Telemedicine screening of diabetic retinopathy using a hand-held fundus camera

Clinical utility of handheld fundus and smartphone-based camera for monitoring diabetic retinal diseases: a review study

Diabetic retinopathy (DR) is the leading global cause of vision loss, accounting for 4.8% of global blindness cases as estimated by the World Health Organization (WHO). Fundus photography is crucial in ophthalmology as a diagnostic tool for capturing retinal images. However, resource and infrastructure constraints limit access to traditional tabletop fundus cameras in developing countries. Additionally, these conventional cameras are expensive, bulky, and not easily transportable. In contrast, the newer generation of handheld and smartphone-based fundus cameras offers portability, user-friendliness, and affordability. Despite their potential, there is a lack of comprehensive review studies examining the clinical utilities of these handheld (e.g. Zeiss Visuscout 100, Volk Pictor Plus, Volk Pictor Prestige, Remidio NMFOP, FC161) and smartphone-based (e.g. D-EYE, iExaminer, Peek Retina, Volk iNview, Volk Vistaview, oDocs visoScope, oDocs Nun, oDocs Nun IR) fundus cameras. This review study aims to evaluate the feasibility and practicality of these available handheld and smartphone-based cameras in medical settings, emphasizing their advantages over traditional tabletop fundus cameras. By highlighting various clinical settings and use scenarios, this review aims to fill this gap by evaluating the efficiency, feasibility, cost-effectiveness, and remote capabilities of handheld and smartphone fundus cameras, ultimately enhancing the accessibility of ophthalmic services.

Diabetic Retinopathy Screening Using a Portable Retinal Camera in Vanuatu

Background and Objective

Proof-of-concept study to test the feasibility of using an all-in-one portable retinal camera for the screening of diabetic retinopathy in the Pacific Island of Vanuatu, which has a high rate of diabetes and its associated complications and a dearth of ophthalmologists.

Study Design/Materials and methods

From February 10, 2020, through February 28, 2020, 49 patients with diabetes mellitus from three islands in Vanuatu were recruited to participate in the study. Demographics, basic health data and retinal photography were obtained. A non-mydriatic, handheld camera was used (Volk Pictor Plus).

Results

Eleven participants (24%) had referral-warranted diabetic retinopathy. There was moderately high inter-rater reliability for our dependent variables: referral status (κ = 0.62, 95% CI 0.42-0.83), retinopathy severity (κ = 0.76, 95% CI 0.55-0.96), and clinically significant macular edema (κ = 0.50, 95% CI 0.25-0.74).

Conclusion

Our study confirms that portable handheld cameras can be used to obtain retinal images of sufficient quality for diabetic retinopathy screening even in resource limited environments like Vanuatu. Among this cohort, a relatively high (24%) prevalence of referral-warranted diabetic retinopathy was found in Vanuatu.

Hybrid spiral scanning in a double-clad fiber-based handheld confocal scanning light ophthalmoscope

High-speed, accessible, and robust in vivo imaging of the human retina is critical for screening of retinal pathologies, such as diabetic retinopathy, age-related macular degeneration, and others. Scanning light ophthalmoscopy (SLO) is a retinal imaging modality that produces digital, en face images of the human retina with superior image gradability rates when compared to the current standard of care in screening for these diseases, namely the flood-illumination handheld fundus camera (HFC). However, current-generation commercial SLO systems are mostly tabletop devices, limiting their accessibility and utility in screening applications. Moreover, most existing SLO systems use raster scan patterns, which are both inefficient and lead to undesired subject gaze drift when used with visible or pseudo-visible illumination. Non-raster scan patterns, especially spiral scanning as described herein, promise advantages in both scan efficiency and reduced subject eye motion. In this work, we introduce a novel "hybrid spiral" scan pattern and the associated hardware design and real-time image reconstruction techniques necessary for its implementation in an SLO system. Building upon this core hybrid spiral scanning SLO (HSS-SLO) technology, we go on to present a complete handheld HSS-SLO system, featuring a fiber-coupled portable patient interface which leverages a dual-clad fiber (DCF) to form a single-path optical topology, thus ensuring mechanically robust co-alignment of illumination and collection apertures, a necessity for a handheld system. The feasibility of HSS-SLO for handheld, in vivo imaging is demonstrated by imaging eight human volunteers.

