Longitudinal Assessment of Structural and Functional Changes in Rod-cone Dystrophy: A 10-year Follow-up Study

Area of Science:

• Ophthalmology
• Genetics
• Retinal Diseases

Background:

• Inherited retinal diseases (IRDs) necessitate understanding long-term progression for clinical trials.
• Rod-cone dystrophies (RCDs) are a group of IRDs affecting vision.

Purpose of the Study:

• To investigate the long-term (10-year) progression of retinal structure and function in patients with RCDs.
• To analyze the impact of genetic diagnosis on disease progression.
• To assess interocular symmetry in disease progression.

Main Methods:

• Longitudinal observational study of individuals diagnosed with retinitis pigmentosa.
• Baseline and 10-year follow-up assessments included visual acuity (VA), Goldmann visual field (GVF), spectral-domain OCT, electroretinogram, and genetic testing.
• Linear mixed models and intraclass correlation coefficients (ICCs) were used to analyze progression and symmetry.

Main Results:

• Of 23 participants, 20 had RCDs; 3 were reclassified based on genetic findings.
• Only 60% of RCD participants showed a ≥15 letter decline in VA over 10 years.
• High symmetry was observed for GVF area progression (ICC=0.87), moderate for VA (ICC=0.50) and ellipsoid zone width (ICC=0.64).

Conclusions:

• Visual acuity alone may not be a sufficient measure for tracking RCD progression over 10 years.
• Interocular symmetry in disease progression varies, which is crucial for selecting outcome measures in IRD clinical trials.
• Genetic diagnosis plays a role in understanding RCD subtypes and progression patterns.