Glokom-Katarakt
2011 , Vol 6 , Num 1
Comparison of Goldmann Applanation Tonometry and Dynamic Contour Tonometry in Eyes with Different Corneal Thicknesses
1Beyoğlu Göz Eğitim ve Araştırma Hastanesi, Göz Hastalıkları, İstanbul, Asist. Dr.2Beyoğlu Göz Eğitim ve Araştırma Hastanesi, Göz Hastalıkları, İstanbul, Uz. Dr.
3Beyoğlu Göz Eğitim ve Araştırma Hastanesi, Göz Hastalıkları, İstanbul, Prof. Dr. Purpose: To compare intraocular pressure (IOP) levels measured with Goldmann applanation tonometer (GAT) and Pascal dynamic contour tonometer (DCT) in patients with various central corneal thicknesses (CCT).
Material and Methods: We studied 103 eyes of 103 consecutive patients who were followed in glaucoma department.Ultrasound pachimeter was used to evaluate CCT in all subjects. Patients were divided into three groups according to their central corneal thicknesses. Group 1 was thin CCT (<520 μ), group 2 was intermediate CCT (520-570 μ), group 3 was thick CCT (>570 μ). All measurements were performed by the same two physicians. The first physician measured IOPs with GAT and at least ten minutes later the second physician measured IOPs with DCT. Measurements were compared between groups.
Results: Mean age of patients was 60.3±12.6 years. Mean CCT values were 488.2±19,6 μ for group 1 (n: 30), 543.2±13.7 μ for group 2 (n: 35 ) and 605.0±29.9 μ for the group 3 (n: 38). Mean IOP measurements obtained with GAT and DCT were 14.5±4.5 and 20.2±5.7 mmHg in group 1; 17.7±3.9 and 21.2±3.8 mmHg in group 2; 20.3±4.8 and 23.9±4.9 mmHg in group 3 respectively. Mean IOP difference between DCT and GAT was 4.2±3.5 mmHg in the whole study group. While this difference was statistically significant between group 1 and 2 (p=0.05), it wasn't significant between group 2 and 3 (p=0.87). There was a positive correlation between CCT and measurements made with both GAT and DCT. Negative correlation was found between CCT and the difference of IOP measured with DCT and GAT.
Conclusion: IOP values obtained with DCT were higher than with GAT for all CCTs. However this difference was statistically significant only in thin corneas. Keywords : Central corneal thickness, goldmann applanation tonometer, intraocular pressure, pascal dynamic contour tonometer
