Hans-Reinhard Koch

Photographic Documentation of Disturbances of the Lens Transparency during Ageing with a Scheimpflug Camera System

Due to its limited depth of focus, the conventional slitlamp photography is not suitable for the documentation of a total lens section which depends on a sufficient depth of focus. By applying the Scheimpflug principle it is, however, possible to demonstrate the optical section through the lens as a slit image which is nearly undistorted and shows sufficient depth of focus. An integrated instrument based on the Scheimpflug principle has been developed, and the present paper demonstrates its importance for clinical and experimental use. After densitometric evaluation, these photos enable to obtain hard data on normal and pathologically changed lenses. Different densitometric methods may be employed for the evaluation. Experiences with the equipment from running clinical test series are reported.

Photo-Cell Device for Slit-Beam Adjustment to the Optical Axis of the Eye in Scheimpflug Photography

In the photographic documentation of lens findings according to Scheim-pflug’s principle, a good reproducibility of the camera adjustment to the patient’s eye is prerequisite for quantitative densitom

Separation of lens proteins in rats with tryptophan deficiency cataracts

Abstract Rats on tryptophan-free diet develop posterior subcapsular (saucershaped) cataracts and discrete anterior subcapsular haze. Trp-deficient rats have a lower lens dry weight than normal lenses of the same age. There is a slight significant increase of lens water in the diet group. The water insoluble lens protein showed no changes by the trp-free diet, whereas β-crystallins were severely affected. After 20 days of trp deficiency the amount of β-crystallin was only 72% of the value found in controls. α- and γ-crystallins were less affected and showed only a slight (but significant for α-crystallin) decrease.

Naphthalene Cataracts in Rats. Association of Eye Pigmentation and Cataract Development

The development of naphthalene cataracts was studied in 5 strains of rattus norvegicus of different pigmentation. Whereas all animals of the pigmented strains (E3, BDE, DA) developed zonular cataracts after latencies of 20 to 28 days, only some of the albinos (Wistar, Sprague Dawley) exhibited less pronounced changes after longer latencies of 32 to 61 days. The possible importance of the melanin-synthetizing enzyme phenol oxidase (tyrosinase) of the iris for the formation of the cataractogenic substance 1,2-naphthodiquinone is discussed.

On the Influence of a Monolateral Carotid Ligation Upon the Formation of Radiation Cataract in Rats (With Colour Plate I)

In a first experiment, it could be shown with the particle distribution method that a monolateral carotid ligature in rats reduces ocular blood flow on the affected side for a period of at least 1–2 w

Investigations on the Influence of Oxyphenbutazone on Formation of Galactose-Induced Cataracts in Rats

Testing the ocular side effects of new drugs, it is not sufficient to investigate cataractogenic effects in normal lenses. Some substances not cataractogenic themselves may act as additionalnoxae when combined with other subliminal cataractogenics. The effect of oxyphenbutazone (5% and 10% Tanderil eye ointment) on formation and progress of galactose-induced cataracts was investigated in rats. OPB did not promote or aggravate the experimental opacities. On the contrary, it seemed to cause a slower progression of cataracts.

