Rarebit fovea test in children: reference data for children aged six to 10 years


Dr Maria Nilsson, Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Box 8056, 104 20 Stockholm, SWEDEN, E-mail: maria.nilsson@ki.se


Introduction:  The most common way to examine vision is to measure visual acuity using letter charts. The Rarebit fovea test was developed for detection of small defects of foveal function at a stage before they cause abnormal visual acuity. In a recent study, the RFT was well tolerated in a smaller group of children between seven and nine years of age; however, the number of subjects in that study was small for the determination of reference values, and therefore the aim of the present study was to establish reference values for a larger group of children aged between six and 10 years and to evaluate the learning effect after repeated tests.

Methods:  Rarebit fovea test data were collected from a group of 108 subjects aged between six and 10 years as part of a screening program at a compulsory school in Stockholm, Sweden. All subjects had good visual acuity and minor refractive errors. They underwent two Rarebit fovea test examinations on one occasion.

Results:  Rarebit fovea test results ranged from a median mean hit rate of 94.0 to 97.5 per cent for pre-school and third-year children, respectively. For the entire group of children the median mean hit rate was 96 per cent (range 57 to 100). The third-year children performed significantly better than the pre-school (p < 0.01) and first-year children (p < 0.05). A significant improvement from the first to second test run was noticed in all groups.

Conclusion:  The Rarebit fovea test proved to be well tolerated among children in a group of six to 10 year olds and more than 90 per cent of children were considered to give reliable results close to what is normal for adults. It would be interesting to further investigate the potential of the Rarebit fovea test for evaluation of foveal function in children.