Early reports suggest that corneal epithelium acts antiangiogenically [74-76], as the different cell populations of the cornea collectively promote the antiangiogenic balance leading to corneal avascularity
. Although the exact mechanisms are not yet fully elucidated, the cells of the limbus act as a physical and physiological barrier against blood and lymphangiogenesis [73, 77].
(21) In the area exhibiting near complete avascularity
by day 1 (Zone I), robust gene modulation occurred during early time interval.
Due to the avascularity
of the anterior chamber, the immune response may be minimal to absent; and serological tests, such as ELISA and the 24-kDa L3 antigen immunoblot, may be negative.
One or more of the following could, therefore, significantly impair visual function: 1) mechanical damage to the optic nerve or retina resulting from rapid decompression-induced exophthalmia (Rogers et al., 2008); 2) physiological damage to the retinal cells resulting from multiple embolisms, low blood oxygen levels in the choroid rete, avascularity
of the retina, and the need of a continuous supply of oxygen in the retinal cells (Fonner et al., 1973; Berenbrink et al., 2005); 3) permanent bleaching of retinal cell photopigments or retinal cell apoptosis (cell death) due to exposure to bright light (Loew, 1976; Wu et al., 2006); and 4) clouding of the cornea or lens (cataract formation) (Midtlyng et al., 1999).
of the eschar results in impaired migration of host immune cells and restricts delivery of systemically administered antimicrobial agents to the area, while toxic substances released by eschar tissue impair local host immune responses.
of the cornea puts it in a relatively immune-privileged position, and complications due to graft rejection can be handled more effectively than in other solid organs.
We suspect that the avascularity
of the cornea and the fewer vessels of the iris may contribute to this minimal thickness change.
The physiological avascularity
of the articular cartilage  is retained by the presence of antiangiogenic factors such as thrombospondin-1 [37, 38], thrombospondin-2 , troponin-I , tenascin , tissue inhibitors of metallo-proteinases (TIMP) 1 and 2 , and chondromodulin-1 [37, 43-45].
In addition, the avascularity
of the adult intervertebral discs suggests that these parts of the spinal column would be involved in the infection at a chronic or advanced stage, and only in organisms with the appropriate proteolytic activity to gain access to the disc space.
(9) The vulnerability of macula is due to abundance of Henle's fibres that are hydrophilic, relative avascularity
that limits fluid absorption and thin basal lamina that does not protect against the biochemical effects.
Mitomycin C augmented glaucoma surgery: evolution of filtering bleb avascularity
, transconjunctival oozing, and leaks.
However, in patients with fat necrosis, localized abscesses or foreign body granulomas, the most common finding on sonography was localized masses with coarse margins and showed avascularity
or low blood supply.