Abstract: By means of electron paramagnetic resonance(EPR), chemistry luminescence and fluorescent spectroscopy, the free radical, superoxide dismutase and water soluble lipid peroxide in tears of normal eyes(150 eyes, 100 cases), Moorens ulcer(9 eyes), coreal grafts rejection(16 eyes) were studied. The results showed that the spin density of the free radical was 3.6(±0.58)×10¹² spins/mL tear, the content of the superoxide dismutase(SOD) was 3.84(±1.45) ng/mL tear, the opposite fluorescent density of the water soluble lipid peroxide was 12.912(±1.691) U/mL tear in normal tears. The normal values are 2.5—4.8×10¹² spins/mL tear for free radical, 2.39—5.29 ng/mL tear for SOD, 9.598—16.225 U/mL tear for water soluble lipid peroxide. There are significant differences in different eyes, different sexes and different ages. The free radical and lipid peroxide are higher obviously in the tears of patients with Moorens ulcer and rejected corneal grafts, compared with those of the normal control subjects(P<0.01), SOD is lower evidently(P<0.01). The above fact shows the pathogenic mechanism of Moorens ulcer and keractoplasty rejection is significantly related to toxicities injuring effect of the free radical. These results have provided important experimental data for studying lacrimalogy and new methods for clinical diagnosis and treatrment.

Key words: Free radical, Superoxide dismutase, Lipid peroxide, Corneal ulcer, Keratoplasty