Blueberry Effects on Dark Vision and Glare Recovery

Atlantic Food and Horticulture Research Center

Status: Completed

Conditions: Blindness and Low Vision

Treatments: Dietary Supplement: Placebo Juice L1; Dietary Supplement: Blueberry Juice S2; Dietary Supplement: Placebo Capsule S2; Dietary Supplement: Blueberry Juice L1; Dietary Supplement: Blueberry Capsules S2

Study type: Interventional

Funder types: Other

Identifiers

NCT01942746

Blueberries and Vision

Details and patient eligibility

About

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.

Full description

Vision Tests: 1. Dark adaptometry, 2. scotopic visual acuity, 3. scotopic contrast sensitivity, 4. rod/cone conversion, 5. recovery after retinal photobleaching

Enrollment: 72 patients

Sex: All

Ages: 35 to 65 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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72 participants in 4 patient groups, including a placebo group

Blueberry Juice

Active Comparator group

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).

Treatment:

Dietary Supplement: Blueberry Juice L1

Dietary Supplement: Blueberry Juice S2

Blueberry Capsules

Active Comparator group

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.

Treatment:

Dietary Supplement: Blueberry Capsules S2

Placebo

Placebo Comparator group

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.

Treatment:

Dietary Supplement: Placebo Capsule S2

Dietary Supplement: Placebo Juice L1

Washout (S2 and L1)

No Intervention group

Description:

Washout periods involved no study products. Washout was 3 weeks in S2 and or 8 weeks (L1) in duration.