Blindness and Low VisionNCT01942746
Blueberry Effects on Dark Vision and Glare Recovery
A study testing Blueberry Juice S2, Blueberry Capsules S2 and Blueberry Juice L1 in people with Blindness and Low Vision, run by Atlantic Food and Horticulture Research Center at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages 35 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Blindness and Low Vision
- What is being tested?
- Blueberry Juice S2, Blueberry Capsules S2 and Blueberry Juice L1
- Type of treatment
- Vaccines, Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 72 participants
- Where
- 1 siteCanada
- Study dates
- Jul 2005to Jul 2006
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 35 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
Canada1 site
Atlantic Food and Horicultural Research Center
Kentville, Nova Scotia, B4N1J5
About this study
Official title: Placebo-controlled Cross-over Studies Examining Blueberries Effects on Dark Vision and Recovery After Photo-bleaching
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.
Read the detailed description
Vision Tests: 1. Dark adaptometry, 2. scotopic visual acuity, 3. scotopic contrast sensitivity, 4. rod/cone conversion, 5. recovery after retinal photobleaching
- Conditions
- Blindness and Low Vision
- Being tested
- Blueberry Juice S2, Blueberry Capsules S2, Placebo Capsule S2, Placebo Juice L1, Blueberry Juice L1
- Keywords
- blueberry, anthocyanin, dark vision, photo bleaching, Visual Perception, Photic Stimulation
- Medical subject headings
- Blindness, Vision, Low
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blueberry Juice S2Dietary supplement
Also called Single-strength blueberry juice, commercially prepared
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.
Blueberry Capsules S2Dietary supplement
Also called freeze-dried blueberry juice powder
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.
Placebo Capsule S2Dietary supplement
Also called Red beet powder
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.
Placebo Juice L1Dietary supplement
Placebo juice was prepared from water, sugars, citric acid, sodium citrate, and artificial colors and flavours, then pasteurized. The placebo juice contains no anthocyanins.
Blueberry Juice L1Dietary supplement
Also called single strength blueberry juice, commercially prepared
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.
| Study group | Role | What they receive |
|---|---|---|
| Blueberry Juice | Active comparator | 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). Receives: Dietary Supplement: Blueberry Juice S2; Dietary Supplement: Blueberry Juice L1 |
| Blueberry Capsules | Active comparator | 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. Receives: Dietary Supplement: Blueberry Capsules S2 |
| Placebo | Placebo comparator | 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. Receives: Dietary Supplement: Placebo Capsule S2; Dietary Supplement: Placebo Juice L1 |
| Washout (S2 and L1) | No intervention | Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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]
Measured: Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout
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]
Measured: Preintervention, and changes after 8 and 12 weeks of intervention and after 4 and 8 weeks of washout
Secondary outcomes (2)
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.
Measured: Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout
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.
Measured: Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Sep 2013 (estimated)
- Study startJul 2005
- Primary completionJul 2006
- Study completionJul 2006
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Blindness and Low VisionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 72 participants (actual)
Sponsor and investigators
- Lead sponsor
- Atlantic Food and Horticulture Research Center
- Sponsor type
- Other government
- Collaborators
- Dalhousie University, U.S. Highbush Blueberry Council
- Responsible party
- Principal investigator, Wilhelmina Kalt, Atlantic Food and Horticulture Research Center
- Investigators
- Wilhelmina Kalt, PhD, Principal investigator, Agriculture and Agri-Food CanadaFrancois Tremblay, PhD, Principal investigator, Dalhousie University and IWK Health Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01942746
- Sponsor's protocol ID
- Blueberries and Vision
- Status last verified
- Sep 2013
- First submitted
- 23 May 2013
- Last updated
- 16 Sep 2013
- Results posted
- No
- Data monitoring committee
- No
Publications
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.
PubMed 25335781
Study at a glance
From the registry record, last updated by the sponsor on 16 Sep 2013. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Placebo-controlled Cross-over Studies Examining Blueberries Effects on Dark Vision and Recovery After Photo-bleaching
- ClinicalTrials.gov ID
- NCT01942746
- Acronym / sponsor ID
- Blueberries and Vision
- Conditions
- Blindness and Low Vision
- Keywords
- blueberry, anthocyanin, dark vision, photo bleaching, Visual Perception, Photic Stimulation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 72 participants (actual)
- Lead sponsor
- Atlantic Food and Horticulture Research CenterOther government
- Collaborators
- Dalhousie University, U.S. Highbush Blueberry Council
- Study start
- Jul 2005
- Primary completion
- Jul 2006 (actual)
- Study completion
- Jul 2006 (actual)
- First posted
- 16 Sep 2013 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Blueberry Juice | Active comparator | Dietary Supplement: Blueberry Juice S2, Dietary Supplement: Blueberry Juice L1Commercially 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). |
| Blueberry Capsules | Active comparator | Dietary Supplement: Blueberry Capsules S2Commercially 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. |
| Placebo | Placebo comparator | Dietary Supplement: Placebo Capsule S2, Dietary Supplement: Placebo Juice L1Volunteers 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 (S2 and L1) | No intervention | –Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration. |
Who may qualify
- Ages
- 35 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (3 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Blueberry Juice S2Also: Single-strength blueberry juice, commercially preparedBlueberry 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. | Dietary supplement | Blueberry Juice |
| Blueberry Capsules S2Also: freeze-dried blueberry juice powderCommercially 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. | Dietary supplement | Blueberry Capsules |
| Placebo Capsule S2Also: Red beet powderPlacebo 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. | Dietary supplement | Placebo |
| Placebo Juice L1Placebo juice was prepared from water, sugars, citric acid, sodium citrate, and artificial colors and flavours, then pasteurized. The placebo juice contains no anthocyanins. | Dietary supplement | Placebo |
| Blueberry Juice L1Also: single strength blueberry juice, commercially preparedBlueberry 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. | Dietary supplement | Blueberry Juice |
Primary outcome
Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2).
Time frame: Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout
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).
Time frame: Preintervention, and changes after 8 and 12 weeks of intervention and after 4 and 8 weeks of washout
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]
2 secondary outcomes
Rate of recovery of visual acuity after retinal photostress (S2).
Time frame: Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout
Rate of recovery of visual acquity after retinal photostress (L1).
Time frame: Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Sep 2013.
- Derived from this study: PubMed 25335781Kalt 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Wilhelmina Kalt, PhD principal investigator
Agriculture and Agri-Food Canada
Francois Tremblay, PhD principal investigator
Dalhousie University and IWK Health Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Blueberry Juice S2, Blueberry Capsules S2 and Blueberry Juice L1 in people with Blindness and Low Vision, run by Atlantic Food and Horticulture Research Center at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Sep 2013. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2). (time frame: Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01942746, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Sep 2013.