Abstract (IGR: 3-2) | International Glaucoma Review #

Abstract #6317 Published in IGR 3-2

Central corneal thickness measurements in patients with normal tension glaucoma, primary open angle glaucoma, pseudoexfoliation glaucoma, or ocular hypertension

Sobottka Ventura AC; Böhnke M; Mojon DS
British Journal of Ophthalmology 2001; 85: 792-795

BACKGROUND/AIMS: Recent studies have revealed patients with ocular hypertension to have thicker than normal central corneas and those with normal-tension glaucoma (NTG) to have thinner than normal ones, as determined by ultrasonic pachymetry. Since corneal thickness measurements and applanation tonometric estimates of intraocular pressure (IOP) correlate positively, monitoring of the former parameter has served as the basis for adjusting readings pertaining to the latter, with the consequence that many patients have had to be reclassified. With a view to validating these pachymetric studies, the central corneal thickness was determined in patients with NTG, primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEXG), or ocular hypertension, as well as that of normal subjects, using optical low coherence reflectometry, which is a new and more precise method than ultrasonic pachymetry. METHODS: Thirty-four patients with NTG, 20 with POAG, 13 with PEXG, and 12 with ocular hypertension, together with 21 control subjects, were included in this observational, concurrent case-control study. One eye per individual was randomly selected for investigation. IOP was measured by Goldmann applanation tonometry and central corneal thickness by optical low coherence reflectomy. RESULTS: Central corneal thickness was significantly higher (p 0.001) in patients with ocular hypertension than in normal individuals or subjects with either NTG, POAG, or PEXG, there being no significant differences between the latter four groups. Patients with ocular hypertension were also significantly younger (p 0.003) than those within any of the three glaucomatous groups. CONCLUSIONS: This study confirms that a significant number of patients with ocular hypertension have normal IOP after the appropriate adjustments have been made for deviations from normal in their central corneal thickness. The accurate measurement of this latter parameter is important, not only for individual patient care in permitting more precise estimations of IOP, but also for clinical studies in ensuring a more reliable classification of subjects.

Dr A.C. Sobottka Ventura, Escola Paulista de Medicine, Universidade Federal de Sao Paulo, Department of Ophthalmology, R. Botucato 822, Sao Paulo 04023-062, Brazil. draventura@oftalmo.epm.com.br

Classification:

2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
9.2.1 Ocular hypertension (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)

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