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Background: Diabetic retinopathy (DR) is a leading cause of low vision and blindness. We evaluated the feasibility of using a handheld, noncontact digital retinal camera, Pictor, to obtain retinal images in dilated and undilated eyes for DR screening. We also evaluated the accuracy of ophthalmologists with different levels of training/experience in grading these images to identify eyes with vision-threatening DR., Methods: A prospective study of diabetic adults scheduled to have dilated eye exams at Duke Eye Center from January to May 2014 was conducted. An imager acquired retinal images pre- and postdilation with Pictor and selected 1 pre- and 1 postdilation image per eye. Five masked ophthalmologists graded images for gradability (based on image focus and centration) and the presence of no, mild, moderate, or severe nonproliferative DR (NPDR) or proliferative DR (PDR). Referable disease was defined as moderate or severe NPDR or PDR on image grading. We evaluated feasibility based on the graders' evaluation of image gradability. We evaluated accuracy of identifying vision-threatening disease (severe NPDR or PDR documented on dilated clinical examination) based on the graders' sensitivity and specificity of grading referable disease., Results: Images were gradable in 86-94% of predilation and 94-97% of postdilation photos. Compared to the dilated clinical exam, overall sensitivity for identifying vision-threatening DR was 64-88% and specificity was 71-90%., Conclusions: Pictor can capture retinal images of sufficient quality to screen for DR with and without dilation. Single retinal images obtained using Pictor can identify eyes with vision-threatening DR with high sensitivity and acceptable specificity compared to clinical exam.

Background: The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly., Literature Review: Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera., Results: Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer., Conclusions: In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

Purpose: To evaluate the resolutions of slit-lamp microscopy photography using various cameras., Design: Evaluation of diagnostic test or technology., Participants: Healthy subjects were imaged with these adapted cameras through slit-lamp microscopy., Methods: A total of 8 cameras, including 6 custom-mounted slit-lamp cameras and 2 commercial slit-lamp cameras, were tested with standard slit-lamp microscopy devices for imaging of the eye. Various magnifications were used during imaging. A standard resolution test plate was used to test the resolutions at different magnifications. These outcomes were compared with commercial slit-lamp cameras., Main Outcome Measures: The main measurements included the display spatial resolutions, image spatial resolutions, and ocular resolutions. The outcome also includes the relationships between resolution and the pixel density of the displays and images., Results: All cameras were successfully adapted to the slit-lamp microscopy, and high-quality ocular images were obtained. Differences in the display spatial resolutions were found among cameras [analysis of variance (ANOVA), P<0.05]. Higher display resolutions were found with cameras using the high-definition multimedia interface (HDMI) compared with others, including cameras in smart phones. The display resolutions of smart phone displays were greater than cameras with video graphics array displays. The display spatial resolutions were found as a function of display pixel density (r>0.95, P<0.05) and magnification (r>0.85, P<0.05). Different image spatial resolutions were found among cameras (ANOVA, P<0.05) as a function of image pixel density (r>0.98, P<0.05) and magnification (r>0.85, P<0.05). The commercial slitlamp with a single lens reflex camera yielded the highest image spatial resolution. However, the ocular resolution through binocular viewing of the slit-lamp microscopy was found to have the highest resolution compared with the display and image spatial resolutions of all of the cameras., Conclusions: Several cameras can be adapted with slit-lamp microscopy for ophthalmic imaging, yielding various display and image spatial resolutions. However, the resolution seemed to not be as good as ocular viewing through the slit-lamp biomicroscope.

