE65-RD and control groups (convergent and discriminant validity).
• Mobility was significantly poorer in RPE65-RD subjects under low illumination.
• The assessment demonstrated good repeatability and approached criterion validity.

Conclusions:

• A novel, quantifiable, and repeatable vision-guided mobility assessment was developed and validated for RPE65-RD.
• This assessment is sensitive to visual impairment in low light and captures phenotypic heterogeneity.
• It serves as a valuable outcome measure for RPE65-RD research and clinical trials.