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Human retinal epithelial cells dividing in culture have been radiolabelled with tritiated thymidine and subsequently transplanted and identified on Bruch's membrane of owl monkey by autoradiography. Such cells have been followed from 2 hours to 7 days after transplantation. The transplant cells reattach within 2 hours to the basement membrane left on Bruch's membrane after the host epithelial cells have been removed by suction after trypsinization. Within 6 to 24 hours they form a layer on Bruch's membrane with junctional complexes between cells and an apical-basal polarity characteristic of such cells in culture or after retinal detachment. After 2 to 7 days multilayers form by continued mitosis but no transplant cells invade the choroid as long as Bruch membrane is intact. Within this time macrophages begin to appear in the choriocapillaris under the transplant. These cells migrate through Bruch's membrane and between the transplant cells but have not been seen phagocytizing transplant cells. Reattachment of the neural retina to the transplant layer has not been attempted but seems technically possible.

In the visual cortex of kittens that have received their only visual experience while wearing a high-power lens before one eye, most neurons are dominated by input from the normal eye. Moreover, contrast sensitivity and resolving power are lower for stimulation through the originally defocused eye, mimicking psychophysical results from human anisometropic amblyopes.

This is a review of primary and secondary tumors of the optic nerve. The emphasis is an optic nerve gliomas and meningiomas. Optic nerve gliomas are slowly growing astrocytic neoplasms of the anterior visual pathways, the majority of which occur within the first two decades of life, with equal sex incidence in about 1 of 200,000 patients presenting with eye complaints. The incidence is greater in neurofibromatosis. The typical presentation is visual impairment in a verbal pre-school child with optic canal enlargement and optic atrophy. An intraorbital location of the tumor leads to axial, irreducible, non-pulsatile proptosis. An intracranial location may disturb hypothalamic and pituitary function and produce hydrocephalus. Ocular findings may also include limited motility on a mechanical-restrictive basis, a pupillary relative afferent defect, nystagmus, and variable, non-specific visual field defects. Roentgenographic studies may show concentric unilateral enlargement of the optic canal with preservation of a well corticated margin, a fossa under the anterior clinoid process in continuity with the optic canal ('J'-shaped sella), and findings of increased intracranial pressure. On pathologic examination the tumor is a smooth, fusiform, intradural enlargement of the optic nerve. Histologically there is proliferation of elongated (pilocytic) astrocytes in reticulated patterns with intervening microcystic spaces containing mucosubstance and surrounding reactive hyperplasia of the arachnoid. Mitoses are not found. The diagnosis is clinical X-ray studies and brain scan should be performed. The differential diagnosis is that of unilateral proptosis in a child and includes acute ethmoiditis, hyperthyrobidism, craniostenosis, other neoplasms, Hand-Schuller-Christian disease, and orbital hemorrhage due to trauma. Surgical resection is performed in cases with unilateral optic nerve involvement, the surgical approach being determined by tumor location. Bilateral or chiasmal cases are treated with radiotherapy when progression occurs. Malignant optic nerve gliomas and optic nerve hyperplasia are also discussed. Optic nerve meningiomas arise from the nerve sheath and are to be distinguished from orbital meningiomas arising from ectopic arachnoidal cells or those secondarily involving the orbit by extension from adjacent sites. Up to 80% of orbital meningiomas occur in females, in two age peaks, 25% in the first decade, and the rest in the 5th decade. Meningiomas present with visual loss and may produce proptosis, papilledema and/or optic atrophy, retinal striae, opticociliary shunts, limitation of extra-ocular movements, and lid edema, Signs of von Recklinghausen's disease should be sought. X-rays are the mainstay of diagnosis. Orbital meningiomas are composed of cells in sheets or in whorls with some spindle shaped cells. Calcifications are typical. Usually the dura is penetrated and the orbit invaded. Primary orbital meningiomas are locally infiltrating but do not metastasize. Complete local excision en bloc is recommended...

SUMMARY Seven cases are presented in which prolonged papilloedema led to the development of acquired optociliary shunt vessels. These vessels may also be found with optic nerve tumours, particularly spheno-orbital meningiomas, optic nerve drusen, glaucoma, and after central retinal vein occlusion. Two A 37-year-old housewife was admitted for increasing weakness of the left arm and leg of 2 years duration and several recent attacks of focal epilepsy. Her past history included migraine episodes for the past 6 years. The general physical examination was unremarkable. Neurological examination showed left pyramidal tract signs and diminished 2-point discrimination in the left hand. There was a loud bruit audible all over the skull. The ocular examination showed a corrected visual acuity of 6/6, N6 in the right eye and 6/5, N5 in the left. There was a right relative afferent pupillary defect. Perimetry showed the visual field of the left eye to be full, but there was some constriction of the nasal field of the right eye. The optic discs had blurred margins and were somewhat pale. The right was paler than the left. There were small drusen-like bodies at the disc margins and tortuous optociliary shunt vessels on both discs. Fluorescein angiography in both eyes showed mild dilatation of the radial peripapillary capillary plexus overlying the disc and nearby retina and leakage of dye into the surrounding retina, confirming the presence of papilloedema (Fig. 1). The shunt vessels filled from the retinal circulation. Arteriography demonstrated a massive superficial arteriovenous malformation in the right middle cerebral artery territory. CASE 2 A 37-year-old electrician was evaluated for diminished visual acuity in the left eye of indeterminate duration and 3 months of intermittent visual obscurations of both eyes. The obscurations were consistently brought on by running down stairs or bending over. The general and neurological examinations were normal except for bilateral papilloedema. Corrected visual acuity was 6/6 in the right eye and 6/18 left. There was a left relative afferent pupillary defect. Perimetry showed the visual field of the right eye to be moderately constricted in a concentric pattern, and the visual field of the left eye to be markedly constricted, especially nasally. There was bilateral papilloedema with tortuous optociliary shunts and temporal pallor of the left disc (Fig. 2). Fluorescein angiography showed profuse dye leakage at both discs and demonstrated the shunt vessels in the left eye to fill from the retinal veins. At operation a colloid cyst of the third ventricle was removed. 267 on 11 April 2019 by guest. Protected by copyright.