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Effects of brightness variations on a smartphone-based version of Radner reading charts

Eye (2024)Cite this article

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Abstract

Objective

The purpose of this study was to evaluate the equivalence of smartphone-based measurements of near visual acuity under different screen brightness conditions with a standard near visual acuity test.

Methods

On a sample of 85 participants, we have evaluated near visual acuity with a smartphone-based version of the Radner reading chart at three distinct screen brightness levels. Results have been compared with those obtained with classical Radner paper charts.

Results

We have found that, when a sufficient screen brightness is employed, the smartphone-based version of the Radner reading chart produces results that are in line with the paper Radner charts while low brightness levels lead to a significant underestimation of reading acuities. This result was consistent across different refractive conditions.

Conclusions

In conclusion, we have shown that handheld devices, such as smartphones, can be potentially exploited for remote measurements of near visual acuity provided a correct control of brightness screen is employed.

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Fig. 1: Schematic illustration of the apparatus used.
Fig. 2: Bland-Altman plots.
Fig. 3: Reading acuities.
Fig. 4: Reading acuities across different ametropic groups.

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Data availability

The raw behavioral data have been deposited at Zenodo repository and are publicly available at the following address: https://doi.org/10.5281/zenodo.8158654.

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Acknowledgements

We want to thank prof. Alessandro Farini for his helpful support in building up the stimuli used. We are grateful to Giulia Nesti and Letizia Lavezzi for their precious help in data collection.

Funding

The study was conducted with the contribution of the researcher Paolo Antonino Grasso with a research contract co-funded by the European Union - PON Research and Innovation 2014–2020 in accordance with Article 24, paragraph 3a, of Law No. 240 of December 30, 2010, as amended, and Ministerial Decree No. 1062 of August 10, 2021.

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Authors and Affiliations

  1. Department of Physics and Astronomy, University of Florence, Florence, Italy

    Paolo A. Grasso, Massimo Gurioli & Laura Boccardo

  2. Institute for Research and Studies in Optics and Optometry, Vinci (FI), Italy

    Laura Boccardo

Authors
  1. Paolo A. Grasso
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  2. Massimo Gurioli
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  3. Laura Boccardo
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Contributions

PAG: Project Administration, Conceptualization, Methodology, Data Collection, Data Analysis, Writing; MG: Supervision, Review & Editing; LB: Supervision, Methodology, Writing, Review & Editing.

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Correspondence to Paolo A. Grasso.

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Grasso, P.A., Gurioli, M. & Boccardo, L. Effects of brightness variations on a smartphone-based version of Radner reading charts. Eye (2024). https://doi.org/10.1038/s41433-024-02950-4

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