Intravitreal bevacizumab administration improves outcomes, and may reduce both intraocular pressure (IOP) and antiglaucoma medication use, in people with diabetes who undergo mitomycin C (MMC) augmented trabeculotomy. This is according to research results published in the British Journal of Ophthalmology.  

Researchers conducted a randomized, nonblinded, comparative trial to assess the success of MMC augmented trabeculectomy with or without intravitreal bevacizumab in people with diabetes without neovascular glaucoma. Participants (n=56) were randomly assigned to 1 of 2 groups: group A received subconjunctival MMC plus intravitreal bevacizumab and group B received subconjunctival MMC alone. The primary outcome measure was intraocular pressure; other outcome measures included surgical success, glaucoma medication usage, and bleb morphology. 

The study included 56 eyes from 56 participants, with 28 patients in each group. At baseline, there were no statistically significant between-group characteristics. All participants had moderate to severe glaucoma and no significant surgical complications were noted. Mean follow-up was approximately 12.3 months and 13.8 months in group and A group B, respectively. 


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Both groups experienced statistically significant decrease in IOP from baseline (P <.001), with a trend for lower IOP after 1 week in group A. Average IOP reduction was approximately 15.5 mm Hg and 11.4 mm Hg in each group (P =.17). At month 6 and month 12, participants in group A were using a significantly lower number of glaucoma medications, with a drop from 3.6 medications before surgery to 0.3 after surgery. 

In the first 3 postoperative months, 5 participants in group A and 8 participants in group B required needling behind the slit lamp to release adhesions of the scleral flap and conjunctiva to underlying tissues, with 1 participant in group B requiring antimetabolite injection (5-FU). In total, 61.5% and 84.2% of participants in each group, respectively, required releasable suture removal during follow-up. 

In terms of IOP, better outcomes were observed among patients in group A, but there was no statistically significant difference between groups. At the conclusion of the 12-month follow-up period, qualified success rates were 82.1% and 57.1% in group A and group B, respectively, based on target IOP ≤15 mm Hg (85.7% and 64.3% based on target IOP ≤18 mm Hg). 

Results of a Cox proportional hazard regression analysis of complete 12-month success found a hazard ratio of 0.98 for age, 0.33 for preoperative lens status, and 1.52 for diabetic retinopathy status. 

Study limitations include the small sample size, lack of sham treatment in the MMC-only group, and the short duration of the follow-up period. 

“In patients with diabetes with primary trabeculectomy, combined administration of intravitreal bevacizumab and subconjunctival MMC resulted in lower IOP and number of antiglaucoma medication compared with subconjunctival MMC alone,” the researchers concluded. Future studies should focus on larger sample sizes with longer follow-up duration. 

Reference

Nilforushan N, Es’haghi A, Miraftabi Z, Abolfathzadeh N, Banifatemi M. Trabeculectomy in patients with diabetes: Subconjunctival mitomycin C with or without intravitreal bevacizumab. Published online December 16, 2020. Br J Ophthalmol. doi: 10.1136/bjopthalmol-2020-317324