Subjective Measurement of the Near Point of Accommodation in Pre/Early Literates

Abstract

PurposeThis study was undertaken to develop a tool and acquire data on subjective accommodation measurements in young children. Previously, subjective measurements of accommodation in children has been assessed with tools requiring literacy or reliable reporting of a blur point with the standard lower age limit of eight years. It was our belief that younger children could yield reliable subjective accommodation measurements given an age appropriate tool.MethodWe devised a tool (modified tape measure using preliterate symbols) which was compared to our gold standard tool (RAF rule). These tools were compared in a literate group of subjects (N = 34) to assess agreement between the two devises. The modified tape measure was also tested on a pre/early literate group of subjects (N = 51) to assess their ability to respond consistently and to acquire data on subjective accommodation values for children ages three to seven.ResultsLiterate group—Agreement between the two devises was good with concordance correlation coefficient values of .84 for the right eye and .87 for the left eyes. Greater than 87% of responses for both devices differed by two centimeters or less. Based on the nature of these types of subjective accommodation tests, agreement of within two centimeters indicates good clinical reliability. Pre/Early Literate group—For the purposes of statistical analysis, the three year olds were not included due to low numbers (N = 5). The four/five year olds (N = 29) and six/seven year olds (N = 17) formed two subgroups for statistical analysis. T test results indicated no significant difference in accommodation amplitudes between a 4–5 year old and 6–7 year subgroups. Evaluation of the best two out of three responses in this group indicated good reliability for most subjects. As a group the mean subjective accommodation amplitude was 9.1 centimeters with a standard deviation of 2.3 centimeters.ConclusionThe new tool appears to be safe, effective, acceptable to young children, and comparable to our current tool used for older age groups.