OCT 22, 2021
This prospective study evaluated 574 eyes of 338 patients undergoing myopic implantable collamer lens (ICL) implantation using optical coherence tomography.
This prospective study evaluated 574 eyes of 338 patients undergoing myopic implantable collamer lens (ICL) implantation using OCT. Central ICL vault was measured intraoperatively with microscope-integrated OCT and also postoperatively with a swept-source OCT (SS-OCT) at 4 and 24 hours.
Mean differences between intraoperative and postoperative vault values were 11.5 ± 29.0% of the mean value 4 hours postoperatively and 2.7 ± 33.5% of the mean value 24 hours postoperatively. Correlation analysis showed significant agreement between vault values obtained intraoperatively and at the two postoperative times, 4 hours and 24 hours. In 73% of cases, postoperative values 4 hours after the surgery could be predicted from intraoperative values. In 56% of cases, postoperative vault values 1 day after surgery could be predicted from intraoperative values.
One limitation of this study is that the intraoperative and postoperative vault measurements were taken using different equipment (SD-OCT for intraoperative; SS-OCT for postoperative). Another limitation is lack of control of pupil size between the 2 measurements. Postoperative measurements were obtained on a physiological pupil while intraoperatively the eye was under induced mydriasis. Another limitation is different patient positioning while the 2 measurements were taken, which could influence the outcomes.
One important takeaway from the study is that high vault values measured intraoperatively tend to remain high postoperatively, and low values intraoperatively tend to remain low. Even though there is a difference in vault size at the different postoperative times, this general principle remains true. As a result, intraoperative use of OCT to measure vault size can potentially help surgeons avoid undesired vault outcomes and vault-related surprises. The use of OCT can guide intraoperative decision-making such as ICL rotation or ICL exchange before the patient even leaves the OR, which can be beneficial as sizing for the ICL still remains challenging. Surgeons who perform a low volume of ICL cases should keep in mind that there are sizing nomograms optimized for white-to-white or sulcus-to-sulcus diameters that work in the majority of cases.