Can Nutrition Play a Role in Ameliorating Digital Eye Strain?

Digital eye strain is a complex, multifactorial condition that can be caused by excessive screen time exposure to various electronic devices such as smartphones, tablets, e-readers, and computers. Current literature suggests oxidative damage concomitant with a chronic pro-inflammatory state represent significant etiopathogenic mechanisms. The present review aims to discuss the potential dietary role for micronutrients with nutraceutical properties to ameliorate various ocular and vision-related symptoms associated with digital eye strain. For ocular surface dysfunction, enhanced anti-inflammatory benefits with omega-3 polyunsaturated fatty acids have been well documented for treatment of dry eye disease. The anti-oxidative and immunosuppressive properties of anthocyanin phytochemicals may also confer protective effects against visually induced cognitive stress and digital asthenopia. Meanwhile, nutraceutical strategies involving xanthophyll macular carotenoids demonstrate enhanced cognitive functioning and overall visual performance that aids digital eye strain. Collectively, preliminary findings seem to offer a strong line of evidence to substantiate the need for additional randomized controlled trials aimed at treating digital eye strain with adjunctive nutraceutical strategies. Further RCT and comparisons on commercially available nutritional supplements are needed to quantify the clinical benefits.

A Pilot, Phase II, Observational, Case-Control, 1-Month Study on Asthenopia in Video Terminal Operators without Dry Eye: Contrast Sensitivity and Quality of Life before and after the Oral Consumption of a Fixed Combination of Zinc, L-Carnitine, Extract of Elderberry, Currant and Extract of Eleutherococcus.

The aims of the study were to investigate the ability and effectiveness of an oral intake of a fixed combination of zinc, L-carnitine, elderberry extract, black currant and Eleutherococcus extract in controlling the symptoms of eyestrain in videoterminal (VDT) users and to record its effects on contrast sensitivity. A single-center, phase II, observational, case-control, 1-month study in VDT workers without dry eye disease was carried out. Demographics and number of actual hours at VDT/day were taken into account. All subjects underwent a complete ophthalmic examination, including assessment of contrast sensitivity, and completed the computer vision symptom scale questionnaire at baseline and one month later. A total of 30 Caucasian subjects adhered to the required inclusion criteria and completed the study; 15 subjects were treated (T) and 15 were controls (C). All clinical data at baseline were similar in both groups (p > 0.05): after one month, all subjects had stable visual acuity, refractive defect and intraocular pressure (IOP); screen exposure time was unchanged. Regarding symptoms, at randomization, the groups had a similar score: 33.1 ± 3.3 in T and 32.8 ± 5.6 in C. One month later, the computer vision symptom scale (CVSS) questionnaire score decreased by -14.1 ± 3, 1 (p = 0.000) and -2.3 ± 1.8 (p = 0.568), respectively. Regarding contrast sensitivity, in group C the values of spatial frequencies remained unchanged, while they improved in almost all the cycles per degree stimuli in the treated group. Oral intake of a fixed combination of zinc, L-carnitine, elderberry extract, black currant and eleutherococcus extract can significantly improve contrast sensitivity and symptoms in VDT workers with no signs of dry eye disease.

A novel botanical formula improves eye fatigue and dry eye: a randomized, double-blind, placebo-controlled study.

BACKGROUND: With the frequent use of video display units, eye fatigue is becoming more common globally. An alternative nutritional strategy is needed to prevent the aggravation of eye fatigue symptoms. OBJECTIVES: The objective was to evaluate the protective effect of a novel botanical combination of lutein ester, zeaxanthin, and extracts of blackcurrant, chrysanthemum, and goji berry on adults with eye fatigue in a randomized, double-blind, placebo-controlled clinical trial. METHODS: We randomly allocated 360 participants into 4 groups to receive placebo and 3 doses of our formula (chewable tablets, containing 6 mg, 10 mg, or 14 mg of lutein) once daily for 90 d. Each participant had 3 visits at baseline (V1), 45 d (V2), and 90 d (V3) during the study. RESULTS: Intervention with the formula improved individual scores of eye fatigue symptoms, including eye soreness, blurred vision, dry eye, foreign body sensation, and tearing. Compared with placebo, the formula at all 3 doses significantly decreased the total score of eye fatigue symptoms and increased the visuognosis persistence time at both V2 and V3. According to the Schirmer test, both 10-mg and 14-mg lutein formula groups had improved tear secretion at V3 compared with the placebo. The keratography results indicated that the first tear break-up time, average tear break-up time, and tear meniscus height were significantly increased after formula intervention. The formula at all 3 doses significantly increased the macular pigment optical density at V2 and V3 compared with the placebo, whereas optical coherence tomography showed no significant difference in retinal thickness and retinal volume across all groups at both visits. CONCLUSIONS: Our botanical formula improves eye fatigue, dry eye, and macular function without changing the retinal structure, and thus it could serve as an effective nutritional strategy in improving eye fatigue without causing serious side effects.Clinical Trial Registry: chictr.org.cn (ChiCTR1800018987).

