Observations on the lobular organization of the human choriocapillaris

Abstract

Vascular casts (Batson mixture) of ocular angioarchitecture were prepared from ten human orbits removed at autopsy. The age of donor specimens ranged from seven months to 68 years. The time interval between death and injection of the orbits averaged seven hours with a range of five hours. The resulting vascular casts were examined using light microscopy and scanning electron microscopy (SEM). We present photomicrographs of our vascular casts that demonstrate predictable variations of the human choriocapillaris angioarchitecture according to the region of the choriocapillaris under examination (i.e. posterior pole, equatorial, peripheral, peripapillary, or submacular areas). Our discussion represents an effort to help clarify some persistent controversies concerning the human choroidal angioarchitecture.

Comparison of non‐invasive methods for the assessment of haemodynamic drug effects in healthy male and female volunteers: sex differences in cardiovascular responsiveness.

“…On the basis of our present results it has to be hypothesised that the fundus pulsations amplitude reflects only pulse pressure but not blood flow in the vessels of the choroid. The wide inter-subject variability of fundus pulsations measurements under baseline conditions (Figure 3) is presumably due to substantial differences in ocular rigidity [24] and to differences in the angioarchitecture of the choroid [25]. However, both parameters are inaccessible to direct measurement in vivo.…”

Blood flow in the choriocapillaris

“…The average capillary and septae diameter increases further from the macula (Salzman 1912;Hogan & Feeney 1961;Garron 1963;Klien 1966;Hogan et al 1971;Fryczkowski et al 1991). The fraction of the volume occupied by the capillaries over lobules -or vascular volume fraction -varies from 0.75 in the macula to 0.5 at the equator (Ramrattan et al 1994;Spraul et al 1999Spraul et al , 2002.…”

“…1966; Hogan et al 1971;Torczynski & Tso 1976;Fryczkowski & Sherman 1988;Fryczkowski, Sherman & Walker 1991). As in other tissues of the human body, the capillaries are composed of a single layer of endothelial cells enclosed by a basement membrane.…”

“…Their thickness varies between 10 and 20 µm, while they measure between 10 and 60 µm in width (Fryczkowski 1994). The septae can be up to the size of a vessel in width (Yoneya, Tso & Shimizu 1983;Fryczkowski, Grimson & Peiffer 1985;Fryczkowski et al 1991;Fryczkowski 1994;Zang 1994). The choriocapillaris is serviced by arterioles and venules running under the plane containing the capillaries and inserting into the capillary bed at approximately a right angle (Salzman 1912;Torczynski & Tso 1976;Fryczkowski 1994).…”

Choroidal Vessel Wall: Hypercholesterolaemia-Induced Dysfunction and Potential Role of Statins

“…In this zone, the arteriole/venule ratio is 3:1, so that the foveal cones can have double their blood supply, even at the cost of greater risk of oedema by vein blockage. At the posterior pole, the arteriole:veinule ratio is 1:2 to 1:4 [34,35]. As a result, these zones of the choriocapillaris could be more susceptible to local blockages of arteries, with the consequent risk of ischaemic damage.…”