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KMID : 0365819640040010055
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Journal of Pusan Medical College
1964 Volume.4 No. 1 p.55 ~ p.67
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Morphological Studies on Vitreous Cells
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Park Pyung-Gook
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Abstract
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n recent years, ophthalmologists have become increasingly interested in the vitreous body; the degree of opacity whether primary or secondary is of clinical importance, ant syneresis and vitreous detachment may be a possible factor in retinal detachment, and some aspects of glaucoma seem to be connected with the state of the vitreous body.
These points which have aroused interest depend on the very specific nature of the vitreous, the so called "hydrophilic gel," having its own consistency and viscosity, governed it is thought, principally by the high concentration of hyaluronic acid. Anatomical considerations are also of importance, since the vitreous body occupying the largest part of the globe, is in close contact with structures that are essential components for vision; they are the retina, the uvea and the lens. The vitreous is an optical medium which preserves the integrity of the globe.
There still remain many unsolved basic problems, however, and the morphology of vitreous cells is one of these. My own study is expected to provide some little additional knowledge.
The investigation was carried out on several hundreds of cow´s eyes, supplemented by six eyes from each of the following: rabbits, pigs, dogs and guinea pigs; in addition eight human adult eyes were used. The results follow.
Vitreous cells were found too be a regular component of the hyaloid membrane of the vitreous body.
The size of vitreous cells ranged is general from that of lymphocytes to that of fibroblasts or fixed macrophages. There was a little difference in size among the different species: the vitreous cells of cows were found to be the largest and of human adult eyes to be next in size, the vitreous cells of pigs, dogs, guinea pigs and rabbits becoming smaller in that order.
Cells were found to be scattered over the vitreous surface, appropriately imbedded in the hyaloid membrane, except anteriorly in the hyaloid fossa, and in the vitreous parenchyme, a deeper structure, where no cells could be found. The cells were arranged in a single layer and showed no specific distribution pattern.
Cells were most numerous in equatorial regions and gradually diminished in number towards the anterior and posterior poles.
Vitreous cells were found to be of four types; round, oval, spindle shaped and irregular. The round and oval cells have been considered to be derived from the leucocytes of neighbouring blood vessels; as a result of this study the spindle and irregular shaped cells were thought to be vitreous cells proper, a kind of fixed macrophages, possessing protoplasmic processes. These cells outnumbered the round and oval cells group.
The intracellular protoplasmic granules were found to be of two kinds, large and small, and their common staining reaction was basophilic. In addition they became faintly stained with osmic acid and Sujan III, and they became heavily stained with PAS reaction. Digestion with human saliva, hyaluronidase and diastase did not alter the reactivity. It is therefore con.eivable that these granules are of mucin-)us material.
Vitreous cells were found to cantain vacuoles of various sites in considerable numbers; a few of these were thought to be lipaid vacuoles ani the rest to be water vacuoles or thin mucinous ones.
The nuclei of these cells were usually located at the center, the shape being ordinarily round, oval or renal but rarely bbelatel. Cell divislon was thoa,;ht to take place in an amitotic figure. The nuclei, hivin; an abuni3nce of chromatin, were in general deeply stained aui contained one or two nucleoli. There was poor development of mitochondria and Golgi apparatus.
From the morphological evidence it seems that vitreous cells become differentiated from the mesodermal element and they phagocytize foreign materials invading the eye, and act as an hematoparenchymal barrier to maintain the extremely transparent state of the
vitreous. Furthermore, it can be deducted from the distribution of the cells that they participate in the production of hyaluronic acid.
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