Comparison of Intraocular Pressure Measurements of Tono-Pen and Perkins Tonometer in Children Under the General Anesthesia

ABSTRACT

Tono-pne and Perkins tonometer have been widely accepted to measure the intraocular pressure(IOP) of children under the general anesthesia because of their portability. We evaluated the difference of IOP between two devices and the IOP variability in 39 children(77 eyes) under age 13 who had undergone surgery for strabismus or entropin under the general anesthesia. One observer measured the IOP three times alternately, and the order of measurement was randomized. Only 5% of Tono-pens coefficient of variance was considered valuable. The range of Tono-pen IOPs was 9~22mmHg, and the average was 15.41+/-3.23mmHg. The range of Perkins IOPs was 4~20 mmHg, with the average of 12.47+/-3.31mmHg. The difference between two methods on average was 2.94mmHg. Tono-pen IOPs were significantly greater than those recorded by Perkins tonometer, but both were within normal range. The IOP variability was not significantly different between two devices. Therefore both methods can be applied effectively in a clinical setting after sedation or general anesthesia of uncooperative children.