Corneal Vascularization

¹ Howe Laboratory of Ophthalmology, Harvard Medical School, and the Massachusetts Eye and Ear Infirmary Boston, Mass.

Superficial vascularization of the cornea consists of a pannus of granulation tissue separating the epithelium from Bowman's membrane. It comprises loops of vessels that appear to migrate by direct extension. Interstitial vascularization consists of vessels that are oriented by reason of the collagenous framework of the cornea and are, in consequence, brushlike. The origin of vessels appears to follow swelling of the stroma in the vicinity of preformed vessels. Nevertheless, vessels will not penetrate a necrotic focus where the tissue has become hyalinized. Interstitial vascularization of the human cornea has its counterpart in experimental vascularization of the rabbit cornea. A regular sequence of events occurs characterized by sacculation of the proximal venules and capillaries followed by multiple minute hemorrhages, profligate formation of new capillaries, and eventual consolidation of these capillaries into a few loops extending toward the lesion. Aside from its optical effects, interstitial vascularization causes the cornea to lose its antigenic immunity, diminishes its capacity to develop epithelial edema, and increases its liability to fat deposition. Deep vascularization consists of a lamina of vessels between the stroma and Descemet's membrane. It has no special significance other than that of being a part of interstitial vascularization.