Sažetak
The purpose of the study is to determine whether central corneal thickness (CCT) is a better predictor than intraocular pressure (IOP) in early identification of those at higher risk of developing glaucoma. Sixty-five subjects were categorized into normals, ocular hypertensives and glaucoma subjects based on clinical characteristics of ocular risk factors. The IOP was assessed with slit-lamp mounted Goldmann applanation tonometer. Prior to applanation tonometry, the central corneal thickness (CCT) of both eyes was assessed with Sonomed PacScan 300AP Biometric/ pachymeter. The difference in mean IOP between normals and glaucoma subjects was statistically significant (unpaired t-test; p<0.05). Similarly, there was a significant difference in mean CCT between normals and glaucoma subjects (p<0.05). The association between CCT and Age was not significant in normals but slightly significant in glaucoma subjects and the linear regression predicts a decrease of 7.0ìm in CCT for every 10 years. A strong association was found between CCT and IOP for ocular hypertensives with a prediction of increase of 0.70mmHg for every 10ìm corneal thickening. The association between CCT and IOP for glaucoma subjects was weak, with an indication of an increase of 0.35mmHg in intraocular pressure for every 10ìm corneal thinning. The central corneal thickness is a better predictor than intraocular pressure in identifying those at higher risk of developing primary open-angle glaucoma when combined with some ocular risk factors.
Keywords: Central corneal thickness, intraocular pressure, glaucoma, ultrasonic pachymetry, Goldmann applanation tonometry.
Résumé
Pour déterminer si l’épaisseur de la cornee centrale est le meilleur predicteur que la pression intraoculaire dans l’identification précoce de ceux en risque de developer le glaucome. Soixante six sujets étaient catégorises in groupes normale, d’hypertension oculaire et de glaucome basé sur es caractéristiques cliniques des facteurs de risque oculaire. La pression intraoculaire était étudié a l’aide du sonomètre de Goldman ainsi que l’évaluation de l’épaisseur de la cornée centrale á l’aide du pachymétre ou Pacscan sonomed 300AP. La différence dans la moyenne de la pression intraoculaire entre les sujets normaux et de glaucome était statistiquement significative. Egalement il y avait une différence significative entre la moyenne de l’épaisseur de la cornee centrale chez les sujets normaux et de glaucome. L’association entre ECC et l’age n’était pas significative chez les sujets normaux et légèrement significatifs chez les sujets ayant le glaucome. La régression linéaire predict une réduction de 7.0ìm en ECC tous les dix ans. Il y avait une association significative entre ECC et PIO chez les groupes ayant l’hypertension oculaire avec une prédiction de croissance de 0.70mmHg pour tous les 10ìm d’épaississement de la cornée. L’association entre ECC et PIO chez le glaucome était faible avec une indication d’augmentation de 0.35mmHg en pression intraoculaire pour chaque 10ìm de cornée. En conclusion l’épaisseur de la cornée centrale est un meilleur predicteur que la pression intraoculaire pour identifier ceux a risque de développer le glaucome d’angle ouvert.
Correspondence: Dr. E. Iyamu, Department of Optometry, Faculty of Life Sciences, University of Benin, Benin City, Edo State, Nigeria. Email: eghosaiyamu@yahoo.com
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