Comparison of rebound tonometer and Goldmann handheld applanation tonometer in congenital glaucoma.
OBJECTIVE
To compare intraocular pressure (IOP) measurements obtained using the rebound tonometer (RBT) and the handheld Goldmann applanation tonometer (Perkins) in children with congenital glaucoma.


METHODS
Using both tonometers, the IOP was prospectively determined in 68 eyes of 68 patients with congenital glaucoma aged 3 to 13 years. Corneal curvature, central corneal thickness (CCT), and axial length were also measured in each patient. The ease of the use of each tonometer was scored using a visual analog scale.


RESULTS
IOP readings obtained using the RBT and Perkins tonometer showed good correlation (r=0.869, P<0.001) although RBT readings were consistently higher (mean difference: 3.1 +/-4.0 mm Hg). According to the Bland-Altman plot, the 95% limits of agreement between the 2 methods were -4.8 to 10.9 mm Hg (slope=0.589, P<0.001). When estimating CCT, the 2 tonometers behaved similarly and correlation was observed between IOP measurements and CCT, with higher IOPs obtained as the CCT increased. In contrast, no correlation was detected between corneal curvature or axial length and the IOPs recorded using either tonometer. Ease of use scores awarded by the examiner was higher for the RBT.


CONCLUSIONS
The RBT overestimates the IOP compared with the Perkins tonometer in patients with congenital glaucoma. Differences in readings between the 2 tonometers become larger as the CCT increases.
Martinez-de-la-Casa
Jose M
JM
Hospital Clinico San Carlos, Instituto de Investigaciones Oftalmologicas Ramon Castroviejo, Universidad Complutense, Madrid, Spain. martinezcasa@ya.com
Garcia-Feijoo
Julian
J
Saenz-Frances
Federico
F
Vizzeri
Gianmarco
G
Fernandez-Vidal
Ana
A
Mendez-Hernandez
Carmen
C
Garcia-Sanchez
Julian
J
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003315:Cornea / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000151:congenital* / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000379:methods* / Q000592:standards