DHA Declines Distance and Retinal Visual Acuity loss in Adults with Retinitis Pigmentosa

Objective

A study was conducted to assess whether a diet high in long chain omega-3 fatty acids can slow the rate of loss of visual acuity among patients with retinitis pigmentosa receiving vitamin A palmitate.

Number of subjects

357 adult patients who were all receiving vitamin A 15,000 IU/day

Study intervention

Vitamin A 15,000 IU/day for 4-6 years and intake of long chain Omega-3 fatty acids (primarily DHA).

Duration of the study

4-6 years

Results

• Mean rates of decline of acuity were slower among those with high omega-3 intake; Early Treatment Diabetic Retinopathy Study (ETDRS) distance acuity: high=0.59 letter/year, low=1.00 letter/year, p=0.001 (see Fig.1).
• The mean annual rates of change of distance and retinal acuity were slower among those with high omega-3 intake (≥ 0.20 g/day) than among those with low intake (<0.20 g/day).
• The mean rates of change in distance acuity were -0.59 letter per year (high omega-3 intake) versus -1.00 letter per year (low omega-3 intake), p=0.001.

Conclusion

The mean annual rates of decline in distance and retinal visual acuities in adults with retinitis pigmentosa taking vitamin A are slower among those consuming a diet rich in omega-3 fatty acids (primarily DHA).

Source

Berson EL, Rosner B, Sandberg MA, et al. ω-3 intake and visual acuity in patients with retinitis pigmentosa receiving vitamin A. Arch Ophthalmol. 2012; 130(6):707-11

DHA Improves Visual Acuity in Aging Population

Objective

Many studies have demonstrated that DHA is essential for development of nervous system and eyes. There is evidence to suggest that DHA deficiencies increase with normal aging. This study was conducted to assess the efficacy of DHA supplement on visual acuity and cognitive decline in elderly population.

Study design

A triple-blind placebo-controlled randomized repeated-measures trial.

Number of subjects

74 healthy patients aged between 45-77 years.

Study intervention

1000 mg of tuna oil comprising 252 mg DHA, 60mg EPA and 10 mg vitamin E or placebo.

Duration of the study

3 months

Results

• The supplement was found to significantly raise the plasma concentration of the DHA levels at the end of the study.
• In subjects with corrected vision, the DHA supplement significantly improved the right eye visual acuity in comparison to the placebo (F (1,22) =7.651; p=0.011; partial n (2) =0.258).

The effect of 90 day supplementation with DHA on visual sharpness in healthy elderly population was found to be positive

Conclusion

It was found that DHA supplementation of elderly population is associated with improved visual sharpness.

Source

Stough C, Downey L, Silber B, et al. The effects of 90-day supplementation with the omega-3 essential fatty acid docosahexaenoic acid (DHA) on cognitive function and visual acuity in a healthy aging population. Neurobiol Aging.2012;33(4):824.e1-3.

DHA Significantly Decreases the Risk of AMD

Objective

This study was conducted to examine whether intake of omega-3 fatty acid has any affect on the incidence of age-related macular degeneration (AMD) in women.

Study population

38,022 women completed the food-frequency questionnaire and were not having AMD.

Outcome measure

Incident AMD responsible for a reduction in best corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review.

Duration of the study

10 years

Data from large cohort of women with no prior AMD indicate that regular intake of DHA significantly reduced the risk of incident AMD

Results

Conclusion

Regular consumption of DHA and EPA significantly reduced the risk of incident AMD. This data appear to be the strongest evidence to support a role for omega-3 long chain fatty acids in the primary prevention of AMD, and also a reduction in the number of persons who ultimately suffer from advanced AMD.

Source

Beneficial Effects of DHA on Retinal Vascular Disease

Objective

Disturbances in the cellular production of nitric oxide (NO) and superoxide (O2) can have detrimental effects on retinal vascular integrity and angiogenic signaling. This study was done to assess the affect of ω-3 polyunsaturated fatty acids (PUFAs) on angiogenic signaling and NO/superoxide production in retinal microvascular endothelial cells (RMECs).

Study Design

• DHA or EPA was used to treat primary RMECs for a period of 48 hours.
• Scratch-wound assay was used to determine the RMEC migration, proliferation by the incorporation of BrdU, and a three-dimensional model of in vitro angiogenesis was used to determine angiogenic sprouting

Results

• DHA treatment increased nitrite and decreased superoxide production, which correlated with the displacement of eNOS from caveolar subdomains and colocalization with the negative regulator caveolin-1.
• DHA significantly reduced the numbers of proliferating cells in control and VEGF-treated cultures (see Fig. 1).
• The anti-proliferative effect was much more pronounced in the DHA-treated cells. AA, in contrast, had no effect on RMEC proliferation.

Conclusion

DHA improves NO bioavailability, decreases superoxide production, and blunts VEGF-mediated angiogenic signaling. These findings suggest a role for omega-3 PUFAs, particularly DHA, in maintaining vascular integrity while reducing pathologic retinal neovascularization.

Source