Functionally Guided Retinal Protective Therapy for Dry Age-Related Macular and Inherited Retinal Degenerations: A Pilot Study

PURPOSE. To review the results of retinal function testing in eyes undergoing panmacular subthreshold diode micropulse laser (SDM) prophylaxis for chronic progressive retinal disease. METHODS. The records of all patients undergoing prophylactic panmacular SDM for high-risk age-related macular degeneration (AMD) and inherited photoreceptor degenerations (IRDs) examined by pattern electroretinography (PERG), automated microperimetry (AMP), and Central Vision Analyzer (CVA) testing before and after treatment were reviewed. RESULTS. A total of 158 consecutive eyes of 108 patients with AMD and 10 consecutive eyes of 8 patients with IRDs, evaluated both before and after SDM by PERG, were eligible for study. The IRD diagnoses included rod-cone degeneration (four eyes), cone-rod degeneration (three eyes), and Stargardt's disease (three eyes). In AMD, AMP was performed in 40 consecutive eyes, and CVA in the subsequent 73 consecutive eyes concurrent with PERG. The SDM treatment consisted of 1800 to 3000 confluent spots throughout the retina circumscribed by the major vascular arcades, including the fovea ("panmacular''). Testing was performed 1 week before and by 1 month after treatment. Results indicated that 149/168 eyes were improved by primary PERG measures: 139/158 eyes with AMD by PERG low-contrast scan Magnitude D (MagD)(mu V)/Magnitude (Mag)(mu V) ratios (P = 0.0001) and 10/10 eyes with IRDs by 24(0) concentric ring scan MagD(mu V)/Mag(mu V) ratios (P = 0.002). Snellen visual acuity (VA) was unchanged, but macular sensitivity by AMP (P = 0.0439) and mesopic contrast VA by CVA (P = 0.006) were improved. There were no adverse treatment effects. CONCLUSIONS. Our findings suggest a role for SDM as retinal protective therapy in chronic progressive retinal diseases. Pattern electroretinography enables (early, preventive) functionally guided, rather than (late, therapeutic) image-guided, disease management.