Effect of central corneal thickness on dynamic contour tonometry and Goldmann applanation tonometry in primary open-angle glaucoma.
OBJECTIVE
To compare the dependence of dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) on central corneal thickness (CCT) in primary open-angle glaucoma.


METHODS
In a prospective study, the interocular (right vs left eye) difference in intraocular pressure measured by DCT and GAT was compared with the interocular CCT difference in 125 patients with primary open-angle glaucoma.


RESULTS
Dynamic contour tonometry measurements (mean +/- SD, 19.4 +/- 4.1 mm Hg) were significantly (P=.004) higher than GAT measurements (mean +/- SD, 15.5 +/- 3.4 mm Hg), correlating significantly with each other (r(2)=0.82, P<.001). The interocular difference in intraocular pressure correlated significantly with the interocular CCT difference for GAT (r=0.30, P=.001) and DCT (r=0.23, P=.02) readings. Dynamic contour tonometry and GAT intraocular pressure differences significantly increased with older age (slope, 0.033 [95% confidence interval, 0.002-0.064] mm Hg/y; P=.03) but not with thicker CCT (slope, 0.006 [95% confidence interval, -0.003 to 0.017] mm Hg/mum; P=.22).


CONCLUSIONS
In this series, GAT and DCT measurements were dependent on CCT in patients with primary open-angle glaucoma. Because intraocular pressure differences between DCT and GAT were independent of CCT, DCT and GAT are susceptible to similar measurement biases depending on CCT.
Grieshaber
Matthias C
MC
Department of Ophthalmology, University Hospital Basel, Mittlere Strasse 91, PO Box, CH-4031 Basel, Switzerland. mgrieshaber@uhbs.ch
Schoetzau
Andreas
A
Zawinka
Claudia
C
Flammer
Josef
J
Orgul
Selim
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000473:pathology*; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008875:Middle Aged; D011446:Prospective Studies; D014065:Tonometry, Ocular / Q000379:methods*