Cataract and cognitive impairment: a review of the literature

Abstract

Acquired cataract and cognitive impairment are both common age-related problems, and ophthalmologists are increasingly likely to encounter patients who have both. Patients with dementia types who display early visuoperceptual impairment may present first to ophthalmology services. When these patients have coexisting cataract, it may be difficult to distinguish visual complaints due to cataract from those due to dementia. The interaction between visual impairment due to cataract and neurodegenerative disorders affecting the central visual pathways, is not fully understood. Visual impairment due to cataract may stress impaired attentional mechanisms and cataract extraction may improve cognitive performance in some patients with early cognitive impairment; however, the benefits of cataract surgery in established dementia are less clear. In this study, the literature on this subject was reviewed and the implications for practice were considered.

Figures

Figure 1. Above, the prevalence rates of dementia from a Delphi consensus study for 3 developed areas of the world with reliable prevalence data.[26] Below, the prevalence rates of cataract in the Blue Mountain’s eye study, 1st and 2nd cohorts which included 3654 and 3509 patients respectively in Australia.[19]

For each cohort prevalence rates of any type of cataract (nuclear, cortical and PSC) including patients who had had previous cataract surgery are shown. Cataract was assessed from lens photographs and without regard to patient symptoms.

Figure 2. A proposed model for elderly patients presenting for cataract surgery.

This gives advice on which patients would require further assessment by a multi-disciplinary team (MDT) including ophthalmologists, neurologists and old age psychiatrists.