ABSTRACT
Optical coherence tomography (OCT) angiography is a promising technique that provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging and offers several advantages over conventional angiography to visualize the chorioretinal vasculature in a rapid and noninvasive manner. However, as with any evolving imaging technique, there are ongoing challenges in terms of need for new equipment, limitations of imaging capability and software processing techniques, as well as in understanding the implications of the imaging and its correlation with pathophysiology of the retina and choroid. This expert panel discussion is structured to provide an insight into the current state of OCT angiography.
ABSTRACT
Twenty-five percent of diabetes-related vision loss stems from complications of proliferative diabetic retinopathy (PDR). Panretinal photocoagulation has been the preferred treatment of high-risk PDR for decades and more recently intravitreal injections of drugs that inhibit the actions of vascular endothelial growth factor have become popular. But despite these treatments PDR may progress uncontrollably to advanced pathologies such as traction retinal detachments (TRDs), combined traction/rhegmatogenous retinal detachments (TRD/RRDs), vitreous hemorrhages, rubeosis iridis, and traction maculopathies, which produce mild-to-severe loss of vision. TDR have long been the most common indication for PDR-related vitreoretinal surgery. Vitrectomy surgery is indicated for recent (<6 months duration) TRD involving the macula, progressive TRD that threatens the macula, and recent data suggest that chronic macula-involving TRDs (>6 months duration) may also benefit. Combined TRD/RRD represents a particularly challenging surgical condition but advances in surgical instrumentation, dissection techniques, and post-operative tamponade have produced excellent success rates. The recent development of small-gauge vitrectomy systems has persuaded most surgeons to switch platforms since these appear to produce shorter surgical times and quicker post-operative recoveries. Pre-operative injections of bevacizumab are frequently administered for persistent neovascularization to facilitate surgical dissection of pre-retinal fibrosis and reduce the incidence of post-operative hemorrhages. Recent trends toward earlier surgical intervention and expanded indications are likely to continue as surgical instrumentation and techniques are further developed.
ABSTRACT
Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy with an increasing prevalence tied to the global epidemic in type 2 diabetes mellitus. Its pathophysiology starts with decreased retinal oxygen tension that manifests as retinal capillary hyperpermeability and increased intravascular pressure mediated by vascular endothelial growth factor (VEGF) upregulation and retinal vascular autoregulation, respectively. Spectral domain optical coherence tomography (SD-OCT) is the cornerstone of clinical assessment of DME. The foundation of treatment is metabolic control of hyperglycemia and blood pressure. Specific ophthalmic treatments include intravitreal anti-VEGF drug injections, intravitreal corticosteroid injections, focal laser photocoagulation, and vitrectomy, but a substantial fraction of eyes respond incompletely to all of these modalities resulting in visual loss and disordered retinal structure and vasculature visible on SD-OCT and OCT angiography. Efforts to close the gap between the results of interventions within randomized clinical trials and in real-world contexts, and to reduce the cost of care increasingly occupy innovation in the social organization of ophthalmic care of DME. Pharmacologic research is exploring other biochemical pathways involved in retinal vascular homeostasis that may provide new points of intervention effective in those cases unresponsive to current treatments.
ABSTRACT
Purpose: To determine the predictive values of baseline optical coherence tomography (OCT) abnormalities on 12-month visual acuity changes in eyes with macular edema (ME) caused by branch retinal vein occlusions (BRVO). Methods: We performed a post hoc analysis of data from 75 participants in the 12-month MARVEL trial. OCT abnormalities at baseline, including ganglion cell layer cystoid spaces (GCL), intraretinal hyper-reflective dots, and central subfield thickness (CST), were correlated with improvements in visual acuity and the number of anti-vascular endothelial growth factor injections required using a multivariate regression model. Results: Eyes with baseline CST > 500 ?m had greater visual gains compared to those with CST <500 ?m (+21.09 vs +16.08 letters, P = 0.04). Eyes with hyper-reflective dots (+13.97 vs +19.93 letters, P = 0.02), and GCL cysts (+9.8 vs +18.9, P = 0.003) had inferior gains in visual acuity. Neurosensory macular detachments at the baseline did not affect gains in visual acuity. Ninety percent of the gain in visual acuity was recorded after two injections and was maintained until month 12. Conclusion: Baseline OCT of <500 ?m, hyper-reflective dots, and GCL cystoid spaces are associated with poorer gains in visual acuity. Most of the visual gain occurs after two injections.