The validity and reliability of intraocular pressure measurement using rebound tonometry in children with ocular and systemic disease

Abstract

Objective: This study examined three main objectives: 1. The validity of Rebound Tonometry (RBT) measurements in children. 2. The reliability of suboptimal RBT readings and the relationship between co-existing characteristics and these measurements. 3. The reliability of suboptimal RBT measurements in children with heritable connective tissue disease (HCTD).Design: A cross-sectional study design was used for objectives 1 and 2 and a case control study was used for objective 3.Setting: The Eye Department of Birmingham Women’s and Children’s Hospital (BWCH).Participants: Fifty children were recruited, including 34 with glaucoma for objectives 1 and 2 and 16 for objective 3 (8 HCTDs, 8 healthy controls).Interventions: RBT measurements were taken at the geometric centre of the cornea of one eye (RBTon) and at 3 mm temporally (RBToff), followed by Goldmann tonometry (GAT). Additional data regarding sex, age, nystagmus, strabismus, type of glaucoma, treatment, visual acuity, spectacle prescription, ethnicity, health and corneal scars were recorded from the participants’ clinical notes. The same procedure was conducted on 8 children with HCTD and 8 controlsResults: Mean RBTon was significantly higher than GAT by 2.4 (SD 3.0) mmHg. A statistical difference was found between the age groups and the IOP status (p < 0.05). Mean RBToff readings were not significantly different from RBTon in children with glaucoma (p = 0.100) and this difference was not associated with co-existing characteristics (p > 0.05). Mean (RBToff - RBTon ) was not significantly different between children with HCTDs and healthy controls (p = 0.06).Conclusion: This study achieved its main objectives and found that:• RBTon measurements differ from GAT but are useful clinically.• The relationship between RBTon and GAT varies with the age of the child.• Suboptimal RBToff measurements are reliable in children with glaucoma with a range of co-existing conditions and in children with HCTDs.