[The change of hyaluronic acid of the vitreous humour by oxidation-reduction-systems (author's transl)]

Vitreous Hemorrhage

The incidence of spontaneous vitreous hemorrhage is approximately 7 cases per 100,000 population. Proliferative diabetic retinopathy (32%), retinal tear (30%), proliferative retinopathy after retinal vein occlusion (11%) and posterior vitreous detachment without retinal tear (8%) are the most common causes of spontaneous vitreous hemorrhage. Vitreous hemorrhage can be caused by the pathologic mechanisms of disruption of normal retinal vessels, bleeding from diseased retinal vessels or abnormal new vessels, and extension of hemorrhage through the retina from other sources. Hemorrhage into the vitreous gel results in rapid clot formation and is followed by slow clearance of approximately 1% per day. The cellular response to vitreous hemorrhage is unusual with regard to hemorrhage in any tissue outside the vitreous cavity and has been compared to a "low-turnover" granuloma. Unique clinicopathologic features of long-standing vitreous hemorrhage include cholesterolosis bulbi (synchysis scintillans), hemoglobin spherulosis, and vitreous cylinders. Complications of nonclearing vitreous hemorrhage are hemosiderosis bulbi and glaucoma. Ghost cell glaucoma, hemolytic glaucoma, and hemosiderotic glaucoma may result from vitreous hemorrhage. The established treatment option for nonclearing vitreous hemorrhage is pars plana vitrectomy. Experimental nonsurgical treatment options involve improvement of physiologic clearance mechanisms in order to accelerate fibrinolysis, liquefaction, hemolysis and phagocytosis.

Comparative investigations of catalase activity in different ocular tissues of cattle and man

As previously published, ocular catalase activity was measured by Warburg's respirometer, the examined material being taken from the local slaughterhouse and keratoplasty-donor eyes. The results were given in microliter O2 per mg soluble protein (Biuret's solution) and showed an extensive parallelism between human and bovine eyes: They were in a decreasing order of catalase activity, i.e., conjunctiva > retina > vitreous > sclera > iris > choroid > cornea > aqueous humor > serum > lens. In the latter, catalase activity was a sensitive indicator of aerobic metabolism. Oxidative processes in the vitreous merit more consideration.

[The action of ethylenediaminetetraacetate on the retina. Electronmicroscopic study (author's transl)]

Electron microscopic investigations show that intravitreal application of EDTA causes destruction of the viteous body and damage in all layers of the retina. Therefore, it is concluded that it is useless to try prevention of metallosis of the eye by EDTA.