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Abstract #21627 Published in IGR 10-3
Effect of central corneal thickness on Goldmann applanation tonometer
Yin H-B; Yun H-M; Liu Y-L; Yu M; Liu X-Y; Chen X-MInternational Journal of Ophthalmology 2008; 8: 1375-1376
AIM: To study the distribution of central corneal thickness (CCT) in a suburb population and to determine the effect of CCT on the measurement of intraocular pressure (IOP). METHODS: In this cross-sectional study, 169 normal subjects were evaluated. CCT was measured with an optical pachymeter by an observer. IOP was measured with Goldmann applanation tonometry by another observer using blind method. RESULTS: Mean CCT was 0.547 mm (95% confidence intervals 0.543-0.751 mm) in right eyes and 0.551 mm (95% confidence intervals 0.553-0. 749 mm) in left eyes. Mean IOP was 15.8 mmHg in right eyes and 15.5 mmHg in left eyes. There was no significant relationship between CCT and age, but a positive relationship was found between CCT and IOP. Linear regression analysis showed an increase of 1 mmHg in IOP with each 0.018 mm increase in central corneal thickness. CONCLUSION: Variation in central corneal thickness is a significant source of variation in IOP measurement. Ocular hypertension can be misdiagnosed by pseudohypertension in the patients with thick CCT, and normal tension glaucoma can be misdiagnosed by primary open-angle glaucoma in the patients with thin CCT. Pachymetry should be included in the diagnosis of glaucoma or ocular hypertension, particularly when IOP is inconsistent with other clinic data. LA: Chinese
Dr. X.-M. Chen, Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041 Sichuan Province, China. chenxm58@163.com
Classification:
6.1.3 Factors affecting IOP (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)