Optimization of Contact Lenses for Corneal Protection During Vitreoretinal Surgery.

OBJECTIVES: To optimize parameters of contact lenses (CLs) and evaluate their ability to protect the cornea during vitreoretinal surgery. METHODS: We compared the protective effects of balanced saline solution, viscoelastic agent, and CLs on rabbit corneas under conditions simulating vitreoretinal surgery. We evaluated CLs of different thicknesses and compared the protective effects of polymethyl methacrylate (PMMA) and gas-permeable fluorosilicone acrylate (XO) lenses on the corneas of rabbits and patients with severe proliferative diabetic retinopathy (PDR). The corneal fluorescein staining score (FSS) was measured to compare the protective effects of CLs. RESULTS: The FSS was significantly lower in the PMMA group than in the balanced saline solution and viscoelastic agent groups. The thickness of the PMMA lenses had no significant effect on the FSS. The FSS was significantly higher in the PMMA group than in the XO group. In patients with PDR, on day 1 after vitreoretinal surgery, the FSS was significantly higher in the PMMA group than in the XO group, although no significant difference was observed on postoperative day 7. CONCLUSION: The XO lens offers better corneal protection during noncontact wide-angle vitreoretinal surgery and protects the corneal epithelium more efficiently during vitrectomy in patients with PDR, irrespective of its thickness.

Challenges and opportunities for modeling coupled human and natural systems.

With the growing recognition of coupled human and natural systems (CHANS), modeling CHANS with two-way feedbacks has become a frontier research area and a critical tool to achieve sustainability. The challenges in CHANS modeling and opportunities to advance its science and application to promote the sustainability of CHANS are discussed in this paper.

Remote sensing assessment and spatiotemporal variations analysis of ecological carrying capacity in the Aral Sea Basin.

The severe shrinkage of Aral Sea and water resources coordination issues in upstream and downstream regions lead to the serious ecological crisis in the Aral Sea Basin (ASB). Comprehensive ecological carrying capacity (ECC) assessment is of great significance for the ecological restoration and sustainable development. Based on the Analytic Hierarchy Process (AHP) and Experts Mark, this paper established the index evaluation system according to the specific ecological situation of the ASB. Combining remote sensing (RS) data and geographic information systems (GIS) technology, the paper assessed the ECC from 2001 to 2018 and explained the variations of the ECC by various data. The results indicate that the ECC is getting better in eighteen years. In 2009, the ECC condition is the best. ECC of the upstream region is better than that of the downstream region. The cause analysis that highlights the precipitation and enforcement of ecological policy has a positive impact on the ECC change. And the disparity of water body in upstream and downstream watercourses contributes to the regional difference of ECC. The paper provides an evaluation system of the ECC in the ASB. The analysis of the ECC variations is instructive to the sustainable development and ecological restoration in the ASB and other similar areas.