Konservative katarakttherapie in klinik und experiment

AbstractUp to the beginning of the 17th century it had been the general belief that a cataract results from the formation of a whitish membrane in the pupil. The first authors who dared to call cataract an opacity of the lens itself were either laughed at or violently attacked. Only after the studies of brisseau (1709) the true nature of cataract became evident. The therapeutic consequence was the development of cataract extraction (daviel, 1753). Surgery became the universally applied way of treatment, while conservative therapy was more or less neglected. Nevertheless, prevention and healing of cataract through drugs has always been a favorite object of ophthalmology.Principal objections, however, have repeatedly been raised against medical treatment of cataract. Time and again it was doubted that lens opacities could be influenced at all. Even believers in a medical cataract treatment disagreed on the question, whether opacities could actually be cleared or only their progress be prevented. becker (1877) gave important impulses for non-surgical therapy. He considered a disturbed nutrient supply of the lens due to senility a possible cause for opacities. Although becker himself was not in favour of a drug therapy for senile cataract, his theory encouraged many others to develop ways of medical treatment. vogt (1931–1942) on the other hand believed nonsurgical treatment to be Utopian, because the onset and development of cataract depended on heredity. He saw his theory confirmed by follow-up studies in identical twins. These opposing approaches of becker and vogt — characterized best by the catchwords senility ”and heredity” — were the ground for endless discussions on the justification of therapeutic efforts. Today they are no longer a matter of dispute. vogts theory of a genetic preformation of senile cataract could not be substantiated, though several types of opacities could be determined as being hereditary conditions. At any rate, vogt was wrong to believe, that hereditary diseases could not at all be treated with drugs. Although to date a conversion of the genotype does not yet seem possible, it is well known, that a manifestation of the phenotype can be influenced by drugs. This drug treatment of cataracts is not principally impossible, even in cases of genetic origin.All major medical achievements of the last century have somehow been introduced in the therapy of senile cataract. During the age of pioneer work in physiological optics, for instance, it was assumed that accomodative stress was the cause of lens opacities. schoen (1887–1889) believed to have found histological evidence backing this theory and tried to prevent cataracts by exact correction of refractive errors.A next step in cataract therapy was the use of inorganic substances. Here potassium, calcium, magnesia, strontium, mercury and cerium were applied in the form of iodide, iodate, nitrate, acetate, citrate, cyanide, lactate, chloride, or chlorate. These substances were supposed to work through substitution of inorganic lens constituents, dehydration of the lens, systemic effects on the organism, or increased blood supply to the eye.Also some organic substances owe their temporary popularity in cataract therapy to an effect on the blood circulation. Dionine, boric acid, glycerine, papaverine, parotin, tetranitol, niacin, and procain were favourites. An evaluation of their influence is, however, complicated by the fact, that an increased blood supply would not be limited to the ciliary body. It could also increase the blood supply to the macula, thus improving visual acuity without affecting the lens.Fortunately, radium was only used for a short period in cataract therapy. As soon as its true effect on the lens became generally known, the method was abandoned.Immunotherapy as a form of cataract treatment was largely propagated by römer (1905–1914). In his opinion cataract had to be considered an autoimmune disease due to so-called lentotoxins. His method to intercept such toxins in the blood stream was to apply lens protein orally. Though römer himself soon abandoned this theory, others used his procedure in several modified ways and applied homologous and heterologous lens proteins parenterally and orally. davis (1922–1937), on the other hand, recommended the use of lens antigens in the place of antibodies.First experiments with hormones were initiated when the importance of the endocrinium for aging organisms became known. One of the first scientists in this field was siegrist (1928). Interest in the hormone therapy was increased by the fact that several diseases of the endocrinium are complicated by cataracts. Although it has been possible to delay the progress of endocrine cataracts by substituting a lacking hormone (e.g. insulin, parathormone) senile cataracts could not be influenced in this way. The name endocrine cataracts” — much popularized by these futile therapeutic attempts — is, however, misleading. On the one hand, the so-called endocrine cataracts are due to totally different causes, while on the other hand there are non-endocrine cataracts of similar etiology (e.g. due to galactose and xylose or to hypocalcemia of non-endocrine origin.) A classification as sugar cataracts and hypocalcemic cataracts is more up to the point. Up to now, nearly all known hormones, — parathormone, insulin, parotin, and even corticosteroids — have been tested in cataract therapy, mostly in polyglandular” form.The