Retina Society 2017 (Day 1): Retinal Vascular Diseases
Irina De la Huerta, M.D. Ph.D.
Vitreoretinal Surgery Fellow
Associated Retinal Consultants/William Beaumont Hospital
Greetings from Boston where the 50th Anniversary Meeting of the Retina Society is under way. Day 1 featured an excellent and highly informative retinal vascular disease symposium. Leo Kim kicked off the scientific sessions and showed that runt-related transcription factor 1 (Runx1) plays important roles in angiogenesis. When he inhibited Runx1 in oxygen induced retinopathy animal models, he found that the number of neovascular tufts was substantially reduced. Perhaps most interestingly, Runx1 localizes to only pathologic endothelial cells, and not to normal vasculature. Bozho Todorich then presented novel histological findings in hemorrhagic occlusive retinal vasculitis (HORV) indicating that the pathophysiology of this condition is grounded in a necrotizing vasculopathy in the absence of retinal vasculitis. We look forward to Dr. Todorich’s dedicated RETINA Roundup post about his study later.
Seenu Hariprasad used aggregated safety data from multiple clinical trials using suprachoroidal injection of triamcinolone to show an incidence of IOP elevation of less than 10% with an otherwise unremarkable overall safety profile. Craig Greven then presented an area under the curve analysis of visual acuity outcomes at 2 years in patients with diabetic macular edema from the FAME and DRCR Protocol I datasets. The analysis demonstrated an overall superiority of ranibizumab to the fluocinolone acetonide implant with the exception of pseudophakic eyes where the visual outcomes were similar.
Retinal Vein Occlusions
Ingrid Scott presented the exciting 6-month results of the SCORE2 randomized non-inferiority trial of bevacizumab versus aflibercept for treatment of macular edema secondary to vein occlusions. Eyes were randomized to receive intravitreal injection of bevacizumab (n = 182) or aflibercept (n = 180) every 4 weeks through month 6. At 6 months there was no significant difference in visual acuity letter score between the bevacizumab and the aflibercept groups. The mean change from baseline in central subfield thickness on SD-OCT was also not significantly different. Post hoc analyses revealed that at month 6, 54.4% of eyes in the aflibercept group had complete resolution of macular edema compared with 28.5% in the bevacizumab group. The odds of complete resolution of fluid averaged over months 1 to 6 was significantly lower in the bevacizumab group compared with the aflibercept group. Dr. Scott commented that similar findings were reported in DRCR.net Protocol T, and in the CATT study where bevacizumab was also associated with a significantly lower proportion of eyes that achieved resolution of macular edema than the comparative on-label anti-VEGF agents. However, in this trial as in CATT, the lower proportion of eyes with resolution of fluid in the bevacizumab group did not translate into poorer VA at the primary outcome visits.
Karl Csaky reported that addition of the intravitreal dexamethasone drug delivery system can significantly reduce the number of PRN bevacizumab injections in patients with macular edema secondary to CRVO. Jason Hsu presented the results of a pilot study showing that the addition of topical dorzolamide-timolol reduced central foveal thickness and improved visual acuity in eyes with persistent macular edema secondary to retinal vein occlusions despite fixed interval anti-VEGF injections. Dr. Hsu hypothesized that dorzolamide-timolol may achieve this effect by slowing down clearance of the anti-VEGF agent.
Intravitreal Injections and Needle Size
Allen Chiang reported the results of a prospective randomized pilot study on patient experience with 33-gauge versus 30-gauge needles for intravitreal injections. There was a slight but significant reduction in pain scores following intravitreal injection with the 33-gauge needle, however this must be balanced against the 3-fold higher cost of the 33-gauge needle compared to the conventional 30-gauge needle.
Intravitreal Injections and IOP
Matthew MacCumber then presented a database analysis from the AAO Iris Registry looking at intraocular pressure in patients receiving injections of anti-VEGF drugs. A sustained rise of at least 6 mm Hg to an IOP over 21 occurred in 2-3% of eyes receiving aflibercept, ranibizumab or bevacizumab injections. A higher percentage of eyes experienced a sustained clinically significant IOP rise (9%) in the subset of patients that received bevacizumab over 25 times. Bernard Doft presented the results of a prospective study examining the effect of needle size on immediate post injection IOP and on the development of late ocular hypertension. Post-injection IOP spike greater than 35 mm Hg occurred in 58.7% of eyes, with late onset ocular hypertension at 6 months diagnosed in 6.5% of eyes. Needle gauge was not significantly associated with either post-injection IOP spike or late onset ocular hypertension.
Sickle Cell Retinopathy
Adrienne Scott discussed the prevalence of, and risk factors for retinopathy in sickle cell patients followed by the Johns Hopkins Sickle Cell Center for Adults. Overall, 42.7% had nonproliferative retinopathy and 24.8% had proliferative retinopathy. Hemoglobin SC and older sickle cell patients were significantly more likely to develop proliferative retinopathy. Finally, Jennifer Lim showed that macular thinning is significantly more prevalent in sickle cell eyes compared to controls. Retinal thinning correlates with age, sickle cell stage, and is more prevalent in hemoglobin SS compared to SC and SThal eyes.