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Original Investigation
May 23, 2019

Association of Intraocular Cataract Lens Replacement With Circadian Rhythms, Cognitive Function, and Sleep in Older Adults

Author Affiliations
  • 1Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Boston, Massachusetts
  • 2Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
  • 3Sleep-Wake-Epilepsy-Center, Department of Neurology, Inselspital, Bern University Hospital, Bern, Switzerland
  • 4Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
  • 5University Eye Clinic in Basel, University of Basel, Basel, Switzerland
  • 6GIGA-Research, Cyclotron Research Centre/In Vivo Imaging Unit, University of Liège, Liège, Belgium
  • 7Augenarztpraxis Klingentalstrasse, Basel, Switzerland
JAMA Ophthalmol. Published online May 23, 2019. doi:10.1001/jamaophthalmol.2019.1406
Key Points

Question  What is the association of intraocular cataract lens replacement with circadian rhythms, cognitive function, and sleep?

Findings  In this cross-sectional study of 13 patients with previous cataract and 16 healthy controls, intraocular cataract lens replacement significantly increased melatonin sensitivity to light by approximately 45%, ultraviolet lens improved cognitive function by approximately 70%, and sleep function by approximately 50% compared with blue-blocking lens.

Meaning  These in-laboratory empirical findings suggest that optimizing the spectral lens transmission in patients with cataract may be associated with better circadian, cognitive, and sleep function.

Abstract

Importance  Cataract is associated with a progressive decline in light transmission due to the clouding and yellowing of the natural crystalline lens. While the downstream effects of aging lenses include long-term disruption of circadian rhythms, cognitive function, and sleep regulation, it remains unknown whether there is an association of intraocular cataract lens (IOLs) replacement with circadian rhythms, cognition, and sleep.

Objective  To test whether IOL replacement (blue blocking [BB] or ultraviolet [UV] only blocking) in older patients with previous cataract is associated with the beneficial light effects on the circadian system, cognition, and sleep regulation.

Design, Setting, and Participants  Cross-sectional study at the Centre for Chronobiology, University of Basel in Switzerland from February 2012 to April 2014, analyzed between June 2012 and September 2018. Sixteen healthy older controls and 13 patients with previous cataract and IOL replacement participated without medication and no medical and sleep comorbidities.

Exposures  Three and a half hours of prior light control (dim-dark adaptation), followed by 2 hours of evening blue-enriched (6500 K) or non–blue-enriched light exposure (3000 K and 2500 K), 30 minutes in dim post–light exposure, 8 hours of sleep opportunity, and 2 hours of morning dim light following sleep.

Main Outcomes and Measures  Salivary melatonin, cognitive tests, and sleep structure and electroencephalographic activity to test the association of IOLs with markers of circadian rhythmicity, cognitive performance, and sleep regulation, respectively.

Results  The participants included 16 healthy older controls with a mean (standard error of the mean [SEM]) of 63.6 (5.6) years; 8 women and 13 patients with previous cataract (mean [SEM] age, 69.9 [5.2] years; 10 women); 5 patients had UV IOLs and 8 had BB IOLs. Patients with previous cataract and IOLs had an attenuated increase in melatonin levels during light exposure (mean [SEM] increase in the BB group: 23.3% [2.6%] and in the UV lens group: 19.1% [2.1%]) than controls (mean [SEM] increase, 48.8% [5.2%]) (difference between means, 27.7; 95% CI, 15.4%-41.7%; P < .001). Cognitive function, indexed by sustained attention performance, was improved in patients with UV lens (mean [SEM], 276.9 [11.1] milliseconds) compared with patients with BB lens (mean [SEM], 348.3 [17.8] milliseconds) (difference between means, 71.4; 95% CI, 29.5%-113.1%; P = .002) during light exposure and in the morning after sleep. Patients with UV lens had increased slow-wave sleep (mean [SEM] increase, 13% [3.4%]) compared with controls (mean [SEM] increase, 5.2% [0.8%]) (percentage of total sleep time; difference between means, 7.9; 95% CI, 2.4%-13.4%; P = .02) and frontal non–rapid eye movement slow-wave activity (0.75-4.5 Hz) during the first sleep cycle (mean [SEM], 79.9 [13.6] μV2/Hz) compared with patients with BB lens (mean [SEM], 53.2 [10.7] μV2/Hz) (difference between means, 26.7; 95% CI, 9.2-48.9; P = .03).

Conclusions and Relevance  These in-laboratory empirical findings suggest that optimizing the spectral lens transmission in patients with previous cataract may minimize the adverse age-related effects on circadian rhythms, cognition, and sleep.

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