Abstract
Purpose:
Ultraviolet (UV) light is a factor for the development of cataracts. One mechanism for damage to the lens is via UV light-induced increases in free radicals. The goji berry is a traditional Chinese health supplement that has antioxidant properties. This study was undertaken to determine whether goji berry can prevent or delay UV-induced cataractogenesis.
Methods:
Lenses were dissected and cultured in medium for 24 hours. Lenses were placed in medium with or without goji berry extract, then placed into an incubation chamber equipped with UVB light (2.0 J/cm2) for two hours. Control lenses were placed in light-proof cardboard boxes before being added to the the UV irradiation chamber. Assessment of optical quality was made using a scanning laser monitor, with clearer lenses showing smaller back vertex distance (BVD) errors at various eccentricities from the optical axis. Lenses were scanned prior to UV-irradiation (baseline), then again at 4 hours, 8 hours, 1 day, 2 days, 7 days, 9 days, 11 days and 14 days post-irradiation. The absorbance of the culture medium with and without goji berry extract was determined for the UV range used (280 - 320 nm).
Results:
In the UV-irradiated lenses cultured in medium only, back vertex distance (BVD) errors increased, and were significantly different from the baseline value at days 11 and 14 (p<0.0001 for both days). The other three groups did not show significant changes across time (p > 0.05 for all groups), although of the three groups, the lenses not exposed to UV light showed the smallest average BVD errors (medium: 0.45 ± 0.05 mm; with goji: 0.56 ± 0.06 mm). Overall, the two groups of lenses treated with UV had greater back vertex distance (BVD) errors than the two control groups, with lenses cultured in medium showing significantly higher BVD errors than those cultured in goji berry supplement (p = 0.0049). Absorbance values for medium with goji berry extract were between 38.0% to 81.3%, while medium without goji berry absorbed between 4.2% to 42.0%.
Conclusions:
Goji berry extract was able was able to attenuate UV-induced cataractogenesis. However, the culture medium played a role in the amelioration, absorbing as much of the UV-irradiation as the cornea is reported to absorb (about 70 to 75%). To determine the true effects of the UV-protective properties of the goji berry, lenses need to be irradiated prior to incubation in goji berry medium.
Keywords: 445 cataract •
630 optical properties •
424 antioxidants