Application of the ICare rebound tonometer in healthy infants

To study the tolerability of the ICare rebound tonometer (RBT) and to establish reference values of the intraocular pressure (IOP) in healthy infants.

Forty-six children were recruited. In 6 infants aged 3 to 18 months, it was not possible to conduct the examination. Five children refused all cooperation. In 1 child, only 1 reading was obtained. In 1, partly uncooperative infant, the difference between the highest and the lowest reading exceeded 3 mm Hg (a difference of 7 mm Hg). These 7 infants were excluded. Totally 39 children, 22 girls and 17 boys, aged 1 month to 36 months were included in the study. The mean age was 14±9 months [mean ± standard deviation (SD)]. One randomly selected eye of each child was examined with the ICare RBT. Three consecutive readings were made. In 10 children, IOP measurements were conducted twice with an interval of 10 to 30 minutes by 2 different ophthalmologists.

The mean IOP value of the 39 infants was 11.82±2.67 mm Hg. The median value was 10 mm Hg with a range of 7.3 to 17.0 mm Hg. In 10 children, the IOP was determined by 2 examiners. The results were virtually identical with differences of 0 to 1 mm Hg in 9 out of 10 children. The mean difference between Examiner 1 and Examiner 2 (0.77 mm Hg) was not statistically significant (P>0.20). The examinations were very well tolerated, and no child showed any sign of discomfort during or after the examination.

The hand-held RBT in the present study is easy to use, it does not require topical anesthesia and it is very well tolerated by cooperative infants. However, 7 out of 46 infants refused cooperation.