Objective To assess the effects of 670nm LED (light-emitting diode) to protect the photoreceptor from the light-induced damage in a rat model. Methods 32 SD rats were randomly assigned to one of eight groups: untreated control group, the LED-treated control group, three groups of light-induced damage,and three groups of light-induced damage treated with LED. Light-induced damage result from exposing to constant light for 3 hours of different illuminations of 900,1800 and 2700 lx, respectively. The LED treatment (50 mW) was delivered for 30 minutes at 3 hours before the light damage and 0,24 and 48 hours after the light damage. Retinal function and morphology were measured by electroretinogram (ERG) and histopathology assay. Results The illumination of 900 lx for 3 hours did not damage the rat retina. The illumination of 1800 lx for 3 hours resulted in thinner ONL and no OS and IS. The ratio of damaged area/total retinal area was 0.48±0.12, the damaged thickness of ONL/normal ONL (L5) was 0.39±0.07,and the amplitude of ERG b wave was (431±120) μV. With the LED treatment the ratio of damaged area decreased (M6=0.17±0.12, P5/6=0.002), and the ratio of the damaged thickness of ONL also decreased (L6=0.22±0.09, P5/6<0.01), and the amplitude of ERG b wave increased to (1011±83) μV(P5/6 <0.001). The illumination of 2700 lx for 3 hours caused severed damage to the rat retina and the LED could not protect them significantly. Conclusions 670 nm LED treatment has an evident protective effect on retinal cells against light-induced damage, which may be a simple and effective therapy to prevent or to delay age-related maeular degeneration.

Background Trachoma is a serious blinding eye disease.At present,the incidence rate of trachoma in China has been greatly reduced with the unremitting efforts of World Health Orgnization (WHO) and Chinese government.However,in some economically underdeveloped areas,there is still active trachoma.Ohjective This study aimed to survey the prevalence of children's active trachoma in rural area of Naxi district and Jiangyang district of Luzhou city and assess the prevention and treatment outcome of trachoma during 10 years.Methods A cross-sectional study was performed in Naxi district and Jiangyang district of Luzhou city,the economic underdeveloping and water-starved regions in the year 2000.The active trachoma was screened in 214 school-age children with the male 113 and female 101 based on simplified trachoma grading system and trachoma rapid assessment survey standards and requirements of WHO.The symptoms of active trachoma were divided into trachomatous follicular (TF),trachomatous inflammation intense (TI),trachomatous scarring (TS),trachoma trichiasis (TT) and corneal opacities (CO).The epidemiological survey was re-assessed in 100 school-age children (with the male 58 and female 42) in these regions in the year 2013 to evaluate the prevalence change of children active trachoma during 10 years.Results In the year 2000,214 children were screened in 4 villages of Naxi district and Jiangyang district,and the prevalence rate of TF was 49.07％ (105/214) in the year 2000.The prevalence rate of TF was 49.05％ (52/106) in the Naxi district and 49.07％ (53/108) in the Jiangyang district,showing no significant difference between them (x2 =0.01,P =0.99).In the 100 school-age children who received survey in Naxi district and Jiangyang district in the year 2013,no TF,TF,TI,TS,TT and CO was found,showing no active trachoma.Conclusions The active trachoma has been controlled in rural areas of Luzhou city following the prevention and treatment of trachoma and the improvement of economic status in past decade.