High doses of omega-3 fatty acids could help treat glaucoma

October 2014
Dr Tassos Georgiou MBChB, MRCOphth, Ms Despina Nicolaou, Mr Panagiotis Kolovos, and Ms Anastasia Neokleous

 

High doses of omega-3 fatty acids, rich in eicosapentaenoic acid (EPA), could help battle neuro-inflammation in glaucoma patients and, therefore, improve visual acuity (VA) and visual field (VF) within 3 months, according to the results of a new study.

Glaucoma is a chronic, neurodegenerative disease characterized by progressive death of retinal ganglion cells (RGC) and loss of RGC axons in the optic nerve. It has a long slow course with an unpredictable rate of progression. It is the second most common cause of blindness globally. In 2010, there were 61 million people worldwide with glaucoma, 25 million of who live in Europe, and these numbers are expected to increase 30% by the year 2020. During the last 20 years, controlled clinical trials have shown that lowering intraocular pressure (IOP) is an effective way to slow progression of glaucoma damage. All available treatments focus on lowering IOP to slow the progression of the disease. The mean loss of VF tests in untreated adults with primary open angle glaucoma, which is the most common type of glaucoma, is 0.5–1.0 dB/ year and the IOP lowering therapy slows the untreated rate of progression by 50–60%.2 There is no therapy that reverses glaucomatous VF loss or
improves VA.

 

Inflammation and glaucoma

Chronic low-grade inflammation has been shown to play a major role in the pathogenesis of glaucoma. Inflammatory molecules such as VEGF, TNF-α, interleukins (IL-1α, IL-2β), have been shown
to be upregulated in glaucoma. Nguyen et al. 4 studied the effect of omega-3 and repeated acute IOP insults on RGC function in dams. Their results indicated that sufficient dietary omega-3 improves RGC function making it less susceptible to IOP stress.

Nakazawa et al. 5 demonstrated, in induced high IOP in mice, the upregulation of TNF-α, followed by oligodendrocytes death and delayed RGC loss. They suggested blocking TNF-α signalling or inflammation maybe helpful in the treatment of glaucoma.

One study showed the RGCs from glaucomatous rat eyes can have a regenerative potential.6 This suggests that a repair mechanism exists in glaucomatous eyes.

The resolution of inflammation is an active process primarily driven by a new family of mediators termed proresolving lipid mediators (resolvins, protectins and maresins) derived from the omega-3 fatty acids, EPA and docosahexaenoic acid (DHA).7 They stop leukocyte infiltration with accompanied active clearance of macrophages, promoting resolution of inflammation and stimulating tissue regeneration.

A pilot study has recently shown improvement of VA in patients with dry macular degeneration with high doses of omega-3 fatty acids rich in EPA.8

We have used high doses of omega-3 fatty acids on patients who are already receiving IOP-lowering treatment, and who have advanced glaucomatous damage with reduced VA, to study whether there are any neuro-rescue effects, in terms of VA and VF.