Clinical trial NCT01942746: 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
Overall status: COMPLETED
Phase: NA
Conditions: Blindness and Low Vision
Keywords: blueberry
anthocyanin
dark vision
photo bleaching
Visual Perception
Photic Stimulation
Lead sponsor: Atlantic Food and Horticulture Research Center
Sponsor class: OTHER_GOV
Collaborators: name: Dalhousie University
name: U.S. Highbush Blueberry Council
First posted: 2013-09-16
Enrollment: 72
Sex: ALL
Minimum age (years): 35
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

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

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

Primary outcomes:
measure: Rate of vision adaptation to low light after blueberry juice and placebo ingestion for 3 weeks (S2).
timeFrame: Pre-intervention, and changes after 3 weeks of intervention, and again after 3 weeks of washout
measure: Rate of vision adaptation to low light after ingestion of blueberry juice and placebo for 12 weeks (L1).
timeFrame: Preintervention, and changes after 8 and 12 weeks of intervention and after 4 and 8 weeks of washout
Secondary outcomes:
measure: Rate of recovery of visual acuity after retinal photostress (S2).
timeFrame: Pre-intervention testing and testing for changes after 3 weeks of intervention and 3 weeks of washout
measure: Rate of recovery of visual acquity after retinal photostress (L1).
timeFrame: Pre-intervention and then testing for changes after 8 and 12 weeks of intervention and 4 and 8 weeks of washout.
Other outcomes:
measure: Visual acuity and contrast sensitivity testing after dark adaptation (S2).
timeFrame: Testing preintervention and testing for changes after 3 weeks of intervention and 3 weeks of washout
measure: Visual acuity and contrast sensitivity testing after dark adaptation (L1).
timeFrame: Testing preintervention and testing for changes after 8 & 12 weeks of intervention and 4 & 8 weeks of washout
Locations:
city: Kentville
country: Canada
facility: Atlantic Food and Horicultural Research Center
state: Nova Scotia
Study officials:
affiliation: Agriculture and Agri-Food Canada
name: Wilhelmina Kalt, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Dalhousie University and IWK Health Center
name: Francois Tremblay, PhD
role: PRINCIPAL_INVESTIGATOR
References:
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.