Senile Ring (senile arc, 'gerontoxon', cholesterol or sodium ring) - two-tier changes of gray or whitish-gray color: in the front - in the marginal areas of cornea, somewhat behind - in the marginal areas of the iris. Ophthalmologists call this sign senile parenchymatous dystrophy of the cornea, usually occurring after 40 years. At first, changes appear as two arcs of gray and gray-yellow color, one of which is arranged concentrically in the upper part of the limb, the other - in the lower part of the limb. In time they merge and look like a ring of 1 mm width, distinctly separated from the limb by the narrow streak of the transparent cornea. Senile ring is imperceptibly turned into the normal tissue of cornea in towards the center of iris. The dystrophic process begins in the deep leyers of iris perenchyma and is spreading forward, injuring stroma and Bowman's capsule, where lipid drops are deposed and in time are turned into the cholesterin crystals. Usually in so doing, the tunic is not changed. Generally, integrity of the epithelium is not violated, thereby the cornea in the senile arc area are still smooth and shining.
The pronunciation of sodium-lipid ring is usually proportional to the stage of cerebral atherosclerosis, age of patients, systolic pressure, prothrombin contents in blood and inversely proportional to the blood flow in the cerebral vessels. Often this sign precedes clinical symptoms, change of microcirculation and obliteration of big vessels, and can be the indicator of early signs of blood circulation deterioration and increased acidosis.
