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The Effect of Cataract on Photoentrainment of the Circadian Rhythm in Humans (CIRCAT)

This study is ongoing, but not recruiting participants.
Information provided by (Responsible Party):
Adam Elias Brøndsted, Glostrup University Hospital, Copenhagen Identifier:
First received: November 30, 2011
Last updated: March 27, 2014
Last verified: March 2014

Cataract is globally the most common cause of blindness and in Denmark the operation with - 50.000 treatments per year - is the most common eye operation. The cause of cataract is growth and denaturation of the lens proteins. This leads to an increased absorption of blue light and increased light scatter. This may affect newly discovered cells in the retina that are involved in the regulation of the circadian rhythm. When the internal circadian rhythm is not synchronized with the external day and night a phase-shift occurs. Most people know of this discomfort as jet-lag, but the consequences may be much more severe such as heighten risk of cancer and cardiovascular disease.

The goal of this project is to study how the circadian regulating cells of the retina is affected by cataract and by the operation. Cataract patients are studied before and after the operation with questionnaires, hormone and activity measurements and with a specialized pupil measurement that measures the indirect response of the circadian regulating cells to blue light.

Results from this study aim to shed light on the regulatory mechanisms of the eye on the circadian rhythm and how these are affected by cataract. Furthermore, choice of intraocular lens is evaluated. This may have impact on clinical practise especially with regard to choice of intraocular lens and widened indications for cataract surgery.

Condition Intervention
Procedure: Yellow Intra Ocular Lens (IOL)
Procedure: Conventional Intra Ocular Lens (IOL)

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: The Effect of Cataract on Photoentrainment of the Circadian Rhythm in Humans

Resource links provided by NLM:

Further study details as provided by Glostrup University Hospital, Copenhagen:

Primary Outcome Measures:
  • Pupillary response to blue light [ Time Frame: 1 year/1month ] [ Designated as safety issue: No ]
    Measurement of the consensual light response to red (630 nm) and blue (470 nm)

  • Melatonin day variety analysis [ Time Frame: 1year/1month ] [ Designated as safety issue: No ]
    Salivary samples collected with 4 hour interval during 24 hours. Analyzed for melatonin concentration with Radio Immuno Assay (RIA).

  • Actigraphy [ Time Frame: 1year/1month ] [ Designated as safety issue: No ]
    Activity measured during 7 days and 7 nights with the Spectrum Actiwatch, Respironics, Philips

Secondary Outcome Measures:
  • Visual acuity [ Time Frame: 1 year/1month ] [ Designated as safety issue: No ]
    Standard clinically evaluated snellen visual acuity

  • Optical coherence tomography (OCT) [ Time Frame: 1 year/1 month ] [ Designated as safety issue: No ]
    SD-OCT scanning with Heidelberg Spectralis OCT

  • Color deficiency [ Time Frame: 1 year/1 month ] [ Designated as safety issue: No ]
    Color deficiency evaluated by Farnsworth D15 saturated test

  • Questionnaire [ Time Frame: 1year/1month ] [ Designated as safety issue: No ]
    Pitsburgh Sleep Quality Index and the Morningness Eveningness Questionnaire

Estimated Enrollment: 300
Study Start Date: February 2011
Estimated Study Completion Date: December 2014
Estimated Primary Completion Date: December 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Conventional Intra Ocular Lens (IOL) Procedure: Conventional Intra Ocular Lens (IOL)
Standard operation with conventional IOL implantation
Experimental: Yellow Intra Ocular Lens (IOL) Procedure: Yellow Intra Ocular Lens (IOL)
Standard operation with blue light filter Yellow IOL implantation


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Age related/senile bilateral cataract
  • Eligible for phaco-emulsification on both eyes

Exclusion Criteria:

  • Known eye disease other than cataract.
  • Known systemic disease, which may affect the retina (untreated hypertension, DM etc.)
  • Known systemic disease, which may affect the lens.
  • Known psychiatric disease.
  • Known sleep or circadian rhythm disorder, not caused by lowered blue light transmission by the lens.
  • Per- and post operative complications
  • Use of drugs that may affect the sleep.

For a subpopulation also:

  • Poor cooperation.
  • Severe refraction abnormalities.
  • Previous eye surgery
  • Nystagmus
  • Congenital or acquired abnormalities of: eye lids and eye area, cornea or iris.
  • Use of medicine that may affect the pupillary response.
  • Use of drugs that may affect the pupillary response.
  Contacts and Locations
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Please refer to this study by its identifier: NCT01686308

Glostrup University Hospital
Glostrup, Denmark, DK-2600
Sponsors and Collaborators
Glostrup University Hospital, Copenhagen
Principal Investigator: Adam E Brøndsted, MD Glostrup UH
  More Information

No publications provided

Responsible Party: Adam Elias Brøndsted, MD, Glostrup University Hospital, Copenhagen Identifier: NCT01686308     History of Changes
Other Study ID Numbers: CIRCAT
Study First Received: November 30, 2011
Last Updated: March 27, 2014
Health Authority: Denmark: Ethics Committee

Keywords provided by Glostrup University Hospital, Copenhagen:
circadian rhythm
blue light transmission

Additional relevant MeSH terms:
Eye Diseases
Lens Diseases processed this record on November 20, 2014