Vision, Entoptic
Conditions
Keywords
macular pigment, glare disability, lutein, photostress, chromatic contrast sensitivity
Brief summary
The purpose of this study is: I. To measure MP optical density (MPOD) in two groups (experimental and placebo) of 50 subjects each (N = 100), during an Lutein + Zeaxanthin supplementation period of 12 months. II. To test the hypothesis that increases in MP (via 12 mg daily Lutein + Zeaxanthin supplementation) will result in significantly improved visual performance under disability glare conditions. III. To test the hypothesis that increases in MP (via 12 mg daily L + Z supplementation) will result in significantly reduced photostress recovery times. IV. To test the hypothesis that increases in MP (via 12 mg daily L + Z supplementation) will result in improved contrast enhancement.
Detailed description
The following measurements will be taken, before and after supplementation with lutein and zeaxanthin: Macular pigment optical density (MPOD) Visual performance under glare conditions Photostress recovery times chromatic contrast sensitivity.
Interventions
DIETARY_SUPPLEMENT12 mg Lutein + Zeaxanthin
10 mg FloraGlo lutein + 2 mg Optisharp zeaxanthin, taken once daily for one year
DIETARY_SUPPLEMENTVisually identical placebo
Visually identical placebo, taken once daily for one year
Sponsors
DSM Nutritional Products, Inc.
University of Georgia
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Intervention model description
Two arms: nutritional supplement vs. placebo.
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Gender: male or female * Age: 18 - 40 years * BMI: 20-30 * No anticipated changes in dieting habits (as relevant to xanthophyll intake). * No anticipated surgical procedures. * Assessed as healthy, based on a pre-study examination including medical history, physical examination, and clinical laboratory. The examination will be performed by an MD or a Nurse Practitioner. * Willingness and ability to give written informed consent and willingness and ability to comply with the study requirements. * Corrected visual acuity (ETDRS): better than 20/60
Exclusion criteria
* BMI \<20 or \>30 * Age \<18 or \>40 years * Smokers * Current or history of relevant diseases (such as AMD) * Corrected visual acuity worse than 20/60 * Inability to reliably perform MPOD measurements by heterochromatic flicker photometry or any of the other ophthalmic tests of the study. * Any condition likely to interfere with normal gastro-intestinal absorption of xanthophylls. * Current use of xanthophyll containing supplements * Use of xanthophyll containing supplements in the past 6 months * Participation in any other study during last 1 month. * Blood donation during the last 3 months. * Known hypersensitivity or allergy to xanthophylls. * Regular intake of medications or supplements, which the principal investigator deems likely to confound the study outcomes. * Suspected lack of compliance with any requirements of the study. * Childbearing potential and unwillingness to refrain from acceptable anticonceptive measures (not including abstinence). * Current pregnancy or breast feeding * Any relevant abnormalities in the routine laboratory tests
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Macular Pigment Optical Density | every three months for one year; 12-month measure reported. | optical density of macular pigment layer of the neural retina at 30-minutes of retinal eccentricity |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Glare Disability | 12-month data point only | light energy needed to obscure or veil a visual target; calculated as log-relative energy, which is the physical energy needed for the subject to report that the visual target has been veiled, given the intensity of the target, logged. |
| Photostress Recovery Time | improvement in recovery time; baseline recovery time (sec) minus 12-month recovery time (sec) | amount of time needed to recover from exposure to a bright light, and to regain sight of a visual target |
| Heterochromatic Contrast Sensitivity | 12-month data point only | amount of short-wave light energy necessary to obscure of veil a visual target, calculated as log-relative energy, which is the physical energy needed for the subject to report that the visual target has been veiled, given the intensity of the target, logged. |
Countries
United States
Participant flow
Recruitment details
Recruitment was initiated in May, 2009. The enrollment period was rolling and lasted for 30 months. Enrollment closed in November, 2011. Participants were recruited from the local Athens, Clarke-County community and the University of Georgia student population.
