Developing fonts from classical and new optotypes
Tàpias, M.; Molinero, X.; Balius, A.; Dvalidze, S.
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Base Information
Volume
V59 - N3 / 2026 Ordinario
Reference
52001
DOI
http://dx.doi.org/10.7149/OPA.59.3.52001
Language
English
Keywords
font, typeface, optotype, visual acuity, reading acuity, reading chart
Abstract
SIGNIFICANCE: Commercial printed acuity charts offer limited adaptability for research, education, and clinical use. This study digitizes classical optotypes, extends Sloan letters, and introduces validated pediatric and reading typefaces. These free fonts enable reliable acuity measurements while offering optometrists high flexibility in test design for diverse settings. PURPOSE: This study aimed to improve visual acuity assessment tools by introducing classic optotypes as digital fonts, expanding the Sloan letters to complete the full English alphabet and numerical digits, based on the Landolt ring concept, and creating and validating novel pediatric optotypes and a novel typeface designed to assess near vision adequacy and reading acuity. METHODS: Classic optotypes (the tumbling E, the Landolt ring, and the Sloan letters) were converted into digital typefaces using Glyphs v3 software. LouiseOPTO-Regular typeface, which extends Sloan original optotypes to include all uppercase letters and numerals, is introduced. New paediatric optotypes, Optotipica-Kids v2022 (Kids), were designed according to the Landolt ring criteria. Additionally, a new typeface, Optotipica 5 v2022 (Optotipica), was created to measure near vision adequacy and reading acuity, with a focus on lowercase letters. Validation was conducted with 30 observers with healthy vision, adhering to ISO standards for optotype presentation and correlation/validation. RESULTS: Validation of Kids and Optotipica against the Landolt ring showed minimal differences in legibility. Statistical analysis confirmed equivalence for the Kids optotypes (p = 0.830), whereas Optotipica presented a small but statistically significant difference (p = 0.028). This difference was deemed clinically negligible, thereby supporting the reliability of both in measuring visual and reading acuity. CONCLUSIONS: The study introduced classic optotypes as digital fonts, extended the Sloan letters, and developed new pediatric optotypes and a comprehensive typeface for assessing visual and reading acuity. These tools, validated against the Landolt ring, provide reliable measurements and are a valuable resource for resource-limited communities by offering affordable and customizable vision assessments.
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