Purpose:   To describe a novel digital single lens reflex (dSLR) camera adaptor for anterior and posterior segment photography., Methods:   The adaptor was used to evaluate canine, feline, and equine patients presenting to Tufts Ophthalmology service. Anterior segment imaging was conducted with the adaptor mounted between a dSLR camera body (Canon 7D) and a macro lens (Canon EF-S 60mm/f2.8). Posterior segment imaging was performed with the aid of an indirect ophthalmic lens mounted in front of the macro lens. Coaxial illumination during viewing was provided by a single white light-emitting diode (LED) within the adaptor, while illumination during exposure was provided by the pop-up flash or an accessory flash. Corneal and/or lens reflections were eliminated using a pair of linear polarizers, having their azimuths at right angles to one another., Results:   This dSLR camera adaptor provides quality high-resolution, reflection-free, images of both the anterior and posterior segments. It was easy to transport, assemble, and handle. The necessary adjustments, positioning, and focusing required for quality images were easily performed., Conclusion:   The described dSLR camera adaptor provides an alternative to existing imaging systems. High-resolution image acquisition occurred at a fraction of the cost of established imaging system, particularly those devoted to the posterior segment., (© 2011 American College of Veterinary Ophthalmologists.)

Purpose: To describe a digital single lens reflex (dSLR) camera adaptor for posterior segment photography., Method: A total of 30 normal canine and feline animals were imaged using a dSLR adaptor which mounts between a dSLR camera body and lens. Posterior segment viewing and imaging was performed with the aid of an indirect lens ranging from 28-90D. Coaxial illumination for viewing was provided by a single white light emitting diode (LED) within the adaptor, while illumination during exposure was provided by the pop-up flash or an accessory flash. Corneal and/or lens reflections were reduced using a pair of linear polarizers, having their azimuths perpendicular to one another., Results: Quality high-resolution, reflection-free, digital images of the retina were obtained. Subjective image evaluation demonstrated the same amount of detail, as compared to a conventional fundus camera. A wide range of magnification(s) [1.2-4X] and/or field(s) of view [31-95 degrees, horizontal] were obtained by altering the indirect lens utilized., Conclusion: The described adaptor may provide an alternative to existing fundus camera systems. Quality images were obtained and the adapter proved to be versatile, portable and of low cost.

Objective: To compare the efficacy of the diabetic retinopathy (DR) screening with digital camera by endocrinologists with that by specialist and resident ophthalmologists in terms of sensitivity, specificity, and level of "loss of chance.", Research Design and Methods: In a cross-sectional study, 500 adult diabetic patients (1,000 eyes) underwent three-field retinal photography with a digital fundus camera following pupillary dilatation. Five endocrinologists and two ophthalmology residents underwent 40 h of training on screening and grading of DR and detection of associated retinal findings. A κ test compared the accuracy of endocrinologist and ophthalmology resident screening with that performed by experienced ophthalmologists. Screening efficiency of endocrinologists was evaluated in terms of "loss of chance," i.e., missed diagnoses that required ophthalmologist referrals., Results: The mean weighted κ of DR screening performed by endocronologists was similar to that of ophthalmology residents (0.65 vs. 0.73). Out of 456 DR eyes, both endocrinologists and ophthalmology residents misdiagnosed only stage 1 DR (36 and 14, respectively), which did not require ophthalmologist referral. There were no significant differences between endocrinologists and ophthalmology residents in terms of diabetic maculopathy and incidental findings except for papillary cupping and choroidal lesions, which were not the main purpose of the study or of the training., Conclusions: The endocrinologist with specific training for DR detection using a three-field digital fundus camera with pupillary dilatation can perform a reliable DR screening without any loss of chance for the patients when compared with identical evaluation performed by experienced ophthalmologists.

A new camera system is described that, when attached to an existing Haag-Streit-type slitlamp, can provide the photographic needs of the general ophthalmologist or optometrist conveniently and at relatively low cost. It can also be used to economically expand photography in a teaching environment. This photographic documentation is particularly beneficial when integrated into an electronic health record., (Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Simultaneous stereoscopic fundus photography is an important tool for classification and follow-up of glaucomatous optic neuropathy. The use of conventional film-based simultaneous stereoscopic fundus cameras is complicated and time-consuming due to film processing and the sensitivity of its mechanical components. Digital simultaneous stereoscopic fundus cameras are not available in Germany, since the existing ones are lacking the CE certificate. The authors realised a solution by transforming a conventional stereophotographic film-based fundus camera into a digital one. The analogue camera of the conventional stereophotographic device was replaced by a digital 36×24 mm full-frame complementary metal oxide (CMOS) camera.

