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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. As one of the these measures, the development of anticataractogenic drugs has reemerged as a focus in the lens research field. Although clinical trials of newly developed drugs are absolutely necessary before they enter the market, they have been considered to be a rather easy task. However, in order to gain accurate and reproducible data from trials, the trial program must be carefully prepared. The numbers of participants to the trial, the selection criteria of the subjects, the objective judgment of cataractous changes, follow-up period, a high technical level for cataract documentation and image analysis are proposed. Although there still remain some difficulties concerning the methods for objective judgment, a scientifically acceptable examination must be conducted.

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. The main problem was that the type of UV induced animal cataracts differs remarkably with respect to onset, localization of the opacity, size and its timely progression from the cataract classes observed in human. The research of the last 10 years comes to the conclusion that beside the direct (acute) damage--as seen in animal studies due to high UV dosages--we have to realize a syn- or co-cataractogenic potential of UV irradiation even below the threshold dose which is able to accumulate in the lens and to initiate together with other risk factors (chronic damage) the opacification of the lens. The mechanism for the animal cataract and the human cataract (with an UV risk participation) are different. The epidemiological research about cataract frequency in different regions of the world have to take into account that UV irradiation--even below a threshold dose--is a possible risk among the multifactorial pathogenesis of human cataract.

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. Methods: 748 eyes with transparent lenses in 383 healthy individuals and 134 eyes with clear lenses in 70 subjects with diabetes were examined. Scheimpflug slit images of the lens were documented by a Nidek EAS-1000 instrument. Biometry for measuring the distance of the single lens layers from the anterior capsule and densitometry for determining the light scattering intensity of six defined lens layers along the (theoretical) optical axis were performed. The index of the lens transparency properties was calculated using the light scattering intensity of a defined lens layer and its distance from the anterior capsule. Results: Lens thickness and light scattering intensities increased linearly with increasing age in the normal population as well as in the diabetic patients. The densitogram pattern of the light scattering intensities in the defined representative six points was similar in both populations, but in the diabetic group the lens thickness was larger and the light scattering intensities were higher at all ages. Conclusion: The index of lens transparency properties calculated with the light scattering intensities of a certain lens area and its distance from the anterior capsule is a useful measure of lens clarity in dependence on age. ‘Clear’ lenses of the diabetic population show significantly higher indices for the lens transparency properties in all age groups.

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. 3) Progressed lens opacification was highest in Singapore. While the main type of lens opacification was cortical in Noto and Reykjavik, that of Singapore was nuclear. 4) A significant correlation between cortical opacification and the history of time spent outdoors was noticed. The UV risk for formation and/or progression of cortical opacification should be acceptable from the epidemiological standpoint. J Epidemiol, 1999; 9 : S33-S38.

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. Images have a full length of 8.8 mm. The images can be taken with only the observation light, no flash is necessary. Thus, the images can also be recorded on a VCR performing a complete rotation of the slit and all lens sections can be monitored obtaining almost three-dimensional information about the lens transparency/cataract formation. The further improvement is the on-line imaging for all SL-45 cameras in having CCD acquisition together with the usual 35-mm film photography. This is very important for the documentation of the lens coloration and for measuring lens fluorescence. For this TOPCON SL 45 (new generation) we are using the ‘2nd Scheimpflug condition’ located within the eye piece of a SL 45 which is taken with a CS b/w No. 8310 C (Tokyo Electronic Industry Co., Ltd.). It is possible to integrate the CCD system in all TOPCON SL 45 Cameras (1 st and 2nd production charge as well as SL 45 B).

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 applica

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). Correlation coefficients, curves of regression as well as calculations of the percentage of density change made obvious, that a minimal increase in lens density occurred in the anterior cortical region.

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). The evaluation of the coefficient of correlation, the representation of the regression straight line as well as the evaluation of the percent changes in lens density showed that during the observation period of 3.5 years a minimum increase in density took place mainly in the anterior cortex.

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. The biochemical analyses provided indications to potential damaging mechanisms; the section-related technique used allows more precise analyses than the processing of whole lenses in a cataract type restricted to a certain layer, as is the case with UV B damage. The most prominent biochemical findings were a significant decrease in glyceraldehyde-3-phosphate dehydrogenase in the equatorial region in the group with the highest irradiation dosage and a decrease in lactate dehydrogenase in the nuclear region. The histological results reflect the local extent of the UV damage as well as its progression after a prolonged irradiation period.

