The effect of vitreous hemorrhage on the retinal structures was studied in twenty young adult pigmented rabbits weighing 2 to 3kgs. The autologous blood was injected intra-vitreally in one eye of the animals. Five animals of each group were sacrificed for light and electron microscopic studies of the retina near the visual streak in the posterior pole in one week, two weeks, one month and two months. In light microscopy of the rabbit retina, hemosiderin-laden macrophages are located in the vitreous cavity. Iron stain positive particles are present in the retina, particularly in the pigment epithelium. These particles are also scattered in the retina after two weeks on. By electron microscopy, there is no significant ultrastructural change in one week. Swelling of mitochondria in the bipolar and Miiller cells, and in the inner segments of the cone cells are noted along with disarrangement of disc stacking in 2 weeks. Many myelin figures appear in the cytoplasm of the inner segments of visual sells, outer plexiform and inner nuclear layers. Hemosiderin pigments appear in the pigment cells and in the cytoplasm Muller cells. In inner nuclear layer, a necrotizing cell demonstrates pyknotic nucleus and focal cytoplasmic degradation in one month. Hemosiderin pigments are present in ganglion cells, Miiller cells and pigment epithelial cells. Disc stacking is altered in outer segment of the visual cells, and the pigment epithelial cell demonstrate increased engulfment of outer segment of visual cells in two months. However, the electrophysiological study with ERG do not demonstrate any abnormality.
Animals ; Cytoplasm ; Ependymoglial Cells ; Epithelial Cells ; Epithelium ; Ganglion Cysts ; Hemosiderin ; Humans ; Iron ; Macrophages ; Microscopy ; Microscopy, Electron ; Mitochondria ; Myelin Sheath ; Rabbits ; Retina ; Retinaldehyde* ; Vitreous Hemorrhage* ; Young Adult

Infectious keratitis is the most common serious ocular infection, and may be caused by various bacteria, fungi, viruses and parasites. The authors performed prospectively an epidemiological study to identify risk factors and causative organisms, and to evaluate clinical manifestations, methods and results of treatment in infectious keratitis under the identical protocol from April 1995 to September 1997. Logistic regression analysis [univariate analysis and multivariate analysis] was used to evaluate possible risk factors. Six hundred sixty cases of infectious keratitis reported from 19 hospitals were studied. Two hundred eighty-three organisms[247 bacteria, 32 fungi, 4 acanthamoeba] were detected in 626 eyes with infectious keratitis excluding 34 pherpetic keratitis. The Pseudomonas aeruginosa, coagulase negative staphylococcus, Staphylococcus aureus and Serratia marcescens were the major orgnisms in bacterial keratitis. Aspergillus, Fusarium and Candida were the major isolates in fungal keratitis. Contact lens wear was a risk factor for bacterial keratitis. Female, age[less than 40 years] and occupation[student, house-wife, office worker, servise] were associated with bacterial keratitis. Risk factors in herpetic keratitis were age[between 40 and 59 years] and ocular adnexal diseases. Male was associated factor with herpetic keratitis.
Adnexal Diseases ; Aspergillus ; Bacteria ; Candida ; Coagulase ; Epidemiologic Studies ; Epidemiology* ; Eye Infections ; Female ; Fungi ; Fusarium ; Humans ; Keratitis ; Keratitis, Herpetic ; Logistic Models ; Male ; Parasites ; Prospective Studies ; Pseudomonas aeruginosa ; Risk Factors ; Serratia marcescens ; Staphylococcus ; Staphylococcus aureus

To identify risk factors and causative organisms, and to evaluate clinical manifestations, methods and results of treatment in infectious keratitis, an epidemiological study was performed prospectively under the identical protocol from April 1995 to March 2000.Logistic regression analysis was used to evaluate possible risk factors. The 1474 cases of infectious keratitis reported from 22 hospitals were studied. Five hundred forty-four organisms(442 bacteria, 82 fungi, 20 A c a n t h a m o e b a)were detected in 1320 eyes with infectious keratitis excluding 154 herpetic keratitis. The Pseudomonas aeruginosa was the most common organism in bacterial keratitis, and Fusariumspp. was the major isolate in fungal keratitis. Contact lens wear and occupation(industry, forester, miner, fisherman)were the risk factors for bacterial keratitis. Risk factors in fungal keratitis were fifth decade of age, farmer, and systemic diseases(diabetes mellitus etc.). Risk factors in herpetic keratitis were male and occupation(office worker, service, student, housewife). Risk factors in Acanthamoeba keratitis was contact lens wear.
Acanthamoeba Keratitis ; Bacteria ; Epidemiologic Studies ; Epidemiology* ; Fungi ; Humans ; Keratitis ; Keratitis, Herpetic ; Male ; Prospective Studies ; Pseudomonas aeruginosa ; Risk Factors