Ocular comorbidities and surgical history may impact cystoid macular edema risk

An analysis of IRIS Registry data suggests that cystoid macular edema (CME) after cataract surgery may be more common among patients with certain preexisting conditions or more complex ocular surgery histories, but the risk of CME is still relatively low overall.

Study design

Using data from the American Academy of Ophthalmology’s IRIS Registry, the authors conducted a retrospective case control study of patients who had undergone cataract surgery between 2016 and 2019 to determine the incidence and risk factors associated with post–cataract surgery CME. Cases included patients who were diagnosed with CME within 90 days after cataract surgery. All other patients who underwent cataract surgery served as controls.

Outcomes

Of 7.3 million cataract surgeries performed during the study period, 3.1 million met the study criteria. Cystoid macular edema was diagnosed in 25,595 of these eyes (0.8%) with a mean onset of 6 weeks after cataract surgery. Patients with CME were more likely to be younger than 65 years of age (p = 0.02), male (p < 0.001), and of Black race (p < 0.001). Certain preexisting ocular comorbidities were more common in eyes with CME, including glaucoma, epiretinal membrane, diabetic retinopathy, macular degeneration, uveitis, retinal vein occlusion, and macular hole. Eyes that had undergone a complex cataract surgery (p < 0.001) or a combined procedure (p < 0.001) were more likely to develop CME than those that had not. Cystoid macular edema was associated with worse visual outcome (p < 0.001), with a mean BCVA of 20/30 compared to a mean BCVA of 20/25 in eyes without CME.

Limitations

The main limitations of this study include its retrospective design and inaccuracies resulting from errors and biases in the IRIS Registry database. Of particular importance to this study is the fact that diagnosis of CME in the IRIS Registry is dependent on the surgeons’ coding patterns and is, therefore, prone to over- or underestimation. Other limitations of the IRIS Registry include a lack of complete datasets regarding BCVA and the preoperative use of steroidal and non-steroidal eye drops. Furthermore, the IRIS registry is prone to selection and reporting biases, so the findings of the study may not be representative of the whole country.

Clinical significance

Considering the large number of cataract surgeries performed in the US and that CME continues to be a major cause of morbidity in patients after cataract surgery, this study allows for the identification of patients who may be at higher risk of developing CME. Although not part of the current study, implementation of certain preoperative or postoperative measures targeted for higher-risk populations may help reduce the risk of developing this visually threatening complication.

Financial Disclosures: Dr. Arman Mashayekhi discloses no financial relationships.