Abstract: DHA and dry eye

Docosahexaenoic acid, protectins and dry eye.
Curr Opin Clin Nutr Metab Care. 2010 Dec 13. [Epub ahead of print]
Cortina MS, Bazan HE.
aDepartment of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, Illinois, USA bNeuroscience Center of Excellence, USA cDepartment of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.

PURPOSE OF REVIEW:
To report recent data on the potential role of omega-3 fatty acids, in particular docosahexaenoic acid and its derivatives, in the treatment of dry eye syndrome.

RECENT FINDINGS:
Dietary supplementation with polyunsaturated fatty acids yields positive results in the improvement of dry eye signs and symptoms. Although several studies have shown this, evidence is still lacking as to which fatty acid or what combination constitutes the most effective treatment. Studies show that treatment with alpha-linoleic acid reduces dry eye-induced inflammation. Eicosapentaenoic acid and docosahexaenoic acid derivatives, particularly resolvin E1 (RvE1) and neuroprotectin D1, appear to be responsible for docosahexaenoic acid's anti-inflammatory effect. This is supported in a study in which topical RvE1 resulted in decreased inflammation in a mouse dry eye model. Topical administration of pigment epithelium-derived factor in combination with docosahexaenoic acid accelerates the regeneration of corneal nerves after their damage during corneal surgery, promoting the return of sensitivity and reducing the signs of dry eye. This combined treatment also reduces objective signs of dry eye, such as rose bengal staining.

SUMMARY:
No firm recommendations can be made regarding optimal dietary supplementation of essential fatty acids that benefit dry eye patients. On the basis of animal data and preliminary human studies, docosahexaenoic acid and its derivatives appear to be a safe, effective topical treatment for dry eye patients. This may result from their role in the resolution of inflammation and the regeneration of damaged corneal nerves.