Abstract
Machemer (I968) and Kroll and Machemer (I969a, b) studied the ultrastructure of mechanically detached retinae in owl and rhesus monkeys. They found that in detached retinae the outer segments of the rods and cones became disorganized; when the retinae were reattached, however, the saccules of the outer segments were regenerated by the inner segments and the retinae resumed their normal architecture. Our interest has been in the pathology of retinitis and the ensuing irreversible changes in the detached retina. Ocular siderosis creates intraocular inflammation which primarily affects the retina (Cibis and Yamashita, 1959; Hogan and Zimmerman, I962). By injecting soluble iron into the vitreous of rabbits we produced a severe retinitis which was studied by light and electron microscopy. The purpose of this paper is to report the ultrastructural changes that occurred in the retina during and after experimental inflammation.
Abstract
Saccharated iron oxide* or iron-dextran complex** was injected directly into the vitreous of albino or pigmented rabbits. Various doses were used: 0 5, I, I-5, and 3 minims. A half-inch 27 gauge hypodermic needle was inserted into the vitreous through the sclera and pars plana about 5 mm. behind the temporal limbus, slanting the needle slightly posteriorly in order to avoid the lens. Only one injection was given, always into the right eye; the left eye remained untreated as a control. Other control eyes were taken from animals that had received no treatment of any kind. The animals were killed at intervals of i, 6, I2, I8, and 24 hours; at I, 2, and 6 weeks; and at 4 and 6 months.
Abstract
For light microscopy, the eyes were fixed in neutral formalin, embedded in paraffin, and sections stained with haematoxylin and eosin, Prussian blue, and the Quinche method for demonstrating iron (Lillie, I965).
Abstract
For electron microscopy, retinal samples were taken from calottes, fixed in buffered i per cent.
Abstract
osmium tetroxide for Ii hours, dehydrated in graded alcohols, and embedded in Maraglas. Sections were cut on a Porter-Blum microtome, stained with lead citrate, and examined and photographed in a RCA EMU 3F microscope.
Material and methods
Saccharated iron oxide* or iron-dextran complex** was injected directly into the vitreous of albino or pigmented rabbits. Various doses were used: 0 5, I, I-5, and 3 minims. A half-inch 27 gauge hypodermic needle was inserted into the vitreous through the sclera and pars plana about 5 mm. behind the temporal limbus, slanting the needle slightly posteriorly in order to avoid the lens. Only one injection was given, always into the right eye; the left eye remained untreated as a control. Other control eyes were taken from animals that had received no treatment of any kind. The animals were killed at intervals of i, 6, I2, I8, and 24 hours; at I, 2, and 6 weeks; and at 4 and 6 months.
Material and methods
For light microscopy, the eyes were fixed in neutral formalin, embedded in paraffin, and sections stained with haematoxylin and eosin, Prussian blue, and the Quinche method for demonstrating iron (Lillie, I965) .
Material and methods
For electron microscopy, retinal samples were taken from calottes, fixed in buffered i per cent.
Material and methods
osmium tetroxide for Ii hours, dehydrated in graded alcohols, and embedded in Maraglas. Sections were cut on a Porter-Blum microtome, stained with lead citrate, and examined and photographed in a RCA EMU 3F microscope.
Material and methods
A. N. Barber, C. Catsulis, and R. J3. Cangelosi
Material and methods
Results LIGHT MICROSCOPY Intraocular injections of the iron-polysaccharide complex caused the following temporal sequence of changes in the retina. The earliest change noted by light microscopy was iron staining of the inner limiting membrane. Then came difluse iron-positive staining suggesting diffusion of iron into the retina. Localization of iron-positive particles was next observed in the photoreceptor cells, and then the Muller fibres became swollen and later hyalinized and fragmented (Fig. I ). An acute inflammation followed with masses of leucocytes and monocytes in the vitreous. An inflammatory infiltrate also appeared in the choroid, and, when Bruch's membrane fragmented, the cells passed into the retina. Fig. 4 .) Many of the rod segments are fragmented and cellular debris has been scavenged by macrophages which have invaded the subretinal space. A portion of a rod outer segment can be seen in the sytoplasm of a macrophage (arrow). Fig. 9 shows a comparable stage in an albino rabbit. In this instance many fragments of rod outer segments are present in vacuoles deep in the cytoplasm of the pigment epithelial cells (arrows), and there is a relative increase in the number of mitochondria.
