Personality profile, psychophysical stress and cycloplegic refraction were evaluated at the baseline (T0) and after 12 months (T1) in 57 university students comprising 39 myopes and 18 emmetropes/hyperopes (controls) whose age, sex distribution and academic results were comparable. At T0, a tendency toward a higher degree of anxiety, somatization and inadequacy was found in myopes in comparison with controls; however, only the anxiety state was different (Wilcoxon signed-rank test P < 0.001). Personality profiles, psychophysical stress and blood levels of cortisol, ACTH, GH, prolactin were similar in myopes and controls. The myopes were classified at T1 as either well-corrected (if their lenses corresponded to refractometer values of +/- 0.50 D and were worn full-time) or undercorrected (if their lenses were > or = 0.75 D with respect to refractometric values and/or were worn part-time). When the spherical cycloplegic values at T0 and T1 were compared, a myopic shift was revealed only in the undercorrected myopes (P < 0.001 in both eyes). These findings suggest that personality profile and psychophysical stress do not play a primary pathogenetic role in myopia. Undercorrection seems to accelerate the progression of myopia.