PURPOSE: To define the incidence of pseudophakic macular edema (PME) after cataract surgery and to identify contributory risk factors.
DESIGN: Retrospective database study of electronic medical records (EMRs).
PARTICIPANTS: A total of 81984 eyes undergoing cataract surgery between December 2010 and December 2014 from 8 independent United Kingdom clinical sites.
METHODS: Structured clinical data mandated by the EMR were anonymized and extracted for each eye undergoing cataract surgery including: perioperative visual acuity, copathologic features, simultaneous surgical procedures, and the presence or absence of a specified list of intraoperative complications. Diabetic status with matched Early Treatment Diabetic Retinopathy Study (ETDRS) grading also was mandated by the EMR. Eyes receiving prophylactic nonsteroidal anti-inflammatory drugs were excluded.
MAIN OUTCOME MEASURE: Diagnosis of cystoid macular edema or new-onset macular edema in patients with diabetes, recorded by a healthcare professional within 90 days of surgery.
RESULTS: Baseline incidence of PME in eyes without operative complications, diabetes, or risk factors was 1.17%. Eyes in which PME developed were more likely to be male, older and to demonstrate risk factors. The relative risk (RR) was increased in eyes with capsule rupture with or without vitreous loss (RR, 2.61; 95% confidence interval [CI], 1.57-4.34), a previous diagnosis of epiretinal membrane (RR, 5.60; 95% CI, 3.45-9.07), uveitis (RR, 2.88; 95% CI, 1.50-5.51), retinal vein occlusion (RR, 4.47; 95% CI, 2.56-5.92), or retinal detachment repair (RR, 3.93; 95% CI, 2.60-5.92). High myopia, age-related macular degeneration, or prostaglandin analog use were not shown to increase risk. Eyes with PME on average had poorer postoperative visual acuity, which persisted to the latest time point assessed, up to 24 weeks. Eyes from patients with diabetes, even in the absence of retinopathy, had an increased RR (RR, 1.80; 95% CI, 1.36-2.36) of new macular edema after surgery. The risk was higher in the presence of any diabetic retinopathy (DR; RR, 6.23; 95% CI, 5.12-7.58) and rose proportionately with increasing severity of DR.
CONCLUSIONS: Pseudophakic macular edema occurs commonly after phacoemulsification cataract surgery, even in the absence of complications and risk factors. This large retrospective study using structured EMR data quantified the RRs of PME and the risk with increasing ETDRS severity of DR. It highlights the need for prophylactic therapy, especially in those groups of eyes with the highest RRs.