Material and methods
Marked degeneration of the nuclear layers followed. In Fig. IO Electron microscopywas particularlyrevealing in the studyof the healing process in experimental retinitis. After degeneration and removal of the cellular elements of the retina and A. NV. Barber, C. Catsulis, and R. J. Cangelosi   FIG. 4 (ontrol eye. Low-power electron micrograph of rabbit pigment epithelium. The external third of the epithelial cells is composed of a deep complex of basal infoldings of the cell membrane which lies adjacent to an inner layer ofmitochondria (Mi). The inner third of the cells contains large disc or irregularly-shaped pigment granules (PG). Many of the granules occupy the ends of microvilli which cover the inner surface of the cells and penetrate between the rod outer segments. Several connecting cilia can be seen between the inner and outer segments. x 5,000 RIS, rod inner segment; ROS, rod outer segment; Cil, connecting cilium; CC, choriocapillaris.
Material and methods
x 5,000 the inner and outer segments of the rods, the remaining Muller fibres were united to each other by the formation of desmosomes. Attachment zones were also formed between outer ends of the Muller fibres and the pigment epithelium (Figs 13, 14, and I5 Fig. 14b .
Material and methods
The desmosomes which united the MIuller fibres with the epithelial cells were very strong. Fig. I5 shows an area where the epithelium was accidently torn from Bruch's membrane, yet it remained with the Muller cells even though the attachment zones were of recent formation. 
Comment
The main contribution of this study is the demonstration of the ultrastructure of degenerative changes during inflammation of the retina and the resolution of these changes. In contrast to reattachment of the retina after mechanical detachment studied by Kroll and Machemer (i 969 a, b) The reorganization of a new outer limiting membrane by formation of desmosomes betwveen the viable Muller fibres that remain in the atrophic retina is also an interesting feature of the healing process. These attachment zones reunite the elements of the retina into an atrophic, but intact membrane. Many of the degenerative changes seen in our material were described by Shakib and Ashton (1966) LG, lipid globule; CC, choriocapillaris; SS, subretinal space. x 4,000 nuclear material in the cytoplasm, and dilatation of the cisternae of the granular endoplasmic reticulum found in our material agree with their observations. We would not confirm their observations on the origin and fate of the phagocytic cells in the pig, since the rabbit retina is free of blood vessels except on the inner surface near the optic disc. Most of the macrophages seen by us arrived from outside the retina at least during the early stages of inflammation. They appeared first in the vitreous and were mainly eosinophils with a few monocytes. Almost immediately afterwards they were found in the stroma and blood vessels of the choroid. As soon as breaks developed in the inner limiting membrane, the macrophages entered the retina. A larger or not the adhesions formed between the retina and choroid after chorioretinal inflammation are desmosomes. Summary Experimental retinitis, created by intraocular injections of an iron-polysaccharide complex, has been studied by means of light and electron microscopy. The electron microscopy A. N. Barber, C. Catsulis, and R. This valuable treatise begins with some discussion regarding the primary functions of the human face, including vision, respiration, smell, intake of food, and speech. The face also has aesthetic functions. The osteology of the face is described with special emphasis on the orbital walls. The anatomy of the orbital adnexa and the orbital contents is discussed. Fracture mechanisms and types of fracture are listed and their aetiology is presented. The importance of the careful clinical examination of patients is emphasized and the clinical record sheet used in Amsterdam is shown. The value of the opinions of otolaryngologists, neurologists, and plastic surgeons is stated. The various complications of facial injury are described, and the useful work of the orthoptic department is emphasized. Radiological examination of facial injuries is essential and this is described and illustrated. Many patients with facial injury suffer damage to the optic nerves with or without fractures of the optic canal. The treatment of all facial injuries is discussed and the surgical methods used are shown in detail. The book is concluded by statistical evaluation of 309 cases of orbital fracture, which shows most interesting results. The author also inserts a chapter on the responsibility of the ophthalmic surgeon in cases of orbital fracture.

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