In this study, 18 patients (34 eyes) with cornea guttata were submitted to tonography. It was noted that 70% (24 eyes) had a Po/C value of 100 or greater, and 82% (28 eyes) had a facility of outflow below 0.18. These findings, if confirmed by further studies including long-term follow up of these 18 patients (34 eyes), would make us believe that cornea guttata could be a valuable early prognostic sign in the diagnosis of open angle glaucoma.