MINIMAL INVASIVE DRAINAGE TECHNIQUE FOR LARGE EXPANDING SUBRETINAL GAS BUBBLE.

PURPOSE: To report a minimally invasive drainage technique for large expanding subretinal gas bubble and conduct a review of the literature. METHODS: Case report, with schematic diagrams and multimodal imaging including fundus photography and spectral domain optical coherence tomography. Controlled drainage of large subretinal gas bubble using a 30-gauge needle introduced through cryotherapy-treated area in office-based setting. RESULTS: Forty-year-old male patient presented with bullous rhegmatogenous retinal detachment and had gas inadvertently injected into the subretinal space during cryo-pneumatic retinopexy. After successful drainage of subretinal gas in clinic, 0.3cc of perfluoropropane (C3F8) gas was injected in different quadrants near the attached retina. The macula remained attached on immediate fundus examination. The gas bubbles of fish eggs coalesced into a single large bubble within 1 week. Spectral domain optical coherence tomography showed unremarkable foveal scans. After 45 days, the gas bubble completely disappeared, the retina remained attached, and vision in the treated eye was 20/20. CONCLUSION: To the best of our knowledge, this is the first case report of a large expanding gas bubble injected into the subretinal spaces being drained successfully by the described minimal invasive technique. Although it may offer a possible office-based approach to a rare complication, it is generally recommended that surgeons capable of dealing with its possible complications may attempt such technique when immediate vitrectomy is not accessible.

360-degree intra-operative laser retinopexy for the prevention of retinal re-detachment in patients treated with primary pars plana vitrectomy.

PURPOSE: To investigate the effect of 360° intra-operative laser retinopexy (ILR) for the prevention of retinal re-detachment in patients treated with pars plana vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD). METHODS: A retrospective single-institution cohort study was performed. Consecutive patients with primary uncomplicated RRD who underwent 23-gauge PPV with gas endotamponade between July 2013 and July 2016 were included in the study (n = 151). Two cohorts were compared: one which received laser retinopexy only around identified tears/holes/lattice zones (Control group, n = 86), and one which received additional 360° intra-operative laser retinopexy (360° ILR group, n = 65). RESULTS: Retinal re-detachment was seen in 4/65 eyes (6%) in the 360° ILR group compared to 18/86 eyes (21%) in the control group. In multiple logistic regression, the 360° ILR was associated with a 75% reduction in the odds of retinal re-detachment compared to control (OR = 0.248, 95% CI [0.079-0.772], p = 0.016). There was no statistically significant difference in the incidence of epiretinal membrane formation between the two groups. CONCLUSIONS: Intra-operative 360° laser retinopexy during PPV with gas endotamponade resulted in a significant reduction in the odds of postoperative retinal re-detachment in eyes with uncomplicated primary RRD.

Vascular retinal biomarkers improves the detection of the likely cerebral amyloid status from hyperspectral retinal images.

INTRODUCTION: This study investigates the relationship between retinal image features and ß-amyloid (Aß) burden in the brain with the aim of developing a noninvasive method to predict the deposition of Aß in the brain of patients with Alzheimer's disease. METHODS: Retinal images from 20 cognitively impaired and 26 cognitively unimpaired cases were acquired (3 images per subject) using a hyperspectral retinal camera. The cerebral amyloid status was determined from binary reads by a panel of 3 expert raters on 18F-florbetaben positron-emission tomography (PET) studies. Image features from the hyperspectral retinal images were calculated, including vessels tortuosity and diameter and spatial-spectral texture measures in different retinal anatomical regions. RESULTS: Retinal venules of amyloid-positive subjects (Aß+) showed a higher mean tortuosity compared with the amyloid-negative (Aß-) subjects. Arteriolar diameter of Aß+ subjects was found to be higher than the Aß- subjects in a zone adjacent to the optical nerve head. Furthermore, a significant difference between texture measures built over retinal arterioles and their adjacent regions were observed in Aß+ subjects when compared with the Aß-. A classifier was trained to automatically discriminate subjects combining the extracted features. The classifier could discern Aß+ subjects from Aß- subjects with an accuracy of 85%. DISCUSSION: Significant differences in texture measures were observed in the spectral range 450 to 550 nm which is known as the spectral region known to be affected by scattering from amyloid aggregates in the retina. This study suggests that the inclusion of metrics related to the retinal vasculature and tissue-related textures extracted from vessels and surrounding regions could improve the discrimination performance of the cerebral amyloid status.

