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BackgroundThe baseline data pertaining to the national epidemiological survey of infectious keratitis remain scarce in China, and currently there is no corneal blindness control strategy developed by the nation.MethodsGeographically defined cluster sampling was used to randomly select a cross-section of residents from representative urban and rural populations in Hubei Province. Participants were selected from village registers, followed by door-to-door household visits. The assessment items included a structured interview, visual acuity testing, external eye examination, and anterior segment examination using slit lamp. Causes and sequelae of corneal disease were identified according to uniform customized protocol.ResultsThe prevalence of presenting corneal diseases was 0.8% (211/26 305), while the prevalence of infectious keratitis was 0.148% (39/26 305). The prevalences of viral, bacterial, and fungal keratitis were 0.065, 0.068, and 0.015%, respectively. There were no significant differences found between the prevalences of viral (accounting for 43.6%) and bacterial (accounting for 46.2%) corneal ulcers. cases of Acanthamoeba keratitis were not found. Infectious keratitis was the leading cause of corneal blindness (85.7%), and the prevalence of blindness in at least one eye resulting from infected corneas was 0.091% (95% CI: 0.067-0.127%).ConclusionsViral and bacterial mechanisms constitute the most important risk factors for infectious corneal ulcers in Central China. To reduce the rate and severity of infectious keratitis, he public health care policy should be focused on designing cost-effective strategies and operational programs for the prevention and prompt treatment of infectious corneal ulcers.

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Objective: Previous studies provided evidence that many factors contribute to retinal angiogenesis, including inducible nitric oxide synthase (iNOS), hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). But the role of nitric oxide generated by iNOS in the regulation of expression of hypoxia-inducible genes in retinopathy of prematurity remains unclear. So we sought to better define the molecular basis of this iNOS-dependent regulation. Methods: In this study, using immunohistochemistry, real-time PCR and Western blotting technologies, we investigated the changes of iNOS, HIF-1α, VEGF and phosphatidylinositol 3-kinase/Akt (PI3K/Akt) expressions. Results: Hypoxia- induced overexpression of iNOS, HIF-1α, VEGF, PI3K/Akt and phosphorylated PI3K/Akt was observed in the untreated retinopathy of the prematurity group. Administration of the selective iNOS inhibitor aminoguanidine hemisulfate markedly decreased the expression of these genes. Conclusions: These results indicate that iNOS mediates HIF-1α activation and VEGF expression in retinal angiogenesis and that the PI3K/Akt signaling pathway may play a role in this process.

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