Back to resultsBlueberry Effects on Dark Vision and Glare Recovery
Primary Purpose
Blindness and Low Vision
Status
Completed
Phase
Not Applicable
Locations
Canada
Study Type
Interventional
Intervention
Blueberry Juice S2
Blueberry Capsules S2
Placebo Capsule S2
Placebo Juice L1
Blueberry Juice L1
Sponsored by
About this trial
This is an interventional basic science trial for Blindness and Low Vision focused on measuring blueberry, anthocyanin, dark vision, photo bleaching, Visual Perception, Photic Stimulation
Eligibility Criteria
Inclusion Criteria:
- visual acuity better than 6/7.5 on EDTRS acuity chart at 2.5m
- visual contrast sensitivity within normal range at 2.5m as tested on Visteck 3000
- stereo acuity better than 80 seconds of arc on Frisby stereoacuity test
- no ocular history other than refractive glasses
- no family history of eye disease
Exclusion Criteria:
- family history of retinal degeneration, glaucoma, diabetes, hypertension, cataract, or amblyopia (dimness in vision).
- evidence in subject (upon examination) of amblyopia (dimness in vision), manifest strabismus (unable to focus both eyes on one spot), or anisotropia (non-uniform responsiveness between both eyes).
- intraocular pressure above 21mmHG from an average of three measures using Mentor tonopen-XL
Sites / Locations
- Atlantic Food and Horicultural Research Center
Arms of the Study
Arm 1
Arm 2
Arm 3
Arm 4
Arm Type
Active Comparator
Active Comparator
Placebo Comparator
No Intervention
Arm Label
Blueberry Juice
Blueberry Capsules
Placebo
Washout (S2 and L1)
Arm Description
Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue'). Volunteers consumed 300 mls of juice/day (247-271 mg anthocyanins (as C3G) daily) while on this intervention, for either 3 weeks (Blueberry Juice S2) or 12 weeks (Blueberry Juice L1).
Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue')was freeze dried to a powder and encapsulated in gelatin capsules (Blueberry Capsules S2). Volunteers consumed 3 capsules/daily (7.11mg anthocyanin (as C3G eq) for 3 weeks.
Volunteers consumed in S2 three placebo capsules daily for 3 weeks. In L1 volunteers consumed 300ml placebo juice for twelve weeks. Placebo products contained no anthocyanins.
Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration.
Outcomes
Primary Outcome Measures
Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2).
Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 3 weeks intervention, again after a 3 week washout.] [Designated as safety issue: No]
Rate of vision adaptation to low light after ingestion of blueberry juice and placebo for 12 weeks (L1).
Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 8 and 12 weeks intervention, and again after 4 and 8 weeks washout] [Designated as safety issue: No]
Secondary Outcome Measures
Rate of recovery of visual acuity after retinal photostress (S2).
After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures), participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured.
Rate of recovery of visual acquity after retinal photostress (L1).
After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures) participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured.
Full Information
NCT ID
NCT01942746
First Posted
May 23, 2013
Last Updated
September 11, 2013
Sponsor
Atlantic Food and Horticulture Research Center
Collaborators
Dalhousie University, U.S. Highbush Blueberry Council
1. Study Identification
Unique Protocol Identification Number
NCT01942746
Brief Title
Blueberry Effects on Dark Vision and Glare Recovery
Official Title
Placebo-controlled Cross-over Studies Examining Blueberries Effects on Dark Vision and Recovery After Photo-bleaching
Study Type
Interventional
2. Study Status
Record Verification Date
September 2013
Overall Recruitment Status
Completed
Study Start Date
July 2005 (undefined)
Primary Completion Date
July 2006 (Actual)
Study Completion Date
July 2006 (Actual)
3. Sponsor/Collaborators
Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
Atlantic Food and Horticulture Research Center
Collaborators
Dalhousie University, U.S. Highbush Blueberry Council
4. Oversight
Data Monitoring Committee
No
5. Study Description
Brief Summary
Clinical evidence for effects of plant anthocyanins on vision, and particularly night vision is controversial. Two clinical trials were conducted to investigate whether blueberry juice consumption affected visual dark adaptation, functional night vision, and recovery after photo-bleaching of the retina. One trial (S2) employed a 3 week intervention and washout period, and two doses of blueberries plus a placebo. The other trial (L1) employed a 12 week intervention plus an 8 week washout and tested one blueberry juice dose against a juice placebo.