Non-invasive in vivo hyperspectral imaging of the retina for potential biomarker use in Alzheimer's disease.

Studies of rodent models of Alzheimer's disease (AD) and of human tissues suggest that the retinal changes that occur in AD, including the accumulation of amyloid beta (Aß), may serve as surrogate markers of brain Aß levels. As Aß has a wavelength-dependent effect on light scatter, we investigate the potential for in vivo retinal hyperspectral imaging to serve as a biomarker of brain Aß. Significant differences in the retinal reflectance spectra are found between individuals with high Aß burden on brain PET imaging and mild cognitive impairment (n = 15), and age-matched PET-negative controls (n = 20). Retinal imaging scores are correlated with brain Aß loads. The findings are validated in an independent cohort, using a second hyperspectral camera. A similar spectral difference is found between control and 5xFAD transgenic mice that accumulate Aß in the brain and retina. These findings indicate that retinal hyperspectral imaging may predict brain Aß load.

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.

Efficacy/safety of ranibizumab monotherapy or with laser versus laser monotherapy in DME.

OBJECTIVE: To compare the efficacy and safety of ranibizumab 0.5 mg intravitreal injection, as monotherapy or in combination with laser, with laser monotherapy in patients with visual impairment caused by diabetic macular edema. DESIGN: Twelve-month, multicentre, open-label, parallel-group, randomized, active-control study. PARTICIPANTS: A total of 220 (ranibizumab monotherapy: n = 75, ranibizumab + laser: n = 73, laser monotherapy: n = 72) patients with a diagnosis of type I or II diabetes and visual impairment caused by macular edema were included in the efficacy analysis. METHODS: Ranibizumab was initiated with a fixed loading phase of 3 monthly injections followed by as needed therapy until stable vision achievement. Efficacy end points were the change in best corrected visual acuity (BCVA), change in central retinal thickness (CRT) measured by optical coherence tomography, proportion achieving a 15-letter BCVA gain, and 12-month Visual Function Questionnaire-25 (VFQ-25) score. Safety was assessed with the incidence and severity of adverse events. RESULTS: At 12 months, significant (p < 0.001) mean BCVA improvements were observed for both the ranibizumab monotherapy (+8.9 [95% confidence interval (CI) 7.0-10.7] letters) and the ranibizumab + laser (+8.2 [95% CI 6.0-10.4] letters) groups compared with the laser monotherapy group (+0.3 [95% CI -2.9 to 3.5] letters). Similarly, a better response in terms of CRT improvement, BCVA letter gain, and VFQ-25 was observed in both ranibizumab groups compared with laser monotherapy. The safety profile was comparable in the 2 ranibizumab groups. CONCLUSIONS: Ranibizumab as monotherapy or combined with laser resulted in significantly higher improvements in visual acuity and vision-related quality of life at month 12 as compared with laser monotherapy.

Photodynamic therapy in young patients with choroidal neovascularization following traumatic choroidal rupture.

PURPOSE: To assesses the role of photodynamic therapy (PDT) with verteporfin in young patients with choroidal neovascularization (CNV) secondary to traumatic choroidal rupture. DESIGN: Retrospective case series. METHODS: Of 26 eyes with traumatic choroidal rupture followed since 1984 at the retina service of university hospitals, all eyes diagnosed with CNV and treated with PDT were included. Medical records including comprehensive eye examination, retinal photography, and intravenous fluorescein angiography (IVFA) were studied. RESULTS: Five patients (mean age, 18 years) developed CNV and received an average of two PDT treatments. Three patients had improved visual acuity (VA), one remained stable, and one experienced visual loss. Final IVFA showed absence of leakage in four eyes and decreased leakage in the eye with decreased VA. CONCLUSIONS: In young patients, PDT may be a reasonable treatment for CNV secondary to choroidal rupture. No ocular or systemic PDT complications were encountered in this young population.