Standardized Bilberry Extract Improves Ocular Fatigue Associated with Visual Display Terminal Tasks

by | May 28, 2020 | 2020, Bilberry, Botanicals, Eye Health

Written by Angeline A. De Leon, Staff Writer. A 12-week supplementation with 240 mg of a standardized bilberry extract (SBE) improved symptoms of eye fatigue in the participants who regularly used visual display terminal (VDT) devices. 

eye health - screen timeEye fatigue has become common place in the modern era of digital screens and electronic devices 1. One survey reported that in 2008, about half of all employees were engaged in tasks associated with visual display terminal (VDT) devices for four or more hours daily 2. Another study in 2016 estimated that over 90% of smartphone users were aged 40 years and younger, suggesting a probable increased trend of ocular fatigue among younger people 3. With prolonged periods of close exposure to digital screens, the ciliary muscles of the eye (responsible for changing the shape of the eye lens to allow for focusing) become strained under excessive load, becoming unstable and causing accommodative microfluctuations (measured as high-frequency component, HFC) 4. Bilberry (Vaccinium myrtillus L.) is a type of dark blue berry recognized for its natural abundance in anthocyanins, antioxidant compounds which are also present in ocular tissues 5,6. Previous work has demonstrated that supplementation with standardized bilberry extract (SBE) can help relieve miosis (excessive contraction of the pupil), improve tonic accommodation of ciliary muscles, and support recovery from VDT-load ocular fatigue 7-9. To determine the long-term impact of SBE consumption on ocular health, researchers in Tokyo (2020) tested the effects of SBE intake on tonic accommodation of ciliary muscles caused by VDT tasks over the course of 12 weeks 10.

Using a randomized, double-blind, placebo-controlled, parallel-group study design, researchers recruited a total of 109 healthy subjects (aged 20-60 years) who reported working with VDT tasks as part of their job and who reported symptoms of ocular fatigue. Subjects were randomized to ingest either 240 mg of SBE (concentration of V. myrtillus anthocyanins = 35.82%) or a control capsule once daily for 12 weeks while adhering to their normal diet. Ocular tests (measurement of HFC of accommodative microfluctations) were performed before and after VDT loading (subjects instructed to play Tetris on an iPhone at close position) at baseline, Week 4, Week 8, and Week 12.

When the difference between before-load and post-load HFC-1 values was calculated (ΔHFC-1), the SBE group was found to have significantly lower values than the placebo group at Week 4 (p = 0.018) and at Week 12 (p = 0.049) (when variation at baseline was covariant). Analyses also indicated that post-load HFC-1 values were significantly better for the SBE group, compared to placebo, at Week 8 (mean value = 50.64 +/- 4.70 vs. 51.13 +/- 5.19, respectively, p = 0.014) and at Week 12 (mean value = 50.65 +/- 4.03 vs. 50.67 +/- 5.13, respectively, p = 0.017). Based on collected blood samples and urine tests, no adverse events were determined to be related to consumption of SBE.

Evidence from the study suggests that in subjects with ocular fatigue, oral supplementation with SBE can effectively mitigate tonic accommodation of ciliary muscles (based on post-load HFC-1 values) in response to VDT load. Significant effects were observable by Week 8 and Week 12, and treatment appeared to be safe and well-tolerated by subjects. Although the exact mechanism associated with SBE’s therapeutic effects require further study, researchers speculate that the clinical outcomes observed here are attributable to the anthocyanin content of SBE. Findings confirm the efficacy of long-term SBE consumption for ocular health. Potential limitations of the study are the failure to account for other dietary sources of anthocyanins through food record-keeping and the lack of data on habitual use of electronic devices outside of work.

Source: Kosehira M, Machida N, Kitaichi N. A 12-week-long intake of bilberry extract (Vaccinium myrtillus L.) improved objective findings of ciliary muscle contraction of the eye: a randomized, double-blind, placebo-controlled, parallel-group comparison trial. Nutrients. 2020; 12: 600. DOI: 10.3390/nu12030600.

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Posted May 28, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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