Abstract
Purpose:
To assess the agreement between gonioscopy and ultrasound biomicroscopy (UBM) in the diagnosis of eyes with narrow angles. To evaluate the iridocorneal angle widening following laser peripheral iridotomy (LPI).
Methods:
This is a prospective, longitudinal and comparative cohort study. We included patients with clinical diagnosis of narrow angle who were scheduled to laser peripheral iridectomy . All patients underwent a complete ophthalmologic examination including best corrected visual acuity (BCVA) assessment with protocol Snellen chart refraction, gonioscopic examination (Shaffer Scale), Intraocular pressure measurement with Goldman applanation tonometer. The UBM was performed before the LPI and 1 week before the procedure. We measured the angle opening distance at 500 μm from the scleral spur (AOD500) the iridotrabecular angle (TIA) and the trabecular to ciliar process distance (TCPD). Each quadrant of the anterior chamber angle was taken as an independent observational unit. Results were analyzed using the Wilcoxon signed-rank test and a T-student for related samples.
Results:
We enrolled 22 eyes (11 patients) with narrow angle. The mean age was 60.8 ± 5.3 years, 9 were female 2 men. The mean intraocular pressure was 13.8 mmHg and the BCVA was 20/30. The mean gonioscopy grade increased significantly from 1.95 to 3.00 (Po 0.001) . The angles widened 6.34 ° from 13.49° pre iridectomy to 19.83° post iridectomy. And so the AOD500 and the TCPD change from 165.93 μm to 254.77 μm and 766.91 μm to 787.72 μm respectively. The laser used was Nd:YAG the mean power used was 6.3 mJ and the treated quadrant were 23 % inferior and 77% superior in which is observed the mayor widening of the angle.
Conclusions:
Changes in the width of the angle after the laser peripheral iridotomy were detected with both, ultrasound biomicroscopy and gonioscopy but those are much better appreciated by UBM. And it help us to measured with better accuracy the changes and to know if they need re-LPI treatment.
Keywords: 550 imaging/image analysis: clinical •
571 iris •
421 anterior segment