Managing the challenge of cataract surgery in eyes with diabetic macular edema

September 1, 2020

Researchers advocate for intraoperative intravitreal steroid during cataract surgery in patients with DME.

Cataract surgery in eyes with diabetic macular edema (DME) presents a challenging situation. In this setting, placing the dexamethasone intravitreal implant 700 µg (Ozurdex) at the time of cataract surgery is a safe and effective procedure for attempting to control DME and lessen surgery-induced inflammation, say researchers from the Ospedale San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy.

Findings from a retrospective study analyzing the functional and anatomical outcomes of 20 eyes with chronic, persistent DME that underwent the combined procedure were reported by Eleonora Corbelli, MD, at the 2020 ARVO Virtual Meeting. Visual acuity (BCVA) and central retinal thickness (CRT) data were analyzed from the day of surgery (baseline) and 1, 4, 12, and 24 months postoperatively. The results were compared with data from a control group treated with deferred dexamethasone injection at 4 to 6 weeks after cataract surgery (baseline) and followed at the same intervals after the baseline visit.

Overall, the functional and anatomical outcomes at the longer-term visits were similar in the two groups. However, mean CRT was significantly lower at 1-month post-injection in the group that received the steroid intraoperatively.

“Diabetic eyes are at risk of developing macular edema after cataract surgery, even after an uncomplicated procedure. Of course, it would be desirable to do the operation in an eye with a dry macula, but this may not be reality,” said Corbelli.

“The short-term anatomical results of our study suggest that using dexamethasone concurrently during surgery may exert a protective role by counteracting the hypothetical cumulative effects of the inflammatory trigger of surgery and the preexisting macular edema.”

The study included patients who were operated on between January 2010 and October 2017. Eligible patients were adults with non-naïve, central involving DME, inactive diabetic retinopathy, and data from follow-up of at least 24 months. Patients were excluded if they had received an intravitreal dexamethasone implant within 5 months prior to cataract surgery or if they had an HbA1c >9% or any other concurrent retinal disease, glaucoma, previous vitrectomy, or significant optical media opacity.

The group undergoing combined surgery and dexamethasone injection and the control group receiving deferred dexamethasone were similar at baseline with respect to gender distribution, mean age (~69 years), mean baseline BCVA (45 ETDRS letters), HbA1c, CRT and proportion with proliferative diabetic retinopathy. At 1 month after surgery in the combined group and 1 month after the deferred dexamethasone injection in the control group, BCVA was significantly improved and CRT significantly decreased. At the 4-month visit, when the pharmacologic effect of the steroid implant had dissipated, BCVA dropped and CRT increased in both groups. Results for the functional and anatomical endpoints were similar in the two groups at subsequent follow-up visits.

In the combination group, 19 of 20 patients had received further treatment for DME by 12 months after surgery, with the majority receiving one or more additional dexamethasone implants. By 2 years, all patients had been re-treated, with many of the dexamethasone-treated eyes switched to a longer-lasting fluocinolone implant. The pattern of further treatments for DME was similar in the deferred group.

No serious adverse events were recorded throughout the 24-month follow-up period. No eyes needed to undergo glaucoma surgery, and the proportion of eyes receiving treatment with IOP-lowering drugs was similar in the combined (15%) and deferred groups (20%) groups.

Corbelli noted that the study has limitations that include its retrospective design, relatively small size, and absence of standardization in the schedule of visits following surgery.

“It should be underlined, however, that patients were enrolled from the real world where specific time points of observation are rarely available,” she said.

“Despite its limitations, we believe the study offers a real-world scenario of a very specific but frequent and crucial aspect of the care of patients with diabetes. We believe that combining dexamethasone injection with cataract surgery should be considered to prevent the inflammatory procedural load and ameliorate the care process.”

Eleonora Corbelli, MD
E: Corbelli.eleonora@hsr.it
Corbelli has no relevant financial interests to disclose.