A model-ready emission inventory for crop residue open burning in the context of Nepal.

Open burning of crop residue is an important source of air pollution which is poorly characterized in South Asia. Currently, the gridded inventory reported by Global Fire Emissions Database for biomass burning including open burning of crop residue are of coarse resolution (0.25° × 0.25°), and may not be appropriate for a simulation for Nepal. This study develops a comprehensive high resolution (1 km × 1 km) gridded model-ready emissions inventory for Nepal to understand the spatial characteristics of air pollutant emissions from open burning. We estimate the national air pollutant emissions from crop residue burned between the years 2003 and 2017. The best available data on agricultural production, residue consumption patterns, agricultural burning parameters and emission factors were derived from secondary sources. The Monte Carlo method was used to estimate uncertainties. The mass of crop residue burned in 2016/17 was 2908 Gg (61-139%), which was 22% of the dry matter generated that year. By multiplying the burned crop residue mass by emission factors, the air pollutant emissions were estimated as 4140 for CO2 (56-144%), 154 for CO (4-196%), 6.5 for CH4 (7-193%), 1.2 for SO2 (60-140%), 24.5 for PM2.5 (30-170%), 8.6 for OC (38-162%), 2.2 for BC (-1-201%), 7 for NOx (54-146%), 22.5 for NMVOC (8-192%) and 2.7 for NH3 (3-197%) in unit of Gg yr-1. More than 80% of air pollutants were generated during the months of February to May from the open burning of crop residue. The findings of this paper indicate that substantial reduction in open field burning would dramatically improve air quality in both the Terai region and other parts of Nepal and help reduce negative health impacts associated with the open burning of residue such as premature deaths, respiratory disease, and cardiovascular disease.

A short term anatomical and visual outcomes of large idiopathic macular holes surgery following inverted internal limiting membrane flap technique.

INTRODUCTION: Large macular holes are not uncommon among Nepalese women population causing severe visual problem. OBJECTIVE: To evaluate the technique of inverted internal limiting membrane (ILM) flaps for the repairment of large macular holes. METHODS: All 10 macular holes (diameter > 400 µm) were treated with pars planavitrectomy with inverted ILM flap technique. The procedure for macular hole surgerywas pars plana vitrectomy, posterior vitreous removal, internal limiting membrane(ILM) peeling with brilliant blue assisted, inverting ILM flap into macular hole, filling of the vitreous cavity with a gas bubble(C3 F8) and post-operative face-down positioning for 1 week. SD OCT images were taken preoperative and postoperative 1 month and 3 months follow up to assess the anatomical outcome of surgery and best corrected visual acuity (BCVA) was used to evaluate the functional outcome during each visit. The BCVA was recorded using the Snellen chart and was converted to the logarithm of the minimum angle of resolution (LogMAR) equivalents. RESULTS: All 10 eyes had complete anatomical closure. The mean age of patients was 64.3 ± 7.53 years. The mean macular hole base diameter was 1039.4 µm (663-1526µm). Mean BVCA pre-operatively was 1.29 log MAR ±SD 0.25. Post-operatively, mean BCVA was 0.925 log MAR ±SD 0.143 (p= 0.002). There were no intra operative or post-operative complications. All the patients were followed up for a period of 3months. CONCLUSIONS: Inverted ILM flaps is effective for closure of the large macular hole and restoration of functional vision.

Prevalence of Closure of Large Macular Hole with Inverted Internal Limiting Membrane Flap Technique in A Tertiary Care Hospital of Nepal.

INTRODUCTION: Large macular holes cause significant reduction in central visual acuity. The aim of the study is to find out short term anatomical and visual outcomes of inverted internal limiting membrane flaps technique for large macular holes (base diameter>1000µm) surgery in patients at a tertiary care hospital. METHODS: A descriptive cross-sectional study was conducted in a tertiary care hospital from January 2018 to December 2018 after ethical clearance from the institutional review committee. The study was done in 12 patients with idiopathic macular holes (base diameter>1000µm), they were repaired with 25 gauge pars plana vitrectomy with brilliant blue assisted large inverted internal limiting membrane flap technique. Statistical analyses were performed using SPSS 19.0 Results: All twelve eyes had complete anatomical closure. Mean best corrected visual acuity preoperatively was 1.48 logMAR±0.246. The mean macular hole base diameter was 1217.0±196.77µm. The mean age of patients was 68.75±4.97 years. Postoperatively, mean best corrected visual acuity was 0.978 logMAR±0.12. There were no postoperative complications. All the patients perceived decreased size of central scotoma. CONCLUSIONS: Inverted internal limiting membrane flaps for large macular holes is suitable method for closure of the very large hole, restoration of functional vision and decreased size of central scotoma.

Morphometric analysis of fovea with spectral-domain optical coherence tomography and visual outcome postsurgery for retinal detachment.

PURPOSE: The purpose of this study was to correlate the postoperative best-corrected visual acuity (BCVA) with spectral-domain optical coherence tomography (SD-OCT) findings in fovea involving rhegmatogenous retinal detachment (RRD) surgery. MATERIALS AND METHODS: Thirty eyes with preoperative fovea-involving RRD, who underwent scleral buckling (SB) (6 eyes) and pars plana vitrectomy (PPV) (19 eyes) and combined SB and PPV (5 eyes) were recruited. Patients underwent clinical examination and SD-OCT scan of fovea preoperatively and at 30 days and 90 days postoperatively. The correlations between SD-OCT findings and BCVA were analyzed. RESULTS: Inner segment/outer segment (IS/OS) junction integrity was the indicator of better BCVA at 30 days and 90 days (P = 0.0002 and P = 0.0003, respectively) whereas outer retinal corrugation (ORC) was related to worse BCVA at 30 days and 90 days (P = 0.001). External limiting membrane did not have a co-relation with visual outcome, but cystoid macular edema showed co-relation at 90 days (P = 0.047). All eyes of SB and 3 eyes of PPV had a minimal subfoveal fluid at 30 days follow-up that had no effect on visual acuity. All retinas were attached at final follow-up. CONCLUSION: IS/OS junction integrity and ORC may be important predictors of postoperative visual outcome after anatomically successful RRD surgery.