Biomedical subjects
G Eisner
Publications and source records attributed to G Eisner.
Indentation laser photocoagulation of peripheral retinal neovascularization.
The treatment of peripheral retinal neovascularization by laser photocoagulation is an accepted technique. One of its limitations is the difficulty in photocoagulating retinal neovascularization that has become even slightly elevated from the underlying pigment epithelium. The failure to close the neovascular frond and the production of a vitreous hemorrhage are the complications from the direct photocoagulation of elevated neovascularization. The currently accepted method of treating the feeding retinal arteriole and venule, although successful, requires multiple treatment sessions. The use of a scleral indentation funnel at the time of laser photocoagulation permits the direct photocoagulation of elevated neovascularization in some cases. This technique increases the number of neovascular fronds that are amenable to direct laser photocoagulation, improves the rate of success of closure of the neovascularization by photocoagulation, decreases the necessary number of treatment sessions, and decreases the risks from treatment.
Transvitreal channel related to an intravitreal developmental anomaly. Slitlamp and electron-microscopical study.
Description of an intravitreal glia particle connected to an atypical transvitreal channel, which was found incidentally during the autopsy of an unfixed sheep vitreous. The anomaly is interpreted as an avulsion of retinal tissue during prenatal development, resulting in a decreased density of the vitreous framework (transvitreal channel) above the retinal defect. In analogy to other observations of transvitreal channels, which occur at all sites where the inner retinal surface is altered, the analysis of the anomaly sustains the hypothesis that framework of the vitreous is formed by elements of the retinal surface. The cells within the particle were examined with electronmicroscopy. They show immature collagen fibrils between glia cells, which may be precursors of vitreous collagen, immigrating through intercellular lacunae into the vitreous.
[The use of a viscous substance (Healon) to improve tactility (author's transl)].
Now that a clinically suitable viscous substance (Healon) has become available for use in ophthalmic surgery, it is worthwhile to examine in greater depth the problems of tactility and methods of resolving them with viscous substances. These are not simple substitutes for aqueous humor which, once introduced, may be left in the eye. It is more appropriate to compare them with mechanical instruments employed for a specific purpose and subsequently removed. Thanks to their stabilizing effect, viscous substances increase safety in many types of manipulation. However, their use calls for a thorough knowledge of their side-effects. This has to be learned, as is the case with any new instrument.
[Cataract surgery (conventional) (author's transl)].
The presently employed methods for cataract operations are characterized by a high success quota. Some details from the fields of anesthesia, separation of the lids, cutting and stitching form, stitching material, cryoextraction which contribute to this success quota are discussed.
[The use of viscous substances as stabilizers (author's transl)].
Viscous substances are important surgical tools for stabilizing otherwise unstable intraocular spaces and subcompartments. They increase the safety of a great variety of operations such as intraocular implants, extraction of subluxated lenses, keratoplasty, cyclodialysis, filtering procedures, vitrectomy, prevention of hemorrhages (as well as maintaining the patency of lacrimal pathways).
[The use of Healon in extracapsular cataract extraction and in the implantation of intraocular lenses (author's transl)].
The use of Healon 1% hyaluronic acid increases the safety of implant operations. The result is a decrease in the number of cases where implantation employing conventional techniques has to be abandoned on account of complications during surgery. Our experience of 65 implants with follow-ups ranging from two to 30 months is presented. A detailed description of the technique and postoperative problems is given.
[Use of a viscous substance (Healon) in spatial tactics of the anterior segment].
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Laser photocoagulation with biomicroscopic scleral indentation.
The treatment of peripheral retinal tears by laser photocoagulation is an accepted technique. One of its limitations is its difficulty in use near the ora serrata. The inability to treat the anterior border of a rentinal tear may allow the tear to progress to clinical retinal detachment despite treatment of the tear's posterior and lateral borders. The use of a scleral indentation funnel at the time of laser photocoagulation permits the sealing of all margins of the break. This technique increases the number of retinal tears that can be treated by the laser, and it may improve the rate of success of photocoagulation of peripheral retinal tears.
Retinal degeneration in rhesus monkeys, Macaca mulatta. Survey of three seminatural free-breeding colonies.
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Age-related changes in the vitreus and lens of rhesus monkeys (Macaca mulatta).
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Ontogeny of single nephron filtration distribution in canine puppies.
The ontogeny of single nephron filtration distribution was studied in 29 canine puppies two hr to 42 days old using the [14C] ferrocyanide method as modified by Coehlo (9). The ratio of 14C counts in outer cortical nephrons (OC) to counts in juxtamedullary nephrons (JM) were plotted against age for each puppy. This ratio (OC:JM) provided an index for comparing the single nephron glomerular filtration between regions. A four-fold increase in OC:JM occurred from two days to four wk. The youngest puppy, two hr old, showed a ratio of zero because no counts were detected in OC at that age. The most rapid increase occurred in the first 8 days of life. By the fourth wk, the mean OC:JM ratio was 0.72 +/- 0.06, approaching values reported by other laboratories for adult dogs. In contrast to age-related changes in OC:JM ratio, the ratio of middle cortical to JM counts showed no age-related increase. Cortical blood flow distribution was determined by the microsphere method. The ratio of blood flow to outer and inner cortex increased from 0.43 at one-half a day to a mean of 2.93 after one wk. The ratio of OC:JM single nephron filtration of OC/inner cortical nephron renal blood flow was 0.36 from 3 days to 26 days (n = 12) and did not change significantly with age, indicating that changes in zonal filtraion matched the alterations in cortical blood flow distribution.
[Posterior hyaloid in the retinol periphery].
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[Photocoagulation: information for non-specialists (author's transl)].
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Regional differences in the binding affinities of beta-adrenergic receptors in the canine kidney cortex.
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[Photocoagulation and vitreous growth. Experiments on development of the vitreous (author's transl)].
The examination in optical section of sheep eyes, photocoagulated several months previously, shows a disturbed vitreous growth above the destroyed retinal areas (Figs. 2-4). The shape of the resulting deficiencies of vitreous structure (holes) suggests that the vitreous is produced by retinal elements and develops by appositional growth. Holes above lesions due to photocoagulation in an early developmental stage are longer (Fig. 1a; Fig. 2) than those above photocoagulations in later stages (Fig. 1b; Fig. 4). Holes above lesions with intensive retinal destruction (Fig. 2a; Fig. 4a) produce more important vitreous deficienceis than do weaker coagulations (Fig. 2b). Structural deficiencies, though extensive at first, become less important during further growth (Fig. 1c; Fig. 2c; Fig. 3 shows transverse sections at a deep and superficial level through the holes of Figure 2c), which is a sign that in the retinal scars a regeneration of elements producing vitreous occurs. Apart from the theoretical implications concerning the development of the vitreous, the results of our experiments should be considered when photocoagulating children.
Macular degeneration in rhesus monkey (Macaca mulatta).
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[Reticular cystoid degeneration (author's transl)].
This is the first description of the biomicroscopic appearance of reticular cystoid degeneration (RCD). The case with exceptionally large RCD illustrates the difficulties of diagnosis in the living eye of this rather common condition. There is no scotoma in the visual field and the pillars transgressing the cystoid spaces obviously contain nervous elements. Morphologically the RCD are not very conspicious and are easily confounded with typical cystoid degenerations. Differential diagnosis between these two cystoid alterations of the retina is therefore difficult and possible only if vessels on the outer layer of the cystoid spaces are found.