Anterior chamber flare and central macular thickness after trabeculectomy versus after phacoemulsification

To compare the inflammatory response in the eye after trabeculectomy to after phacoemulsification, focusing on anterior chamber flare (AC flare) and central macular thickness (CMT).

Data from 436 participants in two randomized controlled trials were analysed. Anterior chamber flare was measured in 69 participants undergoing trabeculectomy and 367 participants undergoing phacoemulsification preoperatively. Postoperative assessments were made on day 7 in trabeculectomy participants and on day 3 in phacoemulsification participants. CMT was assessed at baseline and 3 months postoperatively in both groups and 4 weeks postoperatively for trabeculectomy participants and 3 weeks postoperatively for phacoemulsification participants.

At baseline, AC flare and CMT were comparable between the groups. Early postoperatively, AC flare was 22.1 ph/ms [95% CI 19.1, 25.7] for trabeculectomy and 18.9 ph/ms [95% CI 17.8, 20.2] for phacoemulsification. Both groups significantly increased in AC flare from their baseline values, but the difference in increase between them was not significant (p = 0.46). In the trabeculectomy group, CMT showed no significant increase at 4 weeks but a significant rise of 2.3 microns from baseline to 3 months from 241 microns [95% CI 235.9, 246.1] to 243.3 microns [95% CI 237.6, 249.1] (p = 0.038). In the phacoemulsification group, CMT was significantly increased at 3 weeks and remained significantly elevated at 3 months from 242.6 microns [95% CI 240.4, 244.8] to 249.8 microns [95% CI 247.3, 252.4], increased by 7.2 microns (p < 0.0001). CMT increased significantly more after phacoemulsification compared to trabeculectomy at 3 to 4 weeks (p = 0.014) and 3 months (p < 0.0001) with respect to baseline values.

No significant difference in AC flare was found between trabeculectomy and phacoemulsification participants at baseline and early postoperatively. CMT did not increase at 4 weeks but increased significantly at 3 months after trabeculectomy. Phacoemulsification led to a significantly higher CMT increase at both 3 weeks and 3 months with respect to baseline compared to trabeculectomy.