[The prevalence of combined vision impairment and hearing loss: the importance of comorbidity studies].

Eight recent Dutch studies were analysed to determine the prevalence of dual sensory impairment: impaired vision and hearing loss. The study showed a strong increase in the prevalence of dual sensory impairment above the age of 85. In the general population, there was a 10-fold increase in prevalence between 65-80 years of age (0.5%) and 85 years and older (6%). For all age categories, the prevalence was even higher in nursing homes (7-25%) and among mentally retarded persons (6-13%). Visual impairment and hearing loss have negative effects on well-being because of the impact on resources and because of an increase in dependency and stress. Other forms of comorbidity with vision impairment or hearing loss, such as combinations with cardiovascular or psychiatric diseases, are even more important for healthcare than dual sensory impairment. The influence of comorbidity on functioning and well-being is still poorly investigated and there is a lack of empirical evidence concerning the effect of treatment in comorbid conditions.