To measure central corneal thickness (CCT) within the participants of the European Glaucoma Prevention Study (EGPS). This study was designed to test if lowering intraocular pressure (IOP) by means of dorzolamide is able to prevent or delay conversion from ocular hypertension to glaucoma.
Randomized, double-masked, controlled, observational clinical trial.
Eight hundred fifty-four of 1077 ocular hypertensive participants within the EGPS were investigated. Four hundred twenty-nine patients were treated with dorzolamide and 425 patients received placebo.
Treatment with dorzolamide or placebo (the vehicle of dorzolamide) in 1 or both eyes.
Central corneal thickness as measured by ultrasound pachymetry (DGH-500 Pachette; DGH Technologies, Exton, PA). The CCT measurements were obtained in the morning before measuring IOP. Five measurements were taken from each eye of each patient within 5 minutes of application of anesthetic eye drops.
Mean CCT was 572.6+/-37.4 microm (range, 458.5-695.6 microm). The CCT was higher in younger patients, male patients, and diabetic patients. Mean CCTs for the 429 patients receiving dorzolamide were 574.2+/-38.48 microm (range, 458.5-695.6 microm) and 571.0+/-36.21 microm (469.7-690.1 microm) for the 425 patients receiving placebo (P = 0.205). Central corneal thickness did not correlate with refraction, baseline IOP, or systemic hypertension.
Central corneal thickness measurements within the EGPS were greater than those reported in other studies of normal eyes without ocular hypertension. Larger CCT measurements correlated with male gender, younger age, and diabetes.
"A similar conclusion was reached in the Liwan Eye Study reported by Wang et al.11 Wangsupadilok et al also identified corneal thinning over the lifetime after examining subjects aged 18–96 years.37 Pfeiffer et al, who reported the European Glaucoma Prevention Study, found that younger persons had thicker corneas.12 Narayanaswamy et al who examined 1,132 individuals, reported that biomechanical features of the cornea change with the age, ie, there is a reduction in corneal resistance factor and corneal hysteresis.13 "
[Show abstract][Hide abstract] ABSTRACT: Background
The purpose of this study was to estimate mean central corneal thickness (CCT) and determine whether there are any correlations between CCT, age, and sex in the adult Lithuanian population.
A total of 1,650 Caucasians of Lithuanian origin (aged 18–89 years) comprising 688 (41.7%) men and 962 (58.3%) women were examined. Subjects were stratified by age into seven groups. CCT was measured using ultrasonic pachymetry. Correlations between CCT, age, and sex were sought.
Mean (± standard deviation) CCT for both eyes was 544.6±30.5 μm. Mean CCT was 545.2±30.5 μm in the left eye and 544.6±30.5 μm in the right eye, and was 545.0±25.6 μm in men and 544.4±33.5 μm in women. Mean CCT was 550.8±35.7 μm in subjects aged 18–29 years, 557.5±27.6 μm in those aged 30–39 years, 551.3±31.4 μm in those aged 50–59 years, 544.0±31.4 μm in those aged 50–59 years, 544.2±31.6 μm in those aged 60–79 years, 535.1±27.8 μm in those aged 70–79 years, and 530.1±16.8 μm in those aged 80–89 years. No statistically significant difference in CCT was found between the sexes (P>0.05). However, there was a significant difference in subjects aged 18–29 years; men had higher CCT than women (P<0.05). A statistically significant negative correlation was found between CCT and age (r=-0.263, P<0.05) that was stronger in men (r=-0.406, P<0.05) than in women (r=-0.118, P<0.05).
The mean CCT in adult Lithuanians was 544.6±30.5 μm, of the left eye 545.2±30.5 μm and of the right – 544.6±30.5 μm. CCT of the right eye was equal to the CCT of both eyes. Mean CCT was 545.0±25.6 μm in men and 544.4±33.5 μm in women. Young men tended to have higher CCT than women. CCT decreases over the lifetime, meaning that older people have thinner corneas. CCT’s dependence on age is stronger in men.
"Specifically, OHT subjects with thinner corneas were found to be at increased risk of developing glaucoma compared to subjects with thicker corneas, and this was found to be independent of IOP. This result was subsequently confirmed by the European Glaucoma Prevention Study (EGPS) (Miglior et al., 2007; Pfeiffer et al., 2007) and the merged OHTS–EGPS risk model established CCT as a major element of the glaucoma risk (Gordon et al., 2002; Miglior et al., 2007; Pfeiffer et al., 2007). Ever since these results were published, there have been questions regarding whether the influence of CCT on the risk of developing glaucoma could be solely attributable to the accuracy of IOP measurement or whether other explanations might be advanced, claiming a role for CCT as a truly independent expression of risk. "
[Show abstract][Hide abstract] ABSTRACT: From the results of the Ocular Hypertension Treatment Study emerged the conclusion that ocular hypertensive subjects with thinner central corneal thickness (CCT) are at increased risk of developing glaucoma. Although possible underlying biases that could have led to this conclusion are still under investigation, there is an increasing interest in the scientific community to understand the potential mechanisms of this increased risk profile. It has been proposed that interindividual differences in CCT might be purely responsible for inaccuracies of the tonometric readings with potential underestimation of the true IOP in subjects with thinner CCT although it is becoming progressively clearer that the true IOP is unpredictable with linear correction formulas for CCT, and it is likely that other material properties of the cornea contribute, together with CCT, to the tonometric artifact. Recently, it has become possible to measure the biomechanical properties of the cornea in vivo and it has been suggested that differences in corneal biomechanics may be the expression of interindividual structural differences of the ocular tissues (including lamina cribrosa), with potential consequences on the interindividual susceptibility to the glaucomatous damage under the same IOP level. A possible underlying biological risk related to thinner CCTs, independent of the influence on tonometric reading, has been proposed and largely studied after the results of the OHTS were published. Besides the understanding of the mechanism underlying the role of CCT as a risk factor for the development of glaucoma, it is important to understand how the information about CCT should be integrated in the clinical management of both ocular hypertension (OHT) and glaucoma and whether other ocular properties should be measured to better understand the individual risk profile.
Progress in brain research 02/2008; 173:25-30. DOI:10.1016/S0079-6123(08)01103-5 · 2.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: To compare the central corneal thickness, measured with an ultrasound pachymeter, in normal subjects, those with ocular hypertension, glaucoma suspects and patients with preperimetric glaucoma. Methods: 61 normal eyes (control group), 131 eyes with ocular hypertension, 62 glaucoma suspects (optic nerve head morphology compatible with glaucoma) and 36 patients with preperimetric glau- coma (abnormal short-wavelength automated peri- metry) were prospectively and consecutively selec- ted. Scatter plots of central corneal thickness, against the intraocular pressure values were calcu- lated for each of the study groups. Ultrasound pachymetry measurements were compared between those with normal eyes and the other groups. Results: Ocular hypertensive subjects had higher pachymetry values than the control group (p=0.009). No differences were found in the central corneal thickness between normal eyes and those who were glaucoma suspects, and between normal and preperimetric glaucomatous eyes. A mild direct logarithmic correlation was evident between central corneal thickness and the Goldmann tonometry result in the ocular hypertensive group.
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