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. Dementia types which display early visuo-perceptual 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. Here we review the literature on this subject and consider the implications for practice.

The Prevalence of Visual Impairment in People with Dementia (the PrOVIDe study): a cross-sectional study of people aged 60–89 years with dementia and qualitative exploration of individual, carer and professional perspectives

“…24,25 Acquired cataracts and dementia are both common age-related problems and it is, therefore, likely that they will coexist. 26 Cataract prevalence estimates depend on the definition of when the normal ageing and opacification of the crystalline lens reaches the point at which it becomes sufficient to bring a diagnosis of cataract. Often this point is based on when the cataract causes a significant effect on some aspect(s) of visual performance, normally standard VA measurements.…”

“…There was no evidence for independent age or sex effects, with the estimated differences (95% CI) per year of 0.03 (-0.05 to 0.11; p = 0.49) and between males and females of 1.09 (-0.05 to 2.24; p = 0.06). For the analysis of the range of sMMSE scores in our sample (Tables 5 and 6), each participant was allocated to one of five levels of cognitive impairment based on their total sMMSE score: severe cognitive impairment (sMMSE score of 0-9), moderate cognitive impairment (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), mild cognitive impairment (21)(22)(23)(24), very mild cognitive impairment (25)(26)(27) and no cognitive impairment (28)(29)(30). In the context of the PrOVIDe study, the term mild cognitive impairment is being taken to include people in the sMMSE range of 21-24, although mild cognitive impairment has a different meaning in the general literature, where it often refers to people without dementia but who have a performance of 1.5-2 SDs lower on cognitive (usually memory) testing than age-matched norms.…”

“…146 VI as a result of cataract may cause stress to attentional mechanisms, and cognitive performance may improve following cataract surgery in some patients with early cognitive impairment. 26 In patients with more advanced cognitive impairment the benefits of cataract extraction are less clear. The benefits of expedited cataract extraction, as measured by the effect on falls, are more equivocal.…”

A novel, multidisciplinary clinic for complex visual problems in older people

“…1,2 Complex visual symptoms in such patients may be inadequately explained by eye pathology alone. [2][3][4] Neurodegenerative disease, psychotropic medications, and psychological factors may all manifest with or exacerbate symptoms of visual dysfunction. [5][6][7][8][9][10][11][12][13][14] Such multifactorial visual complaints are difficult to diagnose, and may be best approached by a multidisciplinary team.…”

“…[5][6][7][8][9][10][11][12][13][14] Such multifactorial visual complaints are difficult to diagnose, and may be best approached by a multidisciplinary team. 3 The Visual Perception Clinic in the Newcastle Eye Centre provides such a multidisciplinary service. The clinic adheres to the following format: (1) Multidisciplinary discussion of each case from the referral letter by clinicians from ophthalmology, old-age psychiatry, and neurology followed by designation of a clinical lead.…”