The water-soluble proteins of the human fetal lens (175- and 285-day-old) contain HM-, pre-alpha-, alpha-, beta- and gamma-crystallins. Using the frozen-sectioning technique, it can be demonstrated that the fetal lens does not have an homogeneous distribution of crystallins, but there are gradual differences between the cortices and the nucleus. The frozen-sectioning technique shows for the adult lens significantly increasing amounts of beta-crystallins of pI 4.95-5.55, especially at the posterior supra-nuclear layer, increasing amounts of HM-crystallins and decreasing amounts of beta-crystallins of pI 5.80-7.05 in the nucleus. This microsectioning technique was correlated with Scheimpflug photographs of the fetal and adult lens. In the fetal lens, the anterior capsule and 2 peaks in the anterior and posterior supranuclear layers could be visualized after densitometry. In the adult lens 5 layers could be demonstrated, e.g. the anterior capsule, the anterior supranuclear layer, the nucleus, the posterior supranuclear layer and the anterior capsule.

Lenses of 14-week-old rats were separated into 10 layers or fractions by a frozen-sectioning technique. The biochemical characteristics of these layers were assigned to corresponding parts of the densitometric reading obtained from the Scheimpflug negative, which enables a correlation of light scattering values recorded in vivo to protein patterns in the same area. Calculated as percentage of lens dry weight, all water-soluble crystallins show minima and the water-insoluble crystallins show maxima in the lens nucleus. This demonstrates that the nucleus contains the bulk of the water-insoluble high-molecular-weight and alpha-crystallins, being the source for the Scheimpflug light scattering pattern.

The effects of ultraviolet B (UV-B) irradiation on transmission of the rat cornea were studied in combination with or without naphthalene feeding. UV irradiation as well as naphthalene feeding caused a decrease in transmission in the wavelength region from 315 to 450 nm, UV irradiation being thereby the more hazardous influence. The combination of both noxae did not lead to a pronounced decrease as compared with UV irradiation alone. Although the histological findings of the eye lens suggest a syncataractogenic action of UV-B and naphthalene feeding, a corresponding effect could not be found by means of Scheimpflug photography. This could be possibly due to the alteration in corneal transmission properties following UV-B irradiation.

Ultraviolet (UV) filter photography with the Topcon SL-45 Scheimpflug camera has provided valuable informations about age-related and cataract-type-dependent changes in the spectral properties of the human lens. The present study deals with the same phenomenon in normal lenses of the Brown-Norway rat and in those with true diabetic and naphthalene cataracts. The lenses of all animals of the 3 groups were photographed at the middle and final examination of a 6-week experiment on Kodak Tri-X-pan ASA 400 black-and-white film, using visible light (xenon flash) and UV-filtered light (320-390 nm transmission) from the same light source for recording. The results clearly demonstrate that both cataract models exhibit characteristic fluorescence properties, different from each other and from normal rat lenses. The naphthalene cataract shows the most drastic increase in fluorescence in the cortex, compared to the increase in scattering with visible light. The versatility of the method in preclinical research and the versatility of the cataract models open new aspects of drug-related research in drug toxicity studies.

We studied the handling and the potentials of three different cameras operating according to the Scheimpflug principle and which currently are commercially available. The examinations were performed with the cameras Topcon SL-45, Topcon SL-6E with cataract attachment and Zeiss SLC system. Pigmented Brown-Norway rats with ultraviolet-B-induced cataract were used as the examination model. The image characteristics of the three cameras can be summarized as follows: The Topcon SL-45 camera produces very sharp images with small distortion; the Tocpon SL-6E camera with cataract attachment has the advantage to record simultaneously a slit image and a retroillumination image on the same film frame, but the slit image is quite distorted at the vertical axis; as regards the Zeiss SLC system, the quality of the video image is not as good as a film negative; however, this camera offers a superimposed image to the observer for easy orientation, as for example with small animal eyes. In addition, the direct quality control of the image on the screen increases the reproducibility significantly. However, the slit image is quite distorted at the horizontal axis.

Scheimpflug photography has become the basic method for documentation of lens transparency changes in clinical and experimental ophthalmology, due to its high reproducibility. In animal cataract studies, the reproducibility is strongly influenced by the handling characteristics of the camera used, due to limited cooperation of the animal. The reproducibility of the Zeiss SLC system, which offers a direct quality control of the image on the video screen, was tested with 2 animal cataract models, the ultraviolet B (UVB)-induced cataract and the true diabetic cataract in the Brown-Norway rat. 10 rats each of the 2 cataract models and of an untreated control group were photographed in a random order on 3 occasions on the same day by the same photographer. Quality control and densitometry were performed by the same system operator, the measurement window was positioned standardly, coincident with the optical axis of the eye. Statistical comparison was carried out in the capsular layer, that is the area of initial cataract development in both models, and in the cortical layer, into which the diabetic cataract progresses during its later stages of development. The nuclear layer was also evaluated, but has no direct relation to one of the models employed. The results clearly indicate that the reproducibility is predominantly influenced by the homogeneity or inhomogeneity of the cataract model employed. The system operator and the photographer provided that they are well trained, have minor influence on the reproducibility of the Zeiss SLC system.