A Randomized, Placebo-Controlled Study on the Safety and Efficacy of Daily Ingestion of Green Tea (Camellia sinensis L.) cv. "Yabukita" and "Sunrouge" on Eyestrain and Blood Pressure in Healthy Adults.

The green tea (Camellia sinensis L.) cultivar “Sunrouge” contains anthocyanins, catechins and flavonols. To determine whether ingesting green tea containing anthocyanins improves visual function and blood pressure (BP) in healthy adults, a randomized, double-blind, placebo-controlled study was performed. A total of 120 healthy subjects, aged between 20 and 60 years and with a systolic BP (SBP) value of ≤125 and <155 and a diastolic BP (DBP) value <95, or a DBP of ≤75 mmHg and <95 mmHg and a SBP <155 mmHg, were randomly assigned to one of three groups. For 12 weeks, the placebo group received barley extract without catechin; another group received “Sunrouge” extract containing 11.2 mg anthocyanin and 323.6 mg epigallocatechin-3-O-gallate (EGCG); and a third group received “Yabukita” extract containing 322.2 mg EGCG. Home BP, accommodation ability, visual analog scale questionnaires for eyestrain, and metabolic-associated markers were analyzed at weeks 0, 4, 8, and 12 of the intake period. The ingestion of “Sunrouge” tea significantly improved accommodation ability and eyestrain in subjects younger than 45 years and in subjects who operated visual display terminals every day. It also elevated BP. “Yabukita” tea ingestion significantly increased serum adiponectin levels. No adverse effects were observed. We conclude that long-term intake of “Sunrouge” tea containing anthocyanins and flavonols might improve visual function.

The effect of Vaccinium uliginosum extract on tablet computer-induced asthenopia: randomized placebo-controlled study.

BACKGROUND: To investigate the alleviation effect of Vaccinium uliginosum extract (DA9301) on tablet computer-induced asthenopia. METHODS: This was a randomized, placebo-controlled, double-blind and parallel study (Trial registration number: 2013-95). A total 60 volunteers were randomized into DA9301 (n = 30) and control (n = 30) groups. The DA9301 group received DA9301 oral pill (1000 mg/day) for 4 weeks and the control group received placebo. Asthenopia was evaluated by administering a questionnaire containing 10 questions (responses were scored on a scales of 0-6; total score: 60) regarding ocular symptoms before (baseline) and 4 weeks after receiving pills (DA9301 or placebo). The participants completed the questionnaire before and after tablet computer (iPad Air, Apple Inc.) watching at each visit. The change in total asthenopia score (TAS) was calculated and compared between the groups RESULTS: TAS increased significantly after tablet computer watching at baseline in DA9301 group. (from 20.35 to 23.88; p = 0.031) However, after receiving DA9301 for 4 weeks, TAS remained stable after tablet computer watching. In the control group, TAS changes induced by tablet computer watching were not significant both at baseline and at 4 weeks after receiving placebo. Further analysis revealed the scores for "tired eyes" (p = 0.001), "sore/aching eyes" (p = 0.038), "irritated eyes" (p = 0.010), "watery eyes" (p = 0.005), "dry eyes" (p = 0.003), "eye strain" (p = 0.006), "blurred vision" (p = 0.034), and "visual discomfort" (p = 0.018) significantly improved in the DA9301 group. CONCLUSIONS: We found that oral intake of DA9301 (1000 mg/day for 4 weeks) was effective in alleviating asthenopia symptoms induced by tablet computer watching. TRIAL REGISTRATION: The study is registered at www.clinicaltrials.gov (registration number: NCT02641470, date of registration December 30, 2015).

An experimental study of the protective effects of Chinese medicine compound eye-patch on asthenopia.

OBJECTIVE: To observe the therapeutic efficacy and the mechanism of Chinese medicine eye-patch with invigorating blood circulation and detoxification on asthenopia. METHODS: A total of 180 rabbits were subjected to three tests, namely the skin microcirculation, the microvascular regeneration in the skin and the skin temperature change, with 60 rabbits for each test. The rabbits in each test were randomly and equally divided into three groups: the normal control group was treated with physiological saline on naked back once per day, the low dose group was treated with the eye-patch on naked back for 15 min once per day, while the high dose group was treated for three times per day. Forty Hartley guinea pigs were randomly and equally divided into four groups for the muscle tone test: the normal control group was treated with physiological saline on naked back, the model group was treated without any medication, the low dose group was treated with the eye-patch on naked back for 10 min once per day, while the high dose group was treated for three times per day. All treatments were continued for 14 days until the termination of the test. The microcirculatory blood flow was observed by using a video-microscopy system. The histological sections were used to detect the microvascular regeneration by observing the expression of factor VIII. The temperature changes on the skin surface were measured by using infrared thermometer, and the muscle tone was tested by the electromyography. RESULTS: In compare with the normal or the model group, the improvement in the skin microcirculation and the blood vascular regeneration, and the decreasing in the muscle tone in low dose and high dose groups were statistically significant with confident level at P<0.05. CONCLUSIONS: The eye-patch with invigorating blood circulation and detoxification has great enhancement in blood vascular regeneration and skin microcirculation, and great improvement in the indexes for muscle tone. The study explains certain therapeutic efficacy and mechanism of the eye-patch and shows that it could reduce the symptoms for patients with asthenopia.

