Non-steroidal anti-inflammatory agents for treating cystoid macular edema following cataract surgery

Cataract surgery is the most common ambulatory incisional surgery performed in the USA. Cystoid macular edema (CME), the accumulation of fluid in the central retina due to leakage from dilated capillaries, is the most common cause of vision impairment following cataract surgery. Acute CME, defined as CME of less than four months' duration, often resolves spontaneously. CME that persists for four months or longer is termed chronic CME. Non-steroidal anti-inflammatory drugs (NSAIDs) have been used to treat CME. This update adds new evidence and analyses to the previously published review.

To examine the effectiveness of NSAIDs in the treatment of CME following cataract surgery.

We searched the CENTRAL (2022, Issue 3); Ovid MEDLINE; Embase; PubMed; LILACS; mRCT (discontinued in 2014, last searched August 2011), ClinicalTrials.gov, and WHO ICTRP databases. We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 20 March 2022.   SELECTION CRITERIA: We included randomized controlled trials evaluating the effects of NSAIDs for CME following cataract surgery.

Two review authors independently screened all titles and abstracts, reviewed full-text publications against eligibility criteria, independently extracted data from newly included trials and assessed risk of bias for each included trial. We contacted trial authors for clarification or to request missing information. We provided a narrative synthesis of all included trials and their results. For continuous and dichotomous outcomes, we separately performed pooled analysis and reported mean difference (MD) and risk ratio (RR) as well as the associated 95% confidence interval (CI) whenever feasible. Two review authors independently graded the overall certainty of the evidence for each outcome using the GRADE approach.

We included nine trials with a total of 390 participants (393 eyes). Study participants' mean age was 72.2 years (interquartile range [IQR] 68.8 to 73.6) and 72% were women (IQR 69% to 74%). Three trials included participants with acute CME, and four included participants with chronic CME; the remaining two trials enrolled both participants with acute and chronic CME or participants with unknown CME duration. We assessed trials as having unclear (33%) or high risk of bias (67%). Visual improvement of two or more lines at the end of treatment  Data from one trial in participants with acute CME show no treatment effect of topical ketorolac compared to placebo (RR 2.00, 95% CI 0.46 to 8.76; 22 participants). Data from a three-arm trial in participants with acute CME demonstrate that, when compared with topical prednisolone, topical ketorolac (RR 1.33, 95% CI 0.58 to 3.07; 17 participants) or topical ketorolac and prednisolone combination therapy (RR 1.78, 95% CI 0.86 to 3.69; 17 participants) may have little or no effect on visual improvement. Results of subgroup analysis from two studies in participants with chronic CME suggest that, after treatment for 90 days or longer, NSAIDs may increase participants' likelihood of visual improvement by 1.87 fold (RR 2.87, 95% CI 1.58 to 5.22; I² = 33%; 2 trials, 121 participants) relative to placebo. However, there was no evidence of treatment effects in the subgroup with two months of treatment or less (RR 0.72, 95% CI 0.30 to 1.73; P = 0.19, I² = 41%; 2 trials, 34 participants). Overall, this evidence is very low certainty.  A single-study estimate in patients with mixed CME indicates that topical diclofenac may increase the likelihood of visual improvement by 40% when compared to topical ketorolac (RR 1.40, 95% CI 1.02 to 1.94; 68 participants). However, the same trial reported no difference between the groups in mean final visual acuity in Snellen lines (MD 0.40, 95% CI -0.93 to 1.73). A three-arm trial in patients with mixed CME reporting visual changes in ETDRS letters in comparisons between ketorolac and diclofenac (34 participants) or bromfenac (34 participants) suggests no evidence of effects. Overall, NSAIDs may slightly improve visual acuity in participants with mixed CME but the evidence is very uncertain. Persistence of improvement of vision one month after discontinuation of treatment One trial of participants with chronic CME tested oral indomethacin (RR 0.40, 95% CI 0.10 to 1.60; 20 participants) and the other compared topical ketorolac to placebo (RR 4.00, 95% CI 0.51 to 31.1; 26 participants). While there is no evidence of treatment effects, evidence suggests substantial between-group heterogeneity (P = 0.07, I² = 69.9%; very low-certainty evidence). None of the trials in patients with acute or mixed CME reported this outcome. Proportion of participants with improvement in leakage on fundus fluorescein angiography One three-arm trial in participants with acute CME shows that, when compared with topical prednisolone, there is no treatment benefit of topical ketorolac (RR 1.11, 95% CI 0.45 to 2.75; 17 participants) or topical ketorolac and topical prednisolone combination therapy (RR 1.56, 95% CI 0.72 to 3.38; 17 participants). This evidence is very low certainty. The combined estimate from two trials in participants with chronic CME indicates NSAIDs have little to no effect over placebo on improving leakage (RR 1.93, 95% CI 0.62 to 6.02; 40 participants; very low-certainty evidence). Neither of the trials in patients with mixed CME reported this outcome. Proportion of participants with improved contrast sensitivity Very low-certainty evidence from one trial in participants with acute CME shows no treatment benefit of ketorolac (RR 1.11, 95% CI 0.45 to 2.75; 17 participants) or ketorolac and prednisolone combination therapy (RR 1.78, 95% CI 0.86 to 3.69; 17 participants) compared with topical prednisolone. None of the trials in patients with chronic or mixed CME reported this outcome. Proportion of participants with improved central macular thickness on optical coherence tomography; measures of quality of life No included trial reported these outcomes. Adverse effects Most trials observed no differences in ocular adverse events, such as corneal toxicity or elevated intraocular pressure, between comparison groups.

Evidence on effects of NSAIDs in patients with CME is very uncertain and further investigation is warranted. Our findings are limited by small sample sizes, and heterogeneity in interventions, assessments, and reporting of clinically important outcomes.