Detailed Description
Vision Tests: 1. Dark adaptometry, 2. scotopic visual acuity, 3. scotopic contrast sensitivity, 4. rod/cone conversion, 5. recovery after retinal photobleaching
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Blindness and Low Vision
Keywords
blueberry, anthocyanin, dark vision, photo bleaching, Visual Perception, Photic Stimulation
7. Study Design
Primary Purpose
Basic Science
Study Phase
Not Applicable
Interventional Study Model
Crossover Assignment
Masking
ParticipantOutcomes Assessor
Allocation
Non-Randomized
Enrollment
72 (Actual)
8. Arms, Groups, and Interventions
Arm Title
Blueberry Juice
Arm Type
Active Comparator
Arm Description
Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue'). Volunteers consumed 300 mls of juice/day (247-271 mg anthocyanins (as C3G) daily) while on this intervention, for either 3 weeks (Blueberry Juice S2) or 12 weeks (Blueberry Juice L1).
Arm Title
Blueberry Capsules
Arm Type
Active Comparator
Arm Description
Commercially prepared single strength blueberry juice which was composed of a 50:50 blend of two highbush blueberry species (Vaccinium corymbosum L. 'Rubel' and V. ashei Reade 'TifBlue')was freeze dried to a powder and encapsulated in gelatin capsules (Blueberry Capsules S2). Volunteers consumed 3 capsules/daily (7.11mg anthocyanin (as C3G eq) for 3 weeks.
Arm Title
Placebo
Arm Type
Placebo Comparator
Arm Description
Volunteers consumed in S2 three placebo capsules daily for 3 weeks. In L1 volunteers consumed 300ml placebo juice for twelve weeks. Placebo products contained no anthocyanins.
Arm Title
Washout (S2 and L1)
Arm Type
No Intervention
Arm Description
Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration.
Intervention Type
Dietary Supplement
Intervention Name(s)
Blueberry Juice S2
Other Intervention Name(s)
Single-strength blueberry juice, commercially prepared
Intervention Description
Blueberry Juice S2 was commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars. Colorimetric analysis showed that S2 juice contained 6.04 (SD=0.20) mg anthocyanins (C3G) eq/g dry mass.
Intervention Type
Dietary Supplement
Intervention Name(s)
Blueberry Capsules S2
Other Intervention Name(s)
freeze-dried blueberry juice powder
Intervention Description
Commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars was freeze dried then powdered and encapsulated in gelatin capsules. Colorimetric analysis indicated an anthocyanin concentration in the powder of 2.37(SD=0.18) mg C3G eq per capsule.
Intervention Type
Dietary Supplement
Intervention Name(s)
Placebo Capsule S2
Other Intervention Name(s)
Red beet powder
Intervention Description
Placebo Capsule S2 (containing no anthocyanins) were prepared by freeze drying red beets and grinding them to fine powder before encapsulating in gelatine capsules. Red beets do not contain anthocyanins.
Intervention Type
Dietary Supplement
Intervention Name(s)
Placebo Juice L1
Intervention Description
Placebo juice was prepared from water, sugars, citric acid, sodium citrate, and artificial colors and flavours, then pasteurized. The placebo juice contains no anthocyanins.
Intervention Type
Dietary Supplement
Intervention Name(s)
Blueberry Juice L1
Other Intervention Name(s)
single strength blueberry juice, commercially prepared
Intervention Description
Blueberry Juice L1 was commercially prepared single strength blueberry juice composed of a 50:50 blend of Rubel (Vaccinium corymbosum L.) and Tifblue (Vaccinium ashei Reade) cultivars. Colorimetric analysis showed that L1 juice contained 6.83 (SD=0.20) mg cyanidin-3-glucoside equivalents (C3GE)/g dry mass at the start of the study, declining to 5.52 (SD=0.09) mg C3GE/g dry mass after 3 months refrigerated storage.
Primary Outcome Measure Information:
Title
Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2).