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. Around the middle of the century the stationary analyses measuring the content of certain substances in the lens were more and more replaced by the search for dynamic metabolic processes responsible for lens growth, maintenance of transparency and possibly active participation in lens function (such as accommodation). Also the disturbances as a result of ageing or the formation of lens opacities have been investigated and resulted partially in the elucidation of reaction chains, leading from a trigger to the formation of a cataract. Lens biochemistry is no longer a closed book to us, but there are still many question marks. Why were we not able to solve more problems around lens and cataract? The research effort with a remarkable financial input and a great number of scientists worldwide during the second half of the century does not correspond to the results obtained. There must be something wrong with our strategy, our interpretation of the results or even both. We would like to stress some points which might be regarded as errors or misunderstandings in the lens research community, thus preventing a better outcome of the enormous investment of work and money. A great disadvantage is the missing cooperation between clinicians and epidemiologists on one hand and basic lens researchers on the other. Especially the ignorance of basic researchers regarding the clinical problems of the lens and of cataracts might be to blame for several 'errors and misunderstandings'. It is not even so long ago since the slitlamp microscope examination of animals belonged to the essential standard methods of a lens research team. Another disadvantage still is the use of the general diagnosis 'cataract' by the clinicians without further classification of the topography of the opacification, which supports the concept that all cataracts have the same trigger mechanism. But most regrettable is the fact that many clinicians have never been really interested in basic research of the lens, in cataract pathogenesis and epidemiology of risk factors or in testing the efficacy of cataract-preventing medication. Their main goal was cataract surgery. On the basis of the success of the cataract surgery at the present time clinicians have even developed the opinion that lens and cataract research is no longer necessary to overcome cataract blindness. But as we all know this refers only to highly industrialized countries; millions of cataract-blind people are still without such help and a change of this condition is not in sight. In our opinion lens and cataract research is still necessary and it will be more successful if we bear in mind the mostly unintentional errors of the 20th century but keep them out of our daily practice.

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.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. Lens changes were documented and analyzed. Vitamin E status was confirmed by measuring peroxide-induced hemolysis.After 15 months, 91.7% of the eyes in the EDP group showed development of anterior and posterior cortical cataracts. Supplementation with vitamin E significantly reduced cataract formation (to 38.9% of eyes). Neither a vitamin E-deficient diet nor prednisolone treatment alone significantly increased cataract formation. Hemolysis-susceptibility tests confirmed the expected vitamin E status of rats fed vitamin E-deficient chow and rats supplemented with eye drops containing vitamin E.Vitamin E deficiency and long-term prednisolone treatment together cause cataracts. Singly, however, both conditions are subliminal cataractogenic risk factors.

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. Around the middle of the century the stationary analyses measuring the content of certain substances in the lens were more and more replaced by the search for dynamic metabolic processes responsible for lens growth, maintenance of transparency and possibly active participation in lens function (such as accommodation). Also the disturbances as a result of ageing or the formation of lens opacities have been investigated and resulted partially in the elucidation of reaction chains, leading from a trigger to the formation of a cataract. Lens biochemistry is no longer a closed book to us, but there are still many question marks. Why were we not able to solve more problems around lens and cataract? The research effort with a remarkable financial input and a great number of scientists worldwide during the second half of the century does not correspond to the results obtained. There must be something wrong with our strategy, our interpretation of the results or even both. We would like to stress some points which might be regarded as errors or misunderstandings in the lens research community, thus preventing a better outcome of the enormous investment of work and money. A great disadvantage is the missing cooperation between clinicians and epidemiologists on one hand and basic lens researchers on the other. Especially the ignorance of basic researchers regarding the clinical problems of the lens and of cataracts might be to blame for several 'errors and misunderstandings'. It is not even so long ago since the slitlamp microscope examination of animals belonged to the essential standard methods of a lens research team. Another disadvantage still is the use of the general diagnosis 'cataract' by the clinicians without further classification of the topography of the opacification, which supports the concept that all cataracts have the same trigger mechanism. But most regrettable is the fact that many clinicians have never been really interested in basic research of the lens, in cataract pathogenesis and epidemiology of risk factors or in testing the efficacy of cataract-preventing medication. Their main goal was cataract surgery. On the basis of the success of the cataract surgery at the present time clinicians have even developed the opinion that lens and cataract research is no longer necessary to overcome cataract blindness. But as we all know this refers only to highly industrialized countries; millions of cataract-blind people are still without such help and a change of this condition is not in sight. In our opinion lens and cataract research is still necessary and it will be more successful if we bear in mind the mostly unintentional errors of the 20th century but keep them out of our daily practice.