Purpose: In an elderly Australian population, to evaluate the quality of fundus photographs taken non-mydriatically in both eyes, and to compare the quality of those taken second with those taken first., Methods: From 2258 participants (4516 images) aged 70 years and older who participated in the Melbourne Collaborative Cohort Study (MCCS), digital non-stereoscopic 45 degrees retinal photographs were taken with a Canon CR6-45NM Non-mydriatic Retinal Camera and evaluated. The quality of macular images was assessed as good, fair, and poor and McNemar's test was used to analyze variation in quality., Results: Gradable quality images were obtained from 95.8% eyes of participants, with 93.9% of participants having gradable photos of both eyes. The gradable rate for the eye photographed first (right), was significantly higher than that for the eye photographed second (left): 89.7% vs. 85.6%, respectively (difference of 4.12%, confidence interval [CI] of 2.68-5.54%, p < 0.001). The rate of ungradable photographs from the second eye was slightly greater than the first eye (4.5% and 3.8%, respectively), but the difference in proportion was not statistically significant (difference of 3.6%, CI of 0.17-1.5%, p = 0.384)., Conclusions: In the setting of a large elderly cohort study, non-dilated 45 degrees digital retinal imaging is an excellent method for fundus examination. It is fast, easy to use, non-invasive, and a reliable AMD (age-related macular degeneration)-detecting technique with only a minor loss of information from the second eye.

Ocular photographs are an increasingly important method of documenting lesions for inclusion in medical records, teaching purposes, and research. Availability of affordable high-quality digital imaging equipment has allowed for enhanced capture of desired images because of immediate on-camera viewing and editing. Conversion of the standard digital camera sensor to one that is sensitive to infrared light (i.e. > 760 nm < 1 mm wavelength) can be done inexpensively. In the equine eye, advantages of infrared digital photography include increased contrast of anterior segment images, identification and monitoring of pigmentary changes, and increased visualization of the anterior segment through a cloudy or edematous cornea.

Aim: To show that the non-mydriatic retinal camera (NMRC) using polaroid film is as effective as the NMRC using digital imaging in detecting referrable retinopathy., Methods: A series of patients with diabetes attending the eye out-patients department at the Royal Victorian Eye and Ear Hospital had single-field non-mydriatic fundus photographs taken using first a digital and then a polaroid camera. Dilated 30 degrees seven-field stereo fundus photographs were then taken of each eye as the gold standard. The photographs were graded in a masked fashion. Retinopathy levels were defined using the simplified Wisconsin Grading system. We used the kappa statistics for inter-reader and intrareader agreement and the generalized linear model to derive the odds ratio., Results: There were 196 participants giving 325 undilated retinal photographs. Of these participants 111 (57%) were males. The mean age of the patients was 68.8 years. There were 298 eyes with all three sets of photographs from 154 patients. The digital NMRC had a sensitivity of 86.2%[95% confidence interval (CI) 65.8, 95.3], whilst the polaroid NMRC had a sensitivity of 84.1% (95% CI 65.5, 93.7). The specificities of the two cameras were identical at 71.2% (95% CI 58.8, 81.1). There was no difference in the ability of the polaroid and digital camera to detect referrable retinopathy (odds ratio 1.06, 95% CI 0.80, 1.40, P = 0.68)., Conclusion: This study suggests that non-mydriatic retinal photography using polaroid film is as effective as digital imaging in the detection of referrable retinopathy in countries such as the USA and Australia or others that use the same criterion for referral.

Purpose: To report the application of a digital camera for ophthalmic photography in routine clinical use., Methods: A digital camera (Nikon Coolpix 995) was used both for external macrophotography of the eye and ocular adnexa, and slitlamp photography of the anterior segment of the eye., Results: We were able to take external macrophotographs under high magnification of the eye and ocular adnexa. Slitlamp photography could be performed under diffuse, slit beam, and retroillumination. The structures of the angle, the optic disc and surrounding retina could be photographed using appropriate lenses. The attachment to the operating microscope allowed intraoperative photography. It could also be attached to the laboratory microscope to capture images of various histopathology and microbiology slides., Conclusions: A digital camera is a versatile instrument for ophthalmic photography. It is easy to use in routine clinical practice and provides good quality photographs.

