Original Article

Comparison of Different Methods for Measurement of Intraocular Pressure and Evaluation of Effect of Central Corneal Thickness on Measurement Results - Original Article


  • Yıldırım Bazeyit Şakalar
  • Uğgur Keklikçi
  • Selahattin Balsak
  • Eyyüp Doğan
  • Kaan Ünlü

Received Date: 23.03.2010 Accepted Date: 14.10.2009 Turk J Ophthalmol 2010;40(3):156-159


To compare measurements of intraocular pressure (IOP) by Goldmann applanation tonometer (GAT), tonopen and non-contact tonometer (NCT) in normal eyes, and determine the relationship between the results of IOP measurement and central corneal thickness (CCT).

Material and Method:

Seventy-nine eyes of 41 patients, whose ophthalmologic examination and visual field test revealed no glaucoma, were included into the study. IOP was measured by GAT, NCT and tonopen. CCT was measured with an ultrasonic pachymeter.


The mean IOP measured by GAT was 12.63±2.94 mmHg, by tonopen - 8.51±2.66 mmHg and by NCT - 13.34±3.88 mmHg. In terms of measurement results, there was a statistically significant difference between the three methods (p<0.05). Although the correlation between tonopen and CCT was insignificant (p>0.05), there was a significant correlation between GAT and CCT, as well as between NCT and CCT (p<0.05).


There was a significant difference between measurements of IOP by GAT, NCT and tonopen in normal eyes. Tonopen may not be affected by CCT in normal eyes, while a significant correlation existed between CCT and GAT or NCT in normal eyes.

Keywords: Goldmann applanation tonometer, intraocular pressure, non-contact tonometer, central corneal thickness, tonopen

Full Text (Turkish)