Intraoperative Measurement Of Vault By Oct For The Implantable Collamer Lens (Icl) And Correlation With Vault At 1 Month

To investigate the use of intraoperative lens separation vault measurements by 3D OCT (ARTEVO 800, Carl Zeiss Meditec) in predicting final vault of the Implantable Collamer Lens (ICL) (STAAR Surgical).

London Vision Clinic, London, UK

Retrospective analysis of consecutive V4c EVO and EVO+ ICL procedures using the ARTEVO 800 stereoscopic 3D digital microscope with in-line OCT. ICL size was chosen using Insight 100 VHF digital ultrasound (ArcScan Inc) posterior chamber measurements. ICL positioning and tilt were evaluated and haptic repositioning was performed if indicated. OCT central vault was recorded intraoperatively. Central vault was measured 30 minutes, 1 day and 1 month after surgery by MS-39 OCT (CSO Italia). Mean vault at each time point was calculated. Linear regression analysis was used to evaluate the correlation between vault by intraoperative OCT and vault at 1 month. The standard deviation of the residuals was used to derive the 95% confidence interval.

A total of 81 eyes (43 patients) were included. Mean central vault was 769±278µm (149 to 1230µm) intraoperatively, 829±234µm (88 to 1,467µm) 30 minutes postop, 617±187µm (267 to 1342µm) at 1 day and 595±168µm (260 to 1097µm) at 1 month. The correlation between intraoperative and 1 month vault showed a biphasic correlation (P<.001): vault was higher at 1 month if the intraoperative vault was less than 350µm, and lower at 1 month for an intraoperative vault above 650µm. The R² was 0.467 and the standard deviation of the residuals was 123µm. The 95% confidence interval was ±243µm. Haptic and footplate repositioning was carried out in 13 eyes (16%) based on intraoperative OCT leading to a change in vault in 8 eyes (62%).

Intraoperative OCT is a useful tool to assess the positioning of the haptics for phakic IOLs, which is an essential step for achieving the optimal vault. Intraoperative vault measurement can be used to estimate the potential range for the final postoperative vault. This information might be used to decide to immediately exchange a poorly sized lens and avoid second operations for ICL exchange.