Systemic immune-inflammation index could be associated with pseudophakic cystoid macular edema after an uneventful phacoemulsification surgery in patients without risk factors.

Background: To evaluate the association between serum biomarkers and pseudophakic cystoid macular edema (PCME) in eyes without risk factors after uneventful phacoemulsification cataract surgery.

Methods: This is a case-control study. Patients without risk factors and who developed clinically significant PCME after uncomplicated phacoemulsification surgery were enrolled in the study. The age- and sex-matched control group that had normal fundus examination findings and 10/10 visual acuity in the first week, first month and following postoperative control visits was randomly recruited from the same study cohort. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were obtained from the preoperative complete blood count (CBC) test and compared between the two groups. Linear regression analysis was used to assess the relationship between central macular thickness (CMT) and biomarkers. A binary logistic regression model was generated to evaluate the significance of the biomarkers in predicting PCME. The receiver operating characteristic (ROC) curves of the significant parameters in the logistic regression model were presented to detect the area under the curve (AUC), the cut-off point, the sensitivity and the specificity.

Results: The study cohort included 5352 patients. Of these patients, 52 (0.97%) met the inclusion criteria, and 60 age- and sex-matched patients were recruited as the control group. PLR, NLR, and SII were significantly different between the two groups (p = 0.006, p = 0.002, p < 0.001, respectively). According to the linear regression analysis, SII was found to have a significant relationship with CMT (p < 0.001). Only SII was assessed as significant in the logistic regression model (p = 0.046). In the ROC curve, the AUC of SII was 0.709. The sensitivity and specificity of SII for PCME prediction were 65.38% and 75%, respectively, and the cut-off point was 433.70.

Conclusion: SII is associated with the occurrence of PCME in eyes without risk factors after uneventful phacoemulsification surgery. SII could be a useful tool to predict PCME in eyes without risk factors.