Preliminary investigation of multispectral retinal tissue oximetry mapping using a hyperspectral retinal camera.

Oximetry measurement of principal retinal vessels represents a first step towards understanding retinal metabolism, but the technique could be significantly enhanced by spectral imaging of the fundus outside of main vessels. In this study, a recently developed Hyperspectral Retinal Camera was used to measure relative oximetric (SatO2) and total hemoglobin (HbT) maps of the retina, outside of large vessels, in healthy volunteers at baseline (N = 7) and during systemic hypoxia (N = 11), as well as in patients with glaucoma (N = 2). Images of the retina, on a field of view of ∼30°, were acquired between 500 and 600 nm with 2 and 5 nm steps, in under 3 s. The reflectance spectrum from each pixel was fitted to a model having oxy- and deoxyhemoglobin as the main absorbers and scattering modeled by a power law, yielding estimates of relative SatO2 and HbT over the fundus. Average optic nerve head (ONH) saturation over 8 eyes was 68 ± 5%. During systemic hypoxia, mean ONH saturation decreased by 12.5% on average. Upon further development and validation, the relative SatO2 and HbT maps of microvasculature obtained with this imaging system could ultimately contribute to the diagnostic and management of diseases affecting the ONH and retina.

PREOPERATIVE GAS FOR PARS PLANA VITRECTOMY: A SURGICAL TECHNIQUE FOR REPAIR OF RHEGMATOGENOUS RETINAL DETACHMENTS WITH MULTIPLE, LARGE, OR INFERIOR BREAKS.

PURPOSE: To describe the role of preoperative gas for pars plana vitrectomy (PGP) as an adjunct to surgical repair of rhegmatogenous retinal detachment (RRD). METHODS: This is a retrospective consecutive case series of all rhegmatogenous retinal detachments with multiple breaks in more than one quadrant, large breaks extending greater than one clock hour, and/or inferior breaks requiring PPV, who received intravitreal injection of sulfur hexafluoride (SF 6 ) or perfluoropropane (C 3 F 8 ) 1-2 weeks before PPV between 2016 and 2020 at a tertiary care center. RESULTS: A total of 109 eyes underwent the PGP technique, 73% of which had macular involvement. The rhegmatogenous retinal detachments on average involved 5.5 (SD 2.1) clock hours with inferior retinal breaks in 51%. Based on clinical examination, subretinal fluid was noted to be dissipated in parts of the detached retina before PPV in 57% of cases. The use of perfluorocarbon heavy liquid or posterior drainage retinotomy was required in 16% of cases. A 95% primary anatomical success rate was achieved over the median 177 (interquartile range 105-526) follow-up days. A final visual acuity of 20/50 or better was achieved in 65%. CONCLUSION: PGP as an adjunct to PPV may facilitate ease of surgery, as well as anatomical and functional success for rhegmatogenous retinal detachments with multiple, large, and/or inferior breaks.

Pre-operative optical coherence tomography findings in macula-off retinal detachments and visual outcome.

PURPOSE: To evaluate the correlation between foveal changes in the detached retina in macula-off rhegmatogenous retinal detachments (RRD) and visual acuity outcome following repair. DESIGN: Retrospective, consecutive, observational case series. METHODS: Consecutive patients presenting with macula-off RRD between July 15 and September 15, 2017, underwent SD-OCT imaging and their medical records were reviewed. Specific OCT exam parameters were used to evaluate the fovea of the detached retina. RESULTS: In total, 47 patients with macula-off RRD were treated from July 15 to September 15, 2017. Forty-four eyes of 44 patients could be imaged by SD-OCT and were included in the analysis. Univariate analysis demonstrated a correlation between the height of the detachment, the duration of symptoms, the presence of macular hole and epiretinal membrane to the final VA. Correlation was also found between the presence of MH and the height of the detachment. However, multiple regression analysis demonstrated only a statistically significant correlation between the presence of a macular hole or an epiretinal membrane to the final VA. CONCLUSIONS: Our study is the first to demonstrate the significance of foveal changes in the pathogenesis of lost vision in macula-off retinal detachments. The high rate of macular holes and the correlation between the MH and the height of the detachment suggest that elevated tension in the fovea in high detachments might play a significant role in the visual outcome of macula-off RRD following repair.

Hypotensive efficacy of topical brimonidine for intraocular pressure spikes following intravitreal injections of antivascular endothelial growth factor agents: a randomised crossover trial.

PURPOSE: To determine the effect of topical brimonidine tartrate prophylaxis on intraocular pressure (IOP) spikes following intravitreal injection of antivascular endothelial growth factor (anti-VEGF) agents. METHODS: This is a randomised crossover trial of consecutive non-glaucomatous eyes receiving intravitreal anti-VEGF injections between December 2016 and July 2017. All eyes were randomly assigned to no prophylaxis or topical brimonidine tartrate 0.15 % administered 20 min prior to injection in one of two consecutive visits. Measurements of IOP were obtained immediately (T0), 10 min (T10) and 20 min (T20) after injection during the visits with and without prophylaxis. RESULTS: Among the 58 eyes of 55 patients (116 visits), the mean (SD) age was 74.3 (11.6), and 62% were female. The mean baseline IOP was 15.3 (2.3) mm Hg (range: 11-20). On average, the immediate postinjection IOP during the visit without prophylaxis was 41.6 (12) mm Hg (range: 17-81). Compared with no prophylaxis, the visit with preadministered topical brimonidine tartrate had a lower IOP at T0 (p<0.001), T10 (p=0.001) and T20 (p=0.043), and a smaller proportion of eyes with IOP elevation of greater than 20 mm Hg from preinjection (p=0.002) and IOP greater than 50 mm Hg at T0 (p=0.036). Without prophylaxis, two eyes (two patients) had an IOP of greater than 70 mm Hg at T0 and thus underwent anterior chamber paracentesis. CONCLUSION: Topical brimonidine tartrate prophylaxis for intravitreal injection of anti-VEGF agents effectively reduces IOP spikes in non-glaucomatous eyes and may be easily incorporated into ophthalmologists' current practice. TRIAL REGISTRATION NUMBER: NCT03513172.