Evaluation of a remote telemedicine platform using a novel handheld fundus camera: Physician and patient perceptions from real-world experience

BACKGROUND

Although teleophthalmology has gained traction in recent years, it is at the center of the coronavirus disease pandemic. However, most hospitals are not ready owing to a severe lack of real-world experience. Furthermore, a limited number of studies have evaluated telemedicine applications on remote islands. This study aimed to evaluate real-world clinical and referral accuracy, image quality, physician-perceived diagnostic certainty, and patient satisfaction with telemedicine eye screening using a novel handheld fundus camera in a rural and medically underserved population.

METHODS

This prospective study included 176 eyes from a remote island. All participants underwent a comprehensive ophthalmic examination. Nonmydriatic retinal images obtained using a handheld fundus camera were reviewed by two retinal specialists to determine image quality, diagnosis, and need for referrals. The agreement of diagnosis between image-based assessments was compared with that of binocular indirect ophthalmoscopic assessments.

RESULTS

Image quality of fundus photographs was considered acceptable or ideal in 97.7% and 95.5% of eyes assessed by two reviewers, respectively. There was considerable agreement in diagnosis between the indirect ophthalmoscopic assessment and image-based assessment by two reviewers (Cohen's kappa = 0.80 and 0.78, respectively). Likewise, substantial agreement was achieved in the referrals. The sensitivity for referable retinopathy from the two reviewers was 78% (95% confidence interval [CI], 57%-91%) and 78% (95% CI, 57%-91%), whereas specificity was 99% (95% CI, 95%-99%] and 98% (95% CI, 93%-99%), respectively. For physicians' perceived certainty of diagnosis, 93.8% and 90.3% were considered either certain or reliable. Overall, 97.4% of participants were satisfied with their experiences and greatly valued the telemedicine services.

CONCLUSION

Novel fundus camera-based telemedicine screening demonstrated high accuracy in detecting clinically significant retinopathy in real-world settings. It achieved high patient satisfaction and physician-perceived certainty in diagnosis with reliable image quality, which may be scaled internationally to overcome geographical barriers under the global pandemic.

TREND database: Retinal images of healthy young subjects visualized by a portable digital non-mydriatic fundus camera

Topological characterization of the Retinal microvascular nEtwork visualized by portable fuNDus camera (TREND) is a database comprising of 72 color digital retinal images collected from the students of the Faculty of Medicine at the University of Montenegro, in the period from February 18th to March 11th 2020. The database also includes binarized images of manually segmented microvascular networks associated with each raw image. The participant demographic characteristics, health status, and social habits information such as age, sex, body mass index, smoking history, alcohol use, as well as previous medical history was collected. As proof of the concept, a smaller set of 10 color digital fundus images from healthy older participants is also included. Comparison of the microvascular parameters of these two sets of images demonstrate that digital fundus images recorded with a hand-held portable camera are able to capture the changes in patterns of microvascular network associated with aging. The raw images from the TREND database provide a standard that defines normal retinal anatomy and microvascular network geometry in young healthy people in Montenegro as it is seen with the digital hand-held portable non-mydriatic MiiS HORUS Scope DEC 200.This knowledge could facilitate the application of this technology at the primary level of health care for large scale telematic screening for complications of chronic diseases, such as hypertensive and diabetic retinopathy. In addition, it could aid in the development of new methods for early detection of age-related changes in the retina, systemic chronic diseases, as well as eye-specific diseases. The associated manually segmented images of the microvascular networks provide the standard that can be used for development of automatic software for image quality assessment, segmentation of microvascular network, and for computer-aided detection of pathological changes in retina. The TREND database is freely available at https://doi.org/10.5281/zenodo.4521043.

Evidence-based Canadian guidelines for tele-retina screening for diabetic retinopathy: recommendations from the Canadian Retina Research Network (CR2N) Tele-Retina Steering Committee

OBJECTIVE

The purpose of this report is to develop a consensus for Canadian national guidelines specific to a tele-medicine approach to screening for diabetic retinopathy (DR) using evidence-based and clinical data.

METHODS

Canadian Tele-Screening Grading Scales for DR and diabetic macular edema (DME) were created primarily based on severity grading scales outlined by the International Clinical Diabetic Retinopathy Disease Severity Scale (ICDR) and the Scottish DR Grading Scheme 2007. Other grading scales used in international screening programs and the clinical expertise of the Canadian Retina Research Network members and retina specialists nationwide were also used in the creation of the guidelines.

