Changes in anterior segment parameters after insertion of Ex-PRESS miniature glaucoma implant

PURPOSE: The aim of this study was to evaluate the effect of Ex-PRESS Miniature Glaucoma Implant surgery on corneal curvature and anterior segment parameters obtained with the Pentacam rotating Scheimpflug camera (Oculus Inc.). PATIENTS/METHODS: In this prospective study, a total of 19 eyes of 19 consecutive patients (11 men, 8 women) were evaluated preoperatively, on the first postoperative day, and at 1 week, 1 month, and 3 months postoperatively with the Pentacam. We compared measurements of anterior and posterior corneal curvature, anterior and posterior corneal astigmatism, anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle before and after surgery. All study eyes were pseudophakic. RESULTS: Intraocular pressure decreased significantly from 31.9±10.1 mmHg preoperatively to 6.1±5.7 mmHg on the first postoperative day (P<0.0001) and 15.7±3.6 mmHg at 3 months after surgery (P=0.0011). On the first postoperative day, the anterior corneal astigmatism increased from 2.6±3.3 to 4.7±3.1 D (P=0.19), the posterior corneal astigmatism increased from 0.4±0.2 to 0.9±0.5 D (P=0.008), the ACD decreased from 4.3±0.7 to 3.5±1 mm (P=0.015), and the ACV decreased from 193±35 to 160±49 mm (P=0.006). All of these changes in anterior segment parameters were not statistically significant at 3 months after surgery. CONCLUSIONS: Ex-PRESS Miniature Glaucoma Implant surgery significantly decreased intraocular pressure and had a transient effect on anterior segment parameters. Corneal curvatures, ACD, ACV, and anterior chamber angle were not affected at 3 months of follow-up.