title: Psychophysical Vision Simulation of Diffractive Bifocal and Trifocal Intraocular Lenses.
abstract: OBJECTIVE
  The visual performance of monofocal, bifocal, and trifocal intraocular lenses was evaluated by human individuals using a vision simulator device. This allowed investigation of the visual impression after cataract surgery, without the need actually to implant the lenses.
  
  
  METHODS
  The randomized, double-masked, three-way cross-over study was conducted on 60 healthy male and female subjects aged between 18 and 35 years. Visual acuity (Early Treatment Diabetic Retinopathy Study; ETDRS) and contrast sensitivity tests (Pelli-Robson) under different lighting conditions (luminosities from 0.14-55 cd/m2, mesopic to photopic) were performed at different distances.
  
  
  RESULTS
  Visual acuity tests showed no difference for corrected distance visual acuity data of bi- and trifocal lens prototypes (P =0.851), but better results for the trifocal than for the bifocal lenses at distance corrected intermediate (P =0.021) and distance corrected near visual acuity (P =0.044). Contrast sensitivity showed no differences between bifocal and trifocal lenses at the distant (P= 0.984) and at the near position (P =0.925), but better results for the trifocal lens at the intermediate position (P =0.043). Visual acuity and contrast sensitivity showed a strong dependence on luminosity (P <0.001).
  
  
  CONCLUSIONS
  At all investigated distances and all lighting conditions, the trifocal lens prototype often performed better, but never worse than the bifocal lens prototype.
  
  
  CONCLUSIONS
  The vision simulator can fill the gap between preclinical lens development and implantation studies by providing information of the perceived vision quality after cataract surgery without implantation. This can reduce implantation risks and promotes the development of new lens concepts due to the cost effective test procedure.
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Wolfgang
authors: W
authors: Brezna
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Kirsten
authors: K
authors: Lux
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Nikolaus
authors: N
authors: Dragostinoff
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Christian
authors: C
authors: Krutzler
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Nicole
authors: N
authors: Plank
authors: ACMIT Gmbh, Wiener Neustadt, Austria.
authors: Rainer
authors: R
authors: Tobisch
authors: Department of Clinical Pharmacology, Medical University Vienna, Austria.
authors: Agnes
authors: A
authors: Boltz
authors: Department of Clinical Pharmacology, Medical University Vienna, Austria.
authors: Gerhard
authors: G
authors: Garhöfer
authors: Department of Clinical Pharmacology, Medical University Vienna, Austria.
authors: Reinhard
authors: R
authors: Told
authors: Department of Clinical Pharmacology, Medical University Vienna, Austria.
authors: Katarzyna
authors: K
authors: Witkowska
authors: Department of Clinical Pharmacology, Center of Medical Physics and Biomedical Engineering, Medical University Vienna, Austria.
authors: Leopold
authors: L
authors: Schmetterer
keywords: contrast sensitivity; diffractive multifocal IOL; mesopic vision; trifocal IOL; vision simulator; visual acuity; visual impression