Pre-assignment details
Key events: Telephone screening to confirm eligibility Enrollment Randomization
Participants by arm
| Arm | Count |
|---|---|
| 12 mg Lutein + Zeaxanthin 10 mg FloraGlo lutein + 2 mg Optisharp zeaxanthin
Intervention: 10 mg FloraGlo lutein + 2 mg Optisharp zeaxanthin, taken once daily for one year | 53 |
| Visually Identical Placebo visually identical placebo
Placebo: Visually identical placebo, taken once daily for one year | 56 |
| Total | 109 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Lost to Follow-up | 17 | 17 |
Baseline characteristics
| Characteristic | Visually Identical Placebo | Total | 12 mg Lutein + Zeaxanthin |
|---|---|---|---|
| Age, Continuous | 22.7 years STANDARD_DEVIATION 3.32 | 23.2 years STANDARD_DEVIATION 3.97 | 23.7 years STANDARD_DEVIATION 4.61 |
| BMI | 22.8 kg/cm^2 STANDARD_DEVIATION 2.66 | 22.85 kg/cm^2 STANDARD_DEVIATION 2.56 | 22.9 kg/cm^2 STANDARD_DEVIATION 2.45 |
| Iris Darkness | 2.81 units on a scale STANDARD_DEVIATION 1.27 | 2.86 units on a scale STANDARD_DEVIATION 1.29 | 2.90 units on a scale STANDARD_DEVIATION 1.31 |
| Region of Enrollment United States | 56 participants | 109 participants | 53 participants |
| Sex/Gender, Customized Gender Female | 34 Participants | 65 Participants | 31 Participants |
| Sex/Gender, Customized Gender Male | 22 Participants | 44 Participants | 22 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 53 | 0 / 56 |
| other Total, other adverse events | 0 / 53 | 0 / 56 |
| serious Total, serious adverse events | 0 / 53 | 0 / 56 |
Outcome results
Primary
Macular Pigment Optical Density
optical density of macular pigment layer of the neural retina at 30-minutes of retinal eccentricity
Time frame: every three months for one year; 12-month measure reported.
Population: Participants who completed all four measurements
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Luten + Zeaxanthin | Macular Pigment Optical Density | 0.54 optical density | Standard Deviation 0.1 |
| Placebo | Macular Pigment Optical Density | 0.42 optical density | Standard Deviation 0.1 |
p-value: 0.01t-test, 2 sided
Secondary
Glare Disability
light energy needed to obscure or veil a visual target; calculated as log-relative energy, which is the physical energy needed for the subject to report that the visual target has been veiled, given the intensity of the target, logged.
Time frame: 12-month data point only
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Luten + Zeaxanthin | Glare Disability | 1.81 log relative energy | Standard Deviation 0.1 |
| Placebo | Glare Disability | 1.83 log relative energy | Standard Deviation 0.11 |
Comparison: Analysis compared mean differences between placebo and intervention at the 12-month time point.p-value: 0.21Regression, Linear
Secondary
Heterochromatic Contrast Sensitivity
amount of short-wave light energy necessary to obscure of veil a visual target, calculated as log-relative energy, which is the physical energy needed for the subject to report that the visual target has been veiled, given the intensity of the target, logged.
Time frame: 12-month data point only
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Luten + Zeaxanthin | Heterochromatic Contrast Sensitivity | 1.21 log relative energy | Standard Deviation 0.14 |
| Placebo | Heterochromatic Contrast Sensitivity | 1.16 log relative energy | Standard Deviation 0.1 |
Comparison: analysis conducted on mean change over one year, between groupsp-value: 0.02t-test, 2 sided
Secondary
Photostress Recovery Time
amount of time needed to recover from exposure to a bright light, and to regain sight of a visual target
Time frame: improvement in recovery time; baseline recovery time (sec) minus 12-month recovery time (sec)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Luten + Zeaxanthin | Photostress Recovery Time | 10.5 seconds | Standard Deviation 7.5 |
| Placebo | Photostress Recovery Time | 4.5 seconds | Standard Deviation 6 |
Comparison: Analysis compared mean change from baseline to 12-month time points.p-value: 0.01t-test, 1 sided