To assess the prevalence and causes of visual impairment (VI) in the elderly Chinese rural population in Shaanxi Province. A population-based, cross-sectional study design was used to determine the extent of VI in Chinese people over the age of 50 years in Shaanxi Province. Visual acuity and best-corrected visual acuity were measured using the logarithm of minimum angle of resolution chart. Blindness and low vision were defined according to WHO criteria. The major cause of VI was identified for all participants who were visually impaired. A total of 1912 residents completed a standard questionnaire and underwent a detailed eye examination, and the response rate was 90%. The overall prevalence of blindness and low vision were 1.5% and 8.2%. There was no statistically significant differences between genders in the prevalence of blindness and low vision (P > .05). The prevalence of blindness and low vision was higher among older individuals (P < .05) and lower (P < .05) among those with the highest education level. Cataract, corneal opacity, and glaucoma were considered as the main causes of blindness, which accounted for 67.9%, 10.7%, and 7.1%, respectively. Cataract, refractive error, and age-related macular degeneration were always considered as the leading causes of low vision, which accounted for 66%, 14.7%, and 5.8%, respectively. Cataract, corneal opacity, and glaucoma were the main causes of blindness and low vision in the population aged 50 years or more. The prevalence of these diseases that causes blindness and low vision was higher than that reported in other studies.

Purpose: To evaluate and compare changes in retinal nerve fiber layer (RNFL) thickness in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). Methods: The Cochrane Library, Medline, and Embase were screened using our key words. Results were carefully reviewed to ensure that the included studies met the inclusion/exclusion criteria, and the quality of the studies was assessed using the Newcastle-Ottawa Scale. All included studies categorized patients with OSAHS into 3 groups (mild, moderate, and severe), and measured average and 4-quadrant (temporal, superior, nasal, and inferior) RNFL thickness. All studies included a healthy control group. The weighted mean differences and 95% confidence intervals were calculated for the continuous outcomes. Results: Ten case-control studies were included in the meta-analysis, consisting of a total of 811 OSAHS group and 868 healthy eyes. A meta-analysis of the data showed that the average RNFL thicknesses in the mild, moderate, and severe OSAHS groups were significantly decreased compared to healthy controls. Additionally, RNFL thickness was significantly reduced in all but the temporal quadrant in the moderate and severe OSAHS groups when compared to healthy controls. Conclusions: On the basis of these results, we suggest that peripapillary RNFL thickness as measured by optical coherence tomography could be a useful tool to monitor and assess the severity of OSAHS in patients. Further studies are required in order to differentiate these RNFL changes from glaucomatous changes. This has not been properly examined in any of the studies we were able to identify.

Diabetes induced a serious of complications including diabetic retinopathy. Our study aimed to investigate the role of Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 in diabetic retinopathy. A mice model of diabetic retinopathy was established, and expression of SDF-1 and CXCR4 in retina was examined by Real-time quantitative PCR (qRT-PCR). Cells of human retinal pigment epithelial cell line ARPE-19 were treated with CXCR4 siRNAs and expression vector, and cell viability was detected by MTT assay. We found that expression of SDF-1 and CXCR4 in retina was significantly downregulated in mice with diabetic retinopathy than in normal healthy mice. High glucose treatment downregulated the expression of SDF-1 and CXCR4 in ARPE-19 cells at both mRNA and protein levels. Transfection with CXCR4 siRNAs decreased, while transfection with CXCR4 expression vector increased cell viability under high glucose treatment. We concluded that SDF-1/CXCR4 pathway improved diabetic retinopathy possibly by increasing cell viability. Abbreviations: SDF-1: Stromal cell-derived factor 1; CXCL12: C-X-C motif chemokine 12; qRT-PCR: Real-time quantitative PCR

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes and is a leading cause of visual decline and irreversible blindness. So we designed this study to investigate retrospectively the effect of preoperative photocoagulation on corneal endothelial cells after vitrectomy in patients with PDR.The study included 52 eyes of 46 patients with PDR complicated with vitreous hemorrhage, who underwent vitrectomy. Patients were apportioned to a photocoagulation group (26 eyes/23 patients) or nonphotocoagulation group (26/23 patients), according to their history of preoperative photocoagulation. A specular microscope was used to assess the corneal endothelial cell density and percentage of hexagonal cells (PHC) before surgery, and at 1 week, 1 month, and 3 months after surgery.The cell density was lower 3 months after surgery in the photocoagulation group, but at 1 month in the nonphotocoagulation group, all cases were significantly different from the preoperative value (P < .05 or P < .01). One week after surgery, the mean cell densities between the photocoagulation and nonphotocoagulation groups were not statistically different (P > .05). However, the mean cell densities at 1 and 3 months after surgery in the photocoagulation group were significantly higher than those in the nonphotocoagulation group (P < .05). The PHC values in the photocoagulation group at 1 week and in the nonphotocoagulation group at 1 week, 1 month, and 3 months were much lower than their respective preoperative values (P < .05 or P < .01). More importantly, at 1 and 3 months, the PHC had recovered to preoperative values in the photocoagulation group, but not in the nonphotocoagulation group. As for cell density and PHC, they were both significantly higher 1 and 3 months after surgery in the photocoagulation group than in the nonphotocoagulation group (P < .05).Photocoagulation before vitrectomy reduces subsequent corneal endothelial cell damage in PDR patients.