Abstract
Purpose: :
Tonopen® and Perkins tonometers are portable instruments used for intraocular pressure (IOP) measurements in children. Our aim was to establish if there is agreement between these tonometers in pediatric patients without glaucoma or anterior segment disease undergoing general anesthesia.
Methods: :
Following approval by REB at our institution and informed consent of parents, pediatric patients without glaucoma or anterior segment disease undergoing general anesthesia for ophthalmic procedures were recruited into a prospective comparative clinical study. Tonometry was performed in a randomized sequence followed by central corneal thickness (CCT) using ultrasound pachymetry.
Results: :
We studied 50 patients with mean age 5.3 years (range 1 month to 14 years). Average IOP values obtained with Perkins tonometer were 14.28 mmHg (± 3.29), and with Tonopen® 15.71 mmHg (± 4.59). Mean CCT was 560.2µm (± 40.1). Calculated Intraclass Correlation Index was 0.668. A 3mmHg difference in IOP measurements between both tonometers was chosen as a clinically acceptable limit and significant difference. Within these limits the difference between the measurements taken by the 2 tonometers was not statistically significant (p>0.05) when tested with the student t-test. IOP difference between tonometers showed a tendency to increase with higher CCT values.
Keywords: intraocular pressure • anterior segment • clinical (human) or epidemiologic studies: systems/equipment/techniques