Phakic intraocular Lens implantation in keratoconus patients

Background: Both the anterior chamber and posterior chamber phakic intraocular lenses (pIOLs) implantation are acceptable refractive surgical approaches in keratoconus patients with high anisometropia, contact lens intolerance, or who prefer spectacle and contact lens independent. They are beneficial for correcting anisometropia in stable keratoconus cases or following corneal procedures such as intrastromal corneal ring segments (ICRS), collagen cross-linking (CXL), and keratoplasty. They are suitable for eyes without advanced keratoconus with acceptable best-corrected distance visual acuity (BCDVA) or without highly irregular astigmatism, high comma, and higher-order aberrations (HOAs). Combined procedures for irregular astigmatism reduction and corneal regularization with either ICRS or topography/wavefront-guided transepithelial PRK (with or without CXL) can be associated in advance with pIOLs implantation to improve BCDVA in these cases. Aim: To study and report the evidence regarding the safety and efficacy of pIOLs for KC patients' visual and refractive rehabilitation, we have analyzed the scientific evidence published within the last 10 years (from 2012 onwards). Results: No randomized controlled trials but only eleven retrospective case series and two prospective case series were identified. Satisfactory visual rehabilitation was achieved regarding uncorrected and corrected distance visual acuity (CDVA) and predictability of the refractive correction. Both types of pIOL (iris claw and posterior chamber pIOLs) offer very good results in terms of safety and efficacy with indexes close to or even exceeding 1 Conclusion: pIOLs implantation is a valid refractive therapeutic approach for correcting stable keratoconus with moderate-to-high refractive errors, especially anisometropia associated with regular or mildly irregular astigmatism, and good CDVA.

Automated summary

Background: Anterior and posterior chamber phakic intraocular lenses (pIOLs) implantation is a viable refractive surgical option for keratoconus patients with high anisometropia, contact lens intolerance, or a preference for spectacle and contact lens independence. They are effective in correcting anisometropia in stable keratoconus cases or following corneal procedures such as intrastromal corneal ring segments (ICRS), collagen cross-linking (CXL), and keratoplasty. Combined procedures with ICRS or topography/wavefront-guided transepithelial PRK (with or without CXL) can be done in conjunction with pIOLs implantation to improve visual acuity. Aim: To analyze the scientific evidence published within the last 10 years (from 2012 onwards) regarding the safety and efficacy of pIOLs for keratoconus patients' visual and refractive rehabilitation. Results: There were no randomized controlled trials, but satisfactory visual rehabilitation was achieved with both anterior and posterior chamber pIOLs, with good safety and efficacy. Conclusion: pIOLs implantation is a valid refractive therapeutic approach for correcting stable keratoconus with moderate-to-high refractive errors, especially anisometropia associated with regular or mildly irregular astigmatism, and good visual acuity.