Assessment of calcification presence in hydrophilic acrylic phakic intraocular lenses

Purpose: To evaluate explanted hydrophilic acrylic phakic intraocular lenses (PIOLs) for evidence of calcification, specifically the Implantable Collamer Lens (ICL; Staar Surgical, Monrovia, CA, USA) and the I-CARE (Corneal, Paris, France). Setting: Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design: Retrospective laboratory analysis of explanted PIOLs. Methods: Demographic data from the explanted cases was collected through retrospective chart review. Explanted hydrophilic acrylic PIOLs were examined by gross and light microscopy to evaluate optical clarity, material integrity, and presence of surface or subsurface deposits. A subset of lenses underwent histochemical staining (1% alizarin red) and surface analysis to detect calcium deposits. Additional lenses were analyzed with implant cytology and visible-light transmission testing to assess biological deposition and ultraviolet (UV) blocking capacity. Results: Eighty-four PIOLs were analyzed, including 65 ICLs (mean implantation time 8.78 ± 7.23 years) and 19 I-CARE lenses (mean implantation time 12.99 ± 5.34 years). Trace to mild pigmentary deposition was present in 36 ICLs (55.4%) and 10 I-CARE lenses (52.6%). No opacification or calcification was observed on gross or microscopic evaluation, including peripheral haptic areas. Histochemical staining and surface analysis confirmed absence of calcium deposits. Implant cytology revealed proteinaceous material without cellular components. Light transmission ranged from 93.7% to 97.4%, and all lenses demonstrated effective UV blocking. Conclusions: This large series of explanted hydrophilic acrylic PIOLs showed no evidence of calcification after long-term implantation. These findings support the material stability and biocompatibility of hydrophilic acrylic PIOLs in vivo.