Adaptation to water scarcity in glacier-dependent towns of the Indian Himalayas : impacts, adaptive responses, barriers, and solutions

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 195-203).Among the existing and projected impacts of climate change, impacts on water resources are expected to exacerbate the current and future threat of global water scarcity. Glacier-dependent societies are especially vulnerable to water scarcity due to the more pronounced effects of climate change on glacial systems that govern the water availability of these societies. In this thesis, water scarcity is examined as an impact of climate change in Dharamshala and Leh, two glacier-dependent towns of northern India, while recognizing that climate change is not the only factor causing depletion of water resources in these towns. In order to show the linkage between climate change and water scarcity, evidence is presented on changes occurring in the towns' local climate parameters such as snowfall, rainfall and temperature, as well as changes in the hydrology of the water bodies that make water available to these towns. This establishes that water scarcity in these towns has been induced not only by increasing demand, but also by decreasing supply of water. In light of the water scarcity facing these towns, an investigation of the measures taken by their local governments to address this issue is presented, which reveals that the primary adaptive response employed in both towns has been supply augmentation. The driver behind this response has been the pursuit of economic development to improve the standard of living of Dharamshala and Leh's constituents. It is argued that economic development as a driver has not been effective in inducing holistic adaptive responses to water scarcity. Additionally, climate change considerations have been largely absent in the policy/planning processes that govern water management in both towns, implying that the responses of Dharamshala and Leh to water scarcity have been influenced by the pursuit of short-term economic benefits in a local economy that fails to recognize the importance of the integrity of water resources to its sustenance. The perpetuation of unsustainable economic development and failure to account for climate change impacts in local water management points to the presence of several technological, structural, financial, and political barriers to the planning/implementation of holistic climate-centric strategies for adaptation to water scarcity in Dharamshala and Leh. Therefore, in the concluding part of this thesis, recommendations are offered to enable the local governments of Dharamshala and Leh to overcome these barriers.by Amruta Anand Sudhalkar.M.Eng.M.C.P

Scleral buckling surgery using multiple radial buckles: A valid option?

Purpose: To determine whether radial buckling surgery using two or more radial buckles with or without circumferential silicone tires is still a treatment option for rhegmatogenous retinal detachment (RRD) in the current scenario. Methods: Retrospective chart review. Patients with RRD with two or more horse-shoe tears with/without proliferative vitreoretinopathy up to grade C1 who underwent buckling surgery using at least two radial buckle segments without encircling bands or drainage and with at least a 3 year follow up were included in the study. Data collected included demographics, corrected distance visual acuity (CDVA) at baseline and final follow up, details of the examination, surgical procedure(s) and complications noted, if any. Appropriate statistical analysis was done. Statistical significance was set at p < 0.05. Outcome measures: Proportion of patients who had an attached retina at final follow up, improvement in CDVA and complications. Results: 25 patients (25 eyes; 12 males and 13 females; 9 pseudophakic) were included. Median age: 35.15 ± 8.32 years. Median baseline CDVA: 1.97 ± 1.12 logMAR. Median final CDVA: 0.65 ± 0.37 logMAR (significant improvement). Most common presenting complaint was decreased vision (87.5%). Number of radial buckle segments placed varied between 2 and 4 per eye. One patient required vitrectomy for persistent retinal detachment. One required buckle removal for infection 5 years after the primary procedure. One patient required strabismus surgery. Median follow up: 12.25 years ± 2.14 years. None of the other patients had any complications. Conclusion: Radial buckling surgery (two or more segments) is a reasonably safe and valid alternative to vitrectomy for RDs with multiple breaks in different planes. Keywords: Radial buckle, Scleral buckling, Rhegmatogenous retinal detachmen

Sustained Intraocular Pressure Rise after the Treat and Extend Regimen at 3 Years: Aflibercept versus Ranibizumab

Purpose. To determine the risk factors associated with sustained intraocular pressure (IOP) rise in patients enrolled in the treat and extend (T&E) protocol receiving aflibercept/ranibizumab therapy for 3 years. Design. Retrospective, observational chart review. Setting. Multicentric. Patients. 789 patients (1021 eyes; 602 males) enrolled in T&E using aflibercept/ranibizumab for diabetic macular edema (DME), wet age-related macular degeneration (AMD), or macular edema in retinal vein occlusion (RVO). Intervention. The history, examination (clinical and special investigations), and treatment records were thoroughly scrutinized. Sustained IOP rise was defined as a rise in IOP above baseline by ≥6 mmHg and/or >24 mmHg on 2 or more consecutive visits. The Wilk–Shapiro test was used for confirming normality of data. The Mantel–Haenszel test and generalized estimating equations were used to analyse multicentric data as well as to analyse data from both eyes of the same patients in the event that both eyes were under therapy. The relative risk, chi-square test (with and without Yates’ correction), and univariate and multivariate analysis were used wherever appropriate. Statistical significance was set at P<0.05. The primary outcome measure was the determination of risk factors for sustained IOP rise with ranibizumab/aflibercept therapy. Secondary outcome measures included determining the incidence of IOP rise (short term and sustained), visual field, and retinal nerve fibre layer (RNFL) changes. Results. The mean follow-up was 42.4 months. Male gender, South Asian ethnicity, older age, presence of AMD and vein occlusion, use of ranibizumab, higher number of injections, narrow angles, switch to bevacizumab/ranibizumab, and preexisting glaucoma were associated with sustained IOP rise. No significant visual field and RNFL changes were seen. The overall incidence was 8.91%. No patient required filtering surgery. No patient with IOP rise returned to baseline. Conclusion. IOP rise is an important consideration as the chronicity of the condition can eventually lead to glaucomatous changes in eyes with already compromised vision. Follow-ups and use of appropriate therapy can be determined correspondingly