Combined phaco-vitrectomy provides lower costs and greater area under the curve vision gains than sequential vitrectomy and phacoemulsification.

PURPOSE: A majority of phakic patients undergoing pars plana vitrectomy for epiretinal membrane or macular hole require subsequent cataract surgery within 1-2 years. Combined phaco-vitrectomy eliminates the need for a second surgery and may enable patients to attain their best vision sooner. This study aims to compare the visual outcomes, complication rates, and costs of combined phaco-vitrectomy versus sequential vitrectomy followed by cataract surgery. METHODS: Records were searched by CPT® codes to identify patients with both cataract and vitrectomy surgery at our institution over a 5-year period (2013-2018). Chart review included medical history, demographics, exam findings, operating room records, visual acuity (VA), and clinical outcomes. Statistical analyses were performed with SPSS v19 (IBM). Area under the curve for visual acuity was calculated as the trapezoidal mean of the change in Early Treatment of Diabetic Retinopathy Study letters. RESULTS: After exclusion, 81 eyes of 78 patients underwent both cataract and vitrectomy surgeries at our institution. Thirty-four eyes underwent separate, sequential vitrectomy then phacoemulsification surgery, and 47 eyes had combined phaco-vitrectomy surgery. Total operating room times (120.81 ± 3.41 vs 161.03 ± 5.45 min; p < 0.0001) and associated costs were significantly lower in the combined surgery compared with those in the sequential surgery group. Baseline and final visual acuity were similar between the two groups. Baseline VA was 35.53 letters (~ 20/200) and 32.81 letters (~ 20/220) and increased to final VA of 63.74 (~ 20/53) and 60.91 letters (~ 20/61), in the sequential and combined groups respectively. Area under the curve for vision was greater in the combined surgery group, with subjects gaining an average of + 9.11 ± 3.32 letters from sequential surgery, and + 19.53 ± 3.53 letters in the combined surgery group (p = 0.04). Additionally, patients in the combined group attained their best visual acuity 449 days (15 months) sooner than those receiving sequential surgery. CONCLUSIONS: Combined phaco-vitrectomy surgery resulted in greater area under the curve visual acuity benefit and attainment of best visual acuity 15 months sooner compared with conventional sequential surgeries. There were no significant differences in complication rates or clinical outcomes between the groups, but operative times and costs were lower for combined surgery, supporting a favorable cost-benefit ratio. Graphical abstract.

Whole-lake nitrate addition for control of methylmercury in mercury-contaminated Onondaga Lake, NY.

Methylmercury (MeHg) strongly bioaccumulates in aquatic food webs resulting in exposure to humans and wildlife through consumption of fish. Production of MeHg is promoted by anaerobic conditions and the supply of inorganic Hg (Hg(2+)), sulfate (SO4(2-)), and labile organic carbon. The anaerobic sediments of stratified lakes are particularly active zones for methylation of Hg(2+) and can be an important source of MeHg to the water column during summer anoxia and fall turnover. Nitrate (NO3(-)) addition has recently been proposed as a novel approach for the control of MeHg accumulation in the hypolimnia of Hg-contaminated lakes. In 2011, a whole-lake NO3(-) addition pilot test was conducted in Hg-contaminated Onondaga Lake, NY with the objective of limiting release of MeHg from the pelagic sediments to the hypolimnion through maintenance of NO3(-)-N concentrations >1mgN/L. A liquid calcium-nitrate solution was added to the hypolimnion as a neutrally buoyant plume approximately three times per week during the summer stratification interval. Maximum hypolimnetic concentrations of MeHg and soluble reactive phosphorus (SRP) decreased 94% and 95% from 2009 levels, suggesting increased sorption to Fe and Mn oxyhydroxides in surficial sediments as the regulating mechanism. Increased MeHg concentrations in the upper waters during fall turnover, which had been a generally recurring pattern, did not occur in 2011, resulting in decreased exposure of aquatic organisms to MeHg. Over the 1992-2011 interval, the hypolimnetic NO3(-) supply explained 85% and 95% of the interannual variations in hypolimnetic accumulations of SRP and MeHg, respectively.