Short-term postoperative visual acuity decrease and recovery after Ahmed tube shunt procedure for glaucoma

Abstract Objective To elucidate the vision loss and recovery course after Ahmed tube shunt procedure 6 months postoperatively. To identify risk factors associated with significant vision loss. Design Retrospective chart review. Participants One eye of all adult patients who underwent Ahmed glaucoma valve procedure from January 2008 to December 2017 with a minimum of six-month follow-up. Methods Patients’ preoperative and postoperative corrected visual acuity (CVA) were documented for postoperative 1 week, 1 month, 3 months and 6 months. Main Outcome Measures Pre- and postoperative CVA at various time points were compared using repeated measures ANOVA. The proportions of patients with mild (less than 3 lines of Snellen CVA loss), moderate (3-5 lines, inclusive), severe (more than 5 lines) vision loss were calculated and compared using a Chi-squared test. Logistic regression analysis was conducted to identify risk factors associated with a loss of 3 or more lines of CVA 6 months after surgery. Results A total of 375 patients were included, whose mean preoperative CVA was 0.76. At postoperative 1 week, mean CVA worsened to 0.96 (p 0.05). In terms of any vision loss, 55.6% of patients had worse CVA than pre-operation at postoperative 1 week, including 23.5% who had 3 or more lines of vision loss; these proportions decreased to 39.2% (p Conclusions After Ahmed tube shunt procedure, worst CVA occurred at 1 week postoperatively and mean CVA returned to preoperative level by the third postoperative month. About 40% of patients had any CVA loss compared to pre-operation, while 9.3% of patients had 3 or more lines of CVA loss at the 6th postoperative month. Postoperative anti-metabolite injection was associated with a lower risk of 3 or more lines of postoperative vision loss.