Changes in the Sulcus and Anterior Chamber after horizontal or vertical intraocular lens orientation: a prospective randomized study.

Purpose: To assess the changes in ciliary sulcus (CS) and anterior chamber diameters (ACDi) following horizontal or vertical orientation of the intraocular lens (IOL) in the capsular bag in relation to preoperative axial length (AL) and anterior chamber depth (ACD).

Settings: University hospital.

Design: Prospective, randomized study.

Methods: The first eye was randomized to receive the IOL horizontally or vertically and the second eye had the opposite orientation. Undilated UBM at 0-180o, 45-225o, 90-270o and 135-315oaxes were performed pre- and at 6 weeks. Data on preoperative AL and ACD was collected. a) Primary outcome measure: Change in CS and ACDi in relation to preoperative AL and ACD. b) Secondary outcome measure: Postoperative CS and ACDi in the horizontal vs. vertical IOL placement groups and right vs. left eyes.

Results: Forty-six patients (92 eyes) were recruited. After horizontal placement of the IOL, there was a significant correlation between AL and change in horizontal CS for right (r=0.68, p=0.01) and left eyes (r=0.68, p=0.04). After vertical placement, there was a significant correlation between AL and ACD with change in vertical ACDi in right (AL: r=0.71,p=0.01; ACD: r=0.66,p=0.02) and left eyes (AL: r=0.93,p<0.01; ACD: r=0.65,p=0.04) respectively. There was no significant difference in pre- and postoperative change with horizontal and vertical IOL placements in the right vs. left eyes.

Conclusion: When the IOL is horizontal in the capsular bag, the horizontal CS increases with decrease in AL. The vertical ACDi increases with increased AL or ACD when the IOL is vertical in the capsular bag.