next period in non-surgical cataract therapy was that of the vitamins. This seemed to be a rather promising procedure, as vitamin defiencies had been discovered to be the cause of various diseases. However, the search for a specific lens vitamin, for a cataract-preventive-factor”, proved futile. Special importance was attached to vitamin C, because the lens turned out to have the highest concentration in ascorbic acid next to the adrenals, and because several authors found a decrease of vitamin C in opaque lenses. Although a cataract due to vitamin C deficiency alone could not be detected, it was possible to show that a scurvy could be an additive subliminal factor promoting the action of other cataractogenics. Further experiments were made with the vitamins B1, B2 -complex, riboflavin, niacinamide,B12,D,A,E, and P.Ascorbic acid and riboflavin caused considerable interest being redox-systems. Further knowledge, that an intact and efficient redox-system is essential for maintaining the lens metabolism became important in cataract therapy. Among other SH-substances cysteine and glutathione were given special attendance. They were not only tested for their use in senile cataract, but also for their applicability in the prevention and treatment of irradiation cataracts.New impulses to drug treatment were given by ogino (1955–1957). He was able to show the cataractogenous effect of various quinones. This led to the development of substances intended to act as competitive inhibitors of pathogenic quinones, without inducing opacities themselves. oginos theory on the overall importance of quinones in cataractogenesis could not be verified. In some types of opacities, however, an influence of such compounds seems likely (e.g. naphthalene).All of these attempts were aimed at influencing either the lens directly or its surrounding tissues, There exist, however, other forms of treatment meant to affect systemic diseases which are complicated by cataracts, such as the treatment of diabetes with insulin, of galactosemia with lactose-free diet, or of hypoparathyroidism with parathormone, calcium or AT 10. Experiments on radiation cataracts made obvious that, — aside from therapy — prophylaxis can be of superior importance. The latter can consist in the elimination of cataractogenic factors or the development of protective agents.Up to now, drug treatment of senile cataract was only in part based on biochemical analysis. If certain constituents of the lens were found to be at a decreased level, it was tried to raise their intake by drug application. We have seen numerous examples of such a procedure and have to point out that an administration of missing substances is not sufficient, as long as their concentration at the site of action and their part in metabolism cannot by exactly determined.Today it is evident that the lens transparence is based on intact biochemical processes which are of a rather complex nature. Ophthalmic experimentation has revealed various factors which might disturb these processes and induce lens opacities. Analyses of the lens metabolism in cases of cataract have shown that disturbances of the carbohydrate metabolism may be the primary cause, although the opacity itself is a secondary reaction of the lens proteins to these disturbances. The importance of the intermediary metabolism for a tissue — especially that of the carbohydrates — lies in the energetic balance of endergonic and exergonic processes. Because of their complex interrelations, disorders of the energy balance can effect different lens constituents.In many experimental cataracts it has been possible to elucidate the mechanism of such disorders as well as their effects. It could be shown that the kind and proportion of the lens hazard is related to the age of the animal. We feel that this point is of great importance for future experiments on drug treatment of senile cataract.In most cases senile cataracts are due to aging processes in lens metabolism accompanied by a disturbance of the energy balance. In contrast to the aforementioned experimental disturbance factors, aging is no sudden incident, and not only the individual lens fibre is affected. According to h. k. müller, the process of lens aging is closely related to alterations in the surrounding media.Many biochemical studies on the lens have considered age changes of metamolism. Experimentation mostly involved lenses of animals. As nordmann recently showed in a critical review of the literature, our

Experimental Lens Opacities in Rabbits Induced by Intraocular Application of Acetylcholine

Acute reversible lens opacities were induced in rabbits by intraocular irrigation with I and 5% acetylcholine solutions. Determinations of fresh weights and dry weights in removed lenses, as compared to solvent-treated and untreated controls, showed a significant increase in lens water. A suggested effect of the animals’ age on the degree of lens swelling was not significant.

Experimental Arabinose Cataracts in Young Rats

Rat lens aldose reductase reduces several aldoses such as D-glucose, D-galactose, and D-xylose to polyols, which cause cataracts by lens swelling. L-Arabinose, which has the same configuration at C

Basic Research on the Crystalline Lens and its Importance for Clinical Ophthalmology

Cataract is the most important pathologic condition of the crystalline lens and one of the most frequent causes of blindness in the world. Cataracts may be the consequence of a multitude of developmen