Pharmacological Accommodative Changes of the Anterior Segment and Its Impact on the Vault in Implantable Collamer Lens Implantation

Purpose: To estimate the accommodative changes of the anterior segment and its impact on the central and peripheral vaults after Visian Implantable Collamer Lens (ICL) (STAAR Surgical) implantation. Methods: Eighty eyes of 40 consecutive patients (mean age: 28.05 years; range: 19 to 42 years) were examined 3 months after ICL implantation. Eyes were randomly divided into a mydriasis group and a miosis group. Anterior chamber depth (ACD) to crystalline lens (ACD-L), anterior chamber depth to ICL (ACD-ICL), central distance from endothelium to sulcus to sulcus (ASL), central distance from sulcus to sulcus to crystalline lens (STS-L), central distance from ICL to sulcus to sulcus (STS-ICL), and central (cICL-L), midperipheral (mICL-L), and peripheral (pICL-L) vaults were measured by ultrasound biomicroscopy at baseline and after induction with tropicamide or pilocarpine. Results: After tropicamide treatment, cICL-L, mICL-L, and pICL-L decreased from 0.531 ± 0.200, 0.419 ± 0.173, and 0.362 ± 0.150 mm to 0.488 ± 0.171, 0.373 ± 0.153, and 0.311 ± 0.131 mm, respectively. The values decreased from 0.540 ± 0.185, 0.445 ± 0.172, and 0.388 ± 0.149 mm to 0.464 ± 0.199, 0.378 ± 0.156, and 0.324 ± 0.137 mm after pilocarpine administration, respectively. The ASL and STS showed a significant increase in the mydriasis group (all P ≤ .038), but a decrease in the miosis group (all P < .001). The ACD-L increased and STS-L decreased in the mydriasis group (all P < .001), indicating the backward shift of the crystalline lens, whereas crystalline lens forward shift was observed in the miosis group. Additionally, the STS-ICL decreased in both groups (all P ≤ .021), suggesting the ICL backward shift. Conclusions: Both central and peripheral vaults decreased during the pharmacological accommodation process, and the ciliaris-iris-lens complex contributed to the changes. [ J Refract Surg . 2023;39(6):414–420.]