title: Stereo-acuity in patients implanted with multifocal intraocular lenses: is the choice of stereotest relevant?
abstract: OBJECTIVE
  A randomized and double-blinded study design was implemented to assess the stereo-acuity in patients symmetrically implanted with four types of multifocal intraocular lenses (MIOLs), compared to a monofocal lens (control group). In addition, the influence of the type of test employed for the evaluation of stereo-acuity was explored.
  
  
  METHODS
  Six months after cataract intervention, stereo-acuity was measured with the Titmus and TNO stereotests in 143 patients implanted with one of the following MIOL lens types: hybrid spherical SN60D3, hybrid aspheric SN6AD1, diffractive aspheric ZMA00 and refractive spherical NXG1. A control group implanted with the monofocal aspheric ZA9003 (in which stereo-acuity was measured with a near addition) was also included in the study.
  
  
  RESULTS
  Statistically significant better stereo-acuity was found in the monofocal group with both stereotests (except for the SN60D3 group with the Titmus test) (all p < 0.001). No significant differences in stereo-acuity between MIOLs were found using the Titmus test. However, with the TNO, patients implanted with hybrid diffractive MIOLs exhibited statistically significant worse stereo-acuity than those with the refractive design (SN60D3, p < 0.001; SN6AD1, p = 0.006).
  
  
  CONCLUSIONS
  Patients implanted with MIOLs have worse stereo-acuity than those implanted with monofocal IOLs due to the decrease in retinal image contrast originating in the simultaneous presence of two images. A wavelength-based stereotest such as the TNO induces large differences in image contrast between fellow eyes implanted with diffractive-based MIOLs, which may result in an underestimation of the real stereo-acuity of the patient.
authors.affiliation: Department of Optics and Optometry, Technical University of Catalonia , Terrassa , Spain and.
authors.forename: Consuelo
authors.initials: C
authors.lastname: Varón
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Gil
authors.forename: Francisco
authors.initials: F
authors.lastname: Alba-Bueno
authors.forename: Genís
authors.initials: G
authors.lastname: Cardona
authors.forename: Fidel
authors.initials: F
authors.lastname: Vega
authors.forename: María S
authors.initials: MS
authors.lastname: Millán
authors.forename: José A
authors.initials: JA
authors.lastname: Buil
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015350:Contrast Sensitivity; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification / Q000379:methods*; D011446:Prospective Studies; D011474:Prosthesis Design; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity
keywords: Cataract surgery; chromatic aberration; diffractive optics; multifocal intraocular lens; stereo-acuity