A series of 256 consecutive cases of invasive primary conjunctival malignant melanomas was examined to identify clinical and histopathological prognostic factors. The follow up period varied between 0*3 and 45 9 years (mean 9 years, median 6*3 years). The 5 year survival rate was estimated at 82.9%, the 10 year survival rate at 69.3%. Multiple regression analysis with the Cox proportional hazards model was used to assess sex, age, and a number of baseline features of conjunctival malignant melanoma as possible prognostic factors influencing melanoma related mortality. In assessing each potential prognostic factor, the effects of all other factors were taken into account in the modelling process. Tumours in unfavourable locations -that is, those involving the palpebral conjunctiva, fornices, plica, caruncle, and lid margins, were associated with 2*2 times higher mortality compared with (epi)bulbar melanomas. Patients with mixed cell type tumours had about three times higher mortality compared with those with pure spindle cell melanomas, and histological evidence of lymphatic invasion by tumour cells was also a prognostic feature, carrying a fourfold increase in the death rate. Multifocal tumours were associated with a fivefold increase in mortality among those with tumours in favourable (epi)bulbar locations, but were not prognostic in patients with melanomas in unfavourable sites. The death rate was significantly higher in those with initial tumour thickness of more than 4 mm, but only among patients with unfavourably located melanomas. Sex, age, and clinical origin of the tumour (primary acquired melanosis, pre-existing naevus, or de novo) were not useful prognostic indicators in this study. (BrJ Ophthalmol 1994; 78: 252-259)

The role of orbital exenteration in the management of malignant melanoma of the conjunctiva has been underexplored. The

Sixteen cases of medulloepithelioma are described. Clinical data and follow-up were available on 15. Four patients underwent iridocyclectomy initially; all later needed enucleation and one had an orbital recurrence. The remaining 12 patients underwent primary enucleation. All 15 patients with follow-up are alive with no evidence of tumour recurrence. It is suggested that enucleation be performed for all but the most localised tumour. Rubeosis was noted in 13 of the 16 eyes, and this may assist in making the diagnosis. The World Health Organisation histological classification of medulloepithelioma was applied, but some problems were encountered, particularly where the presence of heteroplastic brain tissue was used as a criterion for teratoid tumour and where rosettes were used as a criterion for malignancy.

No abstract

Descemet's membrane, the specialised basement membrane of the corneal endothelium, contains a form of extracellular matrix described as wide-spaced collagen. In healthy human Descemet's membrane, wide-spaced collagen forms a highly ordered array in a region called the anterior banded zone. However, in corneal endotheliopathies such as Fuchs' endothelial dystrophy and the iridocorneal-endothelial syndrome large amounts of wide-spaced collagen are deposited posterior to Descemet's membrane in a grotesque parody of the anterior banded zone termed a posterior collagenous layer. The purpose of this study was to identify the composition of the wide-spaced collagen found in the Descemet's membrane of normal and diseased human corneas. Tissue from three normal human corneas, three from patients with Fuchs' endothelial dystrophy and five from patients with the iridocorneal-endothelial syndrome was prepared for immuno-electron microscopy by freezing or embedding in Lowicryl K4M resin. Immunocytochemistry on ultrathin sections was performed with antibodies to collagen Types I, III, V, VI and VIII, fibronectin, laminin, P component and tenascin. Ultrastructural labelling of the wide-spaced collagen in the anterior banded zone of normal and diseased corneas and also of the wide-spaced collagen in the posterior collagenous layer of all the diseased corneas was demonstrated with antibody to collagen Type VIII. Wide-spaced collagen was not labelled by any of the other antibodies used. Large amounts of Type VIII collagen are present in discrete regions of healthy and diseased Descemet's membrane. The deposition of Type VIII collagen may significantly influence the pathobiology of the corneal endotheliopathies.

London SummaryThe morphology of the circle of Haller and Zinn and its variations were examined using methyl-methacrylate microvascular corrosion casting of human orbits obtained at post-mortem. It was found to be an elliptical microvascular anastomosis formed by branches of the medial and lateral para-optic short posterior ciliary arteries. The ellipse was divided into superior and inferior parts by the entry points of these branches into the eye, providing an altitudinal blood supply to the retrolam From 'Moorfields Eye Hospital, City Road, London. 2Institute of Ophthalmology,

SummaryThe clinical course of 47 patients with posterior scleritis is reviewed. Though clinical presenta tion varied widely, 73% of the patients presented with a visual acuity of 6/18 or less. Because the posterior scleritis was not always associated with pain or with anterior scleritis, the diag nosis was often not considered when the patient was first seen. The most common findings in the fundus were disc sweUing, retinal detachment, and macular oedema and the most useful in vestigation was B scan ultrasound. No common aetiology was found, although 60% had a sys temic disorder which was accompanied by a vasculitis. Those who were diagnosed and treated with the minimum delay had the most satisfactory visual outcome. However, there appears to be a group of patients with no underlying systemic disease who fail to respond to intensive therapy, and lose vision. A new sub-group of West Indians with the disease is described. The histopathology of 7 cases confirmed the presence of scleral vasculitis of the vessels in and around the sclera in all the specimens. Other significant findings include inflammatory swelling and focal loss of pigment epithelium together with choroidal vascular closure. This could ac count for the fluorescein angiographic findings.

Despite extensive study, the pathogenic mechanisms of Behçet's disease remain uncertain. The ocular inflammation caused by this disease is severe, often causing significant visual loss and, although the nature of the cellular infiltrate has been examined in many of the involved organs, the infiltrating cells in inflamed eyes have not. To investigate the mechanisms involved in perpetuating the ocular inflammation, five enucleated eyes from patients with Behçet's disease were examined by immunohistochemical staining using a panel of monoclonal and polyclonal antibodies. Control eyes from patients with chronic intraocular inflammation from other causes were also examined. Cellular infiltrates were a consistent finding in choroid and periretinal scar tissue, formed almost entirely by mononuclear cells. T lymphocytes were found to predominate (largely the CD4+ subset). B lymphocytes and NK cells were infrequent findings but macrophages were present in significant numbers. No complement or immunoglobulin deposits were found. Infiltrating lymphocytes and macrophages were HLA DR positive. Retinal vascular and retinal pigment epithelium were only occasionally positive. Our findings suggest that cell mediated immunity, rather than immune complex deposition is responsible for the perpetuation of the ocular inflammation in Behçet's disease and that CD4+ T lymphocytes play a central role in this.