A randomized, controlled multicenter study has demonstrated that com­bination topical drop therapy is more effective for preventing cystoid macular edema after cataract surgery in nondiabetic patients than either corticosteroid or NSAID monotherapy; in diabetic eyes, postop combination drop therapy plus a subconjunctival in­jection of triamcinolone acetonide peri­operatively is superior to postop eye drops alone or with combinations involving intravitreal bevacizumab at close of surgery. Lead author Rudy Nuijts, MD, PhD, professor of ophthalmology at the Uni­versity Eye Clinic Maastricht UMC+, The Netherlands, presented the findings of the PREMED (PREvention of Macular EDema after cataract surgery) study at the 35th Congress of the European Society of Cataract and Refractive Surgeons in October.

“The aim of the ESCRS PREMED study was to provide evidence-based recommendations that could serve as a basis for clinical guidelines on the prevention of CME after cataract surgery,” explains study author Laura Wielders, MD, PhD. PREMED looked at two groups of patients who underwent standard phacoemulsification cataract surgery with IOL implantation at 12 centers throughout the EU. There were 914 nondiabetic patients and 213 with diabetes. Patients with proliferative diabetic retinopathy and marked DME were excluded. Patients with monocular function, elevated CME risk or previous surgery in the study eye were excluded from both groups.

For this study, funded by the ESCRS, the nondiabetic patients were randomized to four treatment groups: topical NSAID monotherapy (brom­fenac 0.09%); corticosteroid mono­therapy (dexamethasone 0.1%); or com­bined-drop therapy. The primary outcome measure was mean central macular subfield thickness measured by OCT at six weeks postoperatively versus baseline. Secondary outcomes included the occurrence of CME (an increase in CMST of 10 percent or more over baseline with cystic changes noted on OCT) and clinically significant CME at six and 12 weeks postoperatively (defined as CME on OCT plus less than 0.2 logMAR of CDVA improvement over baseline).

At six weeks, the dexamethasone group had the highest CMST measurements, 9.6 µm greater than those of the combined-drop patients. The incidence of clinically significant CME in the dual-drop therapy group was 1.5 percent at 12 weeks, compared with the NSAID monotherapy group (3.6 percent) and the corticosteroid monotherapy group (5.1 percent).

The 213 diabetic patients all received dual-drop therapy, and were randomized to receive either no additional treatment; 40 mg subconjunctival triamcinolone acetonide at close of surgery; 1.25 mg intravitreal bevacizumab; or both injections. Among the patients who received a TA injection on top of combination-drop therapy, there were no cases of CME. The addition of bevacizumab didn’t affect macular thickness in any significant way. The patients who got subconjunctival TA had a CSMT measurement that was 12.3 µm less at six weeks than in those who did not; at 12 weeks they measured 9.7 µm less than the eyes that didn’t receive TA.

Jeffrey Whitman, MD, president and chief surgeon of Key-Whitman Eye Center, with offices in Dallas and Fort Worth, Texas, says, “This study’s early findings show us that what had been rumored is true: using both a steroid drop and an NSAID drop topically, starting two days preop and continuing postoperatively, makes a statistically significant difference in bringing the  incidence of CME closer to zero in normal patients. Before, there was no paper to substantiate it, but now we have a clinical trial that demonstrates it.

“For diabetic patients,” Dr. Whitman continues, “if you’re afraid to inject triamcinolone or tri-moxi intravitreally, this study says that you can put it in subconjunctivally—along with your topical drop regimen of steroid and NSAID—and you’re going to have an excellent effect in terms of preventing diabetic macular edema and CME.”

Dr. Wielders urges careful decision-making with regard to diabetic eyes, though. “Based on the results of this study, it is not recommended to administer subconjunctival TA in all dia­betic patients undergoing cataract surgery, given the low overall incidence of postoperative CME (4.5 percent), and considering the higher incidence of developing an increased IOP after subconjunctival TA injection (7.1 percent),”  she says.  REVIEW