Prospective evaluation of changes in anterior segment morphology after laser iridotomy in Chinese eyes by rotating Scheimpflug camera imaging

Background To investigate the 3-D morphology changes of anterior segment in primary angle-closure suspect and primary angle-closure after laser peripheral iridotomy (LPI) using rotating Scheimpflug camera. Methods A total of 37 eyes of 25 patients were enrolled in the study. Just before and after LPI, rotating Scheimpflug camera was performed on each selected eye by one skilled ophthalmologist. Comparison of anterior segment parameters before and after LPI such as central corneal thickness, central anterior chamber depth, peripheral anterior chamber depth, anterior chamber volume, pupil diameter and anterior chamber angle of cross-section photographs from 0 degrees to 180 degrees (ACA) were analysed. Results Before and after LPI, central corneal thickness increased from 537.92 +/- 27.92 microm to 541.49 +/- 27.85 microm (P = 0.074); no statistic changes of central anterior chamber depth were found before LPI (1.72 +/- 0.27 mm) and after LPI (1.70 +/- 0.24 mm) (P = 0.337); peripheral anterior chamber depth deepen from 0.89 +/- 0.26 to 1.14 +/- 0.26 mm (P = 0.000); anterior chamber volume increased from 55.54 +/- 14.25 to 82.65 +/- 17.63 mm(3) (P = 0.000); average pupil diameter of all patients are 1.72 +/- 0.42 and 1.63 +/- 0.46 mm, respectively, showed no statistic difference (P = 0.228). ACA widen from 25.51 +/- 5.66 degrees to 28.11 +/- 5.67 degrees in 9 o'clock direction(P = 0.005), and from 25.77 +/- 5.15 degrees to 27.91 +/- 4.87 degrees in 3 o'clock direction after LPI (P = 0.020). Conclusion LPI induce dramatic changes of 3-D anterior segment morphology in primary angle-closure suspect and primary angle-closure.