Effects of dietary supplementation with a combination of fish oil, bilberry extract, and lutein on subjective symptoms of asthenopia in humans.

The aim of this study was to determine the effects of dietary supplementation with a combination of fish oil, bilberry extract, and lutein on subjective symptoms of asthenopia in humans by a double- blind, randomized, parallel-group, and placebo-controlled trial. In the Active group, eleven subjects ingested a supplement containing omega-3 fatty acid-rich fish oil (docosahexaenoic acid 783 mg/day, eicosapentaenoic acid 162 mg/day), bilberry extract (anthocyanidin 59 mg/day), and lutein (17.5 mg/day) in soft gel capsule form, every day for 4 weeks. In the Placebo group, nine subjects ingested placebo capsules. Before and after supplementation, subjects completed a questionnaire to determine their asthenopia symptoms and were also assessed for mental fatigue symptom by the visual analog scale (VAS) test. Asthenopia symptoms such as "stiff shoulder, low back pain", "frustration", "dry-eye", and "stuffy head" were improved in the Active group. Furthermore, a score of mental fatigue was improved after 4 weeks of supplementation, and no side effects were observed after the 4-week supplementation and a 2-week washout period in the Active group. These results suggest that dietary supplementation with the combination of omega-3 fatty acid-rich fish oil, bilberry extract, and lutein may safely improve subjective symptoms of asthenopia and mental fatigue in humans.

[The clinical efficacy and safety study of Esculin and Digitalis glycosides Eye Drops in treating ametropic asthenopia].

OBJECTIVE: To study the clinical efficacy and safety of the Esculin and Digitalis glycosides Eye Drops used in the patients of ametropic asthenopia. METHODS: Multicenter clinical trial. Asthenopia patients were chosen from eleven hospitals cross China from July, 2008 to January, 2009. The experiment was conducted asthenopia patients who used the Esculin and Digitalis glycosides Eye Drops for 4 weeks continuously. Symptoms of asthenopia, UCVA (uncorrected vision acuity), refraction, amplitude of accommodation, accommodative lag, accommodative sensitivity and positive/negative relative accommodation were measured at different time points, such as treated before, 1 week and 4 week in treated after. RESULTS: After the 4-week's use of Esculin and Digitalis glycosides Eye Drops, each subjective symptom of the patients was decreased significantly (F=353.30, P<0.05). In addition, most of the objective exams of accommodation ability were significantly improved, such as UCVA (left eye: F=23.39, P<0.05; right eye: F=15.62, P<0.05), refraction (left eye: F=10.34, P<0.05; right eye: F=17.13, P<0.05), amplitude of accommodation (left eye: F=14.46, P<0.05; right eye: F=8.29, P<0.05; eyes: F=13.86, P<0.05), accommodative lag (F=14.89, P<0.05) and accommodative sensitivity (left eye: F=62.67, P<0.05; right eye: F=68.77, P<0.05; eyes: F=82.74, P<0.05). And no patient appeared any adverse reaction in whole experiment. CONCLUSIONS: Esculin and Digitalis glycosides Eye Drops is effective and safety for use in the patients of ametropia asthenopia.

A novel in vitro model for screening and evaluation of anti-asthenopia drugs.

Patients suffering asthenopia are steadily increasing with an expanding use of visual display terminals such as computers. An attempt was made to develop an in vitro model for asthenopia. Ciliary muscle removed from eyeballs of a rabbit was stimulated with acethylcholine, resulting in contraction of the muscle. Repeated stimulations caused decreased contraction, which may be related to fatiguing of ciliary muscle and hence asthenopia. Treatment of the repeatedly stimulated muscle with cyanocobalamin restored contraction dose-dependently. Thus, the model developed in this study can be used to screen drug candidates for treating asthenopia.

Effects of black current anthocyanoside intake on dark adaptation and VDT work-induced transient refractive alteration in healthy humans.

The effects of oral intake of a black currant anthocyanosides (BCA) concentrate on dark adaptation, video display terminal (VDT) work-induced transient refractive alteration, and subjective asthenopia symptoms (visual fatigue) were examined in a double-blind, placebo-controlled, crossover study with healthy human subjects. In a dark adaptation study, intake of BCA at three dose levels (12.5-, 20-, and 50 mg/subject, n = 12) appeared to bring about dose-dependent lowering of the dark adaptation threshold. Statistical analysis comparing the values before and after intake indicated there was a significant difference at the 50 mg dose (p= 0. 011). Comparing the refraction values for the dominant eye, BCA intake (50 mg/subject, n = 21) resulted in no decrease in the average value after the visual task; whereas, a placebo trial resulted in a large decrease in the average value, resulting in borderline significance (p = 0.064). In the assessment of subjective asthenopia symptoms by questionnaire, significant improvement was recognized on the basis of the statements regarding the eye and lower back after BCA intake.