TJ-CEO
2012 , Vol 7 , Num 2
Comparison of Goldmann Applanation Tonometry, Tonopen-Avia and Ocular Response Analyser On Intraocular Pressure Measurement and The Effect of Central Corneal Thickness
1M.D., Beyoglu Training and Research Hospital, Eye Clinic, İstanbul/TURKEY2M.D., Beyoglu Training and Research Hospital, Eye Clinic, İstanbul/TURKEY
3M.D. Professor, Beyoglu Training and Research Hospital, Eye Clinic, İstanbul/TURKEY
4M.D., Necmi Ayanoglu Silivri State Hospital, Eye Clinic, İstanbul/TURKEY Purpose: To compare the intraocular pressure measurements obtained with a Goldmann applanation tonometer (GAT), Tono-Pen AVIA, and ocular response analyzer (ORA) and to investigate the effect of central corneal thickness (CCT).
Materials and Methods: Seventy-seven eyes followed because of primary open angle glaucoma were studied prospectively. IOP was measured by GAT, Tono-Pen AVIA, and ORA. The patients were divided into 3 groups as follows: group 1, thin (<545 µm); group 2, moderate (545-580 µm); and group 3, thick (>580 µm) according to CCT measured by ultrasonic pachymetry. Measurements were compared between the groups.
Results: The average age was 57.31±10.87 years. The average CCT was 528.92±12.58 μm for group 1, 557.40±9.14 μm for group 2, and 601.90±19.01 μm for group 3. GAT, Tono-Pen AVIA, and ORA measurements were 15.6±3.3, 16.7±2.9, and 16.9±3.9 mmHg in the whole study group; 15.1±3.9, 16.2±3.0, and 16.9±4.4 mmHg in group 1; 15.4±2.8, 16.5±2.5, and 16.4±3.7 mmHg in group 2; and 16.4±3.1, 17.7±3.4, 17.6± 3.6 mmHg in group 3, respectively. GAT measurements were significantly lower than Tono-Pen AVIA and ORA measurements in the whole study group (p=0.001, p=0.000), but there was no significant difference between Tono-Pen AVIA and ORA (p=0.64). According to CCT, while GAT values were lower than Tono-Pen AVIA measurements in groups 2 and 3 (p=0.015, p=0.18), no significant difference was observed in group 1 (p=0.075). Moreover, GAT values were lower than ORA measurements in groups 1 and 2 (p=0.003 and p=0.020), but there was no significant difference in group 3 (p=0.068).
Conclusion: IOP values measured with GAT were lower than those measured with ORA in thin corneas, and lower than those measured with Tono-Pen AVIA in thick corneas. Keywords : Intraocular pressure, Goldmann applanation tonometer, Tono-Pen AVIA, ocular response analyzer, central corneal thickness