Purpose: To develop and test a procedure to measure and compare light sensitivity, linearity and step response of electronic cameras., Methods: The pixel value (PV) of digitized images as a function of light intensity (I) was measured. The sensitivity was calculated from the slope of the P(I) function, the linearity was estimated from the correlation coefficient of this function. To measure the step response, a short sequence of images was acquired. During acquisition, a light source was switched on and off using a fast shutter. The resulting PV was calculated for each video field of the sequence., Results: A CCD camera optimized for the near-infrared (IR) spectrum showed the highest sensitivity for both, visible and IR light. There are little differences in linearity. The step response depends on the procedure of integration and read out.

Aims: To devise a method to measure tear meniscus curvature by a non-invasive specular technique., Methods: A photographic system was devised. The system consisted of a camera and an illuminated target with a series of black and white stripes oriented parallel to the axis of the lower tear meniscus. The target was mounted on a flash gun close to the objective of a Brown macrocamera and calibrated using a graduated series of glass capillaries of known diameter, ground down to expose the inner wall. It was then applied to normal human eyes (n = 45) to measure the tear meniscus curvature. A video system was also assessed which provided qualitative online information about the tear meniscus., Results: Using the photographic system, measured values for capillary radii were in excellent agreement with theoretical calculations (r2 = 0.996, p < 0.0001). The radii of curvature of lower tear menisci in normal human subjects (mean 0.365 (SD 0.153) mm, range 0.128-0.736; n = 45) were similar to those reported in the literature. Both systems demonstrated variations in meniscus shape. The video system provided stable images of human menisci over prolonged periods of time and promises to be useful for the analysis of dynamic changes in meniscus volume., Conclusions: Reflective meniscometry is a non-invasive technique providing quantitative information about tear meniscus shape and volume and of potential value in the study of ocular surface disease.

Objective: To compare the magnification properties of 11 different fundus cameras (including 1 stereo fundus camera), a Rodenstock (infrared) scanning laser ophthalmoscope (SLO), the Heidelberg Laser Tomographic Scanner (LTS), and the Heidelberg Retina Tomograph (HRT)., Design: A cross-sectional study of the relationship between the true size of a fundus feature and its photographic-computer image in 14 different fundus imaging devices. This relationship was evaluated for each instrument using a model eye adjusted for axial ametropia between +11 diopter (D) and -14 D. To simulate refractive ametropia, the "crystalline lens" was removed to render the model eye aphakic, and the axial length was adjusted to give aphakic ametropia from emmetropia to +20 D., Main Outcome Measures: A correction factor (p) was calculated for each instrument, which can be used in calculations for determining true retinal size., Results: The following were found to be of telecentric construction, Zeiss Oberkochen (WS240 Heidelberg), Zeiss Oberkochen (UK), Zeiss Oberkochen (Cologne), Nikon NF505, Kowa RCXV, SLO prototype (UK), LTS, and the HRT, and each exhibited a constant relationship between p and degree of ametropia of the model eye. The Canon CF6OU, Canon CF6OS, Canon CR4-45NM, Nidek 3-DX, Olympus GRCW, and Carl Zeiss Jena Retinophot were found not to be telecentric and exhibited a linear relationship between p and degree of ametropia of the model eye. For all instruments, p remained unchanged for axial and refractive ametropias of the same degree., Conclusions: The study has shown that not all fundus imaging systems are telecentric, so the use of a single magnification correction value may not be appropriate. These findings have important implications for the way in which true retinal size calculations are performed. Examples are given to show how the tabulated values of correction factors can be used for both telecentric and nontelecentric cameras in image size calculations.

