Vasculature of the anterior eye segment

Quantitative study of the microvasculature and its endothelial cells in the porcine iris

“…The overall arrangement of iris vascular layers with the larger arteries and veins sandwiched between a superficial and a deep compact capillary plexus also concurs with previous finding using corrosion cast technique on porcine and primate eyes (Funk and Rohen, 1990;Rohen and Funk, 1994;Simoens, 1985). Similarly as reported in primate eyes (Rohen and Funk, 1994), the large porcine iris arteries were more tortuous whereas the veins tend to be straighter. However, previous studies were not able to provide the detailed morphological information at cell level as presented in this study due to technical limitations.…”

“…The structure of the porcine retina demonstrates a typical primate-like architecture (Beauchemin, 1974;Riva et al, 1986). The overall arrangement of iris vascular layers with the larger arteries and veins sandwiched between a superficial and a deep compact capillary plexus also concurs with previous finding using corrosion cast technique on porcine and primate eyes (Funk and Rohen, 1990;Rohen and Funk, 1994;Simoens, 1985). Similarly as reported in primate eyes (Rohen and Funk, 1994), the large porcine iris arteries were more tortuous whereas the veins tend to be straighter.…”

“…In recent decades, the vascular endothelium has emerged not merely as an inert barrier but also an active signal transducer for circulating influences as well as the key regulator of material exchange (Deanfield et al, 2007). Previous studies using corrosion casts had provided some qualitative information on the iris vasculature Rohen, 1987, 1990;May, 2011;Ninomiya et al, 2008;McCartney, 1989a, 1989b;Risco and Nopanitaya, 1980;Rohen and Funk, 1994). Whilst limited information is available on the iridal endothelium both in the structural and functional aspects, this study provided some detail information on iridal endothelium morphometrics and vessel density.…”

Topical Proparacaine and Episcleral Venous Pressure in the Rabbit

“…4–7 The episcleral circulation is complex and has numerous arteriovenous anastomoses (AVAs). 8–13 To add further complexity, the blood supply to this network comes from vessels originating inside and outside the eye. 8 As a result, blood flow changes in episcleral supply vessels can affect the rate of aqueous entering the episcleral venous system.…”

“…8–13 To add further complexity, the blood supply to this network comes from vessels originating inside and outside the eye. 8 As a result, blood flow changes in episcleral supply vessels can affect the rate of aqueous entering the episcleral venous system. Moreover, there is strong evidence that the episcleral circulation is richly innervated and that a variety of vasoactive neurotransmitters are present (e.g., nitric oxide, acetylcholine, norepinephrine, vasoactive intestinal peptide, neuropeptide Y, and substance P), but their influence on EVP remains to be determined.…”