Eales' disease: accumulation of reactive oxygen intermediates and lipid peroxides and decrease of antioxidants causing inflammation, neovascularization and retinal damage

PURPOSE. To measure the blood levels of oxygen and lipid-free radicals as lipid peroxidation products and of vitamins E, C and A, in order to explain intraocular inflammation, retinal neovascularization and detachment in Eales' disease. METHODS. Levels of the lipid peroxidation products produced by oxygen and lipid free radicals (estimated as thiobarbituric acid reactive substances-TBARS), vitamin E with ferric chloride, vitamin C with 2,6-dichlorophenol-indophenol and vitamin A with antimony trichloride were all evaluated in three groups of subjects between 20 and 40 years of age. Twenty three were patients with Eales' disease in the active perivasculitis stage (Group I), 19 were patients with Eales' disease in the healed-perivasculitis stage (Group II), and 46 were healthy volunteers (Group III), used as normal controls. Patients in each group were subdivided into two age groups, 20-30 and 31-40 years, each group containing both sexes. RESULTS. The results showed a 4.6- and 5.6-fold increase in the levels of TBARS in erythrocytes of patients with Eales' disease in the active perivasculitis stage (Group I) and a 2-fold increase in patients with Eales' disease in the healed perivasculitis stage (Group II), when compared to levels in the controls (Group III). On the other hand, there was a decrease of 75 and 76.2% in the levels of vitamin E in serum, 34 and 40.9% of vitamin C in plasma and 72.8 and 67% of vitamin A in serum in patients with Eales' disease in the active perivasculitis stage (Group I), as compared to the controls (Group III). Also decreases of 56 and 43.5% of vitamin E in serum, 26.8 and 12.5% of vitamin C in plasma and 50.5 and 49.4% of vitamin A in serum were found in patients with Eales' disease in the healed perivasculitis stage (Group II) as compared to the healthy controls (Group III). The two values of variations between the patients and the normal control group given above for TBARS, vitamins E, C and A are for the two age groups, 20--30 and 31-40 respectively. The differences were statistically significant (P < 0.01 to 0.001). CONCLUSIONS. Lowered levels of antioxidant vitamins E and C and consequent accumulation of oxygen and lipid free radicals, or vice versa, could explain the inflammation, neovascularization and retinal pathology in patients with Eales' disease. Also, vitamin A deficiency could aggravate retinal illness.