Of the methods developed (e.g., phakometry, magnetic resonance imaging, etc.) for noninvasive measurement of the geometry of the anterior segment of the human eye, Scheimpflug photography offers the best resolution and the highest precision. The primary obstacle encountered with this or any other image-based method has been in obtaining quantitative measurements directly from the images. Image enhancement (gray-scale gradient analysis) and pattern recognition methods (Hough transform and recursive least-squares algorithms) are developed so that parametric representations of lens surfaces and zone boundaries can be obtained directly from the images. Methods to correct for nonlinear Scheimpflug camera reproduction ratios and provide error estimates for geometrical parameters are also developed and will be presented separately. Combined, these techniques yield representations of lens geometry having sufficient precision, to which paraxial ray tracing can be applied to determine lens optical properties by using well-posed optical models with one unknown.

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 (1st and 2nd production charge as well as SL 45 B).

We developed a semi-automated retroillumination image analysis system which combines speed, ease of operation and interactive analysis. The system measures cataract area and integral of cataract density (ID). For system reproducibility evaluation, 20 eyes with posterior subcapsular opacities were captured twice by two photographers. Variability was estimated under a random effects analysis of variance model. Measurement errors for area and for ID were each small contributors to total variability (the sum of variability between study eyes plus measurement error), being 0.4% and 0.1% respectively. The largest contributor to area measurement error was image analysis variability (97%). For ID measurement error, the variability in images (44%) and in image analysis (46%) were major contributors. The reproducibility is comparable to previously described retroillumination analysis systems. This easy to use system may therefore be useful in clinical research studies including possible clinical trials of anti-cataract drugs.

We performed Scheimpflug slit lamp photography and computerized image analysis on 20 normal and 25 cataractous lenses using 18 slit images for each lens taken 10 degrees apart. The data gathered from the normals served as the reference to estimate the accuracy of representation of the cataracts by the least number of views (18 and less) using a Fourier interpolative algorithm. Using the error obtained with one view for the normals, our study suggests that the minimum number of views necessary for adequate characterization is two for cortical cataracts, two for nuclear cataracts, and six for posterior subcapsular cataracts. This information will be useful in longitudinal studies of cataracts, since most researchers presently use only one view, which may be adequate for normals but not for cataractous lenses. We found the Fourier interpolative algorithm useful in estimating the minimum views required for the current method of analyzing Scheimpflug images, and it can be easily applied to other similar images.

We examined 447 hypercholesterolemic and 108 normocholesterolemic Eastern Finnish men, aged 42, 48, 54, or 60 years, who were participating in the Kuopio Atherosclerosis Prevention Study. Two newly developed lenticular opacity grading methods, the Lens Opacities Classification System II and Lensmeter 701, were compared. There was fair agreement between the two grading methods for nuclear color and opalescence, but the agreement was weaker for cortical and posterior subcapsular opacities. The Lens Opacities Classification System II grading of nuclear opacities explained 48% (for the right eye) and 32% (for the left eye) of the variation of Lensmeter readings. Attributable fractions were lower for the other types of lens opacities.

The Otago photoscreener is a 35 mm single len reflex camera in which the flash light comes from a narrow ring around the outer margin of its lens. The margin is also the limiting aperture of the optic system and in the centre of the lens is a flickering fixation light. In a colour photograph taken at a distance of 66 cm from the face of the subject who is accurately focusing on and fixing the camera fixation light with both eyes, the fundus reflex in each pupil is very dark red and the corneal light reflexes are symmetrical. If either or both eyes are not appropriately focused or fixing, the fundus reflex is brighter and yellow or white. This article describes a prospective trial of the performance of the Otago photoscreener in a series of 1000 infants with actual or suspected amblyopia, refractive error or strabismus. In this study photoscreening showed a sensitivity of 94% and a specificity of 79%. Photoscreening also identified some cases of esotropia and of refractive error which were missed on clinical examination. In this series photoscreening passed as normal three children with mild to moderately severe amblyopia. This represents les than 1% of the clinically abnormal children.

