Association of MPOD Values With Blue Light.

This study aims to investigate in healthy adults 18-65 years of age the association of electronic device blue light exposure and macular pigment optical density (MPOD) considering usual dietary intake of lutein and zeaxanthin (L/Z) as confirmed by serum lutein and zeaxanthin concentrations.

It is hypothesised in healthy adults 18-65 years of age:

1. Higher usual daily electronic device blue light exposure will be negatively correlated with MPOD value.
2. Usual dietary intake of L/Z will be positively correlated with MPOD value.
3. L/Z concentration will be positively correlated with MPOD value.
4. Usual dietary intake of L/Z will be positively correlated with plasma L/Z concentrations.
5. Higher usual intake of L/Z will mitigate the effect of higher electronic device exposure on MPOD value.

Exponential uptake of modern technology over the last 30 years (computers) and 10 years (smartphones) has resulted in remarkable increase in artificial blue light exposure amongst all age groups. This suggests the incidence of age-related macular degeneration (AMD) could be increasing significantly in the population in the years to come. It is unknown whether the extent of daily blue light exposure influences macular pigment optical density (MPOD) in young to middle age adults. Stringham et al. (2017) showed that, in 18-25 year old healthy adults, exposed to electronic devices over 6 hours daily, MPOD value and visual performance significantly improved after 6 months of lutein/zeaxanthin/meso-zeaxanthin supplementation. The findings of this project may inform on the risks of high exposure to electronic screens and the need to address with preventive measures the potential decline in MPOD and increased risk of AMD. The impact of usual dietary intake of macular xanthophylls on circulating concentrations and MPOD will be investigated. Findings may inform guidelines on recommended daily intake of these food constituents either through diet or supplementation.

Data Management and Confidentiality of Data Collected:

Consent is sought for extended use of the collected data which means it may be used in future research. For example, in the future if more sensitive methods for detecting L/Z, or other macular pigments become available, stored blood samples may be re-analysed. Furthermore, data may be used for subsequent statistical analysis and statistical analysis may be published in peer-reviewed journals, however no identifiable personal details will be published or used. Any personal information, such as full name and date of birth will remain confidential to only the study investigators at all times.

All hard copy personal information and measures taken as part of the study protocol will be stored in locked filing cabinets when not in use, and will only be accessible to approved study investigators. Any electronic data collected for the study will be stored using the UQ Research Data Management system. Data will be de-identified through the use of participant ID numbers allocated at enrolment. Re-identification of participant information will only be accessible by study investigators. At the conclusion of the study, participant hard copy files and trial documents are kept in locked filing cabinets for a period of 15 years. After this time, records will be disposed of by a certified record destruction, such as shredding.

Blood samples will be collected for research purposes, specifically for the measurement of plasma lutein and zeaxanthin concentrations. Collected samples will be stored as per the extended consent sought, held for up to 15 years. After this time, they will be destroyed via incineration. Collected plasma samples will only be identifiable via the participant study number allocated at enrolment. All publicly shared data or data used in publications will be in a non-identifiable form.

Data recorded and maintained for this trial will be controlled in accordance with the national Privacy Principles and Privacy Act 1988.

Sample Size:

Sample size calculation was performed on the basis of a MPOD coefficient of variation of 0.187 optical density units (ODU) measured in a sample of 5581 adults using the Macular Pigment Screener II (18). A minimum of 105 participants was calculated using a two tailed, random model, linear multiple regression with an alpha error probability: 0.05, power: 0.90, number of predictors: 4. This also allows for a 20% drop out rate.

Statistical Tests:

Analysis will be conducted using GraphPad Prism 8. Participants will be stratified by MPOD.

1. Descriptive statistics will be performed.
2. All data will be tested for normality of distribution using the D'Agostino-Pearson normality test.
3. Based on the outcome of testing for normality of distribution, Spearman or Pearson's correlations will be used to test for correlation between the following variables.

   1. MPOD and daily hours of electronic device use.
   2. MPOD and usual dietary intake of lutein and zeaxanthin (L/Z).
   3. MPOD and serum L/Z concentration.
   4. Serum L/Z concentration and usual dietary intake of L/Z.
4. Multiple linear regression will be used to test for correlation to MPOD with the following variables:

   1. Daily hours of electronic device use.
   2. Usual dietary intake of L/Z.
   3. Age
   4. Gender

Results will be considered statistically significant if p\<0.05.

Eligibility Criteria:
Inclusion Criteria:

* Male and females 18 to 65 years.
* Generally healthy.
* No participant reported history of clinically significant medical conditions including, but not limited to, cardiovascular, neurological, psychiatric, renal, immunological, endocrine (including uncontrolled diabetes or thyroid disease) or haematological abnormalities that are uncontrolled.
* Non-smoker

Exclusion Criteria:

* Participant reported diagnosis of serious ocular conditions (e.g. cataracts, glaucoma, diabetic retinopathy, retinitis pigmentosa, Stagardt's disease)
* Participant reported diagnosis, or current treatment of age-related macular degeneration.
* Participant reported diagnosis of epilepsy.
* Current or past smoker (within last 12 months).
* Under 18 or over 65 years of age.