Agreement between Lea Symbols and Patti Pics visual acuity in children and adults

Arjun Sapkota; Sanjeeta Sitaula; Gauri Shankar Shrestha; Niraj Dev Joshi; Bipin Koirala; Nabin Paudel

doi:10.1016/j.optom.2023.01.004

Agreement between Lea Symbols and Patti Pics visual acuity in children and adults

J Optom. 2023 Jul-Sep;16(3):229-235. doi: 10.1016/j.optom.2023.01.004. Epub 2023 Jan 29.

Authors

Arjun Sapkota¹, Sanjeeta Sitaula², Gauri Shankar Shrestha², Niraj Dev Joshi², Bipin Koirala³, Nabin Paudel⁴

Affiliations

¹ Himalaya Eye Institute, Pokhara University, Nepal. Electronic address: sapkotaarjun73@gmail.com.
² Department of Ophthalmology, B.P.Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Kathmandu, Nepal.
³ Himalaya Eye Institute, Pokhara University, Nepal.
⁴ Center for Eye Research Ireland, Technological University Dublin, Ireland.

Abstract

Background: Patti Pics (PP) and Lea Symbols (LS) are commonly used by eye care practitioners worldwide. Although the relationship between the two tests is fairly well understood, the availability of different chart designs (single optotypes, multiple optotypes, multiple optotypes with crowding box) merits futher understanding. The purpose of this study is to explore the agreement between the acuity measures obtained with Patti Pics and Lea Symbols in children and adults and compare their performance with the Sloan Letter (SL) chart in adults.

Methods: Monocular visual acuity was obtained from ninety-three 3 to 5-year-old children using Patti Pics and Lea Symbols. Acuities were also obtained from 113 adults using the same tests under identical conditions. Acuity results obtained with the pediatric tests were compared with the gold-standard Sloan Letter chart in adults. The Bland-Altman method was implemented to compare the level of agreement between tests.

Results: Patti Pics yielded worse visual acuity than the Lea Symbols by approximately half a logMAR line in both children (mean difference: -0.07 ± 0.07 logMAR, p <0.01) and adults (Mean difference: -0.05 ± 0.06 logMAR, p <0.01). The 95% limits of agreement between Lea Symbol acuity and Patti pics acuity in children was ± 0.14 logMAR. Mean difference between the Sloan Letter chart and Lea Symbols acuity was not statistically significant (p = 0.08) in adults but the difference was statistically significant between PP and SL (p<0.001). The 95% limits of agreement between LS and SL and between PP and SL was ± 0.19 logMAR and ± 0.22 logMAR, respectively.

Conclusion: Patti Pics consistently underestimated visual acuity as compared to Lea Symbols both in children and adults although the differences were not clinically significant. The LS and PP did not yield clinically significant differences in acuities when compared with Sloan letters in adults.

Keywords: Children; Lea symbols; Patti pics; Visual acuity.

Publication types

Comparative Study

MeSH terms

Adult
Child
Child, Preschool
Humans
Vision Tests* / methods
Visual Acuity*