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Elena Vecino, Alejandro Bayón, Carlos Micó, Carmen Palao; Retrobulbar Optic Nerve Section In Pig: Optical Coherence Tomography (oct) And Multifocal Electroretinography (mferg) Study. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4683.
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It has previously been report histopathological and electrorretinography changes in the pig, rat, mouse eye without retinal vein occlusion after optic neurotomy. However it is required in vivo assessment of progressive changes that occur at the level of the retina and optic disc using noninvasive techniques such as OCT and its relation to the findings gathered by mfERG.
An axotomy was performed in the normal right eyes of three Landrace pigs. Surgery was carried out in the incision of the conjunctiva and lateral rectus muscle resection, then of adipose tissue was disected until the optic nerve was exponed and finally cross-section proximal to the eyeball. Examination by OCT and multifocal electroretinography was performed before surgery and at 15, 30, 45 days after axotomy.
Based on the study conducted by OCT changes were observed in all retinal layers, most notably a decreased thickness at the nerve fibers followed by the ganglion cells and photoreceptors consequently causing a decrease in total thickness. In addition to these findings also revealed a decrease in retinal thickness at the periphery of the optic disc. All these changes might even observe a more significant from day 45. As the ratio cup / disk were not altered in relation to day 0.By multifocal electroretinography progressive decreases were observed at voltages (a and b waves) from day 0 to day 45 being most significant in peripheral areas than in closed areas to the optic disc. On day 15 the responses were very similar to those of day 0. However at day 30 showed a consistent reduction in amplitude while 45 days was nearly absent.
After the axotomy, with mfERG and OCT techniques can assess the involvement of different layers of the retina. Comparing both techniques, we can deduce that by mfERG get earliest changes (for example at the photoreceptor layer) than with OCT. This may be due to cell death produced in the layer of nerve cells, ganglion and photoreceptor means no significant differences in thickness to more than 45 days, as we have been able to demonstrate through this study.
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