Validity of the Kindergarten Chart to Measure Pediatric Visual Acuity.

Background: Several validated, age-specific recognition visual acuity measurement charts used in research and vision screenings follow national and international guidelines for standardized eye charts. The Kindergarten (aka Sailboat) chart is widely used to measure visual acuity in children, but no literature has evaluated its accuracy. This study evaluates the chart against a validated chart. Methods: School children (n = 51, 42% female, 58% male) were recruited from El Monte, California. The mean age of the participants was 5.7 years (SD = 1.7 years). Visual acuities were assessed with Lea symbols, a validated chart, and the Kindergarten chart on one randomized eye per child. Acuities (converted to logMAR) were recorded using the letter-by-letter method. Data were analyzed using letter-by-letter and line-by-line scoring (≥50% on a line) using 2-tailed paired t-tests and Bland-Altman analysis, including 95% limits of agreement (LOA). Results: Mean (±SD) logMAR acuities for the Lea symbols chart were 0.15 ± 0.16 and 0.14 ± 0.17 for letter-by-letter and line-by-line methods, respectively. For the Kindergarten chart, it was 0.25 ± 0.20 for both methods. The approximate 1-line difference between the charts using either scoring method was significantly different (p < 0.001). The 95% LOAs were ±0.28 for both scoring methods. Conclusions: The Kindergarten chart resulted in a visual acuity approximately one line worse than the chart using Lea symbols. The Kindergarten chart had poor agreement with the chart using Lea symbols. Clinicians using the Kindergarten chart should be cautious in interpreting the recorded visual acuity, as this could lead to false positives and subsequent over-referral of children. It would be more prudent simply to discontinue using the Kindergarten chart, especially when much better visual acuity charts for children are readily available. [ABSTRACT FROM AUTHOR]