Retinal Displacement after Scleral Buckle versus Combined Buckle and Vitrectomy for Rhegmatogenous Retinal Detachment: ALIGN Scleral Buckle versus Pars Plana Vitrectomy with Scleral Buckle.

PURPOSE: To assess the risk of retinal displacement after scleral buckle (SB) versus pars plana vitrectomy with SB (PPV-SB). DESIGN: Multicenter prospective nonrandomized clinical trial. METHODS: The study took place at VitreoRetinal Surgery in Minneapolis, Minnesota, Sankara Nethralaya in Chennai, India, and St. Michael's Hospital in Toronto, Canada from July 2019 to February 2022. Patients who underwent successful SB or PPV-SB for fovea-involving rhegmatogenous retinal detachment with gradable postoperative fundus autofluorescence (FAF) imaging were included in the final analysis. Two masked graders assessed FAF images 3 months postoperatively. Metamorphopsia and aniseikonia were assessed with M-CHARTs and the New Aniseikonia Test, respectively. The primary outcome was the proportion of patients with retinal displacement detected with retinal vessel printings on FAF in SB versus PPV-SB. RESULTS: Ninety-one eyes were included in this study, of which 46.2% (42 of 91) had SB and 53.8% (49 of 91) underwent PPV-SB. Three months postoperatively, 16.7% (7 of 42) in the SB group and 38.8% (19 of 49) in the PPV-SB group had evidence of retinal displacement (difference = 22.1%; odds ratio = 3.2; 95% confidence interval [CI], 1.2-8.6; P = 0.02) on FAF. The statistical significance of this association increased after adjustment for extent of retinal detachment, baseline logarithm of the minimum angle of resolution, lens status, and sex in a multivariate regression analysis (P = 0.01). Retinal displacement was detected in 22.5% (6 of 27) of patients in the SB group with external subretinal fluid drainage and 6.7% (1 of 15) of patients without external drainage (difference = 15.8%; odds ratio = 4.0; 95% CI, 0.4-36.9; P = 0.19). Mean vertical metamorphopsia, horizontal metamorphopsia (MH), and aniseikonia were similar between patients in the SB and PPV-SB groups. There was a trend to worse MH in patients with retinal displacement versus those without retinal displacement (P = 0.067). CONCLUSIONS: Scleral buckle is associated with less retinal displacement compared with PPV-SB, indicating that traditional PPV techniques cause retinal displacement. There is a trend toward increased risk of retinal displacement in SB eyes that underwent external drainage compared with SB eyes without drainage, which is consistent with our understanding that the iatrogenic movement of subretinal fluid, such as that which occurs intraoperatively during external drainage with SB, may induce retinal stretch and displacement if the retina is then fixed in the stretched position. There was a trend to worse MH at 3 months in patients with retinal displacement. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Primary ocular toxoplasmosis secondary to venison consumption.

Purpose: To describe primary ocular toxoplasmosis infection related to ingestion of undercooked venison. Observations: This single site, retrospective case series reviewed 4 patients with primary ocular toxoplasmosis that was acquired by ingesting undercooked venison. De-identified data was collected regarding baseline patient characteristics including age, sex, past medical and ocular history, onset of symptoms, visual acuity (VA), response to treatment, and workup. All patients with acquired toxoplasmosis had similar chronology of systemic and ocular symptoms. Exposure occurred in October or November and systemic symptoms developed within 2 weeks, followed by ocular symptoms an average of 2.6 months later. Average age at onset was 56 ± 13 (age ± SD) years old and all were male. Average initial and final VA were 20/50 and 20/50, respectively. Positive anti-toxoplasma IgM and IgG serologies were found in all cases. All patients were treated with trimethoprim/sulfamethoxazole and achieved rapid improvement. Complications occurred in 50% of cases and included epiretinal membrane, cystoid macular edema, vitreoretinal traction, and neovascularization. Conclusions and importance: Consumption of undercooked venison is a source of primary ocular toxoplasmosis even in immunocompetent hosts and has a clear chronology. A presentation of retinochoroiditis during the winter months should prompt questioning for exposure to wild game.

Trends in the Clinical Presentation of Primary Rhegmatogenous Retinal Detachments During the First Year of the COVID-19 Pandemic.

