Prevalence and risk factors of lens opacities in rural populations living at two different altitudes in China

AIM： To investigate the prevalence of and risk factors for lens opacities in populations living at two different altitudes in China.·METHODS： A total of 813 subjects aged ≥40y in Lhasa（Tibet Autonomous Region, China. Altitude： 3658 m） and Shaoxing（Zhejiang Province, China. Altitude： 15 m） were underwent eye examinations and interviewed in this cross-sectional study. Participants＇ lens opacities were graded according to the Lens Opacities Classification System II（LOCS II） and the types of opacities with LOCS II scores ≥2 were determined. Univariate and stepwise logistic regression were used to evaluate the associations of independent risk factors with lens opacities.· RESULTS： Lens opacities were significantly more prevalent in the high-altitude than in the low-altitude area（χ2=10.54, P 〈0.001）. Lens opacities appear to develop earlier in people living at high than at low altitude. The main types of lens opacity in Lhasa and Shaoxing were mixed（23.81%） and cortical（17.87%）,respectively. Independent risk factors associated with all lens opacities were age, ultraviolet（UV） radiation exposure,and educational level. Compared with participants aged40-49 y, the risk of lens opacities increased gradually from 2 to 85 times per 10 y [odds ratio（OR）=2.168-84.731,P 〈0.05）. The risk of lens opacities was about two times greater in participants with the highest UV exposure than in those with the lowest exposure（OR=2.606, P =0.001）.Educational level was inversely associated with lensopacities; literacy deceased the risk by about 25%compared with illiteracy（OR=0.758, P =0.041）.·CONCLUSION： Old age, higher UV exposure and lower educational level are important risk factors for the development of lens opacities. Lens opacities are more prevalent among high-altitude than low-altitude inhabitants.

Correlation between contrast sensitivity and the lens opacities classification system III in age-related nuclear and cortical cataracts

Background Contrast sensitivity （CS） testing can detect differences in functional vision and is highly correlated with visual performance. This study was designed to investigate the association between CS and the grading score using the lens opacities classification system （LOCS） III as well as the association between CS and visual acuity （VA） in nuclear or cortical age-related cataract （ARC） patients. Methods A total of 270 eyes with ARC and 30 control eyes were divided into nuclear opacity （NO）, nuclear color （NC）, cortical cataract （C） based on LOCS II1. The CS values measured at all spatial frequencies under photopic and glare conditions that resulted in contrast sensitivity function （CSF） were evaluated, and LogMAR VA was tested with the Early Treatment Diabetic Retinopathy Study （ETDRS） chart. The correlation between CSF and LOCS III grading scores, and between CSF and LogMAR VA were analyzed. Results Compared to the controls, CSF of the nuclear or cortical ARC significantly declined. There are significant correlation between CSF and LogMAR VA, and between CSF and LOCS III grading scores. Compared to the VA, a stronger correlation existed between CSF and LOCS III grading score than that of LogMAR VA and LOCS III grading score. CS at some spatial frequencies is significantly influenced with LOCS III grading score. Conclusions CSF significantly declined with the increasing ARC grading scores. Comparing to VA, CSF reflected the severity of cataract more comprehensively. CS at low spatial frequency is significantly influenced by ARC. Therefore, CS is more precise than VA in assessing the visual function of ARC patients.

Low power density microwave radiation induced early changes in rabbit lens epithelial cells

Objective To determine whether low power density microwave radiation can induce irreversible changes in rabbit lens epithelial cells (LECs) and the mechanisms of the changes.Methods One eye of each rabbit was exposed to 5mW/cm2 or 10mW/cm2 power density microwaves for 3 hours, while the contralateral eye served as a control. Annexin Ⅴ-propidium iodide (PI) two-color flow cytometry (FCM) was used to detect the early changes in rabbit lens epithelial cells after radiation. Results Lots of rabbit LECs were in the initial phase of apoptosis in the 5mW/cm2 microwave radiation group. A large number of cells became secondary necrotic cells, and severe damage could be found in the group exposed to 10mW/cm2 microwave radiation. Conclusion Low power densities of microwave radiation (5mW/cm2 and 10mW/cm2) can induce irreversible damage to rabbit LECs. This may be the non-thermal effect of microwave radiation.