Purpose: The retinoid cycle is partly associated with the pathogenesis of retinitis pigmentosa. There are reports demonstrating that 9-cis-retinal and its precursor 9-cis-β-carotene are effective in inhibiting the progression of fundus albipunctatus and other types of retinitis pigmentosa. The purpose of this study is to investigate the impact of a food product containing 9-cis-β-carotene-rich microalgae Dunaliella bardawil on Japanese patients with retinitis pigmentosa.
Subjects and methods: This study was performed at three facilities as a multicenter prospective study. Fifty-nine eyes of 30 patients (13 men and 17 women) diagnosed with retinitis pigmentosa and capable of undergoing fundus photography were enrolled. The mean age was 56.4±14.1 years. Before and after 3-month uptake of Dunaliella bardawil, best-corrected visual acuity and parameters evaluated using Humphrey field analyzer (HFA), Goldmann perimetry (GP), and electroretinogram (ERG) were measured. In GP, visual field was digitized, and the area obtained by subtracting I-4 isopter scotoma from V-4 isopter visual field was measured. We compared the mean retinal sensitivity of the four central measurement points on HFA and b-wave amplitude on ERG.
Results: Best-corrected visual acuity significantly improved from 0.51 to 0.48 in the logarithm of minimum angle of resolution (logMAR, p=0.008). Mean retinal sensitivity of four measurement points on HFA significantly improved from 15.7 to 16.3 dB (p=0.034). On GP, visual field significantly expanded from 206,763 to 220,933 pixels (p=0.048). The amplitude of b-wave on ERG somewhat decreased from 63.4 to 56.5 μV, but this change was not significant (p=0.109).
Conclusions: Three-month supplementation with food product containing 9-cis-β-carotene-rich microalgae Dunaliella bardawil improved visual acuity and visual field in patients with retinitis pigmentosa. However, a further long-term randomized clinical trial may need to be conducted and the relationship of causative gene and visual outcome may need to be investigated.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc)122: 372-378, 2018.