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C.T. O. Nguyen, B.V. Bui, A.J. Vingrys; The Effect of Dietary Omega–3 Fatty Acid Manipulation on Intraocular Pressure and Retinal Function . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3446.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To consider whether Omega–3 (ω–3) fatty acid dietary deficiency, common in western diets, results in generalised ocular dysfunction involving intraocular pressure as well as inner and outer retinal processing. Methods: Sprague–Dawley dams were mated and then fed either ω–3 sufficient (SUF) or deficient (DEF) diets. After weaning, pups were maintained on their mothers diet (SUF, n = 51; DEF, n = 41). All procedures were conducted under anaesthesia (Ketamine : Xylazine, 60 : 5 mg/kg). Intraocular pressure (IOP) was measured (Tonopen XL) at 5, 10 and 20 weeks of age. On a subgroup of animals, full field dark–adapted electroretinogram (ERG) responses were recorded at 10 and 20 weeks (SUF, n = 16; DEF, n = 13). Dim flashes were used (–7.2 to –5.1 log cd s m–2) to elicit the scotopic threshold response (STR) and brighter flashes (–4.6 to 2.2 log cd s m–2) to assay the a–wave, b–wave and oscillatory potentials (OPs). Photoreceptoral responses were modelled using a delayed Gaussian. ERGs were band pass filtered (25 and 280 Hz) to expose OPs for root–mean–square amplitude measurement. A and b–waves were measured following digital subtraction of OPs from raw ERGs. Results: At 10 weeks of age no significant change in IOP or ERG was observed between the two diet groups. After 20 weeks IOP was reduced (relative to 5 weeks of age) by 6 ± 3% in the ω–3 sufficient diet group, but increased by 11 ± 2% (p<0.001) in the ω–3 deficient group. Additionally, by 20 weeks ω–3 deficient animals showed significant reduction in phototransduction sensitivity (SUF 3.43 ± 0.06 vs. DEF 3.13 ± 0.04 log m2 cd–1 s–3). The nSTR was significantly (p<0.01) reduced by ω–3 deficiency however the pSTR was not (p=0.57). Paradoxically, ω–3 deficient animals had significantly larger OP amplitudes (SUF 59 ± 7 vs. DEF 133 ± 11 µV). A consistent delay in all ERG parameters was observed in ω–3 deficient animals, including the pSTR (∼29 ms, p<0.001), nSTR (∼ 60 ms, p<0.001), b–wave (∼ 25 ms, p<0.001) and OPs (∼ 5 ms, p<0.001). Conclusions: Our findings indicate that ω–3 deficiency induces generalised physiological dysfunction that involves inner and outer retinal processing as well as intraocular pressure. One possible candidate for such generalised dysfunction might be a common abnormality on membrane bound protein activity induced by altered membrane biophysics consequent to ω–3 deficiency.
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