We describe the coexistence of artefactual ocular hypertension due to increased central corneal thickness (CCT>585 microm), with primary open angle glaucoma (POAG) in a French Canadian kindred. Seventeen members of the family were examined and classified as to their glaucoma status. The mean CCT for our glaucoma patients (580 microm; n=5) and that for normals (552 microm; n=6) were within two standard deviations of the mean value provided in the literature (531 microm +/- SD=29 microm). The mean CCT of 611 microm for the suspect group (n=6) was considerably higher than for the glaucoma and normal groups. All but one of the suspects were classified as ocular hypertensives on the basis of high intraocular pressures (IOPs). When the IOPs for these patients (mean 22.6 mmHg) were corrected for their CCTs, all had pressures of