To determine the risk factors and incidence of cataract formation over a long-term mean follow-up of 7.5 years after type V4 implantable collamer lens (ICL) implantation.

We analyzed the preoperative, 3-month postoperative, 3-year postoperative, and last follow-up data of 228 eyes (118 patients) with mean preoperative spherical equivalent of -12.7 D and minimum postoperative follow-up of 3 years. Additionally, we determined the risk factors for cataract formation and calculated the 10.3 year cumulative cataract formation rate and 10.3 year cumulative cataract surgery rate using a survival curve.

After type V4 ICL implantation with minimum follow-up of 3 years, the calculated 10.3 year cumulative cataract formation rate was 20% and actual cataracts developed in 34 eyes (14.9%). The 10.3 year cumulative cataract surgery rate was 12% based on a survival curve and actual cataract surgery was performed in 12 eyes (5.3%). The risk factors for cataract formation were age (odds ratio [OR] = 1.10, p = 0.00), preoperative spherical equivalent (OR = 0.90, p = 0.00), crystalline lens thickness (OR = 9.54, p = 0.00), axial length (OR = 1.33, p = 0.00), 3 months postoperative vault (OR = 0.50, p = 0.03), and existence of peripheral touch between ICL optic margin and crystalline lens at last follow-up (OR = 7.84, p = 0.00).

We suggest one of the main risk factors for cataract formation after ICL implantation is decreased central vault and peripheral touch between ICL optic margin and crystalline lens.