Lacrimal Hypofunction as a New Mechanism of Dry Eye in Visual Display Terminal Users

BACKGROUND: Dry eye has shown a marked increase due to visual display terminal (VDT) use. It remains unclear whether reduced blinking while focusing can have a direct deleterious impact on the lacrimal gland function. To address this issue that potentially affects the life quality, we conducted a large-scale epidemiological study of VDT users and an animal study. METHODOLOGY/PRINCIPAL FINDINGS: Cross sectional survey carried out in Japan. A total of 1025 office workers who use VDT were enrolled. The association between VDT work duration and changes in tear film status, precorneal tear stability, lipid layer status and tear secretion were analyzed. For the animal model study, the rat VDT user model, placing rats onto a balance swing in combination with exposure to an evaporative environment was used to analyze lacrimal gland function. There was no positive relationship between VDT working duration and change in tear film stability and lipid layer status. The odds ratio for decrease in Schirmer score, index of tear secretion, were significantly increased with VDT working year (P = 0.012) and time (P = 0.005). The rat VDT user model, showed chronic reduction of tear secretion and was accompanied by an impairment of the lacrimal gland function and morphology. This dysfunction was recovered when rats were moved to resting conditions without the swing. CONCLUSIONS/SIGNIFICANCE: These data suggest that lacrimal gland hypofunction is associated with VDT use and may be a critical mechanism for VDT-associated dry eye. We believe this to be the first mechanistic link to the pathogenesis of dry eye in office workers

Clinical Evaluation of a Royal Jelly Supplementation for the Restoration of Dry Eye: A Prospective Randomized Double Blind Placebo Controlled Study and an Experimental Mouse Model

<div><p>Background</p><p>Dry eye is a multifactorial disease characterized by ocular discomfort and visual impairment. Lacrimal gland function has been shown to decrease with aging, a known potent risk factor for dry eye. We have previously found that orally administrated royal jelly (RJ) restored tear secretion in a rat model of dry eye.</p><p>Methods and Findings</p><p>We examined the effects of RJ oral administration on dry eye in this prospective, randomized, double-blind, placebo-controlled study. Forty-three Japanese patients aged 20–60 years with subjective dry eye symptoms were randomized to an RJ group (1200 mg/tablet, six tablets daily) or a placebo group for 8 weeks. Keratoconjunctival epithelial damage, tear film break-up time, tear secretion volume, meibum grade, biochemical data, and subjective dry eye symptoms based on a questionnaire were investigated at baseline, and at 4 and 8 weeks after intervention. Adverse events were reported via medical interviews. In the RJ group, tear volume significantly increased after intervention (<i>p</i> = 0.0009). In particular, patients with a baseline Schirmer value of ≤10 mm showed a significant increase compared with baseline volume (<i>p</i> = 0.0005) and volume in the placebo group (<i>p</i> = 0.0051). No adverse events were reported. We also investigated the effect of RJ (300 mg/kg per day) administration using a mouse model of dry eye. Orally repeated administration of RJ preserved tear secretion, potentially through direct activation of the secretory function of the lacrimal glands.</p><p>Conclusion</p><p>Our results suggest that RJ improves tear volume in patients with dry eye.</p><p>Trial Registration</p><p>Registered NO. the University Hospital Medical Information Network in Japan (UMIN000014446)</p></div

Effects of royal jelly (RJ) on dry eye symptoms assessed by ophthalmological examinations.

<p>Effects of royal jelly (RJ) on dry eye symptoms assessed by ophthalmological examinations.</p

Baseline characteristics of patients with dry eye who received placebo (PB) or royal jelly (RJ).

<p>Baseline characteristics of patients with dry eye who received placebo (PB) or royal jelly (RJ).</p

CONSORT flowchart.

<p>CONSORT flowchart.</p

Change in Schirmer (baseline, ≤10 mm) values in patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablet.

<p>Data represent mean ± standard deviation **<i>p</i><0.01, ***<i>p</i><0.005 vs. pre-treatment values Between-group score comparisons at each time point (baseline, week 4, and week 8) were performed using the Aspin-Welch test (†<i>p</i><0.05).</p

Change in Schirmer values in patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.

<p>Error bars represent standard deviation. **<i>p</i><0.01 vs. pre-treatment values.</p

Biochemical analyses for patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.

<p>Biochemical analyses for patients with dry eye symptoms who received royal jelly (RJ) or placebo (PB) tablets.</p