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The pathology of pars plana incisions of four patients is described: three with light microscopy and one with light and electron microscopy. Two eyes were removed because of choroidal melanoma, immediately and 8 days after vitrectomy and transvitreous retinal biopsy. Considerable disruption of tissues surrounding the pars plana incisions was observed. Vitreous was incarcerated in the wounds, which healed with granulation tissue. One eye was examined 4 months after vitrectomy for diabetic retinopathy and a failed pars plana filtering operation. It contained fibrovascular ingrowth from all the incisions, infiltrating the vitreous base with granulation tissue and causing vitreous haemorrhage and retinal detachment. One eye was removed 1 year after vitrectomy for anterior hyaloidal fibrovascular proliferation and early phthisis. The wound had fibrous ingrowth histologically and evidence of active fibroplasia.

A light microscopic study was done to investigate retinal changes in healthy and immunosuppressed mice after intraocular inoculation of murine cytomegalovirus (MCMV). A 0.01-ml inoculum containing 10(5) plaque-forming units of MCMV was placed behind the lens in 138 4-week-old Swiss Webster mice. Ninety-eight mice were immunosuppressed with 0.2 mg/g of cyclophosphamide given intraperitoneally at the time of inoculation and 0.1 mg/g of cyclophosphamide every 5 days thereafter. Selected eyes were examined on postinoculation days 5, 10, 15, and 16-20. Evidence of viral infection was most prominent in uveal tissue. Uveal infection developed whether or not animals received cyclophosphamide, but retinal necrosis developed only in immunosuppressed mice. Focal retinal necrosis, primarily involving the outer retinal layers and retinal pigment epithelium, was first observed in an eye examined on day 10. Retinopathy from MCMV was present in three of five eyes (60%) examined on day 15, and in six of 16 eyes (37.5%) examined between days 16-20. Retinal disease was characterized by full-thickness retinal necrosis, scattered cytomegalic cells, intranuclear and intracytoplasmic viral inclusions, and acute and chronic inflammation. These results indicate that MCMV can produce a necrotizing retinopathy in mice and that immunosuppression facilitates infection. Although ocular MCMV infection in immunosuppressed adult mice is a potential model for study of human CMV retinopathy, many differences exist between human CMV and MCMV and between the ocular diseases they produce.

Three premature infants with no family history of eye disease showed bilateral cystoid maculopathy on post-mortem examination. These macular lesions are indistinguishable macroscopically from the macular lesions of sex-linked juvenile retinoschisis. Cystoid change was observed at various vertical retinal levels. The oldest child had a schisis cavity within the nerve fibre layer. All cases had reduced numbers of retinal ganglion cells and central nervous system (CNS) abnormalities. The authors believe these are the first reported cases of a cystoid macular lesion present at birth and the first description of the pathological features of a cystoid macular lesion in infants.

A case of metastatic tapioca melanoma of the iris in a 12-year-old girl is reported. The patient had heterochromia, a red painful eye, and was treated for iritis with secondary glaucoma. In the course of 5 months iris lesions with the clinical appearance of tapioca pudding developed, and biopsy disclosed a melanoma. The eye was immediately enucleated, and pathological examination showed a melanoma with predominantly epithelioid-type cells which had infiltrated the angle, the posterior chamber, and the surgical wounds. Conjunctival extension was noted 10 months after enucleation, and regional lymph node metastases were found 4 months later. Previously reported cases are reviewed and compared with the present case.

The authors sought S-100 protein in sections cut from formalin- or glutaraldehyde-fixed, paraffin-embedded tumors from the eye and other sites by an immunoperoxidase technique, using rabbit antibovine S-100 protein antiserum, swine antirabbit serum, a peroxidase-antiperoxidase preparation, and amino-ethylcarbizole as developer. Tissue from 26 intraocular tumors was examined, the pathologic diagnosis being unknown to the investigators at that time that the tests were performed. Thirteen of 16 malignant melanomas of the choroid contained S-100 protein (81%), while only one of seven retinoblastomas contained S-100 protein (14%). One cutaneous malignant melanoma metastatic to the eye contained S-100 protein, while none of three metastatic nonmelanocytic, nonneural tumors contained the protein. These results are similar to our findings with nonocular tumors, in which 56 of 56 cutaneous melanomas contained S-100 protein (100%) and only 1 of 51 nonneural, nonmelanocytic tumors contained S-100 protein (2%). S-100 protein may be useful as a marker for ocular malignant melanoma.

S-100 protein is a 21,000 dalton acidic calcium-binding protein present in ocular melanomas and some normal ocular tissues. Ocular fluids and extracts of ocular tumours were examined by a sensitive radioimmunoassay that could detect less than 5 ng of S-100 protein in minute volumes of fluid. Three ocular melanoma biopsy specimens had S-100 protein at levels between 25 and 1300 ng/ml, comparable to that found in a cutaneous melanoma biopsy specimen (1000 ng/ml). (SI conversion: ng/ml = microgram/l.) Six melanoma culture lines had 1000 to 125,000 ng/ml. Four lymphoblastoid cultures had less than 2 ng/ml, and three colon carcinoma cultures had 180 ng/ml. Subretinal fluid from 23 melanoma-containing eyes had 10 to 76,800 ng/ml. Lesser amounts were found in eyes with small, anteriorly located, lightly pigmented tumours. Vitreous from 3 melanoma-containing eyes had 10,000 to 11,000 ng/ml. Vitreous obtained from three eyes during tractional retinal detachment repair had 500 to 1600 ng/ml, and vitreous obtained at necropsy from six normal eyes had 2 to 120 ng/ml. Aqueous from six melanoma-containing eyes had 10 to 30 ng/ml, levels not significantly different from those observed in three normal eyes (80-120 ng/ml). This approach provides new insight into the interaction of ocular tumours and adjacent ocular fluids and may, with more specific tumour markers, have diagnostic applications.

This report reviews current knowledge of the ultrastructural features of the vitreoretinal juncture in its normal state, in eyes with posterior vitreous detachment (PVD), and in eyes with epiretinal membranes (ERM's) and then presents new concepts concerning the interrelationship of ERM's and the vitreous. Results show no vitreous residues on retinal surface following uncomplicated rhegmatogenous (senescent) PVD. In eyes that develop ERM's before vitreous detachment, however, a layer of vitreous may be entrapped beneath the ERM and on adjacent membrane-free retina when PVD ocurs. ERM's may be a cause as well as an effect of PVD.

For a rabbit model of hematogenous endophthalmitis caused by Candida, 80 New Zealand white rabbits were given intravenous injections of 10-5 Candida albicans. Two weeks after infection 88 percent of infected rabbits had ocular lesions with clinical appearance identical to that of human lesions. Cultures of the chorioretina and kidneys averaged 10-4.3 and 10-3.9 organisms per g of tissue, respectively, three days after infection and remained positive for 38 days. Ninety-five percent of rabbits with positive cultures of the chorioretina had positive cultures from other organs. The ocular lesions were focal chorioretinitis characterized by a combination of granulomatous and acute suppurative reactions. Hematogenous endophthalmitis caused by Candida in the rabbit is a useful model for study of the pathogenesis and treatment of the disease in humans.