Measurement of Intraocular Pressure Using Schiotz vs Tono-pen Tonometers in Patients with Primary Congenital Glaucoma

To compare the Tono-pen and Schiotz tonometers in measurement of intraocular pressure (IOP) in patients with primary congenital glaucoma.

This study was conducted on 38 eyes of 20 patients with primary congenital glaucoma. All measurements were performed under general anesthesia. One minute after receiving Halothane 3% IOP was determined by Tono-pen and then by Schiotz tonometers. Data were analyzed by regression analysis and Bland-Altman bias plot.

Mean age of patients was 19.4±14.5 months and 15 (75%) of them were male. Glaucoma was bilateral in 18 (90%) and unilateral in 2 (10%) subjects. Mean IOP measured by Tono-pen and Schiotz tonometers was 19.39±8.51 and 18.84±8.9 mmHg, respectively. These tonometers had good concordance in determination of IOP in primary congenital glaucoma according to the results of regression analysis and Bland-Altman bias plot.

Considering the sample size of this study, the Tono-pen and Schiotz tonometers are highly concordant regarding intraocular pressure measurement in children with primary congenital glaucoma.