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Supplement Shown to Benefit Dry Eye Patients

Dry eye is a Public Health Problem

Dry eye is one of the most prevalent eye diseases and reasons for seeking eye care. Dry eye prevalence is expected to rise as the population ages, along with increased costs in care. The current economic burden of dry eye is estimated to be $3.84 billion in direct annual health care costs (1).

While a wide variety of treatments are available, many have disadvantages: some provide only transient relief, or have cost or compliance issues. Others have been associated with GI, ocular or systemic side effects. Thus, clinicians continue to seek additional treatment options.

Dietary Supplement Reported to Benefit Dry Eye

One promising option is dietary supplementation with polyunsaturated fatty acids (PUFAs). Ocular surface inflammation contributes to the irritation symptoms and ocular surface disease that can develop in dry eye, while PUFAs such as GLA, EPA and DHA are known to help counteract inflammation.

Investigators from Baylor College of Medicine and Virginia Eye Consultants recently evaluated a dietary supplement (HydroEye®, ScienceBased Health) – containing black currant seed and fish oils (sources of GLA / ALA and EPA / DHA, respectively), antioxidants and nutrient co-factors – for its effects on moderate-to-severe dry eye in older women (2).

The researchers report that women taking the supplement had significant improvement in dry eye symptoms over time, and vs. placebo. A smoother corneal surface and lower levels of inflammation were also noted in the supplemented group.

Study Design

The purpose of this randomized, double-blind trial was to evaluate the effect of a PUFA formulation on:

• The severity of irritation symptoms,
• Ocular surface disease, measured by corneal and conjunctival dye staining,
• Topographic corneal smoothness indexes, SAI and SRI.
• Inflammation, measured by average mean signal intensity of CD11c-positive and HLA class II-positive dendritic cells in conjunctival impression cytology.

Thirty-eight eligible post-menopausal women were randomly assigned to receive two softgels twice daily of a PUFA supplement (HydroEye®, ScienceBased Health) or an identical placebo for 24 weeks.

Ocular Surface Disease Index (OSDI), Schirmer test, tear breakup time, conjunctival fluorescein and lissamine green staining, topographic corneal smoothness indexes, and other parameters were assessed at baseline and at 4, 12, and 24 weeks.

Results

Mean OSDI scores in the supplement group were significantly improved by 12 weeks and at 24 weeks (P = 0.004), and were significantly lower than placebo (21 ± 4 vs. 34 ± 5) after 24 weeks (P = 0.05). [See Fig. 2].

FIGURE 2. OSDI scores (mean ± SEM) decreased consistently over the 24-week treatment period after supplement treatment. †Significant improvement when compared to baseline, P = 0.004. *Significant improvement compared to placebo, P = 0.05.

SAI is a marker of corneal smoothness that has been found to increase in dry eye (3) and to correlate with quality of vision. SAI was significantly lower in supplement-treated subjects (0.37 ± 0.03) than placebo (0.51 ± 0.03) at 24 weeks (P = 0.005).

HLA-DR is a dendritic cell activation marker that increases when exposed to inflammatory cytokines, and increased HLA-DR expression in the conjunctiva has been observed in dry eye. CD11c is a molecule on certain dendritic cells that regulates their migration.

HLA-DR intensity significantly increased from baseline to 24 weeks in the placebo group (P=0.03). CD11c intensity was also significantly increased at 12 and 24 weeks in placebo (P= 0.004). Compared to the supplemented group, the placebo group had significantly increased intensity for both biomarkers – by 36% ± 9% for HLA-DR, and by 34% ± 7% for CD11c – at the study’s conclusion (P= 0.001). [See Fig. 3 and 4].

FIGURE 3. Fluorescence intensity (mean ± SEM) of CD11c positive dendritic cells in conjunctival impression cytology. †Significant increase in CD11c positive cell staining compared to baseline, P = 0.004. *Significantly greater staining intensity compared to supplement, P = 0.001.

FIGURE 4. Fluorescent intensity (mean ± SEM) of HLA-DR positive dendritic cells in conjunctival impression cytology. †Significant increase in HLA-DR positive cell staining compared to baseline, P = 0.03. *Significantly greater staining intensity compared to supplement, P = 0.001.

Neither treatment had any effect on tear production, tear breakup time, or corneal or conjunctival staining.

Comments

The PUFA, antioxidant and nutrient combination clearly had a positive impact in this patient population.

The OSDI score began to improve early on, reaching significance within 3 months. No progression of ocular surface inflammation was seen with supplementation, while inflammation worsened in placebo-takers. Participants taking the supplement also maintained corneal smoothness while surface irregularity progressed in placebo takers.

No difference in corneal fluorescein staining between the treatment groups was observed in this trial. The authors suggest that this may be due to visit-to-visit variability in dye staining in certain patients, and that the HLA-DR biomarker may be a more relevant measure than ocular surface dye staining with regard to irritation symptoms.

The effects of individual nutrients in the test supplement were not separately evaluated. The supplement, for example, contains a much higher level of vitamin C than is typically consumed from the diet. Although the beneficial effects of vitamin C have been reported in cases of dry eye and moderate Sjögren’s syndrome, the trial only examined the effects of the supplement as a whole.

This trial studied post-menopausal women, the largest group of dry eye sufferers. However, the salutary effects of the PUFA formulation may well apply to other populations suffering from dry eye since inflammation is believed to be a common thread in this condition.

References

1. Cardarelli WJ, Smith RA. Managed care implications of age-related ocular conditions. Am J Manag Care 19:s85-91, 2013.
2. Sheppard JD, Pflugfelder SC, et al. Long-term supplementation with n-6 and n-3 PUFAs improves moderate-to-severe Keratoconjunctivitis Sicca: A randomized double-blind clinical trial. Cornea 0:1–8, ePub ahead of print July, 2013.
3. Sade de Paiva, C et al. Assessing the severity of keratitis sicca with videokeratoscopic indices. Ophthalmology 110:1102–09, 2003.