PURPOSE: We carried out a prospective study based on variables related to the age of appearance of presbyopia (AAP): refraction defect, sex, iris color, profession and pupil diameter. METHOD: Our sample population was made up of 179 persons who present consecutively for the first optical correction of presbyopia as sole reason, having a refractive defect equal to 1 diopter or less. RESULTS: In our series the AAP was not influenced by the small refraction defect, neither by sex or iris color. Different professions showed a significant AAP difference later in life (farmers, x = 51.76 D.E. 5.47 years) or earlier (services workers, x = 46.15 D.E. 3.55 years) (p<0.000003, ANOVA), than other professions such as housewife (48.42 D.E. 4.71 years) and construction workers (47.54 D.E. 3.93 years). We found significant differences in AAP among subjects with intense miosis (<2,5 mm, x = 51 D.E. 5.39 years) and without miosis (3 to 7 mm, x = 47.47 D.E. 4.71 years) (p<0.02 t Student). CONCLUSIONS: The variables which determine a significant delay in the AAP are: profession (farmer and housewife) and miosis, a 1 mm pupilar diameter reduction, in near vision, could contribute to a delay of 1.53 years in AAP.