A higher number of postoperative intravitreal injections (IVIs) may be associated with better success rates of traditional glaucoma surgery among patients with glaucoma who were also treated with IVIs for retinovascular disease, according to a study published in Ophthalmology Glaucoma. More specifically, the research suggests that 7 or more IVIs following traditional glaucoma surgery may result in a lower risk of surgical failure compared with undergoing 0 to 6 IVIs.
Past research on the effects of IVIs on long-term intraocular pressure (IOP) elevation and glaucoma progression has yielded inconclusive and conflicting results. In addition, the effects of multiple, serial IVI injections on postoperative outcomes of trabeculectomies or glaucoma drainage device (GDD) surgery have not been determined. In this retrospective cohort study, researchers compared outcomes of GDD implantations and trabeculectomies with and without postoperative IVIs in glaucoma patients with a history of preoperative IVIs.
In total, 133 eyes of 133 glaucoma patients who underwent GDD implantation or trabeculectomy were included in the study. All patients received at least 1 IVI prior to surgery between January 2005 and October 2020 at Massachusetts Eye and Ear.
The primary outcome measures were the cumulative success probabilities obtained from Kaplan-Meier (KM) analyses, fully-adjusted hazard ratios (HRs) derived from the multivariate Cox proportional hazard (PH) regression model, IOP, medication burden, best-corrected visual acuity (BCVA), and complications. The investigators performed all statistical analysis via R statistical programming software (version 4.0.3).
Of the 133 patients, 94 patients received IVIs following surgery (48.9% women, mean age 64.9 years), and 39 patients did not receive IVIs postoperatively (25.6% women, mean age 62.8 years). The researchers found that baseline demographics were similar between the group with postoperative IVIs and the group without postoperative IVIs.
The group with postoperative IVIs had more patients with diabetic retinopathy and retinal vascular occlusions, whereas the group without postoperative IVIs had more patients with age-related macular degeneration. IOP, medication burden, and visual acuity were noted to be similar between both groups, with the exception of IOP at 6 weeks, which was lower in the group with postoperative IVIs.
The group with postoperative IVIs had significantly more preoperative IVIs compared with the group without postoperative IVIs (6.6 vs 3.3, P =.017). The Kaplan-Meier analyses demonstrated similar success rates between groups of eyes with and without postoperative IVIs.
When stratified by the number of IVIs, patients who received 7 or more IVIs had significantly higher success rates than patients who received 0 to 6 IVIs. Overall, patients who received 0 to 6 postoperative IVIs had a success rate of 49.7%, and patients who received 7 or more IVIs at 3 years had a success rate of 80.3%. According to investigators, each additional postoperative IVI resulted in a 7.2% reduction in the hazard of failure to achieve the specified success criteria.
The group with postoperative IVIs had a higher incidence of vitreous hemorrhage (18.5% vs 3.2%, P =.039) compared with the group without postoperative IVIs.
The researchers noted several limitations to their work, including the retrospective nature of the study, the relatively small sample size of patients with postoperative IVIs, and inadequate follow-up length for some patients. Additionally, the patients in the study may have more complex glaucoma, which may preclude these results from being generalizable to the general glaucoma population.
“The results of this project will thus provide evidence on the effects of multiple IVIs on long-term IOP progression after glaucoma surgery for multiple types of glaucoma,” the researchers explain. “This will allow for better understanding of the expectations regarding the success probability of glaucoma surgery in patients with comorbid refractory glaucoma and proliferative retinovascular diseases requiring IVIs.”
Chang EK, Gupta S, Hall N, Neeson CE, Chang TC, Sola-Del Valle DA. Effects of postoperative intravitreal injections (IVIS) on outcomes of traditional glaucoma surgery in patients with preoperative IVIS. Ophthalmol Glau. Published online September 6, 2021. doi:10.1016/j.ogla.2021.08.007