title: The Effect of Cataract Surgery on Circadian Photoentrainment: A Randomized Trial of Blue-Blocking versus Neutral Intraocular Lenses.
abstract: OBJECTIVE
  Cataract decreases blue light transmission. Because of the selective blue light sensitivity of the retinal ganglion cells governing circadian photoentrainment, cataract may interfere with normal sleep-wake regulation and cause sleep disturbances. The purpose was to investigate the effect of cataract surgery on circadian photoentrainment and to determine any difference between blue-blocking and neutral intraocular lenses (IOLs).
  
  
  METHODS
  The study was a single-center, investigator-driven, double-masked, block-randomized clinical trial.
  
  
  METHODS
  One eye in 76 patients with bilateral age-related cataract eligible for cataract surgery was included.
  
  
  METHODS
  Intervention was cataract surgery by phacoemulsification. Patients were randomized to receive a blue-blocking or neutral IOL.
  
  
  METHODS
  Primary outcome was activation of intrinsic photosensitive ganglion cells using post-illumination pupil response (PIPR) to blue light from 10 to 30 seconds after light exposure as a surrogate measure. Secondary outcomes were circadian rhythm analysis using actigraphy and 24-hour salivary melatonin measurements. Finally, objective and subjective sleep quality were determined by actigraphy and the Pittsburgh Sleep Quality Index.
  
  
  RESULTS
  The blue light PIPR increased 2 days (17%) and 3 weeks (24%) after surgery (P < 0.001). The majority of circadian and sleep-specific actigraphy parameters did not change after surgery. A forward shift of the circadian rhythm by 22 minutes (P = 0.004) for actigraphy and a tendency toward an earlier melatonin onset (P = 0.095) were found. Peak salivary melatonin concentration increased after surgery (P = 0.037). No difference was detected between blue-blocking and neutral IOLs, whereas low preoperative blue light transmission was inversely associated with an increase in PIPR (P = 0.021) and sleep efficiency (P = 0.048).
  
  
  CONCLUSIONS
  Cataract surgery increases photoreception by the photosensitive retinal ganglion cells. Because of inconsistency between the significant findings and the many parameters that were unchanged, we can conclude that cataract surgery does not adversely affect the circadian rhythm or sleep. Longer follow-up time and fellow eye surgery may reveal the significance of the subtle changes observed. We found no difference between blue-blocking and neutral IOLs, and, because of the minor effect of surgery in itself, an effect of IOL type seems highly unlikely.
authors.affiliation: Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health Sciences, University of Copenhagen, Denmark. Electronic address: adelbr01@regionh.dk.
authors.forename: Adam Elias
authors.initials: AE
authors.lastname: Brøndsted
authors.affiliation: Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark.
authors.forename: Birgit
authors.initials: B
authors.lastname: Sander
authors.affiliation: Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Haargaard
authors.affiliation: Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund-Andersen
authors.affiliation: Faculty of Health Sciences, University of Copenhagen, Denmark; Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Jennum
authors.affiliation: Clinical Biochemistry Section, Department of Diagnostics, Rigshospitalet, Glostrup, Denmark.
authors.forename: Steen
authors.initials: S
authors.lastname: Gammeltoft
authors.affiliation: Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health Sciences, University of Copenhagen, Denmark.
authors.forename: Line
authors.initials: L
authors.lastname: Kessel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm / Q000502:physiology / Q000528:radiation effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D008875:Middle Aged; D018918:Phacoemulsification; D017440:Photoperiod; D011474:Prosthesis Design; D011680:Pupil / Q000528:radiation effects; D012165:Retinal Ganglion Cells / Q000528:radiation effects; D012463:Saliva / Q000378:metabolism; D012890:Sleep / Q000502:physiology
chemical_list: D008550:Melatonin