RESULTS

National Tele-Screening Guidelines for DR and DME with and without optical coherence tomography (OCT) images are proposed. These outline a diagnosis and management algorithm for patients presenting with different stages of DR and/or DME. General guidelines detailing the requirements for imaged retina fields, image quality, quality control, and follow-up care and the role of visual acuity, pupil dilation, OCT, ultra-wide-field imaging, and artificial intelligence are discussed.

CONCLUSIONS

Tele-retina screening can help to address the need for timely and effective screening for DR, whose prevalence continues to rise. A standardized and evidence-based national approach to DR tele-screening has been proposed, based on DR/DME grading using two 45° image fields or a single widefield or ultra-wide-field image, preferable use of OCT imaging, and a focus on local quality control measures.

Review of retinal cameras for global coverage of diabetic retinopathy screening

The global burden of diabetes has resulted in an increase in the prevalence of diabetic retinopathy (DR), a microvascular complication of diabetes. Lifelong repetitive screening for DR is essential for early detection and timely management to prevent visual impairment due to the silent sight-threatening disorder. Colour fundus photography (CFP) is helpful for documentation of the retinopathy as well as for counselling the patient. CFP has established roles in DR screening, detection, progression and monitoring of treatment response. DR screening programmes use validated mydriatic or non-mydriatic fundus cameras for retinal imaging and trained image graders identify referable DR. Smartphone-based fundus cameras and handheld fundus cameras that are cost-effective, portable and easy to handle in remote places are gaining popularity in recent years. The images captured with these low-cost devices can be immediately sent to trained ophthalmologists for grading of DR. Recent increase in numbers of telemedicine programmes based on imaging with digital fundus cameras and remote interpretation has facilitated larger population coverage of DR screening and timely referral of those with sight-threatening DR to ophthalmologists. Good-quality retinal imaging and accurate diagnosis are essential to reduce inappropriate referrals. Advances in digital imaging such as ultra-wide field imaging and multi-modal imaging have opened new avenues for assessing DR. Fundus cameras with integrated artificial intelligence (AI)-based automated algorithms can also provide instant DR diagnosis and reduce the burden of healthcare systems. We review the different types of fundus cameras currently used in DR screening and management around the world.

Practice Guidelines for Ocular Telehealth-Diabetic Retinopathy, Third Edition

Contributors The following document and appendices represent the third edition of the Practice Guidelines for Ocular Telehealth-Diabetic Retinopathy. These guidelines were developed by the Diabetic Retinopathy Telehealth Practice Guidelines Working Group. This working group consisted of a large number of subject matter experts in clinical applications for telehealth in ophthalmology. The editorial committee consisted of Mark B. Horton, OD, MD, who served as working group chair and Christopher J. Brady, MD, MHS, and Jerry Cavallerano, OD, PhD, who served as cochairs. The writing committees were separated into seven different categories. They are as follows: 1.Clinical/operational: Jerry Cavallerano, OD, PhD (Chair), Gail Barker, PhD, MBA, Christopher J. Brady, MD, MHS, Yao Liu, MD, MS, Siddarth Rathi, MD, MBA, Veeral Sheth, MD, MBA, Paolo Silva, MD, and Ingrid Zimmer-Galler, MD. 2.Equipment: Veeral Sheth, MD (Chair), Mark B. Horton, OD, MD, Siddarth Rathi, MD, MBA, Paolo Silva, MD, and Kristen Stebbins, MSPH. 3.Quality assurance: Mark B. Horton, OD, MD (Chair), Seema Garg, MD, PhD, Yao Liu, MD, MS, and Ingrid Zimmer-Galler, MD. 4.Glaucoma: Yao Liu, MD, MS (Chair) and Siddarth Rathi, MD, MBA. 5.Retinopathy of prematurity: Christopher J. Brady, MD, MHS (Chair) and Ingrid Zimmer-Galler, MD. 6.Age-related macular degeneration: Christopher J. Brady, MD, MHS (Chair) and Ingrid Zimmer-Galler, MD. 7.Autonomous and computer assisted detection, classification and diagnosis of diabetic retinopathy: Michael Abramoff, MD, PhD (Chair), Michael F. Chiang, MD, and Paolo Silva, MD.