Description
Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 3 weeks intervention, again after a 3 week washout.] [Designated as safety issue: No]
Time Frame
Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout
Title
Rate of vision adaptation to low light after ingestion of blueberry juice and placebo for 12 weeks (L1).
Description
Effect of blueberry products and placebo on the rate of vision adaptation to low light. The rate of vision adaptation is measured by lowest perceptible light intensity after 30 min of darkness (dark threshold); time to reach dark threshold (min); time to reach rod/cone transition (min) [Time Frame: Pre-intervention, after 8 and 12 weeks intervention, and again after 4 and 8 weeks washout] [Designated as safety issue: No]
Time Frame
Preintervention, and changes after 8 and 12 weeks of intervention and after 4 and 8 weeks of washout
Secondary Outcome Measure Information:
Title
Rate of recovery of visual acuity after retinal photostress (S2).
Description
After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures), participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured.
Time Frame
Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout
Title
Rate of recovery of visual acquity after retinal photostress (L1).
Description
After dark adaptation testing (primary outcome) and contrast sensitivity and visual acuity testing (other pre-specified outcome measures) participants are subjected to photostress of the retina using bright light. The time (sec) required to recover pre-stress acuity is measured.
Time Frame
Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout.
Other Pre-specified Outcome Measures:
Title
Visual acuity and contrast sensitivity testing after dark adaptation (S2).
Description
After dark adaptation testing (primary outcome measure) and before measuring rate of recovery from photo stress (secondary outcome) visual acuity in darkness and contrast sensitivity in darkness was measured using defined optotypes with different degrees of crowding and contrast. Performance was defined as the number of correct answers in 12 tests of acuity and 8 tests of contrast sensitivity.
Time Frame
Testing preintervention and testing for changes after 3 weeks of intervention and 3 weeks of washout
Title
Visual acuity and contrast sensitivity testing after dark adaptation (L1).
Description
After dark adaptation testing (primary outcome measure) and before testing rate of recovery from photo stress (secondary outcome) visual acuity in darkness and contrast sensitivity in darkness was measured using defined optotypes with different degrees of crowding and contrast. Performance was defined as the number of correct answers in 12 tests of acuity and 8 tests of contrast sensitivity.
Time Frame
Testing preintervention and testing for changes after 8 & 12 weeks of intervention and 4 & 8 weeks of washout
10. Eligibility
Sex
All
Minimum Age & Unit of Time
35 Years
Maximum Age & Unit of Time
65 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria:
visual acuity better than 6/7.5 on EDTRS acuity chart at 2.5m
visual contrast sensitivity within normal range at 2.5m as tested on Visteck 3000
stereo acuity better than 80 seconds of arc on Frisby stereoacuity test
no ocular history other than refractive glasses
no family history of eye disease
Exclusion Criteria:
family history of retinal degeneration, glaucoma, diabetes, hypertension, cataract, or amblyopia (dimness in vision).
evidence in subject (upon examination) of amblyopia (dimness in vision), manifest strabismus (unable to focus both eyes on one spot), or anisotropia (non-uniform responsiveness between both eyes).
intraocular pressure above 21mmHG from an average of three measures using Mentor tonopen-XL
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Wilhelmina Kalt, PhD
Organizational Affiliation
Agriculture and Agri-Food Canada
Official's Role
Principal Investigator
First Name & Middle Initial & Last Name & Degree
Francois Tremblay, PhD
Organizational Affiliation
Dalhousie University and IWK Health Center
Official's Role
Principal Investigator
Facility Information:
Facility Name
Atlantic Food and Horicultural Research Center
City
Kentville
State/Province
Nova Scotia
ZIP/Postal Code
B4N1J5
Country
Canada
12. IPD Sharing Statement
Citations:
PubMed Identifier
25335781
Citation
Kalt W, McDonald JE, Fillmore SA, Tremblay F. Blueberry effects on dark vision and recovery after photobleaching: placebo-controlled crossover studies. J Agric Food Chem. 2014 Nov 19;62(46):11180-9. doi: 10.1021/jf503689c. Epub 2014 Nov 6.
Results Reference
derived
Learn more about this trial
Blueberry Effects on Dark Vision and Glare Recovery
We'll reach out to this number within 24 hrs