Posterior embryotoxon: its epidemiology and significance as a sign of glaucoma

Abstract

Background: Posterior embryotoxon (PET) forms part of a spectrum of anterior chamber developmental anomalies, several of which are risk factors for glaucoma. Posterior embryotoxon also occurs as an isolated anomaly. This study was undertaken to determine the prevalence of PET and whether PET in isolation is a risk factor for glaucoma. Methods: Consecutive patients were examined for PET and their intraocular pressures recorded. Consecutively presenting patients having glaucoma were also examined for PET. All patients having PET or glaucoma were further examined by gonioscopy for evidence of other anterior chamber developmental anomalies. Results: PET occured in 47 (6.1 per cent) of 765 patients. There was no statistically significant difference between the intraocular pressure of patients having PET and those who did not. Patients having glaucoma did not have higher prevalence of PET than normals. Axenfeld's anomaly occurred in four of the non-glaucoma PET patients and in one of the glaucoma patients. Conclusions:PET in isolation does not appear to be a risk factor for glaucoma but might be an appropriate indication for gonioscopy. (Clin Exp Optom 1995; 78: 2: 74–78)