Purpose
Human milk has been used as a natural therapy for many ailments throughout history but very few studies have been conducted to show efficacy. We designed a study to test if human milk is therapeutic for dry eye in a mouse model.
Methods
Benzalkonium chloride (BAK), an agent known to induce dry eye, was applied at a concentration of 0.2% to the mouse ocular surface for 4 days. We measured tear volume, fluorescein staining, and corneal epithelial thickness to verify that the animals had dry eye. In addition to continuing BAK treatment, some animals were additionally treated with whole human milk, fat-reduced human milk, cyclosporine, or physiological saline applied as drops twice daily for 7 days. At the end of the 11-day study, we measured corneal thicknesses in all treatment groups as a metric to compare their efficacy against dry eye.
Results
The mean corneal thickness at day 11 in the BAK-induced dry eye was 29.33μm±0.38. Mean corneal thickness after 7 days of treatment for saline vehicle control was 36.05μm±0.06, human milk was 34.64μm±0.14, fat reduced milk was 35.04μm±0.48, and cyclosporine 37.44μm±1.19, where ± SEM and N=9.
Conclusions
Treatment with cyclosporine, human milk, and fat-reduced milk for 7 days restored corneal thickness that had been reduced by BAK in our mouse model. Further studies are required to determine if human milk may be safely used to treat dry eye in patients.