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

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.

Study Overview

• Status: Completed
• Conditions: Cataract
• Intervention / Treatment: Procedure: Conventional Intra Ocular Lens (IOL); Procedure: Yellow Intra Ocular Lens (IOL)

• Study Type: Interventional
• Enrollment (Actual): 76
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Glostrup, Denmark, DK-2600
    • Glostrup University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Conventional Intra Ocular Lens (IOL); Standard minimal incision cataract surgery by phacoemulsification and posterior intraocular lens implantation.	Procedure: Conventional Intra Ocular Lens (IOL); Standard operation with conventional IOL implantation
Experimental: Yellow Intra Ocular Lens (IOL); Standard minimal incision cataract surgery by phacoemulsification and posterior intraocular lens implantation.	Procedure: Yellow Intra Ocular Lens (IOL); Standard operation with blue light filter Yellow IOL implantation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pupillary response to blue light	Measurement of the consensual light response to red (630 nm) and blue (470 nm)	1 year/1month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Questionnaire	Pittsburgh Sleep Quality Index and the Morningness Eveningness Questionnaire	1year/1month
Questionnaire	Morningness-eveningness questionnaire	1 year/1 month
Melatonin day variety analysis	Salivary samples collected with 4 hour interval during 24 hours. Analyzed for melatonin concentration with Radio Immuno Assay (RIA).	1year/1month
Actigraphy	Activity measured during 7 days and 7 nights with the Spectrum Actiwatch, Respironics, Philips	1year/1month

Collaborators and Investigators

• Sponsor: Glostrup University Hospital, Copenhagen
• Investigators: Principal Investigator: Adam E Brøndsted, MD, Glostrup UH

Study record dates

Study Major Dates

• Study Start: February 1, 2011
• Primary Completion (Actual): December 1, 2014
• Study Completion (Actual): December 1, 2014

Study Registration Dates

• First Submitted: November 30, 2011
• First Submitted That Met QC Criteria: September 17, 2012
• First Posted (Estimate): September 18, 2012

Study Record Updates

• Last Update Posted (Estimate): February 10, 2015
• Last Update Submitted That Met QC Criteria: February 9, 2015
• Last Verified: February 1, 2015

More Information

Terms related to this study

• Keywords: sleep; cataract; questionnaire; circadian rhythm; pupillometry; blue light transmission
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: CIRCAT