Ionizing radiations (IR) produce changes in the eye and, above all, in the lens. Several studies on radiotherapy in neoplastic diseases and dangerous nuclear accidents like Chernobyl have indicated the percentage and the exposure level at which the eye becomes the target organ of IR. The aim of the study was to establish the association between ocular tension and low-level IR exposure. The incidence of ocular hypertension in the general population is about 1-2% in persons aged 30-40 years and 10% in the 70-80 years age group; the frequency of glaucoma is 0.2-0.5% in persons aged 50-55 years and 2% in those aged 70 years and over; after 15 years of disease, conversion from ocular hypertension to glaucoma is observed in 40% of the cases. We examined 128 subjects occupationally exposed to IR (42 radiologists and 86 radiology technicians) and 130 non-exposed. For each subject we recorded age, length of employment, job titles, dosimetry, ocular tension, refraction and motility impairments. The data obtained from a complete ophthalmologic test was analyzed by the t-Student test, Chi-square and Pearson's test. The ocular tension of 33 occupationally exposed subjects and 2 non-occupationally exposed subjects was higher than the cut-off value of 18 mmHg. There was no analogy between age distribution of ocular hypertension in the groups under study and the general population. There seems to have been a relationship between ocular tension and job titles since a higher incidence was observed among the radiology technicians than among the radiologists and also in the 30-40 years age class.(ABSTRACT TRUNCATED AT 250 WORDS)