title: Posterior chamber collamer phakic intraocular lens for myopia and hyperopia.
abstract: OBJECTIVE
  To assess the feasibility of correcting refractive errors using a foldable posterior chamber phakic intraocular lens.
  
  
  METHODS
  Thirty-four foldable posterior chamber phakic intraocular lenses (STAAR Collamer intraocular lens) were consecutively implanted by the same surgeon (PMP) in 19 myopic eyes and 15 hyperopic eyes. In myopic eyes, mean preoperative spherical equivalent refraction was -16.65 +/-3.37 D (range, -8.12 to -21.25 D). In hyperopic eyes, mean preoperative spherical equivalent refraction was +7.77+/-2.08 D (range, +4.75 to +11.75 D). Mean follow-up was 12 months (range, 6 to 18 mo). Two hyperopic eyes were not included in the data analysis because of removal of the intraocular lens due to pupillary block.
  
  
  RESULTS
  Myopic eyes (n=19)-Mean spherical equivalent postoperative refraction was -1.51+/-1.37 D (range, -5.50 to+0.38 D). Postoperative refraction was within +/-0.50 D in 4 eyes (21.05%) and within +/-1.00 D in 8 eyes (42.10%). Uncorrected visual acuity was 20/40 or better in 12 eyes (63.15%) and 20/25 or better in 3 eyes (15.78%). No eye had an uncorrected visual acuity of 20/20 or better. Spectacle-corrected visual acuity was 20/40 or better in all eyes, 20/25 or better in 12 eyes (63.15%), and 20/20 or better in 1 eye (5.26%). Spectacle-corrected visual acuity was unchanged in 10 eyes (52.63%) and improved in 9 eyes (47.36%). A retinal detachment developed in 1 eye (5.26%). Hyperopic eyes (n=15)-Mean spherical equivalent postoperative refraction was +0.02+/-0.64 D (range, -1.00 to +1.50 D). Postoperative refraction was within +/-0.50 D in 9 eyes (69.25%) and +/-1.00 D in 12 eyes (92.30%). Uncorrected visual acuity was 20/40 or better in 6 eyes (46.15%) and 20/25 or better in 3 eyes (20.25%). No eye had an uncorrected visual acuity of 20/20 or better. Spectacle-corrected visual acuity was 20/40 or better in 7 eyes (53.84%), 20/25 or better in 6 eyes (46.15%), and 20/20 or better in 2 eyes (15.38%). Spectacle-corrected visual acuity was unchanged in 10 eyes (76.92%), significantly improved in 2 eyes (15.38%), and worse in 1 eye (7.69%). Two of 15 eyes (13.33%) developed a severe pupillary block necessitating removal of the implants. One eye (7.69%) developed an anterior subcapsular cataract.
  
  
  CONCLUSIONS
  Refractive predictability appears better for hyeropia than for myopia using the STAAR Collamer foldable posterior chamber phakic intraocular lens. In hyperopic eyes, development of pupillary block may occur.
authors.affiliation: Centro di LaserChirurgia e di MicroChirurgia Oftalmica di Ivera, Genova, Italy.
authors.forename: P M
authors.initials: PM
authors.lastname: Pesando
authors.forename: M P
authors.initials: MP
authors.lastname: Ghiringhello
authors.forename: P
authors.initials: P
authors.lastname: Tagliavacche
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000601:surgery*; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011183:Postoperative Complications; D011184:Postoperative Period; D012029:Refraction, Ocular; D014792:Visual Acuity