Update on Screening for Sight-Threatening Diabetic Retinopathy

PURPOSE

The aim of this article was to describe recent advances in the use of new technology in diabetic retinopathy screening by looking at studies that assessed the effectiveness and cost-effectiveness of these technologies.

METHODS

The author conducts an ongoing search for articles relating to screening or management of diabetic retinopathy utilising Zetoc with keywords and contents page lists from relevant journals.

RESULTS

The areas discussed in this article are reference standards, alternatives to digital photography, area of retina covered by the screening method, size of the device and hand-held cameras, mydriasis versus non-mydriasis or a combination, measurement of distance visual acuity, grading of images, use of automated grading analysis and cost-effectiveness of the new technologies.

CONCLUSIONS

There have been many recent advances in technology that may be adopted in the future by screening programmes for sight-threatening diabetic retinopathy but each device will need to demonstrate effectiveness and cost-effectiveness before more widespread adoption.

Diagnostic test accuracy of diabetic retinopathy screening by physician graders using a hand-held non-mydriatic retinal camera at a tertiary level medical clinic

Background

The evidence on diagnostic test accuracy (DTA) of diabetic retinopathy (DR) screening utilising photographic studies by non-ophthalmologist personnel in low and middle-income country (LMIC) settings is scarce. We aimed to assess DTA of DR screening using a nonmydriatic hand-held digital camera by trained general physicians in a non-ophthalmic setting.

Methods

This study is a validation of a screening intervention. We selected 700 people with diabetes (PwDM) > 18 years of age, not previously screened or treated for DR, presenting at a tertiary medical clinic in Sri Lanka. Two-field retinal imaging was used to capture fundus images before and after pupil dilatation, using a hand-held non-mydriatic (Visuscout 100®-Germany) digital retinal camera. The images were captured and graded by two trained, masked independent physician graders. The DTA of different levels of DR was assessed comparing physician’s grading with a retinologist’s clinical examination by mydriatic bio-microscopy, according to a locally adopted guideline.

Results

Seven hundred eligible PwDM were screened by physician graders. The mean age of participants was 60.8 years (SD ±10.08) and mean duration of DM was 9.9 years (SD ±8.09). Ungradable image proportion in non-mydriatic imaging was 43.4% (either eye-31.3%, both eyes 12.1%). This decreased to 12.8% (either eye-11.6%, both eyes-1.2%) following pupil dilatation. In comparison to detection of any level of DR, a referable level DR (moderate non-proliferative DR and levels above) showed a higher level of DTA. The sensitivity of the defined referable DR was 88.7% (95% CI 81.7–93.8%) for grader 1 (positive predictive value [PPV] 59.1%) and 92.5% (95% CI 86.4–96.5%) for grader 2 (PPV 68%), using mydriatic imaging, after including ungradable images as screen positives. The specificity was 94.9% (95% CI 93.6–96.0%) for grader 1 (negative predictive value [NPV] 99%) and 96.4% (95% CI 95.3–97.3%) for grader 2 (NPV 99.4%).

Conclusions

The Physicians grading of images from a digital hand-held non-mydriatic camera at a medical clinic, with dilatation of pupil of those who have ungradable images, provides a valid modality to identify referable level of DR. This could be a feasible alternative modality to the existing opportunistic screening to improve the access and coverage.

Trial registration

Current Controlled Trials ISRCTN47559703. Date of Registration 18th March 2019, Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1092-3) contains supplementary material, which is available to authorized users.

Telemedicine screening of retinal diseases with a handheld portable non-mydriatic fundus camera

Background

We modified and reconstructed a high image quality portable non-mydriatic fundus camera and compared it with the tabletop fundus camera to evaluate the efficacy of the new camera in detecting retinal diseases.

Methods

We designed and built a novel portable handheld fundus camera with telemedicine system. The image quality of fundus cameras was compared to that of existing commercial tabletop cameras by taking photographs of 364 eyes from the 254 patients. In all 800 fundus images taken by two camera types, 400 images per camera, were graded with the four image clarity classifications.

Results

Using the portable fundus camera, 63% (252/400) images were graded as excellent overall quality, 20.5% (82/400) were good, 11.75% (47/400) were fair, and 4.75% (19/400) were inadequate. Using the tabletop fundus camera, 70.75% (283/400) images were graded as excellent overall quality, 20.4% (51/400) were good, 13.25% (53/400) were fair, and 3.25% (13/400) were inadequate. Common retinal diseases were easily identified from fundus images obtained from the portable fundus camera.

