Factors Associated With Low Vault Following Evo Icl Implantation

To assess the factors associated with a low vault after EVO ICL implantation utilizing ultrasound bimicroscopy (UBM).

Ultrasound biomicroscopy (UBM) can facilitate objective and quantitative estimation of anterior segment parameters, especially the anatomy of the ciliary body.The anatomical configuration of the ciliary– sulcus complex, where the ICL rests is postulated to influence haptic positioning and the vault after operation. However, there have been limited previous studies on the risk factors for low vault.

A total of 69 eyes from 69 patients (only the right eye was included) who underwent EVO ICL implantation and had completed at least 1-year follow-up were recruited in this study. The eyes were divided into two groups: 23 eyes from 23 consecutive patients with a vault less than 250μm (low vault group) and 46 eyes from 46 consecutive patients with a vault of 250μm or greater (normal vault group). Preoperative biometric parameters and clinical outcomes were compared between the two groups. Anterior segment parameters were estimated using UBM and their impact on vault was evaluated. Additionally, the number of haptics present in the ciliary sulcus (ICS) and the position of the haptics, quantified as iris root to haptic tip (IRH), were measured.

No significant anterior subcapsular cataracts were observed. Significant differences were found in preoperative trabecular–ciliary process distance (TCPD), iris–ciliary angle (ICA), trabecular–ciliary angle (TCA), ciliary process length (CPlength) between the two groups (P<0.05). Postoperative IRH was also differed statistically between groups (P<0.05). Multiple linear regression analysis revealed that the CPlength, IRH, and ICL size were significantly associated with vault. The ICS distribution was ≤ 2 ICS in 20 eyes (87.0%), > 2 ICS in 3 eyes (13.0%) in low vault group, and ≤ 2 ICS in 19 eyes (41.3%), > 2 ICS in 27 eyes (58.7%) in normal vault group. The proportions of ICS in different groups were statistically different (P<0.05).

A shorter ciliary process appears to be a potential risk factor for a low vault after EVO ICL implantation. Malposition of the ICL haptic was also associated with a low vault. Increasing the number of haptics present in the ciliary sulcus (ICS) may reduce the risk of a low vault following implantation.