title: Gradient refractive index optics IOL: theoretical background and clinical results.
abstract: OBJECTIVE
  To present the theoretical optical background and clinical results of a new multifocal intraocular lens (MIOL) concept-gradient refractive index optics (Gradiol).
  
  
  METHODS
  Original mathematical modeling software was used to calculate optimal construction of the MIOL optic constructed from two polymer materials with different refractive indices. Gradiol lenses were manufactured from hydrophobic acrylic utilizing original step-by-step polymerization technology with the final power difference of of 3.5 D between optic components. Non-comparative prospective clinical study included 26 patients (29 eyes) who were candidates for MIOL implantation. All surgeries were performed at the S. Fyodorov Eye Microsurgery Complex State Institution, Moscow, Russia. After implantation of the Gradiol lenses, the postoperative evaluations included distance (best corrected visual acuity (BCVA)) and near visual acuity (NVA), contrast sensitivity (CS), and amplitude of pseudoaccommodation. Subjective patient's satisfaction was assessed using a questionnaire (VF-14).
  
  
  RESULTS
  The mean age of the patients was 62.5 ± 5.7 years (range 27-82 years). All surgical procedures were uneventful. At 6 months postoperatively, the mean uncorrected distance VA was 0.73 ± 0.18, mean uncorrected near VA was 0.57 ± 0.19, mean corrected distance VA was 0.89 ± 0.15, mean corrected near VA was 0.84 ± 0.07, and amplitude of pseudoaccommodation was 4.75 ± 0.5 D. Eighty-six percent of patients were spectacle independent for daily activities and reading. Optical disturbances that were functionally significant were reported by 10.7% of patients postoperatively.
  
  
  CONCLUSIONS
  The clinical outcomes of this study confirmed the theoretical calculations of constructing MIOL optics from materials with different refractive indices.
authors.affiliation: S. Fyodorov Eye Mucrosurgery Complex State Institution, Beskudnikovsky Blvd, Moscow, Russian Federation.
authors.forename: Boris
authors.initials: B
authors.lastname: Malyugin
authors.affiliation: S. Fyodorov Eye Mucrosurgery Complex State Institution, Beskudnikovsky Blvd, Moscow, Russian Federation.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Morozova
authors.affiliation: S. Fyodorov Eye Mucrosurgery Complex State Institution, Beskudnikovsky Blvd, Moscow, Russian Federation.
authors.forename: Valentin
authors.initials: V
authors.lastname: Cherednik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D055095:Optics and Photonics; D017060:Patient Satisfaction; D018918:Phacoemulsification; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology
keywords: Gradient Refractive Index; Intraocular Lens; Multifocal; Pseudoaccomodation