BACKGROUND: A Senior Assembly Proposal was presented to the California Assembly calling for a change in over-the-counter (OTC) medication labeling to make the print more readable. It proposes that a panel of optometrists and ophthalmologists be created to define "readable" print. This proposal came about because a large segment of the 60 years and older population is unable to read the printed material on OTC medication labels. METHODS: This study investigated the effects of vertical letter height and horizontal letter compression on readability. Three labels with lettering of different size and compression were used. RESULTS AND CONCLUSIONS: It was found that letter compression significantly affected readability while letter height was less of a factor. Results of this study suggest that the lettering on OTC medication labels should be at least 1.2mm in vertical height, or 20/40 Reduced Snellen (RS) visual acuity level, and should have no more than 40 characters per inch.
BACKGROUND: A Senior Assembly Proposal was presented to the California Assembly calling for a change in over-the-counter (OTC) medication labeling to make the print more readable. It proposes that a panel of optometrists and ophthalmologists be created to define "readable" print. This proposal came about because a large segment of the 60 years and older population is unable to read the printed material on OTC medication labels. METHODS: This study investigated the effects of vertical letter height and horizontal letter compression on readability. Three labels with lettering of different size and compression were used. RESULTS AND CONCLUSIONS: It was found that letter compression significantly affected readability while letter height was less of a factor. Results of this study suggest that the lettering on OTC medication labels should be at least 1.2mm in vertical height, or 20/40 Reduced Snellen (RS) visual acuity level, and should have no more than 40 characters per inch.