[Comparison of central corneal thickness in patients participating in a glaucoma screening programme and those who were examined in the glaucoma unit].

BACKGROUND The aim of this study was to compare central corneal thickness (CCT) and intraocular pressure in patients participating in a glaucoma screening programme and patients who were examined in the glaucoma unit. MATERIALS AND METHODS 406 patients of a glaucoma screening programme (Salzburg-Moorfields collaborative glaucoma study) were included in this study. In addition a group of 406 patients who were admitted to the glaucoma clinic for a detailed glaucoma examination was included (outpatient clinic group). In all participants central corneal thickness (CCT) was measured and possible relations of CCT within the study groups were statistically analysed. RESULTS In the population screening group the mean central corneal thickness in normal subjects was 536+/-4.3 microm, in patients with ocular hypertension (OHT) 552+/-5.7 microm, patients suffering from a normal tension glaucoma (NTG) showed a mean CCT of 534+/-14.2 microm and those with primary open angle glaucoma (POAG) had a value of 521+/-17.9 microm. In the 'outpatient clinic group' the OHT subgroup had a mean CCT of 553+/-6.8 microm, the NTG subgroup of 529+/-26.5 microm and the one with POAG had a mean of 527+/-19.8 microm. In addition, CCT was measured in all glaucoma patients whose "partner" eye was healthy (544+/-5 microm) and included in this study as part of the normal subgroup. In both groups (screening group and outpatient group), CCT was significantly higher in OHT patients than in normals. In contrast, no statistically significant difference between normals and NTG or POAG patients was detected. Intraocular pressure was significantly lower in the screening groups than in the other ones. CONCLUSIONS Our data confirm the previously published results concerning OHT and healthy subjects. In this study no significant difference between NTG or POAG subjects and normal eyes was detected. The lower IOP in the screening population can be explained by the fact that patients contacting the screening program are self selected whereas patients of the glaucoma unit are admitted by practising ophthalmologists and are, therefore, rather advanced cases or carrying special risk factors.

[1]  Steven Givner.  Central corneal thickness and normal tension glaucoma: a cross-sectional study. , 2006, Optometry.

[2]  Dong Myung Kim,et al.  Relationship Between Central Corneal Thickness and Localized Retinal Nerve Fiber Layer Defect in Normal-tension Glaucoma , 2006, Journal of glaucoma.

[3]  Shan C. Lin,et al.  Correlation Between Intraocular Pressure, Central Corneal Thickness, Stage of Glaucoma, and Demographic Patient Data: Prospective Analysis of Biophysical Parameters in Tertiary Glaucoma Practice Populations , 2006, Journal of glaucoma.

[4]  E. Spoerl,et al.  Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry. , 2006, Archives of ophthalmology.

[5]  J. Jonas,et al.  Central corneal thickness correlated with glaucoma damage and rate of progression. , 2005, Investigative ophthalmology & visual science.

[6]  Y. Lachkar,et al.  Central corneal thickness and vascular risk factors in normal tension glaucoma. , 2005, Acta ophthalmologica Scandinavica.

[7]  Robert Ritch,et al.  The Low-pressure Glaucoma Treatment Study (LoGTS) study design and baseline characteristics of enrolled patients. , 2005, Ophthalmology.

[8]  Chris A. Johnson,et al.  The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. , 2002, Archives of ophthalmology.

[9]  C. Rapuano.  CENTRAL CORNEAL THICKNESS IN THE OCULAR HYPERTENSION TREATMENT STUDY (OHTS) , 2002 .

[10]  D. Mojon,et al.  Central corneal thickness measurements in patients with normal tension glaucoma, primary open angle glaucoma, pseudoexfoliation glaucoma, or ocular hypertension , 2001, The British journal of ophthalmology.

[11]  R. P. Singh,et al.  Central Corneal Thickness, Tonometry, and Ocular Dimensions in Glaucoma and Ocular Hypertension , 2001, Journal of glaucoma.

[12]  C. Creuzot-Garcher,et al.  Falsely elevated intraocular pressure due to increased central corneal thickness , 1999, Graefe's Archive for Clinical and Experimental Ophthalmology.

[13]  A. Hofman,et al.  Distribution of central corneal thickness and its association with intraocular pressure: The Rotterdam Study. , 1997, American journal of ophthalmology.

[14]  A. Mermoud,et al.  Corneal thickness in ocular hypertension, primary open-angle glaucoma, and normal tension glaucoma. , 1999, Archives of ophthalmology.