Lens and cataract research of the 20th century: a review of results, errors and misunderstandings.

Lens and cataract research from a clinical, biophysical, biological and mainly biochemical point of view has a long tradition. Already since the beginning of the 20th century research relating to the chemical composition and metabolism of the lens was conducted. With these analyses an attempt was made to understand the existence and maintenance of lens transparency and the mechanisms leading to lens opacities.

Low vitamin E level as a subliminal risk factor in a rat model of prednisolone-induced cataract.

Purpose: To investigate the relationship between vitamin E deficiency and prednisolone-induced cataract formation, long-term examination of lens changes was performed in rats under the condition of vitamin E deficiency or supplementation and administration of prednisolone.

Methods: Rats were divided into six groups: normal chow (N), vitamin E-deficient chow (ED), normal chow with prednisolone instillation (NP), vitamin E-deficient chow with prednisolone instillation (EDP), NP treatment with vitamin E supplementation (NP+VE), and EDP treatment with vitamin E supplementation (EDP+VE). Prednisolone (1 mg/kg small middle dot d) and vitamin E (5%; 10 microL per administration per eye, 1 mg/kg small middle dot d) were applied in the cul-de-sac.

High hurdle of clinical trials to demonstrate efficacy of anticataractogenic drugs.

Recently, the rapid progression of cataract surgical technique has led cataract patients in industrialized countries to ignore the possibilities of drug therapy. Globally, however, it will be impossible in the near future to treat cataract by surgery alone, mainly due to medicoeconomic reasons. Preventative measures must be sought.

UV damage to the eye lens: further results from animal model studies: a review.

UV irradiation has the potential to induce the development of lens opacities. This has been demonstrated since long with animal experiments. Unfortunately these animal cataracts did not explain or elucidate the epidemiological observation that the frequency of human cataracts--such as the so called senile cataract--is remarkably higher in regions with increased cosmic UV irradiation or in the population being in close professional contact with UV-irradiation.

Epidemiological studies on UV-related cataract in climatically different countries.

Cataract epidemiological surveys applying objective judgement through lens images in the climatically different places of Noto and Amami, Japan, Singapore and Reykjavik, Iceland yielded several significant results about the influence of solar UV. 1) The percentage of transparent and of lens opacification was significantly higher in the Reykjavik subjects than in the Singaporeans. 2) The percentages including early changes were higher in Amami and Singapore than in Noto and Reykjavik.

Light scattering in the human lens in childhood and adolescence.

The age-related increase in normal light scattering in the adult human lens has frequently been documented with Scheimpflug imaging techniques. There are only insufficient data on lens light scattering, however, from the first 2 decades of human life. After having obtained informed consent from their parents, the anterior eye segments of 26 children of both genders were documented with a Topcon SL-45 Scheimpflug camera on Kodak Tmax 400 ASA black-and-white film in 3 meridians.

An index for human lens transparency related to age and lens layer: comparison between normal volunteers and diabetic patients with still clear lenses.

Objective: The light scattering intensity of normal, clear lenses varies with age and with the localization within the lens. Realizing the biometry of single lens areas together with their relevant light scattering intensity one should be able to calculate an index to express the lens transparency properties of normal human lenses in dependence on age. Performing the same procedure in cases of diabetic patients with still clear lenses it should become possible to obtain an index for the lens transparency properties of lenses under the 'risk factor' diabetes.

Location and severity of UVB irradiation damage in the rat lens.

We investigated the location and severity of lens opacities and epithelial alterations following ultraviolet-B (UVB) irradiation in vivo, using Brown Norway rats. A group of 9 rats received 65 mJ/cm2 UVB irradiation from overhead lamps every 6 days. Lens changes were documented and evaluated by an anterior eye segment analysis system.

In vitro UV-B effect on lens protein solutions.

To investigate the effects of UV-B exposure on the protein solutions of different lens parts, rabbit lenses were separated into the equator (Eq), anterior cortex (Ac), nucleus (Nu) and posterior cortex (Pc). After homogenization, the water-soluble protein from each part was irradiated with UV-B at 0 to 0.225 J/cm2.

Rotating slit image camera TOPCON SL 45. New developments for simultaneous image acquisition by photographic and CCD-assisted on-line documentation.

In a first approach the photographic camera part of the SL 45 B has been replaced by a CCD camera (2/3" black-and-white camera/Teli CS 3440 CCD B/W Tokyo Electronic Industry Co., Ltd.) unit thus enabling direct image acquisition and computer assisted analyses.

In vivo morphological changes in rat lenses induced by the administration of prednisolone after subliminal X-irradiation. A preliminary report.

In order to induce steroid cataracts in rat lenses, prednisolone acetate was administered together with a single subliminal dose of X-irradiation, which was applied unilaterally before steroid application started. The rats were divided into a control group (without prednisolone acetate administration), a group with a topically administered daily dose of 1 mg/kg prednisolone acetate suspension and a group with a systemically applied daily dose of 0.8-1.