Conclusion

The new type of non-mydriatic portable fundus camera was qualified to have professional quality of fundus images. The revolutionary screening camera provides a foundational platform which can potentially improve the accessibility of retinal screening programmes.

The English National Screening Programme for diabetic retinopathy 2003-2016

The aim of the English NHS Diabetic Eye Screening Programme is to reduce the risk of sight loss amongst people with diabetes by the prompt identification and effective treatment if necessary of sight-threatening diabetic retinopathy, at the appropriate stage during the disease process. In order to achieve the delivery of evidence-based, population-based screening programmes, it was recognised that certain key components were required. It is necessary to identify the eligible population in order to deliver the programme to the maximum number of people with diabetes. The programme is delivered and supported by suitably trained, competent, and qualified, clinical and non-clinical staff who participate in recognised ongoing Continuous Professional Development and Quality Assurance schemes. There is an appropriate referral route for those with screen-positive disease for ophthalmology treatment and for assessment of the retinal status in those with poor-quality images. Appropriate assessment of control of their diabetes is also important in those who are screen positive. Audit and internal and external quality assurance schemes are embedded in the service. In England, two-field mydriatic digital photographic screening is offered annually to all people with diabetes aged 12 years and over. The programme commenced in 2003 and reached population coverage across the whole of England by 2008. Increasing uptake has been achieved and the current annual uptake of the programme in 2015-16 is 82.8% when 2.59 million people with diabetes were offered screening and 2.14 million were screened. The benefit of the programme is that, in England, diabetic retinopathy/maculopathy is no longer the leading cause of certifiable blindness in the working age group.

Clinical Components of Telemedicine Programs for Diabetic Retinopathy

Diabetic retinopathy is a leading cause of new-onset vision loss worldwide. Treatments supported by large clinical trials are effective in preserving vision, but many persons do not receive timely diagnosis and treatment of diabetic retinopathy, which is typically asymptomatic when most treatable. Telemedicine evaluation to identify diabetic retinopathy has the potential to improve access to care, but there are no universal standards regarding camera choice or protocol for ocular telemedicine. We review the literature regarding the impact of imaging device, number and size of retinal images, pupil dilation, type of image grader, and diagnostic accuracy on telemedicine assessment for diabetic retinopathy. Telemedicine assessment of diabetic retinopathy has the potential to preserve vision, but further development of telemedicine specific technology and standardization of operations are needed to better realize its potential.

Retinal Imaging Techniques for Diabetic Retinopathy Screening

Due to the increasing prevalence of diabetes mellitus, demand for diabetic retinopathy (DR) screening platforms is steeply increasing. Early detection and treatment of DR are key public health interventions that can greatly reduce the likelihood of vision loss. Current DR screening programs typically employ retinal fundus photography, which relies on skilled readers for manual DR assessment. However, this is labor-intensive and suffers from inconsistency across sites. Hence, there has been a recent proliferation of automated retinal image analysis software that may potentially alleviate this burden cost-effectively. Furthermore, current screening programs based on 2-dimensional fundus photography do not effectively screen for diabetic macular edema (DME). Optical coherence tomography is becoming increasingly recognized as the reference standard for DME assessment and can potentially provide a cost-effective solution for improving DME detection in large-scale DR screening programs. Current screening techniques are also unable to image the peripheral retina and require pharmacological pupil dilation; ultra-widefield imaging and confocal scanning laser ophthalmoscopy, which address these drawbacks, possess great potential. In this review, we summarize the current DR screening methods using various retinal imaging techniques, and also outline future possibilities. Advances in retinal imaging techniques can potentially transform the management of patients with diabetes, providing savings in health care costs and resources.

Three principles for determining the relevancy of store-and-forward and live interactive telemedicine: reinterpreting two telemedicine research reviews and other research

The Agency for Healthcare Research and Quality sponsored two telemedicine research reviews. The latest review concluded that telemedicine is most relevant to specialties, such as psychiatry and neurology, where high levels of patient interaction are crucial to assessment. Telemedicine research studies cited in the reviews having positive findings in the specialties of ophthalmology, otolaryngology, obstetrics and gynecology, gastroenterology, and cardiology and more recent research in these areas are reviewed to identify criteria other than degree of interaction for determining the appropriateness of telemedicine interventions. These criteria include congruity or the extent that procedures used in telemedicine are similar to those of in-person examination, fidelity or the degree to which the information used for assessment in remote examinations is of similar quality to that used in-person, and reliability or the consistency with which information can be gathered and transmitted.

