How accurate is an LCD screen version of the Pelli–Robson test?


Purpose: To evaluate the accuracy and repeatability of a computer-generated Pelli–Robson test displayed on liquid crystal display (LCD) systems compared to a standard Pelli–Robson chart. Methods: Two different randomized crossover experiments were carried out for two different LCD systems for 32 subjects: 6 females and 10 males (40.5 ± 13.0 years) and 9 females and 7 males (27.8 ± 12.2 years), respectively, in the first and second experiment. Two repeated measurements were taken with the printed Pelli–Robson test and with the LCDs at 1 and 3 m. To test LCD reliability, measurements were repeated after 1 week. Results: In Experiment 1, contrast sensitivity (CS) measured with LCD1 resulted significantly higher than Pelli–Robson both at 1 and at 3 m of about 0.20 log 1/C in both eyes (p < 0.01). Bland–Altman plots showed a proportional bias for LCD1 measures. LCD1 measurements showed reasonable repeatability: ICC was 0.83 and 0.65 at 1 and 3 m, respectively. In Experiment 2, CS measured with LCD2 resulted significantly lower than Pelli–Robson both at 1 and at 3 m of about 0.10 log 1/C in both eyes (p < 0.01). Bland–Altman plots did not show any proportional bias for LCD2 measures. LCD2 measurements showed sufficient repeatability: ICC resulted 0.51 and 0.65 at 1 and 3 m, respectively. Conclusions: Computer-generated versions of Pelli–Robson test, displayed on LCD systems, do not provide accurate results compared to classic Pelli–Robson printed version. Clinicians should consider that Pelli–Robson computer-generated versions could be non-interchangeable to the printed version.

Publication DOI:
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > School of Optometry
College of Health & Life Sciences > Ophthalmic Research Group
College of Health & Life Sciences > Vision, Hearing and Language
Additional Information: The final publication is available at Springer via
Uncontrolled Keywords: computerized-based stimuli,contrast sensitivity,LCD systems,Pelli–Robson test,Ophthalmology
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2018-08
Published Online Date: 2017-06-21
Accepted Date: 2017-06-21
Submitted Date: 2017-03-29
Authors: Zeri, Fabrizio (ORCID Profile 0000-0003-0529-555X)
Calcatelli, Paolo
Funaro, Eleonora
Martelli, Marialuisa
Naroo, Shehzad A. (ORCID Profile 0000-0002-6373-7187)



Version: Accepted Version

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