BACKGROUND/AIM: The aim of this study was to assess the difference in outcome between the first-operated and the second-operated eyes after nonpenetrating deep sclerectomy (DS), and to identify potential success predictors for the second eye.
METHODS: This single-surgeon, retrospective study analyzed the outcomes of all bilateral nonsimultaneous DS with at least 24 months of follow-up. Its main outcome measure was surgical success, defined as unmedicated intraocular pressure (IOP) ≤15 mm Hg associated with a relative reduction ≥20%.
RESULTS: In all, 104 eyes of 52 patients who underwent bilateral (standalone or combined) DS, within a mean of 344.3±526.3 days of each other, were analyzed. Postoperatively, the mean medicated IOP decreased from 20.7±7.9 (first-operated eyes) and 19.3±6.6 mm Hg (second-operated eyes) at baseline (P=0.107) to 13.8±4.8 [(-33.3%; P<0.001) first-operated eyes) and 12.7±3.8 mm Hg [(-34.2%; P<0.001) second-operated eyes] after 2 years (P=0.619). Postoperative IOP and treatment reduction, respectively, showed fair (r=0.53) and good (r=0.71) levels of correlation between fellow eyes. The rates of complete success were comparable between first-operated and second-operated eyes (32.7% and 40.4%, respectively; P=0.364). At 2 years, among patients whose first-operated eyes were considered a success, 82.4% of surgeries in second eyes were successful (P=0.001). The odds ratio of a second-operated eye experiencing complete success were 6.32 (P=0.011) if the first-operated eye experienced complete success.
CONCLUSIONS: The present study demonstrated a strong association between first-operated and second-operated eyes after DS, in terms of surgical outcomes and IOP reduction. In effect, surgical success in the first-operated eye increases the odds of success in the second eye by 6-fold.