Association of anterior chamber angle open parameters with postoperative intraocular pressure following laser peripheral iridotomy

Objective

To evaluate the relationship between anterior chamber angle and intraocular pressure (IOP) after laser peripheral iridotomy (LPI) treatment.

Methods

A retrospective cases control study was adopted.Fifty-eight patients (58 eyes) who were diagnosed as primary angle closure (PAC) were included in this study.Ultrasound biomicroscopy (UBM) parameters in angle opening distance (AOD), trabecular iris area (TISA) and angle recess area (ARA) examination were performed before LPI.The changes of intraocular pressure (IOP) were compared between different time-points (before and 1 hour, 2 hours, 8 hours, 24 hours, 2 weeks, 6 months and 12 months after LPI). The patients were divided into IOP≤21 mmHg group (41 eyes) and IOP>21 mmHg group (17 eyes) after LPI.Relationship between anterior chamber angle and IOP after LPI treatment was explored.This study was approved by Ethic Committee of the Henan Eye Institute and informed consent was obtained from each patient.

Results

The IOPs were increased in 1 hour, 2 hours after LPI and lowered in 2 weeks, 6 months, 12 months after LPI compared with IOP before LPI, with significant differences between them (all at P<0.01). Twelve patients suffered transient elevated IOP and recovered by self-healing or treatment.IOP of 4 patients were elevated after 6 months to 1 year follow-up.The IOPs in 2 weeks, 6 months and 12 months after LPI were lowered compared with IOP before LPI, with significant differences between them (all at P<0.01). The UBM parameters were significantly increased in 2 weeks, 6 months, 12 months after LPI in comparison with IOP before IPL (all at P<0.01). IOP and UBM parameters values were significantly different between IOP>21 mmHg group and ≤21 mmHg group after LPI.Regression analysis indicated that ARA750 (OR=0.75, P<0.05) was correlated to the IOP after LPI rather than IOP before operation, AOD and TISA (P>0.05).

Conclusions

ARA750 value is correlated with the IOP variations after LPI.UBM structured observation can improve the surgical successful rates and safty and prevent complications.

Ultrasound biomicroscopy; Biometry; Anterior chamber; Ocular hypertension/surgery; Laser/treatment use; Laser peripheral iridomtomy; Retrospective study