Development of Clock Chart Driving Edition for self-checking the binocular visual field

Abstract

Purpose : Recently, Japan has been experiencing the problem of automobile accidents caused by drivers unaware of their visual field defects under binocular vision. We developed a simplified self-check screening sheet (Clock Chart Driving Edition: Clock Chart DE) to help those possible patients to notice abnormalities in binocular visual field and evaluated its clinical usefulness.

Methods : Our test chart facilitates subjects in noticing their own visual field defects. It has four targets of a child, bicycle, car and traffic light displayed at 10°, 15°, 20°, and 25° eccentricity zones, respectively. Subjects rotate the chart through a 360° turn by themselves and come to recognize defects. This clinical research enrolled 88 eyes of 44 glaucoma patients (21 males, 23 females; mean age: 64.4 ± 13.1 years) and 64 eyes of 32 normal individuals(22 males, 10 females; mean age: 32.0 ± 8.4 years). The glaucomatous patients were given both Clock Chart DE testing and static visual field testing. HFA SITA-Standard 30-2 and binocular Esterman Program were used for testing static visual field. Binocular visual field was obtained by the Best Location Method. The normal individuals were also tested to obtain the Clock Chart DE specificity.

Results : The sensitivity of Clock Chart DE was 85% and 82% for HFA and Esterman, respectively when contiguous two or more scotomata (<10 dB) within the central 30° were defined as the visual field defect. We also used another definition similar to the British standards for driver’s license and obtained the sensitivity of 88%. The specificity of Clock Chart DE was 100% for the normal subjects.

Conclusions : Unlike the traditional perimetry, Clock Chart DE enabled the patients to notice their visual field abnormalities by themselves under the binocular condition. It will be a useful visual field self-check tool for occasions such as acquisition and renewal of the driver’s license.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.