Critical print size is a stable and consistent measure over two reading parameters

Main author: Oda, Koichi; Tokyo Woman's Christian University; Japan

Purpose

Bailey et al (2002) argued that the critical print size (CPS), the smallest size at which maximum reading speed is achieved, has variability depending on many reading parameters such as reading modes - reading silent or aloud, difficulty of materials, and relationship among words. We studied the stability of CPS measure over two reading parameters.

Method

In experiment 1, two reading charts were used; one with meaningful easy-to-read sentences in Kana and Kanji characters and the other consisting of unrelated Kana words. In experiment 2, CPS was compared between reading aloud and reading silently. Fifty normally sighted college students participated with three visual acuity attributes - normal, simulated low vision 0.7, and 1 logMAR. CPS was estimated by the algorithm developed by Mansfield et al (1996) and compared.

Results

In experiment 1, there was no significant difference between two types of charts. In experiment 2, two way ANOVA revealed that the primary effect of visual acuity was significant but not reading modes. No interaction was found.

Conclusion

CPS values were quite consistent and robust across two reading conditions tested. CPS would represent more visual aspect of observers than what was thought previously.

Reference

I L Bailey et al. Evaluating reading performance and the design of reading tests. Vision 2002 Abstract No. R36, 2002.