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Predictions of postoperative visual outcome in subjects with cataract: a preoperative and postoperative study
  1. William A Douthwaite,
  2. Marta Vianya-Estopà,
  3. David B Elliott
  1. Department of Optometry, University of Bradford, Bradford, West Yorkshire, UK
  1. Correspondence to: Professor W A Douthwaite Department of Optometry, University of Bradford, Bradford, West Yorkshire BD7 1DP, UK; w.a.douthwaite{at}


Aim: To assess the ability of critical flicker frequency (CFF) and optimal reading speed (ORS) to predict the potential vision in patients with cataract with and without ocular comorbidity.

Methods: The two novel tests were compared with two well established potential vision tests (PVTs), the potential acuity meter (PAM) and the laser interferometer (LI). Measurements were made preoperatively in 1 eye of 88 subjects using the battery of 4 PVTs. Postoperative measurements were made with the CFF and the ORS. The subjects studied were consecutive cases over a 12-month period who fulfilled the inclusion and exclusion criteria, and agreed to participate in this study.

Results: CFF was the PVT most resistant to the presence of cataract. Both CFF and ORS give a similar predictive precision in the presence of cataract and ocular comorbidity, although CFF seems more precise when the cataract is dense.

Conclusions: The PAM and the LI showed a limited clinical capability in predicting postoperative visual acuity, particularly with dense opacities. The CFF shows the most promise as a PVT, particularly with dense cataract. Further evaluation is required for both CFF and ORS.

  • AHCPR, Agency for Health Care Policy and Research
  • CFF, critical flicker frequency
  • LED, light emitting diode
  • LI, laser interferometer
  • LOCS III, Lens Opacity Classification System III
  • logMAR, logarithm of the minimum angle of resolution
  • ORS, optimal reading speed
  • PAM, potential acuity meter
  • PVT, potential vision test
  • wpm, words read per minute

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  • Published Online First 22 November 2006

  • Subjects were examined before and after cataract surgery. The study and data accumulation gained approval from the hospital ethical committee and followed the Declaration of Helsinki for research involving human subjects. Informed consent was obtained from all subjects.

  • Competing interests: None.