Bleb assessment after post-trabeculectomy subconjunctival ranibizumab injection

Mamikonyan V. R.
Professor, Med.Sc.D., Director¹

Mazurova Yu. V.
MD, PhD, Head of the Surgical Department¹

Petrov S. Yu.
PhD, Leading Research Associate of the Glaucoma Department¹

Safonova D. M.
M.D., Post-graduate Student¹

Sorokin A. S.
PhD in Economics, Associate Professor²³

1 - Scientific Research Institute of Eye Diseases, 11a Rossolimo st., Moscow, Russian Federation, 119435
2 - Plekhanov Russian University of Economics, 36, Stremyanny per., Moscow, 113054
3 - Sinergia Moscow University of Finance and Industry, 80, Leningradsky Prospect, Moscow, 125190

None declared.

PURPOSE: to study bleb characteristics dynamics after post-trabeculectomy adjuvant ranibizumab injection.

METHODS: 90 patients (90 eyes) with primary open-angle glaucoma who underwent trabeculectomy were randomized into 3 groups of 30 each: group I was injected with 0.05 ml (0.5 mg) subconjunctival ranibizumab into the bleb area on day 2 after the surgery, group II – on day 7, patients in the Control group received no postoperative injections.

Tonometry and bleb characteristics according to the parameters of vascularization, corkscrew vessels, encapsulation and microcysts (Wurzburg bleb classification score) were assessed in the postoperative period on the following day after the surgery, as well as on weeks 1, 2 and 1, 3, 6 and 12 months after the injection in groups I and II and after the surgery – in the Control group. Bleb hyperemia was measured by means of specially designed software «Hyperemia-3». Complex ophthalmological examination including visometry, perimetry, and retinal tomography was conducted before trabeculectomy and 6 and 12 months after.

RESULTS. Intraocular pressure compensation according to the individual IOP scale without hypotensive therapy in Group I was observed 16% more often than in the Control group. With additional hypotensive therapy – 13% more often. Group II showed a 6% more often compensation without hypotensive therapy and an equal compensation rate when hypotensive therapy was needed.

Bleb characteristics dynamics according to all WBCS criteria as well as Hyperemia index showed a corresponding pattern: their mean values in both injection groups were higher than those in the Control group. Comparative analysis between injections on days 2 and 7 revealed a statistically significant differences in vascularization and corkscrew vessels (p<0.001) and encapsulation, (p=0.03) in favour of earlier injections.

Total WBCS score revealed a similar pattern: on week 1 mean difference between the groups equaled 1.47 (Group I vs. Control) and 1.0 (Group II vs. Control) points. By week 2 mean difference reached 1.67 and 1.37 points correspondingly, by month 1 – 0.73 and 0.70 points, by month 3 – 0.4 points in both groups, by month 6 the difference lowered to 0.47 and 0.27 points, and by the end of the follow-up period it equaled 0.87 and 0.44 points.

Hyperemia index analysis showed a significant bleb hyperemia decrease after adjuvant ranibizumab, starting from the first day after the injection and reaching as much as 20% in difference with the Control group.

CONCLUSION: Subconjunctival ranibizumab injections (0.05 ml, 0.5 mg) into the bleb area help stabilize postoperative hypotensive effect, enhance bleb characteristics and subdue postoperative hyperemia. Injections on day 2 were superior in efficacy and had a more pronounced hypotensive effect to those on day 7.

glaucoma, trabeculectomy, wound healing, VEGF inhibitors, renibizumab, bleb, WBCS

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