Tonometry in pediatric patients: a comparative study among Tono-pen, Perkins, and Schiötz tonometers.

Measuring the intraocular pressure (IOP) in children can be difficult. We compared the accuracy of IOP measurements in pediatric patients using three tonometers: Perkins, Schiötz, and Tono-pen. Seventy-seven children (132 eyes; average age, 1 year, 7 months; range, 1 month to 60 months), mainly afflicted with retinopathy of prematurity (107 eyes), were evaluated. A good correlation (r = 0.867) was found between the Tono-pen and the Perkins tonometers. No statistical difference was found between the mean difference of IOP values obtained with the Tono-pen and the Perkins (P > .05). The Schiötz measurements were significantly higher than those obtained with the Perkins and the Tono-pen tonometers (P < .05). We concluded that the Tono-pen tonometer has a higher correlation coefficient, comparable to the Perkins tonometer, and can be used reliably to assess IOP in pediatric patients.