Abstract
Purpose :
Aqueous humor outflow facility was compared preoperatively and postoperatively to elucidate the mechanism of intraocular pressure (IOP) reduction by microhook ab interno trabeculotomy (μLOT), a minimally invasive glaucoma surgery.
Methods :
Fifty-one eyes of 37 subjects (mean age, 67.2±11.8 years) were included in the study. The outflow facility coefficient (C) was estimated by pneumatonography ((Model 30 Classic, Reichert Technologies, Depew, NY, USA). Using the paired t-test, the IOP, number of medications, and C value were compared between pre- and post-operatively of μLOT. Possible correlations between the C value and IOP or number of medications were assessed by using linear regression analysis. To adjust for biases derived from the inclusion of both eyes of a patient and differences in background, the pre- and post-operative C values were compared using a mixed-effects regression model.
Results :
Compared to the preoperative IOP of 18.2 mmHg and number of medications of 2.8, the postoperative IOP of 13.5 mmHg and medications of 2.3 decreased significantly by 26% (p<0.0001) and 18% (p<0.0001), respectively. Compared to the preoperative C value of 0.27 µl/min/mmHg, the postoperative C value of 0.51 µl/min/mmHg increased significantly by 47% (p<0.0001). By linear regression analysis, higher IOP was associated with lower C values (estimate, -0.01/mmHg, p=0.0107), while number of medications was not associated with the C value (estimate, -0.04/medication, p=0.1739). By mixed-effects regression analysis, the postoperative measurement (estimate, 0.11/preoperative measurement, p<0.0001) was associated with higher C value, while age, sex, µLOT procedure, IOP, and number of medications were not.
Conclusions :
After µLOT, significant increase of outflow facility was observed. The results provide the evidence that increased conventional outflow by elimination of the outflow resistance at the trabecular meshwork is the main mechanism of IOP reduction after µLOT.
This is a 2021 ARVO Annual Meeting abstract.