The central corneal zone is depicted on keratoscope photographs using a small target aperture and a large object distance. Information on the peripheral area is included by employing a hemispherical target with a dense circular and radial pattern. On a 16 mm (R = 8 mm) reference steel sphere the diameter of the innermost reflected mire is 0.20 mm and the distance between mires 0.13 mm. The standard deviation on focusing precision, determined to 0.20 mm employing a fixed object, corresponds to an error of 0.06% in linear measurements on keratographs. The variation in object distance due to the curved image plane is at most 0.55 mm within 60 deg from the optical axis of the system for the reference sphere. Nevertheless, all reflected mires are distinctly reproduced on the keratoscope photograph. For a test object the slopes of light intensity curves on the passage between black and white areas are reduced by only 1.0% with a variation in object distance of 0.55 mm around focus.

A wide-angle funduscopic lens was used to take slit-lamp photographs of the posterior vitreous. The lens was then evaluated for its optics, magnification, field of view, and photographic usefulness and compared with the photographs taken using double aspheric preset lenses. The advantages of the wide-angle funduscopic lens were its wider field of view and ability to photograph the vitreous in the presence of a small pupil and cataract. The drawbacks were the darker image, low magnification, and artifactitious light reflection from the lens. The slit-lamp photographs using the wide-angle funduscopic lens were very useful in some complicated cases.

The Lens Opacities Classification System II (LOCS II) utilizes photographic standards (two retroilluminated Neitz-CTR and one standard slit lamp Zeiss photographs) for the classification of cortical and posterior subcapsular cataracts, nuclear color and nuclear opalescence. However, dedicated photographic devices, particularly retroillumination cameras, are not always available and this study was aimed at evaluating the suitability of a retroillumination photographic technique with a standard slit lamp camera for cortical and posterior subcapsular cataract classification according to LOCS II. Two observers examined 273 eyes. Kappa statistics demonstrated that agreement between the standard slit lamp, clinical grading (according to published LOCS II methodology) and photographic grading (according to our photographic technique), as well as inter- and intraobserver reproducibility, were excellent (Kappa > 0.74) for the classification of all lenticular regions. The results indicate that a standard slit lamp camera can be as useful as a dedicated retroillumination camera when LOCS II standards are used for cataract classification.

Photodocumented measurements of the lens thickness using an EAS-1000 Scheimpflug camera were performed in 261 cataract eyes (162 pure type) compared with 52 control eyes. The lens thickness in normal eyes usually increased with age by 0.015 mm annually. The cataractous lens, especially in the anterior subcapsular type combined with the superficial cortical and posterior subcapsular types of opacity, showed statistically significant lens thinning. The photodocumented values of lens thickness were higher in 7.9%, and those of the anterior chamber depth were lower in 5% compared with A scan ultrasonographic measurements.

A newly developed anterior eye segment system, EAS-1000, was applied to animal experiments. Since the device was developed to be used with human eyes, several minor changes were made to facilitate the use with animals. These changes included an animal-holding place instead of a chin rest, an additional monitor screen for help in alignment, a foot pedal for flushing and image cancellation and variable illumination for adjusting the volume of the retroillumination image. The examined animals were mice, rats, rabbits, dogs and monkeys. The image quality of this camera was almost always satisfactory. One advantage of this device is that the quality of the images can be checked instantly, making it possible to store only images of superior quality. The mean of the repeatability test had a coefficient of variation of 6%.

Real lens diameter and real lens volume cannot be measured by Scheimpflug photography, but the apparent lens radii and the lens thickness (anterior and posterior) can. Some stereometric equations allow us to calculate lens volume and lens diameter. Equations for the adaptation of the data points to nonlinear curves are given. There are no linear but sigmoid relationships between the age-dependent parameters. These can be estimated with the aid of equations 2 and 3 presented in this paper. When carrying out further investigations a greater number of parameters should be included in the analysis. It is conceivable that the equations must be expanded in order to be able to take other important parameters into consideration. Preliminary results of the calculations with regard to age are reported.

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)

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.

The purpose of the Committee on Ophthalmic Procedures Assessment is to evaluate on a scientific basis new and existing ophthalmic tests, devices, and procedures for their safety, efficacy, clinical effectiveness and appropriate uses. Evaluations include examination of available literature, epidemiological analyses when appropriate, and compilation of opinions from recognized experts and other interested parties. After appropriate review by all contributors, including legal counsel, assessments are submitted to the Academy's Board of Directors for consideration as official Academy policy.