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.

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. The age of the children, who had either a normal visual acuity or best corrected visual acuity, ranged from 4 to 18 years. Thirty minutes prior to photography, maximal mydriasis was induced by 3-fold instillation of Mydriaticum Roche®. Parallel to the Scheimpflug photographic documentation, all eyes were subjected to a basic ophthalmological examination. All images obtained were evaluated with microdensitometry as described earlier. The density data in young children demonstrate that there is very little light scattering in the central lens parts and only a faint zone of discontinuity apart from the 2 signals caused by the anterior and posterior capsules. Starting at the age of 14–15 years, the first separations occur in the zones of discontinuity, thus the first age-correlated increase in light scattering. The data obtained demonstrate that the development of light scattering in the young lens differs from that in the adult lens. Our results point to the assumption that the development of protein light scattering in the lens correlates with physical life-time of the individual and not with the period of life in different species with various life expectancies.

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. Lens epithelial cells were examined postmortem in flat preparations. After 8 weeks of the irradiation schedule (total dose: 0.6 J/cm2), an anterior polar opacity was apparent; at 16 weeks, the opacities had progressed more deeply into the cortex. At postmortem examination, cells in the central region displayed disorganization, clumping, some pyknotic nuclei and mitosis. There were deeper opacities and cell damage was more severe above the central horizontal plane than below it. This present study demonstrated that UVB damage differed in the superior and inferior parts divided by a horizontal plane through the lens anterior pole, when the UVB source was above and there was no reflection from below or laterally. The lens epithelial cells, and associated lens fibers, are the first target of UVB irradiation.

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. Alterations in the content of protein SH, carbonyl groups, light scattering intensity and SDS-PAGE pattern were measured to compare the effect of UV-B on the protein solutions of various lens parts with or without additional GSH to test its preventive effect. The results showed that after UV-B irradiation, the protein sulfhydryl groups are gradually reduced. The nonprotein thiol (GSH added to the protein solution) was lost more rapidly than the protein sulfhydryl. The high molecular bands on the SDS-PAGE pattern mainly aggregated with disulfide. UV-B damage also increased the content of carbonyl groups and light scattering, irrespective of the lens parts. Lens proteins from the equator suffered the least damage while those of the nucleus were most strongly affected by UV-B exposure. This study suggests that the lens proteins from various lens parts have different responses to UV-B exposure; the sensitivity was in the following order: EqAcor = PcNu.

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. Two approaches have been used in the past: 1) subjective methods of lens observation (based on slit lamp microscopy) and 2) objective methods with measurements of lens transparency or lens opacity respectively based on slit image documentation according to the Scheimpflug principle combined with the retroillumination technique. With ageing, the light transparency of the lens is subjected to considerable changes. Even without the formation of an opacity the transmission of the wavelengths in the UV-B/UV-A and the visible range is diminished. The single lens layers are affected by this phenomenon to different degrees. These changes which might also indicate an early stage of ‘cataract formation’ cannot be discerned by subjective methods. The densitometric image analysis of Scheimpflug slit images, however, allows the exact measurement of the light scatter in the single lens layers and enables the early recognition of disturbances in transparency which is of crucial importance particularly in cataract epidemiology. In view of our present knowledge the evaluation of risk factors which might be of importance in multifactorial cataract processes will hardly be possible by carrying out prevalence and/or incidence studies involving a single examination of the population. In this case follow-up studies (cohort studies) with repeated examinations are prerequisite. The ‘objective methods’ for classification alone are able to ensure the necessary reproducibility and the possibility to measure transparency changes in the lensbefore visible (and therefore subjectively recognizable) opacifications occured. The methodical procedure with respect to an epidemiological study on the involvement of UV-B radiation in the processes of cataract formation in man requires the application of objective methods for cataract classification.

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. Ophthalmological examination and Scheimpflug photography were performed at the beginning and every 6 months. Increases or decreases in the visual acuity were distributed very similarly in the three groups. Definite evidence of side effects was not found, nor was there evidence of deleterious effects on refraction. The intraocular pressure revealed intraindividual fluctuations without clinical significance. Many changes were observed in the lens, all were minimal, including those of the extreme lens periphery which had no effect on visual acuity. The present study shows the great value of Scheimpflug photography with densitometric image analyses because of its objectivity when compared with other methods. Our observations provide good evidence that lovastatin and simvastatin have no undesirable toxic effects on the lens and other ocular tissues, compared with fenofibrate.

