LAUSR

Dear Editor, Trabeculotomy (LOT) reduces intraocular pressure (IOP) by eliminating aqueous flow resistance by cleavage of the trabecular meshwork and inner walls of Schlemm’s canal at the point of outflow resistance of the aqueous humor. Measurement of anterior chamber flare (ACF) is the established method for estimating postoperative inflammation [1]; however, few studies have estimated postoperative inflammation by ACF after LOT. The Ethics Committee of Shimane University Hospital approved the current study. Based on the regulations issued by the Japanese Government, the study protocol did not require each patient to provide written informed consent; instead, the protocol was posted in the outpatient clinic to notify the patients of the study. The study complied with the tenets of the Declaration of Helsinki. We searched the department database for eyes that underwent ab externo LOT by one surgeon (MT) to manage glaucoma between January 2008 and June 2010. The inclusion criteria were consecutive cases with primary open-angle glaucoma (POAG) or exfoliat ion glaucoma (EXG); measurement of IOP by Goldmann applanation tonometry preoperatively and 1, 3, and 6 months postoperatively; and measurement of the ACF by the FM-600 laser flare meter (Kowa, Nagoya, Japan) preoperatively and more than 2 times within 6 months postoperatively. If both eyes of a patient were eligible, the eye that underwent surgery first was included. The surgical procedure was described previously [2]. At the end of surgery, 1.65 mg of dexam e t h a s o n e s o d i um ph o s p h a t e w a s i n j e c t e d subconjunctivally, and 1.5% levofloxacin and 0.1% betamethasone were applied topically four times daily for 3 to 4 weeks postoperatively in all cases. A topical non-steroidal anti-inflammatory drug was used in cases treated with combined LOT and cataract surgery. No severe surgical complications such as vitreous loss, suprachoroidal hemorrhage, and endophthalmitis were noted. Ultimately, 96 eyes of 96 subjects (mean age, 75.7 years; 51 [53%] men; 32 POAG and 64 EXG) were included. The demographic data of the subjects are shown in Table 1. All statistical analyses were performed using the JMP Pro version 14.2 statistical software (SAS Institute, Inc., Cary, NC, USA). By mixed-effects regression model, the IOP and number of medications decreased significantly for up to 6 months postoperatively in all patients and in the POAG and EXG groups (Table 1). Compared with preoperatively, a significant increase in the ACF occurred 1 week postoperatively in all patients and in the POAG and EXG groups; the ACF was significantly higher in the EXG group than POAG group at 1 and 2 weeks and 1 and 3 months postoperatively (Table 1). The mixedeffects regression model showed that EXG rather than POAG, presence of prolonged hyphema, and incidence of after cataract or capsulorhexis contraction were associated with a higher ACF level; female gender and later postoperative period were associated with a lower ACF level; while age, surgical procedure (LOT alone or combined LOT), IOP and medication reductions at 6 months postoperatively, and presence of a transient IOP spike were not associated with the ACF level (Supplementary Table S1). The scatterplot of ACF during the early postoperative period showed significantly higher ACF in the EXG group than the POAG group within 6 weeks postoperatively with no overlap of the 95% confidence Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00417-020-04962-8) contains supplementary material, which is available to authorized users.