Central corneal thickness in normals, patients with ocular hypertension, low-tension glaucomas, and open-angle glaucomas - a clinical study

Background: The relation between Goldmann applanation tonometry and central corneal thickness (CCT) was investigated in several studies during the las t thirty years. It was the aim of the present study to evaluate CCT in norm als, patients with ocular hypertension, low-tension, and open-angle glaucom as. Patients and Methods: CCT was measured in 135 normal eyes, 137 with ocular hypertension, 65 with low-tension, and 94 with primary and secondary open-a ngle glaucomas using the AL-11000-pachymeter (Tomey). The results were comp ared using the unpaired t-test. Results: CCT was significantly higher in the patients with ocular hypertens ion (586 +/- 43 mum) than in the normal group (566 +/- 37 mum, p<0.0001), i n low-tension glaucomas (555 +/- <mu>m, p<0.0001), and in open-angle glauco mas (558 +/- 31 <mu>m, p<0.0001). The latter three groups did not differ si gnificantly. There was no significant correlation between CCT and age, the actually measured IOP, the highest IOP in the patient's history, or the sph erical equivalent. Conclusions: Only patients with ocular hypertension showed a significant di fference in CCT compared with normals. Pachymetry thus should be conducted in those patients to avoid overestimation of the IOP by applanation tonomet ry. In most of the patients with low-tension and open-angle glaucomas howev er, CCT regarded without other parameters (e.g, corneal or scleral rigidity ) plays a minor role in detection of elevated IOP according to the results of this study.