Construction of an inexpensive, hand-held fundus camera through modification of a consumer "point-and-shoot" camera

PURPOSE

To construct a low-cost, easy-to-use, high-image-quality mydriatic fundus camera with "point-and-shoot" operation, and to evaluate the efficacy of this camera to accurately document retinal disease.

METHODS

A prototype portable fundus camera was designed by interfacing a novel optical module with a Panasonic Lumix G2 consumer camera. Low-cost, commercially available optics were used to create even illumination of the fundus, providing a 50° retinal field of view. A comparative study assessing the image quality of the prototype camera against a traditional tabletop fundus camera was conducted under an Institutional Review Board (IRB)-approved study.

RESULTS

A stand-alone, mydriatic camera prototype was successfully developed at a parts cost of less than $1000. The prototype camera was capable of operating in a point-and-shoot manner with automated image focusing and exposure, and the image quality of fundus photos was comparable to that of existing commercial cameras. Pathology related to both nonproliferative and proliferative diabetic retinopathy and age-related macular degeneration was easily identified from fundus images obtained from the low-cost camera.

CONCLUSIONS

Early prototype development and clinical testing have shown that a consumer digital camera can be inexpensively modified to image the fundus with professional diagnostic quality. The combination of low cost, portability, point-and-shoot operation, and high image quality provides a foundational platform on which one can design an accessible fundus camera to screen for eye disease.

Cup-to-disc and arteriole-to-venule ratios in children aged 6-7 and 12-13 years

PURPOSE

Little data exist detailing the normal cup-to-disc (CD) ratios and arteriole-to-venule (A/V) ratios of school age children. In addition, controversy exists in the literature regarding associations between CD and A/V ratios and visual and biometric parameters. The present study investigates the success rates of obtaining useable optic disc images from the portable Nidek Handheld Non-Mydriatic Fundus Camera (NM-200D) from school-age children and describes the distribution of CD ratios and A/V ratios in children aged 6-7 years of age and 12-13 years of age. In addition, the present study explores associations between CD and A/V ratios and a range of visual function and biometric parameters in children.

METHODS

Fundus images were obtained from 195 6-7 year old children and 227 12-13 year old children participating in a wider study of visual function in childhood (Northern Ireland Childhood Errors of Refraction Study or NICER). ImageJ software was used to obtain CD and A/V ratios from the digital images. Visual function measures and biometric parameters were also available for all participants including; cycloplegic refractive error, vision, corneal curvature, axial length, height and weight.

RESULTS

One hundred and eighty fundus images (92.3%) from the 6-7 year olds and 194 images (85.5%) from the 12-13 year olds children were considered useable. Analysis (one way anova) demonstrated statistically significant differences between CD ratios and A/V ratios between the age groups. Participants aged 12-13 years had larger CD ratios and smaller A/V ratios (mean CD ratio 0.37 ± 0.09, mean A/V ratio 0.75 ± 0.10) than 6-7 year old participants (mean CD ratio 0.30 ± 0.09, mean A/V ratio 0.78 ± 0.12). No significant associations were noted between CD ratios and A/V ratio and any visual, ocular or biometric parameters.

CONCLUSIONS

The present study provides novel normative data on CD and A/V ratios in UK school age children for clinicians in practice.

Ophthalmic imaging today: an ophthalmic photographer's viewpoint - a review

Ophthalmic imaging has changed dramatically since the 1960s with increasingly complex technologies now available. Arguably, the greatest changes have been the development of the digital camera and the speed, processing power and storage of electronic data. Already, ophthalmic practices in many major institutions overseas have paperless medium storage and electronically generated reporting from all equipment that use a computer interface. It is hard to remember the widespread use of photographic film with its attendant costs, or even to remember the days before optical coherence tomography (OCT). These latest technical improvements in ophthalmic imaging are now standard in large Australian institutions and becoming more widespread in smaller private practices. The technicians that operate and maintain this ever-increasing plethora of gadgetry have seen their work practices change from the darkroom to the complexities of data-based imaging and storage. It is a fitting time to examine the contemporary state of ophthalmic imaging and what lies on the horizon as we move towards 2020.

