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Abstract #9744 Published in IGR 5-3
Influence of corneal thickness on comparative intraocular pressure measurements with Goldmann and non-contact tonometers in keratoconus
Štabuc Šilih M; Hawlina MKlinische Monatsblätter für Augenheilkunde 2003; 843-847
BACKGROUND: The influence of corneal thickness and curvature on the difference between intraocular pressure (IOP) measurements obtained with non-contact (NCT) and those with the Goldmann applanation tonometer (GAT) was studied in patients with keratoconus. MATERIAL AND METHODS: The authors examined 113 patients with keratoconus. IOP was measured by the Canon TX 10 non-contact tonometer and the Goldmann tonometer, corneal curvature and thickness were obtained by Humphrey automatic refractometer keratometer and Orbscan Version 3.0 Bausch & Lomb Surgical. RESULTS: The IOP measured by NCT was significantly lower than that measured by GAT. The mean pachymetry of the thinnest point was 423.15 ± 98.43 μm for the right eyes and 426.7 ± 93.88 μm for the left eyes. The difference between NCT-GAT and corneal thickness showed a significant negative correlation (r = -0.427, p < 0.0001; t = -3.677, p < 0.0001). Values of NCT measurements were significantly increasing with corneal thickness (F = 6.505, p < 0.0001 for right eyes and F = 4.37, p = 0.004 for left eyes), while GAT measurements did not show a significant influence of the corneal thickness. The keratometry had no effect on the difference between NCT-GAT measurements (t = 1.090, p = 0.278). CONCLUSIONS: The thin cornea has more influence on the measurement with NCT than GAT. The relative precision of NCT compared with GAT seems to be influenced by the corneal thickness.
Dr. M. Štabuc Šilih, University Eye Clinic Ljubljana, Ljubljana, Slovenia
Classification:
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
