بررسی ارتباط بین ضخامت مرکز قرنیه و میزان فشار داخل چشمی اندازه گیری شده با تونومتر گلدمن

To determine the effect of central corneal thickness (CCT) on measured intraocular pressure (IOP) and evaluating the relationship between them in each of the groups of patients including: Normal subjects, ocular hypertension patients and patients with primary open angle glucoma (POAG). Correlation between intraocular pressure (Measured by Goldman applanation tonometer) and central corneal thickness (Measured by ultrasond pachymetry) were studied in 48 Normal subjects, 19 patients with ocular hypertension and 30 POAG patients. Correlation between CCT and IOP was evaluated in each group seperately and also Mean CCT of each group was compared between all three groups. Mean central corneal thickness in ocular hypertension (OHT) patients was 570±18.6μm and in POAG patients was 530±20.4μm and in normal subjects was 537±18μm. CCT in the ocular hypertension group was significantly(P=0.000) higher than Normal subjects or POAG patients. There was no significant difference in CCT between the latter 2 groups. Simple regression analysis showed statisticaly significant correlation between IOP and CCT in Normal subjects (P=0.002) and OHT patients (P=0.028) but not in POAG patients. Linear regression analysis showed an increase of 0.43mmHg in IOP with each 10 μm increase in CCT in Normal subjects group. The results of the present study are consistent with other studies and indicates that intraocular pressure measured with applanation tonometer is positively related to central corneal thickness, so that IOP is overestimated in patients with thick corneal. Therefore, CCT is an important variable for accurate assessment of IOP and it is desirable to check the CCT on patients suspected of having glucoma and/or ocular hypertension.