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. The post-mortem analysis comprised biochemical and histological investigations. This paper deals with the histological part of the study. A generally beneficial effect of the substances in question could not be found by means of histological methods. The best effect in relative terms was obtained by the use of 3.0% PE after a pretreatment of 7 days before starting UV irradiation. This result is in agreement with the evaluation of the Scheimpflug photography by microdensitometric image analysis.

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. Two examinations with a 1-week interval were performed. In addition, a direct comparison of the EAS 1000 with the Topcon SL-45 was carried out with 32 volunteers that were photographed at 0 degree and 45 degrees; a retroillumination photo was additionally recorded. The video images were evaluated with the computer software, the SL-45 negatives were standardly measured with a Joyce-Loebl densitometer. The handling of the EAS 1000 in clinical use was found to be easy and comfortable for the patient, as the alignment is done with infrared light. Difficulties occur only with the retroillumination photography in that the infrared light for imaging may outshine the red fixation light during exposure. However, shadowing problems due to the eyelashes occur in oblique slit positions, especially in those patients with a pronounced front head. In studying the reproducibility, the mean values of the individual coefficients of variation for light scattering (density) were in a range between 3.6 and 5.06%, but more than 35% of the single values show a variation coefficient above 5% (maximum 20.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Electromagnetic radiation is involved in the generation of several different diseases especially those of the skin. Even the eye is subjected to the influence of electromagnetic radiation, which first reaches the cornea and the conjunctiva. These structures being superficial eye tissues, are naturally the first to be subjected to actinic influences. Additionally all other eye structures can be reached and possibly damaged by ultraviolet radiation being dependent on wavelength and intensity. In this respect, it is of crucial importance whether the damage in question is due to acute radiation or is to be considered a consequence of chronic exposure.

Up to now, the attention of ophthalmic surgeons has been focused mainly on the clinical results of epikeratophakia, demonstrating its safety, relative predictability, and capability of correcting a wide range of refractive errors. However, no prospective study has ever been undertaken to evaluate the influence of epikeratophakia on various physiologic and morphologic parameters of the cornea. The authors investigated some of these parameters prospectively in eight consecutive patients undergoing epikeratophakia with prelathed, lyophilized tissue. Fluorophotometric evaluation of the epithelial barrier function, corneal densitometry by means of Scheimpflug photography, and endothelial specular microscopy were performed preoperatively and 2, 4, 8, 12, and 24 weeks after epikeratophakia. The epithelial barrier function was shown to return to normal 4 weeks after surgery. The optical density of both the epi-lenses and the host corneas increased early after surgery, but was comparable to that of unoperated corneas 6 weeks postoperatively in all cases but one. The endothelial cell density was not altered by surgery in any patient. Despite the limited number of patients, this study indicates that most functional and morphologic parameters of the cornea are normal as early as 6 weeks after epikeratophakia in most cases.

Documentation of pathologic findings in the lens over a prolonged period is rather difficult. Until recently, only written reports or drawings of the process have been employed. Photography with the slit-lamp microscope has not been effective because of the insufficient depth of field and the poor reproduction capacity of instrumental parameters. Occasionally, opacifications of the lens have been photographed using the retroillumination technique1,2 where the cataracts appear as shaded areas, which may then be evaluated by planimetry. Application of this method to clinical problems, however, has met with difficulties,3–7 which may in part be attributed to problems of image analysis but are mostly due to inadequate reproducibility.8,9

Topcon Tokyo manufactured the first series of SL-45 in 1980 and a second in 1982/83, which were completed in Bonn with all technical improvements developed so far. In 1987, the SL-45B was manufactured which included all previously added improvements. To compare both camera types, we carried out a test with 10 volunteers and the following technical variables for the SL-45: (1) miosis; (2) mydriasis; (3) flashbulb 1; (4) flashbulb 2; (5) film batch 1; (6) film batch 2, and (7) different types of film. Afterwards, 5 of these volunteers were photographed with the SL-45B. Photographer and reader were identical in all cases. Based on microdensitometry it could be demonstrated that, with the exception of a different film type, all variables can be compensated for by using the corneal peak as an external standard.

The ophthalmic examination of patients with hypertrophic cardiomyopathy treated with high doses of verapamil over a considerable period of time showed no evidence of a side effect of the drug, thus pr