By the same authors

From the same journal

New light for old eyes: comparing melanopsin-mediated non-visual benefits of blue-light and UV-blocking intraocular lenses

Research output: Contribution to journalArticlepeer-review


  • Conrad Schmoll
  • Ashraf Khan
  • Peter Aspinall
  • Colin Goudie
  • Peter Koay
  • Christelle Tendo
  • James Cameron
  • Jenny Roe
  • Ian Deary
  • Bal Dhillon


Publication details

JournalBritish Journal of Ophthalmology
DateE-pub ahead of print - 24 Oct 2013
DatePublished (current) - Jan 2014
Issue number1
Number of pages5
Pages (from-to)124-128
Early online date24/10/13
Original languageEnglish


Background/aims: Melanopsin-expressing photosensitive retinal ganglion cells form a blue-light-sensitive non-visual system mediating diverse physiological effects including circadian entrainment and cognitive alertness. Reduced blue wavelength retinal illumination through cataract formation is thought to blunt these responses while cataract surgery and intraocular lens (IOL) implantation have been shown to have beneficial effects on sleep and cognition. We aimed to use the reaction time (RT) task and the Epworth Sleepiness Score (ESS) as a validated objective platform to compare non-visual benefits of UV- and blue-blocking IOLs.

Methods: Patients were prospectively randomised to receive either a UV- or blue-blocking IOL, performing an RT test and ESS questionnaire before and after surgery. Optical blurring at the second test controlled for visual improvement. Non-operative age-matched controls were recruited for comparison.

Results: 80 participants completed the study. Those undergoing first-eye phacoemulsification demonstrated significant improvements in RT over control (p=0.001) and second-eye surgery patients (p=0.03). Moreover, reduced daytime sleepiness was measured by ESS for the first-eye surgery group (p=0.008) but not for the second-eye group (p=0.09). Choice of UV- or blue-blocking IOL made no significant difference to magnitude of cognitive improvement (p=0.272).

Conclusions: Phacoemulsification, particularly first-eye surgery, has a strong positive effect on cognition and daytime alertness, regardless of IOL type.

    Research areas

  • Aged, Cataract, Circadian Rhythm, Cognition, Female, Humans, Lens Implantation, Intraocular, Lenses, Intraocular, Light, Male, Phacoemulsification, Prospective Studies, Questionnaires, Reaction Time, Regression Analysis, Rod Opsins, Sleep

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