Reliability of screening methods for diabetic retinopathy

AIM

To review studies of the reliability (reproducibility) of the commonly used methods (ophthalmoscopy and inspection of retinal images) of screening for diabetic retinopathy (DR).

RESEARCH DESIGN AND METHODS

Literature search.

RESULTS

We found six studies of the intra-examiner agreement after examining the same retinal images. Three of these found an almost perfect agreement (k > 0.8) after inspecting colour slides and digital images; three other studies reported 'significant differences' in microaneurysm counts and only 39-85% agreement rates between two assessments by the same examiner. The inter-examiner agreement was reported in 24 studies. Using stereoscopic photographs, one study found almost perfect agreement after examining seven fields; another study found a substantial to moderate (k = 0.4-0.8) agreement after examining five fields and a third study found a fair agreement (k = 0.2-0.4) after examining a single field. Studies using single- or two-field monoscopic photographs also have reported agreement rates that have varied between almost perfect, substantial and moderate. In four other studies using biomicroscopy, agreement levels varied between perfect and moderate.

CONCLUSIONS

Relative to the large number of studies on the validity of the various methods for screening for DR, there are only few studies of their reliability, with a marked variability in their findings. We suggest that future studies of the effectiveness of the various methods for screening for DR should also include data on their reliability.

Diagnosis, access and outcomes: Update of a systematic review of telemedicine services

Telemedicine services are being increasingly used. Although insurers and other payers are covering some services in the USA, the rationale for these coverage decisions is not always evidence-based. We reviewed the literature for telemedicine services that substitute for face-to-face medical diagnosis and treatment. We focused on three types of telemedicine services: store-and-forward, home-based and office/hospital-based services. Studies were included if they were relevant to at least one of the three study areas, addressed at least one key question and contained reported results. We excluded articles that did not study a service requiring face-to-face encounters (i.e. teleradiology was excluded). Our search initially identified 4083 citations. After review, 597 were judged to be potentially relevant at the title/abstract level. Following a full-text review, 106 studies were included. Store-and-forward services have been studied in many specialties, the most common being dermatology, wound care and ophthalmology. The evidence for their efficacy is mixed. Several limited studies showed the benefits of home-based telemedicine interventions in chronic diseases. Studies of office/hospital-based telemedicine suggest that telemedicine is most effective for verbal interactions, e.g. videoconferencing for diagnosis and treatment in specialties like neurology and psychiatry. There are still significant gaps in the evidence base between where telemedicine is used and where its use is supported by high-quality evidence. Further well-designed research is necessary to understand how best to deploy telemedicine services in health care.

Use of real-time telemedicine in the detection of diabetic macular oedema: a pilot study

PURPOSE

The high prevalence of diabetic retinopathy (21-36%) and 2 yearly reviews recommended by the National Health and Medical Research Council for diabetics with no retinopathy creates a considerable burden for review in rural and regional Australia. Screening for diabetic retinopathy using telemedicine has significant implications. If effective, such a tool would have an impact on finance and resource allocation. The purpose of the study was to establish if telemedicine could distinguish clinically significant macular oedema (CSME) from eyes free of this form of disease.

METHODS

A study population with representative examples of normal fundi and the different grades of retinopathy was chosen from existing records. The specificity and sensitivity of telemedicine diagnosis was compared with fundus photography and examination by an experienced ophthalmologist as a 'gold standard', in a blinded manner. Real-time telemedicine assessment was performed with live video and audio connections with the transmitting and receiving units set in different areas of the ophthalmology department. The transmission end consisted of a video camera mounted on a slit lamp and the receiving unit consisted of a 21'' LCD monitor. A video conference link was established using three ISDN lines capable of 128 kb per second transfer per line allowing for a total of 348 kb per second when utilizing all three lines for high resolution images. Fundus photographs were taken with a Zeiss FF 450 Plus Digital imaging system.

RESULTS

For telemedicine, sensitivity was 38% (95% CI, 35-40%) and specificity was 95% (95% CI, 91-99%). For photography, sensitivity was 75% (95% CI, 71-79%) and specificity was 95% (95% CI, 91-99%).

CONCLUSIONS

In this pilot study, sensitivity of detection of CSME by photography was considerably better than for live-link telemedicine. This study tends to confirm the continued superiority of examination of the patient by an experienced ophthalmologist as the best method of screening for CSME, a sight threatening form of diabetic retinopathy.

