Normal values for the Rarebit Fovea Test in children

Abstract

Abstract Purpose Visual acuity (VA) testing using optotypes is insensitive for detecting subtle defects in the visual function. The Rarebit Fovea Test (RFT) was therefore developed for detection of small defects of the foveal function (Frisén, 2002) at a stage before these defects affect VA. The RFT has been found to be well tolerated by children between 7 and 9 years of age. However, for determination of reference values the number of subjects in previous studies has been to small. The aim of the present study was to establish normal values for children between 6 and 10 years of age, and to evaluate the learning effect after repeated tests. Methods RFT was conducted in a group of 181 subjects between 6‐10 years as part of a screening programme at a compulsory school, in Stockholm, Sweden Results Normal values ranged from median MHR (Mean Hit Rate) 94.0 to 97.5% between pre‐school children and 3rd year children. For the entire group of children the median MHR was 96% (range 57‐100). The 3rd year children performed significantly better than pre‐school children (p<0.01) and 1st year children (p<0.05). An improvement from first to second test was noticed in all groups. There was a very weak but significant correlation between MHR and age (p<0.0001; R2=0.17) and between MHR and VA (p= 0.0093; R2=0.063). Conclusion The RFT proved to be well tolerated among children in an age group between 6‐10 years and more than 90% of the children were considered to give reliable results close to what is normal for adults. Therefore the Rarebit Fovea Test proved to be useful for evaluation of the foveal function in children.