Purpose
To investigate the safety and present clinical experiences of the Visian implantable Collamer lens (ICL) implantation in patients with shallow anterior chamber.
Methods
This retrospective study included patients with anterior chamber depth (ACD) lower than 2.8 mm who underwent ICL implantation. Implanted ICL size, pre- and postoperative visual acuity, refractive errors, postoperative central vault, intra- and postoperative complications were recorded through a medical chart review. The implanted ICL size and vault at 6 months follow-up were compared with a calculated ICL size and expected vault using a regression formula reported by the same author previously. Pneumatic tonometer, specular microscopy, and ultrasound biomicroscopy (UBM) were performed before and after surgery to evaluate the safety by measuring intraocular pressure (IOP), endothelial cell count (ECC), ICL vault, angle opening distance at 500 μm from the scleral spur (AOD 500) and trabecular-iris angle (TIA).
Results
The mean follow-up period of 16 eyes of 9 patients was 28.00 ± 15.03 months and preoperative ACD was 2.70 ± 0.08 mm. Preoperative and postoperative spherical equivalent (SE) were -10.27 ± 2.38 and -0.11 ± 0.51 diopters, respectively. Postoperative uncorrected and best corrected visual acuity were 0.89 ± 0.24 and 0.98 ± 0.19, respectively. The implanted ICL size revealed no significant difference with calculated ICL size (independent t-test, p=.356). However, postoperative vault was 0.346 ± 0.179 mm, which was lower than expected vault of 0.531 ± 0.173 mm calculated by a regression formula (independent t-test, p=.000). The pre- and postoperative mean AOD 500 were 0.379 ± 0.088 and 0.267 ± 0.111 mm, and mean TIA were 33.68 ± 5.37 and 23.67 ± 8.33 degrees, respectively. There were significant differences between preoperative and postoperative AOD500 and TIA (independent t-test, p=.000). However, there was no severe complication such as elevated IOP, ECC reduction, cataract formation or angle closure glaucoma.
Conclusions
ICL implantation performed in the eyes with shallow ACD showed good visual outcomes without severe complication during relatively long follow-up period. The size of ICL which was calculated to get ideal vault of 500 to 750 μm, but it resulted in lower vault than expected. It suggests the necessity for modulation of ICL sizing method in patients with low anterior chamber depth.
Keywords: 685 refractive surgery: phakic IOL