title: A comparison of small aperture implants providing increased depth of focus in pseudophakic eyes.
abstract: OBJECTIVE
  Presbyopia is characterized by a decreasing ability of accommodation - the eye's ability to alter the focus between far and near distance objects. After cataract surgery, accommodation is completely lost. Several years ago, small aperture (pinhole) implants have been presented in order to increase the depth of focus providing functional vision at far and near distance without the need for spectacles. We simulated the theoretical depth of focus with three different pseudophakic eye models in order to investigate the potential benefit arising from the implantation of small aperture optical (SAO) implants. The purpose was to compare the achievable defocus range of a SAO intraocular lens with a SAO corneal inlay.
  
  
  METHODS
  We created three pseudophakic eye models with an aberration correcting intraocular lens (IOL): one with a corneal SAO implant (M1), a second one with a SAO intraocular lens (M2) and a third one with a conventional intraocular lens of the same optical design but without SAO (M0). Defocus curves were created by varying the focal length of a thin lens in front of the eye - which mimics the clinical assessment of defocus curves.
  
  
  RESULTS
  With a Strehl ratio threshold of 0.05, the reference design M0 provided a maximum defocus range of approximately 1.7D (with a 2.0mm pupil) whereas both pinhole implants (M1 and M2) showed a defocus range up to 3.0 and 3.3D, respectively. With large natural pupil diameter, where light passes outside the SAO aperture, the defocus range drops to 0.8D/0.7D for M1 and M2 compared to 0.7D with M0.
  
  
  CONCLUSIONS
  The SAO intraocular lens showed a similar defocus range as the SAO corneal inlay. Both concepts have the potential of increasing depth of focus compared to a conventional intraocular lens. In case of large physiological pupil diameters these advantages of SAO implants may be lost.
authors.affiliation: Institute of Experimental Ophthalmology, Saarland University, Kirrberger Strasse 100, Bldg. 22, 66424 Homburg/Saar, Germany. Electronic address: timo.eppig@uks.eu.
authors.forename: Timo
authors.initials: T
authors.lastname: Eppig
authors.affiliation: Department of Ophthalmology, Saarland University Medical Centre, Kirrberger Strasse 100, Bldg. 22, 66424 Homburg/Saar, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Spira
authors.affiliation: Department of Ophthalmology, Saarland University Medical Centre, Kirrberger Strasse 100, Bldg. 22, 66424 Homburg/Saar, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
authors.affiliation: Department of Ophthalmology, Saarland University Medical Centre, Kirrberger Strasse 100, Bldg. 22, 66424 Homburg/Saar, Germany; Department of Ophthalmology, Semmelweis University, Maria utca 39, 1085 Budapest, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Szentmáry
authors.affiliation: Institute of Experimental Ophthalmology, Saarland University, Kirrberger Strasse 100, Bldg. 22, 66424 Homburg/Saar, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Langenbucher
mesh_terms: D003198:Computer Simulation; D003867:Depth Perception; D019544:Equipment Failure Analysis; D008904:Miniaturization; D008954:Models, Biological; D054120:Phakic Intraocular Lenses; D011305:Presbyopia / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D011474:Prosthesis Design; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014792:Visual Acuity
keywords: IC-8; Intraokularlinse; KAMRA; Lochblende; Presbyopia; Presybopie; Schärfentiefe; Small aperture optics; depth of focus; intraocular lens; pinhole; small aperture optics