Comparison of the Icare tonometer and the hand-held goldmann applanation tonometer in pediatric aphakia.

PURPOSE: To compare the intraocular pressure (IOP) measurements obtained by the Icare and the hand-held Goldmann applanation tonometer (also called Perkins) in aphakic children after congenital cataract surgery.

METHODS

We investigated 125 children with aphakia after congenital cataract surgery in this study. A younger group (3 to 30 mo) and an elder group (31 to 72 mo) were divided in those patients by their age. In the younger group, all measurements were performed under sedation using chloral hydrate. Axial length of the eye and central corneal thickness (CCT) were also measured from all patients.

RESULTS

Significant correlation was found on IOP readings obtained by the Icare and the Perkins tonometers (r=0.943, P<0.001). After establishing a Bland-Altman plot, we found that 95% limit of the agreement between the 2 methods distributed between -1.6 to 5.6 mm Hg. The IOPs recorded from the Icare increased faster than that from the Perkins tonometer with the increase of the CCT thickness; a significant association relationship was found on the IOP difference between the 2 measurements (r=0.408, P<0.001). However, no statistical correlation was identified between the axial length and the IOPs recorded by either tonometer.

CONCLUSIONS

Most of the young patients accepted the Icare tonometer under unsedated conditions. This significant advantage indicated that the Icare tonometer will be overall better tolerated in pediatric aphakia population, although it could overestimate the IOPs compared with the measurements obtained from the Perkins tonometer. Differences in readings between the 2 tonometers become bigger as the CCT increase.