Icare rebound tonometry in children with known and suspected glaucoma

Background: Accurate intraocular pressure (IOP) measurement, important in managing pediatric glaucoma, often presents challenges. The Icare rebound tonometer shows promise for screening healthy children and has been reported comparable with Goldmann applanation in adults with glaucoma. The purpose of this study was to evaluate the Icare tonometer against Goldmann applanation for clinic IOP measurement in pediatric glaucoma.

Methods: This was a prospective study comparing Icare versus Goldmann tonometry in pediatric glaucoma. Children with known or suspected glaucoma were recruited from scheduled clinic visits. IOP was measured with the Icare tonometer by a clinician and subsequently measured with Goldmann applanation tonometry (GAT) by a different single masked clinician.

Results: A total of 71 eyes of 71 children with known or suspected glaucoma were included. IOP by GAT ranged from 9 to 36 mm Hg. Icare readings ranged from 11 to 44 mm Hg. Mean difference between Icare and GAT was 2.3 ± SD 3.7 mm Hg, p < 0.0001. Icare IOPs were within ± 3 mm Hg of GAT in 63%. Icare IOPs were ≥GAT IOPs in 75%. The following factors were not associated with Icare IOPs greater than GAT: child's age, glaucoma diagnosis, strabismus, nystagmus, central corneal thickness, Icare instrument-reported reliability, number of glaucoma surgeries or medications, corneal abnormalities, and visual acuity.

Conclusions: IOP by Icare tonometry was within 3 mm Hg of IOP by GAT in 63% and greater than GAT in 75%. This device may be reasonable to estimate IOP in selected children with known or suspected glaucoma whose IOP cannot otherwise be obtained in clinic; however, correlation of Icare IOPs with clinical findings must continue to be considered in each case.