[Comparative follow-up study of unselected male population with congenital defective color vision from inland and Mediterranean areas of Croatia].

Aim: The aim of this ten-year study (from the end of 1998 to the end of 2008) was to assess the prevalence of congenital dyschromatopsia in unselected healthy male population aged 15-45 from two Croatian regions, i.e. inland and Mediterranean parts of Croatia. Results collected in these two regions were compared and respective conclusions drawn. The results primarily referred to the prevalence of color vision disturbances and their differences according to the main color groups (dichromacy and anomalous trichromacy) and subgroups (protanopia, deuteranopia, protanomaly, deuteranomaly, and others). To our knowledge, no such a long-term study in a large population sample has been carried out in southeast Europe to date.

Methods: Color vision was examined after complete ophthalmologic examination in all subjects presenting for examination required for amateur driver license. Color vision examination was performed by use of pseudoisochromatic Ishihara tables, Nagel II anomaloscope and Panel D-15 color test at industrial medicine offices and ophthalmology departments in the two regions. There were 12,974 and 9,974 subjects in inland and Mediterranean Croatia, respectively.

Results: The results confirmed the hypothesis and clinical perception of a lower prevalence of color vision disturbances in southern parts, i.e. in Mediterranean Croatia (8.50%) as compared with inland Croatia (8.90%). The rate of dichromacy was higher in Mediterranean Croatia (2.40%), while the rate of anomalous trichromacy was greater in inland Croatia (6.93%).

Conclusion: The results of this study provide better insight in the status of color vision disturbances and possible differences between the relatively close areas of north (inland) and south (Mediterranean) Croatia.