Background/aims Car accidents caused by drivers unaware of their visual field (VF) defects under binocular vision have become an issue. We developed a simple self-check chart (CLOCK CHART binocular edition (CCBE)) to help patients with glaucoma recognise their abnormalities in the binocular VF and evaluated its usefulness.
Methods The chart has four targets displayed at 10°, 15°, 20° and 25° eccentricities. The examinee gradually rotates the chart 360° clockwise. At every 30°, the examinee confirms the fixation and indicates if all four targets can be seen. This study enrolled 88 eyes of 44 patients with glaucoma (mean age, 64.4±13.1 years) and 64 eyes of 32 visually normal individuals (mean age, 32.0±8.4 years). Except the CCBE test, static VF testing using the Humphrey field analyser (HFA) Swedish Interactive Threshold Algorithm-Standard 30-2 and binocular Esterman programmes was also performed for the subjects with glaucoma.
Results VF abnormality was defined as two or more contiguous points with a sensitivity of <10 dB within the central 30°. The CCBE test had sensitivities of 85% and 82% with respect to the HFA and Esterman results, respectively. We also used the British VF standards for Group 1 (car/motorcycle) drivers, and a sensitivity of 88% was obtained for the CCBE. The chart had a specificity of 100% for the visually normal subjects.
Conclusion The CCBE test enables drivers with glaucoma to notice their VF abnormalities under binocular condition. The application of this simple self-check method appears promising for occasions such as driver licensing.
- self-check screening
- CLOCK CHART®
- binocular edition
- binocular visual field
- binocular Esterman
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Correction notice This paper has been corrected since it was published Online First. Figure 1 has been updated with a new version.
Contributors MI, CM: were responsible for the research concept and the design of the study. MI, SO, SH, HN, FT, ME, TK, TN: were responsible for experimental data collection. SH, ME: analysed the acquired data. MI, CM, SK: ensured the accuracy and integrity of the work by making it appropriately investigated. MI, SH, SO, HN, FT, TK, TN, SK: prepared and revised the manuscript to make it suitable for publication. All authors read and approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests The authors have no conflicts of interest to declare expect CM, who has patent pending on CLOCK CHART
Patient consent for publication Obtained.
Ethics approval The ethics committee of Kindai University Faculty of Medicine (N0. ID22-4) has approved the study.
Provenance and peer review Not commissioned; externally peer reviewed.