Rabia Mobeen, Adnan Afsar, Faisal Rasheed, Faiza Jabeen.
Test & Re-test Reliability of Visual Acuity in Children using Lea Symbols Chart.
Ophthalmol Update Jan ;14(4):149-53.

Objective: The purpose of this study was to evaluate the reliability of Lea Symbols LogMAR Chart in 3-5years old children. Methodology: Best corrected monocular visual acuity of a subset of children (n = 50) enrolled in the correction of refractive errors. At 1st visit visual acuity was measured at baseline after the correction of refractive error at Lea Symbol Chart and visual acuity was again measured after 3 days. Children started with LogMAR 0.4 (6/15 or 20/50) and read each letter on all subsequent lines until they missed all letters in 1 line. Results: At baseline, the mean best corrected LogMAR visual acuity in the right eye and in the left eye was measured. The signed difference between VA measured at baseline and that measured after 3 days was significant in either eye. The age and gender of the subjects are other potential sources of variability. Given the limited age range of the subjects in this study (3 to 5years) it is showing that age was not associated with the significant difference in either eye. The variation was not associated with any specific age group. Almost each year child has an equal change variation in visual acuity. Gender is also has equal contribution for both eyes visual acuity. P value was less than 0.05 in both cases. Conclusion: The reliability of Lea symbols chart in children age 3 to 5 years is logarithmic in principle. A mean difference of visual acuity measurements between the 2 visits is approximately 1 line difference or difference in letters in same line, equal to 0.1 log unit, if all other parameters like child`s mood, environment etc is kept constant.

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