[Relationship between central corneal thickness, intraocular pressure and severity of glaucomatous visual field loss].

OBJECTIVE to determine central corneal thickness in normal subjects, glaucomatous patients and ocular hypertension patients, to evaluate if the central corneal thickness is related to the presence of glaucoma or ocular hypertension. Furthermore, we aim to verify the relationship between central corneal thickness and severity of glaucomatous visual field loss. METHODS comparative study including 150 eyes of 150 subjects, separated into three groups: normal (47 eyes), ocular hypertension (35) and glaucomatous (68). This last group was subdividided in three subgroups depending on the Hodapp-Parrish-Anderson criteria for scoring Humphrey visual field defects (initial, moderate and advanced). We evaluated the visual field, the central corneal thickness measured by pachymetry and the intraocular pressure measured by Goldmann tonometry. Results were analysed using the Student's t-test for normally distributed independent samples. RESULTS the central corneal thickness was 526+/-25 microns (mean +/-standard deviation (SD)) in glaucomatous patients, 560+/-27 microns in ocular hypertension patients, and 556+/-27 microns in the normal group. Statistical significance could be found between the glaucomatous group of patients and the other groups (p< 0.01), but not between the ocular hypertension group and normal subjects (p= 0.4). The comparison between central corneal thickness of the subgroup with advanced damage of the visual field and the two other subgroups was also statistically significant (p< 0.01), but not between the subgroups of initial damage and moderate damage (p= 0.7). CONCLUSIONS the central corneal thickness in glaucomatous patients is lower than in normal subjects and in ocular hypertension patients. Patients classified as having advanced damage in their visual field have significantly lower central corneal thickness measurements than patients classified as having initial or moderate damage.