A report on a simple adapter for the Haag-Streit slit lamp, by means of which a standard SLR camera can be attached to one of the eyepieces. Using highspeed film it is thus easily possible to obtain satisfactory photographs of the anterior segment, the refractive media and the fundus without flash.

The Equator-Plus camera can photograph a 148-degree view of the fundus, measured from the nodal point of the eye. We tested this instrument clinically more than 800 times on over 700 eyes. The large field, which is three to four times that of any conventional fundus camera, is achieved by using a special contact lens as the front element in the camera optics. Photographs taken with the Equator-Plus camera can resolve a lesion as small as one-eighth of a disk diameter, if the contrast is good. Protruding tumors, choroidal or retinal detachment, and extensive disease of the choroid and fundus show up well with this technique. We obtained good pictures in 87% of the clinical tests. We have not observed complications of any kind after photography with the Equator-Plus camera.

A readily adjustable, quick-mounting attachment frame allows use of an unmodified Polaroid SX-70 Alpha I camera with several available ophthalmic slit lamps. Initial results with this arrangement have proved to be easily obtainable and of good quality. Several important uses for instant color photographs obtained with this sysetm are suggested here.

Line copy presentation slides with white letters on a blue background can be produced with a two-step process. The slides are more permanent than diazo slides, and the process is faster and less expensive.

A practical method for detecting in vivo cataracts has been developed using a commercially available slit-lamp camera and by utilizing a measuring grid photographic technique. The basis of the method is to photograph a series of slit-beam sections through a lens at varying angles to the optic axis. The areas of opacity show up as localized regions of light back-scatter where the opacities intersect the path of the beam. A set of measuring grids compensated for angle distortion have been prepared. These are superimposed on the appropriate photograph. By taking a sufficient number of sections through a cataractous lens, a tomographic representation of the opacities can be constructed using a lens map. An example of the procedure of three-dimensional mapping is presented using actual lens pictures. The photographic parameters used in this method are explained in detail. The method achieves the goals of ease of use, reproducibility, and applicability to research and clinical studies.

A portable system for external photography combines a focusing lamp and movable flash unit with a wide focusing range. The system is arranged to operate from a single two-position trigger and may be hand-held or mounted on a slitlamp stand. It is designed for use in general ophthalmology in a multilaned office practice or bedside use in a hospital situation.

We designed a rigid support platform to facilitate ocular photography of infants or small animals. The platform is versatile because it is compatible with either the Zeiss fundus camera or Zeiss Photo Slit Lamp.

The method of stereoscopic fundus photography, where both photographs are taken simultaneously, yields the most consistent and reproducible record of depths in the fundus. However, all systems devised to date have had undesirable photographic aberrations. For the most part, this has resulted because the optical axis of each image is not the same as that of the objective lens. A single-axis system has now been devised to minimize distortions in the stereoscopic photographs, which therefore makes stereophotogrammetry relatively simple. This design also has other advantages such as simplified alignment procedures, the use of Barlow lenses for multiple magnifications, and various paired apertures for obtaining photographs especially adapted to unusual situations.

Anatomical details in the ocular fundus can be seen with increased contrast when appropriate monochromatic illumination is used. This technique permits more accurate visualization and documentation than can be achieved with white light. This article reports the optimal spectral ranges for visualization of the different fundus structures. It describes and illustrates the appearance of individual structures and areas of the fundus under different spectral illuminations. There is a detailed discussion of the optical properties of the fundus layers that provides a background for interpreting the data and a baseline for examination of pathologic conditions.

The aim of the present work was to create a simple and cheap device for photographing the anterior segment and the media of the eye in direct illumination and by retroillumination. By illuminating the eye from a point near the centre of the anterior surface of the camera lens, the anterior segment and the media of the eye can be photographed. Pictures made in this manner and technical data for the device used are presented.