Influence of Ophthalmic Nerve Fibers on Choroidal Blood Flow and Myopic Eye Growth in Chicks

Intrinsic Neurons in the Duck Choroid are Contacted by CGRP-Immunoreactive Nerve Fibres: Evidence for a Local Pre-central Reflex Arc in the Eye

“…Trigeminal primary afferents contacting ICN might also play a role in regulation of choroidal thickness via in¯uence on contractility of intrinsic choroidal smooth muscle ®bres, which are closely involved in alterations of the refractive state (see below) and probably also intraocular pressure (Bill, 1975;Wilkinson and Hodos, 1991;Wildsoet and Wallman, 1995;Nickla et al, 1998;Schmid et al, 1999). These pre-central re¯ex arcs via ICN may function in a complementary way to axon re¯exes mediated by trigeminal peptidergic afferents alone (Holzer, 1988;Shih et al, 1999). In addition, the same ICN are innervated by TH-immunoreactive ®bers.…”

“…A signi®cant innervation of ICN by mechanosensory trigeminal afferents may provide a basis for local regulation adjusting choroidal thickness. Innervation of ICN by thermosensitive trigeminal afferents (Shih et al, 1999) may form part of an ocular cooling system which has been ascribed to the choroid (Parver, Auker and Carpenter, 1980;Bill, 1985). This trigeminal afferent-ICN pathway is subject to sympathetic modulation.…”

“…This local effector function renders peptidergic trigeminal afferents an important factor for the regulation of ocular blood supply and in¯ammatory processes (Stjernschantz, Geijer and Bill, 1979;Uusitalo, Krootila and Palkama, 1989;Bill, 1991;Kahl and Reid, 1995;Maggi, 1995). Recently, choroidal vasodilation by thermosensitive CGRPcontaining afferents has been interpreted as a protective thermoregulatory response (Shih et al, 1999). However, primary afferent mediated vasoregulation may also in¯uence choroidal thickness which undergoes day/night¯uctuation and is related to the refractive state of the eye (Nickla, Wildsoet and Wallman, 1998;Papastergiou et al, 1998;Schmid et al, 1999).…”

Regional Blood Flow in the Myopic Chick Eye during and after Form Deprivation: a Study with Radioactively-labelled Microspheres

“…Previous studies utilizing laser Doppler technique to measure blood¯ow indicate that the choroidal blood ow is reduced in form deprivation myopia (Shih et al, 1993a;Shih, Fitzgerald and Reiner, 1993b;Reiner, Shih and Fitzgerald, 1995;Shih et al, 1999). A reduction in choroidal blood¯ow has also been demonstrated in myopic human eyes with the pulsatile ocular blood¯ow technique (Ravalico et al, 1997).…”

Central serous chorioretinopathy and bright light

“…It was shown that choroidal vessel diameter is mainly influenced by the temperature of the chorioretinal complex (Parver 1991); an increase in the temperature of the chorioretinal complex induces choroidal vascular dilation in both a passive (Parver et al 1980) and a reflexive manner (Parver et al 1983;Shih et al 1999). The chorioretinal complex may be heated up by the light absorption in the melanosomes of the retinal pigment epithelium (RPE) and the choroid (Parver 1991).…”