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D.P. Joseph; Collateral Circulation of the Choroid: Conditions for RPE-Choroid Translocation . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3159.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To define the limits of collateral blood flow from adjacent choriocapillaris (CC) required to maintain the integrity of the photoreceptors (Ph), retinal pigment epithelium (RPE) and CC blood flow in a given section of retina. Methods: Full-thickness retinal-choroidal (RC) incisions were made in adult rabbits using an erbium:YAG laser scalpel. The RC incisions were oriented to create one-, two-, three- and four-sided flaps of RC tissue. Fundus exam, fluorescein angiography, and histology were performed at various postoperative intervals to assess blood flow and RC morphology in surgically created RC flaps. Viability of RC flaps was defined by preservation of blood flow and Ph in the body of the RC flap. Results: Good collateral blood flow and Ph survival were demonstrated in all flap designs except the four-sided flaps. Two types of four-sided flaps were examined, those with posterior ciliary arteries (PCA) and those without. The four-sided flaps with PCA appeared to be perfused immediately postoperatively but lost perfusion when examined postoperatively as early as one week. Histological examination of these four-sided flaps showed total degeneration of Ph-RPE-CC as early as two weeks after surgery. In contrast, three-sided RC flaps demonstrated excellent perfusion and preservation of Ph-RPE-CC morphology six months postoperatively. Further examination of RC flaps with residual connections to the body of the choroid demonstrated the need for some minimal connection to adjacent choroid to maintain viability. Conclusion: The choroid exhibits tremendous capacity for collateral blood flow capable of maintaining Ph viability, but when a section of choroid is isolated from venous drainage CC circulation was not re-established and the Ph-RPE-CC integrity was lost.
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