Entire Eye Research Articles

Management of retained lenticular material by enzymatic zonulysis.

Unplanned extracapsular cataract extractions resulting in retention of lenticular material present a formidable problem in postoperative management to the ophthalmic surgeon. The incidence of complications in such an eye is significantly greater than an eye from which this residual lens material has been removed. However, it is frequently impossible at the time of initial surgery to extract this residuum without endangering the entire eye. Rarely, this problem of retained lenticular material becomes apparent at the first or second postoperative dressing after an operation which was thought to be an uneventful intracapsular extraction. More commonly, the surgeon is faced with the task of removing loose cortical and capsular material after a traumatic cataract with simultaneous rupture of the capsule. The purpose of this report is to describe how enzymatic zonulysis may facilitate the more complete and safe removal of retained lens material. Since Barraquer's8initial report, many papers have appeared

Corneal transplantation; indications and contraindications.

IN AN earlier report 1 on the visual and cosmetic results of corneal transplantation, the unfortunate effect of the glaring publicity attending this operation was discussed. It was suggested that this tidal wave of optimism has blinded both the layman and the physician to the true facts about corneal transplantation. The general public has been so misinformed about this operation that people have been led to believe that entire new eyes can be transplanted to replace diseased ones, and that corneal transplantation is a cure for total blindness. Physicians have been so influenced by this publicity that many have believed the statements that corneal transplantation is attended by visual results as good as, or even better than, cataract extraction. In the preceding paper, 1 a brief review of the literature on the results of corneal transplantation revealed that there is no accord among ophthalmologists concerning the outcome of this procedure

The corneal epithelium as a source of mammalian somatic mitoses.

Dividing cells that occur abundantly in the lowermost layers of the corneal epithelium of various laboratory mammals provide a reliable and readily procurable source of mitotic figures for studies of chromosome number and form. Preparations may be secured quickly by fixing and staining entire eyes in an orcein-alcohol-acetic-acid mixture, or by fixing in acetic-alcohol and then staining with orcein or with leucobasic f uchsin as used in the Feulgen technic. For cytological examination of the epithelial cells and for determination of mitotic rates, the cornea is dissected from the eye and mounted as a flat preparation. Squashes of the epithelial cells are useful if mitotic counts are not required.

Notes on Australian Cerambycidae. II. Notes on the genus Syllitus, with descriptions of new species

The genus Syllitus forms a small but extremely interesting group of the Cerambycidae, which on account of the small size and dull coloration of its members appears to be generally overlooked and neglected by collectors, and there is little doubt that systematic collecting would add considerably to the number of known species. Although the insects are mostly of small size and sombre coloration when viewed with the naked eye, a microscopic examination reveals them to be of considerable beauty, diverse in the arrangement of the raised costae and the sculpture of the elytra. The genus Syllitus was founded by Pascoe in 1858 (Trans. Ent. Soc. Lond. (N.S.), v, p. 24) for the reception of Stenoderus grammicus, S. deustus, and S. rectus, all of which had been described by Newman. Pascoe considered that these species were "so different, yet so closely allied to each other, that their separation as a distinct group is advisable. I propose for it, therefore, the name of Syllitus; technically it may be at once distinguished from Stenoderus by its large oblong entire eyes." Later, in 1862 (Journ. Ent., i, 5, April, 1862, p. 366), he amplified this diagnostic character, and stated that: "I proposed to separate, under the name of Syllitus, those species of Stenoderus with elevated longitudinal lines on the elytra, from the ordinary red and black ones which constituted the genus originally." Further, in 1864 (Trans. Ent. Soc. Lond., iii (3), 1864–69, p. 554–5), he added that, with one exception—S. albipennis, from Morty—the eyes were "coarsely granulate", a character which holds good for the known Australian species. The affinities of Stenoderus and Syllitus are undoubtedly very close, and their separation is somewhat arbitrary, as is the case with other Cerambycid genera, yet they fall into two convenient and recognizable groups, so that the distinction may be permitted to remain on the ground of expediency and the lack of more satisfactory generic characters upon which the separation could be based.

Experimental studies on the eye of the frog embryo

1) If an entire eye is removed from an embryo ofRana palustris, the tissues of the head are incapable of regenerating a new one. 2) There is no development of an eye if all of the eye-forming region of the fore-brain is destroyed before the medullary folds have closed. 3) Destroying any part of the fore-brain except the eye-forming region does not interfer with the normal development of the eye. 4) The eye-forming tissue of the fore-brain appears to have the power of self-differentiation as it will develop into a more or less normal optic cup when removed from its connection with the rest of the brain and without the presence of a lens. 5) Any ectoderm of the head appears to have the power to produce a lens provided it receives the proper stimulus. 6) Contact between the optic cup and the ectoderm is not necessarily the stimulus that leads to the development of a lens, as a lens can be formed from the ectoderm when the optic cup is some distance beneath the surface of the body. 7) A lens-like structure may be formed from the ectoderm when there is no optic cup on the same side of the head. The process appears to be a self - differentiation of lens-forming tissue of the ectoderm. 8) It seems probably that, under certain conditions, a lens can develop from the upper edge of the optic cup as is the case in the regeneration of the lens in the eye ofTriton.