Displacement of submacular hemorrhage using subretinal cocktail injection versus pneumatic displacement: a real-world comparative study.

INTRODUCTION: To compare the outcome of submacular hemorrhage (SMH) displacement using pneumatic displacement with intravitreal expansile gas versus pars plana vitrectomy (PPV) with subretinal injection of tissue plasminogen activator (tPA), anti-vascular endothelial growth factor (VEGF) agent and air as primary surgery. METHODS: Retrospective interventional case series of 63 patients who underwent surgical displacement of SMH secondary to neovascular age-related macular degeneration (nAMD) or polypoidal choroidal vasculopathy (PCV) from May 1, 2015 to October 31, 2022. Medical records were reviewed for diagnosis, logMAR visual acuity (VA), central subfield thickness (CST) and post-operative displacement rates and complications up to 12 months after operation. RESULTS: The diagnosis was nAMD in 24 (38.1%) and PCV in 39 (61.9%) eyes. There were 40 (63.5%) eyes in the pneumatic displacement group (38 received C3F8, 2 received SF6) and 23 (36.5%) eyes in the subretinal cocktail injection. Mean baseline VA was 1.46 and 1.62, respectively (p=0.404). The subretinal injection group had more extensive SMH (p=0.005), thicker CST (1006.6m vs 780.2m, p=0.012) and longer interval between symptom and operation (10.65 vs 5.53 days, p<0.001). The mean post-operative VA at 6 months was 0.67 and 0.91 (p=0.180) for pneumatic displacement and subretinal injection group, respectively, though VA was significantly better in the pneumatic group at 12-month visit (0.64 vs 1.03, p=0.040). At least 10 Mean change in VA were >10 letters gain in both groups up to 12 months. Post-operative CST reduction was greater (625.1m vs 326.5m, p=0.008) and complete foveal displacement (87.0% vs 37.5%), p<0.001, odds ratio (OR) = 11.1) and displacement to arcade or beyond (52.5% vs 17.5%, p=0.009, OR = 5.15) were more frequent in the subretinal injection group. Two patients with failed pneumatic displacement were successfully treated with subretinal cocktail injection as a second operation. CONCLUSION: Surgical displacement of SMH lead to clinically meaningful improvement in VA. PPV with subretinal cocktail injection is more effective than pneumatic displacement in displacing SMH with similar safety profile despite longer interval before operation, higher CST and more extensive SMH at baseline. Retinal surgeons could consider this novel technique in cases with thick and extensive SMH or as a rescue secondary operation in selected cases.

Data-entry keyboard geometry and keying movement times.

Experiments on fifteen simulated keyboards with different key sizes and inter-key spacings are reported. It was found that the movement time on these keyboards was well described by the model of Drury (Drury and Hoffmann 1992). Minimum movement times occurred when the inter-key spacing was approximately equal to the finger pad size. There was found to be an effect of the number of keys moved, which was not predicted by the model. This effect remained in a further experiment in which the target keys were marked.