PURPOSE: To evaluate the effect of 1 full year of the coronavirus disease 2019 (COVID-19) pandemic on clinical presentation of acute, primary rhegmatogenous retinal detachment (RRD). DESIGN: Single-center, retrospective observational cohort study. METHODS: Patients were divided into 2 cohorts: consecutive patients treated for primary RRD during the COVID-19 pandemic (March 9, 2020, to March 7, 2021; pandemic cohort) and patients treated during the corresponding time in previous year (March 11, 2019, to March 8, 2020; control cohort). MAIN OUTCOME MEASURES: Proportion of patients presenting with macula-involving (mac-off) or macula-sparring (mac-on) RRD. RESULTS: A total of 952 patients in the pandemic cohort and 872 patients in the control cohort were included. Demographic factors were similar. Compared with the control cohort, a significantly greater number of pandemic cohort patients presented with mac-off RRDs ([60.92%] pandemic, [48.17%] control, P = .0001) and primary proliferative vitreoretinopathy ([15.53%] pandemic, [6.9%] control, P = .0001). Pandemic cohort patients (10.81%) had significantly higher rates of lost to follow-up compared with the control cohort (4.43%; P = .0001). Patients new to our clinic demonstrated a significant increase in mac-off RRDs in the pandemic cohort (65.35%) compared with the control cohort (50.40%; P = .0001). Pandemic cohort patients showed worse median final best-corrected visual acuity (0.30 logarithm of the minimum angle of resolution) compared with the control cohort (0.18 logarithm of the minimum angle of resolution; P = .0001). CONCLUSIONS: Patients with primary RRD during the first year of the COVID-19 pandemic were more likely to have mac-off disease, present with primary proliferative vitreoretinopathy, be lost to follow-up, and have worse final best-corrected visual acuity outcomes.

Quantifying the temperature dependence of glycine-betaine RNA duplex destabilization.

Glycine-betaine (GB) stabilizes folded protein structure because of its unfavorable thermodynamic interactions with amide oxygen and aliphatic carbon surface area exposed during protein unfolding. However, GB can attenuate nucleic acid secondary structure stability, although its mechanism of destabilization is not currently understood. Here we quantify GB interactions with the surface area exposed during thermal denaturation of nine RNA dodecamer duplexes with guanine-cytosine (GC) contents of 17-100%. Hyperchromicity values indicate increasing GB molality attenuates stacking. GB destabilizes higher-GC-content RNA duplexes to a greater extent than it does low-GC-content duplexes due to greater accumulation at the surface area exposed during unfolding. The accumulation is very sensitive to temperature and displays characteristic entropy-enthalpy compensation. Since the entropic contribution to the m-value (used to quantify GB interaction with the RNA solvent-accessible surface area exposed during denaturation) is more dependent on temperature than is the enthalpic contribution, higher-GC-content duplexes with their larger transition temperatures are destabilized to a greater extent than low-GC-content duplexes. The concentration of GB at the RNA surface area exposed during unfolding relative to bulk was quantified using the solute-partitioning model. Temperature correction predicts a GB concentration at 25 °C to be nearly independent of GC content, indicating that GB destabilizes all sequences equally at this temperature.

Muscle activation patterns while lifting stable and unstable loads on stable and unstable surfaces.

In an attempt to mimic everyday activities that are performed in 3-dimensional environments, exercise programs have been designed to integrate training of the trunk muscles with training of the extremities. Many believe that the most effective way to recruit the core stabilizing muscles is to execute traditional exercise movements on unstable surfaces. However, physical activity is rarely performed with a stable load on an unstable surface; usually, the surface is stable, and the external resistance is not. The purpose of this study was to evaluate muscle activity of the prime movers and core stabilizers while lifting stable and unstable loads on stable and unstable surfaces during the seated overhead shoulder press exercise. Thirty resistance-trained subjects performed the shoulder press exercise for 3 sets of 3 repetitions under 2 load (barbell and dumbbell) and 2 surface (exercise bench and Swiss ball) conditions at a 10 repetition maximum relative intensity. Surface electromyography (EMG) measured muscle activity for 8 muscles (anterior deltoid, middle deltoid, trapezius, triceps brachii, rectus abdominis, external obliques, and upper and lower erector spinae). The average root mean square of the EMG signal was calculated for each condition. The results showed that as the instability of the exercise condition increased, the external load decreased. Triceps activation increased with external resistance, where the barbell/bench condition had the greatest EMG activation and the dumbbell/Swiss ball condition had the least. The upper erector spinae had greater muscle activation when performing the barbell presses on the Swiss ball vs. the bench. The findings provide little support for training with a lighter load using unstable loads or unstable surfaces.