Effects of Photo-Biomodulation in Stargardt Disease

PURPOSE: Stargardt disease (STGD1) is the most common hereditary macular degeneration and currently no treatments have been approved to interrupt the progression of the disease. The aim of this study was to evaluate the efficacy of photo-biomodulation in patients with Stargardt disease 1 year after treatment, considering as primary outcomes improvements in best corrected visual acuity (BCVA), microperimetry, and pattern electroretinography (PERG) amplitude. MATERIALS AND METHODS: Ninety eyes of 45 patients with a diagnosis of Stargardt disease stage 1 were prospectively recruited at the University of Bologna. Selected patients were treated with photo-biomodulation therapy for 1 year for 10 minutes a day, twice a day, and 5 days per week for 12 months. A light emitting diode (LED) of 10 Hz and wavelength 650 nm was used. BCVA and microperimetry were assessed before treatment and 1 year after photo-biomodulation, whereas PERG was assessed at baseline, 1, 3, 6, and 12 months after treatment. RESULTS: BCVA improved from 0.7 [interquartile range (IQR)=0.6–0.9)] to 0.4 (IQR=0.2–0.5)] after treatment (95% CI=−0.3, −0.35; p=<0.001) and PERG negative wave at 35 ms (N35)-positive wave at 50 ms (P50) amplitude improved from 0.9 (IQR=0.74–1.21) to 2.12 (95% CI=1.11, 1.28; p<0.001). MP-1 Microperimetry improved from 26.5% (IQR=16.75–40) of median preferred retinal loci (PRL) within an area of 2° of diameter to 38% (IQR=29–50.25; 95% CI=10.50, 14.50; p=<0.001); on the other hand, PRL within 4° of diameter raised from 72% (IQR=51.5–80) to 80% (IQR=76–87) after photo-biomodulation (95% CI=4.50, 7.50; p<0.001). Also, patients with an improvement of more than 1.205 PERG N35-P50 ratio amplitude at 3 months and more than 1.29 at 6 months tended to present an improvement of more than 0.2 logMar in BCVA at 12 months (p=0.28, AUC=0.630; p=0.30, AUC=0.636). CONCLUSION: BCVA, PERG, and MP-1 significantly improved 1 year after treatment. Also, improvement of PERG N35-P50 amplitude at 3 and 6 months was correlated to BCVA improvement at 1 year, suggesting that PERG could be useful in predicting visual outcome after photo-biomodulation.