Scientists evaluated macular contraction after anti-vascular endothelial growth factor injections for diabetic macular edema by documenting the displacement of macular capillary vessels and epiretinal membrane formation.

A total of 130 eyes were included in the retrospective study. The study group consisted of 63 eyes that had intravitreal anti-VEGF injections for DME, and the control group included 67 eyes without central DME. Both groups were balanced in terms of diabetes duration and HbA1c. Scientists measured the distances between the bifurcation of the macular capillary retinal vessels, and evaluated ERM status based on spectral-domain optical coherence tomography findings on initial and final visits.

In the study group, the mean number of injections was 4.7 ±2.6 (range: 3 to 14) and the mean follow-up time was 16.7 ±7.8 months vs. 20.7 ±10.9 months in the control group (p=0.132). The change in distance measurements between the reference points on macular capillary vessels was significant in all lines except line c (p<0.05 for lines a, b, d, e and f) in the study group, while this change was only significant in line e in controls (p=0.007, paired samples test). However, when the change in macular thickness was accounted for as a confounding factor, the change in distances between the reference points from the initial and final visits lost its significance (repeated measures ANCOVA, p>0.05). During follow-up, the number of cases with ERM formation changed from 10 to 12 in the study group although it remained three in the control group.

Scientists found a displacement of macular capillary vessels associated with a change in macular thickness in eyes having anti-VEGF injections for DME. They added that the number of ERM cases didn’t change significantly during the follow-up.

In a pivotal clinical trial conducted by Ivantis, researchers compared cataract surgery with implantation of Ivantis’ Hydrus Schlemm’s canal microstent and cataract surgery alone to reduce intraocular pressure and medication use after 24 months, as part of the prospective, multicenter, single-masked, randomized controlled HORIZON trial. They included subjects with concomitant primary open-angle glaucoma, visually significant cataract and washed-out modified diurnal IOP (MDIOP) between 22 and 34 mmHg.

Researchers randomized subjects 2:1 to receive a single Hydrus Microstent in Schlemm’s canal or no stent after uncomplicated phacoemulsification. Comprehensive eye exams were conducted at one day and one week, and then at one, three, six, 12, 18 and 24 months postoperatively. Medication washout and MDIOP measurement were repeated at 12 and 24 months.

The primary end point was the proportion of subjects demonstrating a 20 percent or greater reduction in unmedicated MDIOP, and the secondary end point was the effectiveness change in mean MDIOP from baseline to 24 months. Hypotensive medication use was tracked, and safety measures included the frequency of surgical complications and adverse events.

A total of 369 eyes were randomized after phacoemulsification to Hydrus Microstent (HMS) and 187 to no microstent (NMS).
• At 24 months, unmedicated MDIOP was reduced by ≥20 percent in 77.3 percent of HMS eyes and in 57.8 percent of NMS eyes (difference=19.5 percent; CI, 11.2 to 27.8 percent, p<0.001).
• The mean reduction in 24-month unmedicated MDIOP was -7.6 ±4.1 mmHg (mean ±SD) in the HMS group and -5.3 ±3.9 mmHg in the NMS group (difference= -2.3 mmHg; CI, -3.0 to -1.6; p<0.001).
• The mean number of medications was reduced from 1.7 ±0.9 at baseline to 0.3 ±0.8 at 24 months in the HMS group and from 1.7 ±0.9 to 0.7 ±0.9 in the NMS group (difference= -0.4 medications; p<0.001).
• No serious ocular adverse events related to the microstent were reported, and researchers found no significant differences in safety parameters between the two groups.

Researchers wrote that the study demonstrated superior reduction in MDIOP and medication use among subjects with mild-to-moderate POAG who received a Schlemm’s canal microstent combined with phacoemulsification compared with phacoemulsification alone.