Small Text on Product Labels Poses a Special Challenge for Emerging Presbyopes.

Journal Article (Journal Article)

SIGNIFICANCE:Approximately 10% of the lowercase text on nonprescription drug labels is smaller than the 1 mm required by the Food and Drug Administration. The small size, combined with the progressive decline in accommodative amplitude and gain, poses a reading challenge for middle-aged emerging presbyopes. PURPOSE:The purpose of this study was to evaluate the impact of progressing presbyopia and near adds on the ability of middle-aged patients to read small text routinely encountered on product labels. METHODS:Geometrical optics was used to determine the impact of changing viewing distance, accommodation, and pupil size on retinal blur size. We photographed 261 consumer product labels in grocery, personal care, and nonprescription (over-the-counter) drug categories and used character recognition software to identify and size 255,298 printed letters. We computed the impact of viewing distance on the ratio of blur to letter detail and used published blur ratios of ≤4 and ≤2 to identify the conditions that allowed for letter recognition and proficient reading, respectively. RESULTS:Median/mode lowercase letter heights (in millimeters) were 1.39/1.16, 1.29/1.15, and 1.18/1.01, respectively, for groceries, personal care, and over-the-counter drug categories. Despite the increased angular subtense of approaching letters, blur ratios generally increased with reduced viewing distance because of increased defocus. Increased viewing distance decreased blur, but small (e.g., 1 mm) letters became too small to read proficiently (angular size <10 arcminutes) for distances beyond 37 cm. With larger pupils, blur ratios were too large to support proficient reading when accommodative amplitude dropped to ≤3 diopters. An add power sufficient to bring the far point closer than 37 cm was required to proficiently read small text. CONCLUSIONS:Product labels, especially nonprescription drug packages, typically use fonts that are too small to be read proficiently by unaided emmetropes with emerging presbyopia. This problem can be ameliorated by correction of presbyopia at an earlier age and with higher add powers.

Full Text

Duke Authors

Cited Authors

  • Xu, R; Chelales, E; Rickert, M; Muessel, R; Meyer, D; Thibos, LN; Bradley, A; Kollbaum, P

Published Date

  • April 2019

Published In

Volume / Issue

  • 96 / 4

Start / End Page

  • 291 - 300

PubMed ID

  • 30907860

Electronic International Standard Serial Number (EISSN)

  • 1538-9235

International Standard Serial Number (ISSN)

  • 1040-5488

Digital Object Identifier (DOI)

  • 10.1097/opx.0000000000001362

Language

  • eng