Cataract is a  common disease of the crystalline lens, a vision-impairing disease characterized by gradual, progressive thickening of the lens, creating a clouding effect varying in degree from slight to complete opacity, thus obstructing the passage of light. Cataracts occur when the lens loses its transparency by either scattering or absorbing light such that visual performance, (assessed through functional visual acuity recording), is compromised.By far the most important risk factor in the development of cataracts is age- age related cataracts constitute the great majority of all cataracts (e.g. congenital and juvenile cataracts are relatively rare) and are a major public health problem in the world. Oxidative damage to lens constituents is believed to be a primary factor in the formation of  age-related cataracts.

The literature shows that prior to this study there was no work in the field of forensic document examination and the graphonomics regarding the influence of cataractus vision in the individual characteristics of handwriting. This is something that could be perceived as peculiar due to how common this disease is, especially to the population group of older people.

The results of this research suggest that cataractus vision does not influence significantly the individual characteristics of handwriting to an extend that the pre-operational samples would appear to belong to a different variation group than that of the post-operational samples. Both the forensic comparison and the blind test furthermore suggest that the influence of cataractus vision is such that it would not lead an expert to an erroneous conclusion.

You can find my paper regarding cataract and handwriting here.