Ocular drug safety and HMG-CoA-reductase inhibitors.

150 patients suffering from primary hypercholesterolemia were divided into three different groups receiving (1) lovastatin, (2) simvastatin, or (3) fenofibrate as controls. The aim of the study was to detect possible drug-induced ocular side effects, especially in the lens. The study period was 2 years.

Cataract classification.

Opacifications of the eye lens--generally defined as cataracts--develop in various different parts of the lens. Therefore, one has to differentiate the types of opacities. For epidemiological studies it is prerequisite to classify the cataracts according to their localization within the lens as well as to the size and intensity of the opacified area.

[Biochemistry of the lens. Retrospect of thematic and methodologic developments, prospects for future research].

Since beginning of the 20 century research about chemical composition of the lens and the importance of biochemical processes for the maintenance of lens transparency is conducted. The review article covers the development of research subjects and their adaptation by the introduction of new analytical techniques.

Histological changes of rat lenses after UV-irradiation and D-penicillamine treatment.

The aim of the study was to investigate the effects of local treatment of rat eyes with D-penicillamine (PE) or D-penicillamine disulfide eye drops and their influence on the development of UV-induced lens opacities. 126 Brown Norway rats were divided into 14 groups to test the efficacy of different concentrations of the drugs. During the investigation period, slitlamp examinations and Scheimpflug measurements were performed.

[Objectified measurement of eye lens transparency in elderly probands. Results of a Scheimpflug photography study over the course of three and a half years].

Lens density has been followed-up in 32 healthy volunteers (mean age 65 years) over a period of 3.5 years. The negatives of Scheimpflug-photos (Topcon SL-45) were evaluated by linear microdensitometry in three measure planes (Joyce Loebl 3 CS).

[Aspects of physiology, pathology and epidemiology of cataract].

World Health Organization estimates that 23 million people have a visual acuity of 0.05 or less. For 12-15 million people cataract is the cause of poor visual acuity or blindness and the majority of those afflicted live in Third World countries.

[Ocular side effects of drugs].

Drug-induced side effects manifested by the human eye are characterised by the specific anatomical, histological and functional features of the eye. Such ocular changes may arise after local or systemic drug application. The following article outlines the clinically relevant common drug-related side effect on the lids, cornea, conjunctiva, lens, retina, uvea, and the optic nerve, as well as effects on the intraocular pressure, refraction and accommodation.

Comparison of the Nidek EAS 1000 system and the Topcon SL-45 in clinical application.

Some years ago, Nidek developed a new imaging system for the anterior eye segment, which offers the possibility of recording Scheimpflug and retroillumination images. The system consists of 2 different technical units, a camera unit for image recording and a computer unit for storage, system operation and image analysis. To evaluate the clinical use of the system and its reproducibility, a study with 31 volunteers/patients was performed that were photographed with the Nidek EAS 1000 at the meridians 0 degree, 45 degrees and 180 degrees.

Scheimpflug photography in clinical ophthalmology. A review.

The development of a slitlamp camera system based on the Scheimpflug principle with image analysis has been a major improvement in lens and cataract research. Since its introduction into ophthalmology by Brown and Niesel in the sixties of this century and further technical amelioration by Hockwin, Dragomirescu and Sasaki it has been applied in various experimental and clinical investigations. The purpose of this paper is to summarize and review the application of Scheimpflug photography in clinical ophthalmology and to show possibilities and indications for the use of the Scheimpflug technique in clinical studies.

Objectified measurements of eye lens transparency in a volunteer group of advanced age, carried out over a period of 3.5 years. Results of a Scheimpflug-photographic study.

The present study deals with a prospective investigation on the optical density of the eye lenses of 32 volunteers with initially normal eyes (mean age 65 years) over a period of 3.5 years. The negatives of the Scheimpflug photographs (Topcon SL-45) were evaluated by linear densitometry in 3 measure planes (Joyce Loebl 3CS).

A new approach to drug penetration study.

To investigate the route of drug penetration into the eye and drug distribution patterns in the lens, the distribution of aldose reductase inhibitor (AL-04114) in the lens was measured in short term bovine lens organ cultures and topical administration to rabbit eyes. A micro lens sectioning technique was applied to determine drug localization within the lens. Freshly enucleated bovine lenses were incubated with different concentrations of an ARI (AL-04114)-containing medium for 3 hours.

Biochemical and morphological changes in rat lenses after long-term UV B irradiation.

The aim of the present study was to investigate biochemical and morphological changes in rat lenses following long-term UV B irradiation. After an irradiation period of 156 days with follow-up documentation by means of Scheimpflug photography, section-related biochemical analyses of the lenses as well as histological investigations were performed. The video-based Scheimpflug photography (Zeiss SLC) again proved to be an excellent method for the documentation of the UV cataract induced in rats.