A Web-based Telemedicine System for Diabetic Retinopathy Screening Using Digital Fundus Photography

The purpose was to design and implement a Web-based telemedicine system for diabetic retinopathy screening using digital fundus cameras and to make the software publicly available through Open Source release. The process of retinal imaging and case reviewing was modeled to optimize workflow and implement use of computer system. The Web-based system was built on Java Servlet and Java Server Pages (JSP) technologies. Apache Tomcat was chosen as the JSP engine, while MySQL was used as the main database and Laboratory of Neuro Imaging (LONI) Image Storage Architecture, from the LONI-UCLA, as the platform for image storage. For security, all data transmissions were carried over encrypted Internet connections such as Secure Socket Layer (SSL) and HyperText Transfer Protocol over SSL (HTTPS). User logins were required and access to patient data was logged for auditing. The system was deployed at Hubert H. Humphrey Comprehensive Health Center and Martin Luther King/Drew Medical Center of Los Angeles County Department of Health Services. Within 4 months, 1500 images of more than 650 patients were taken at Humphrey's Eye Clinic and successfully transferred to King/Drew's Department of Ophthalmology. This study demonstrates an effective architecture for remote diabetic retinopathy screening.

The influence of age, duration of diabetes, cataract, and pupil size on image quality in digital photographic retinal screening

OBJECTIVE

To evaluate the effect of age, duration of diabetes, cataract, and pupil size on the image quality in digital photographic screening.

RESEARCH DESIGN AND METHODS

Randomized groups of 3,650 patients had one-field, non-mydriatic, 45 degrees digital retinal imaging photography before mydriatic two-field photography. A total of 1,549 patients were then examined by an experienced ophthalmologist. Outcome measures were ungradable image rates, age, duration of diabetes, detection of referable diabetic retinopathy, presence of early or obvious central cataract, pupil diameter, and iris color.

RESULTS

The ungradable image rate for non-mydriatic photography was 19.7% (95% CI 18.4-21.0) and for mydriatic photography was 3.7% (3.1-4.3). The odds of having one eye ungradable increased by 2.6% (1.6-3.7) for each extra year since diagnosis for nonmydriatic, by 4.1% (2.7-5.7) for mydriatic photography irrespective of age, by 5.8% (5.0-6.7) for non-mydriatic, and by 8.4% (6.5-10.4) for mydriatic photography for every extra year of age, irrespective of years since diagnosis. Obvious central cataract was present in 57% of ungradable mydriatic photographs, early cataract in 21%, no cataract in 9%, and 13% had other pathologies. The pupil diameter in the ungradable eyes showed a significant trend (P < 0.001) in the three groups (obvious cataract 4.434, early cataract 3.379, and no cataract 2.750).

CONCLUSIONS

The strongest predictor of ungradable image rates, both for non-mydriatic and mydriatic digital photography, is the age of the person with diabetes. The most common cause of ungradable images was obvious central cataract.

Clinical outcomes associated with telemedicine/telehealth

This paper is a comprehensive review and synthesis of the literature concerning clinical outcomes associated with various telemedicine applications. It starts out with a brief description of the findings reported by similar literature reviews already published. Subsequently, it proposes a conceptual model for assessing clinical outcomes based on Donabedian's formulation of the Medical Care Process. Accordingly, research findings are reported in terms of the relevant components of the medical care process, namely, diagnosis, clinical management, and clinical outcomes. Specific findings are organized according to the designated clinical and diagnostic application. This is followed by a general report of studies dealing with patient satisfaction.

Sensitivity and specificity of digital retinal images in grading diabetic retinopathy

PURPOSE

To assess three novel digital fundus cameras for diabetic retinopathy (DR) screening.

METHODS

Digital colour and red-free retinal imaging (Topcon TRC 50 IA, Canon CR6-45NM, and MediTell) was used to capture 427 images of 70 diabetes patients and control subjects. The images were graded for DR by three readers in a randomized and masked manner using a modified Early Treatment Diabetic Retinopathy Study classification. The reference standard was based on mydriatic ophthalmoscopy and colour and red-free images.

RESULTS

Digital 50 degrees red-free imaging had sensitivity of 97.7%, two-field 50 degrees colour imaging 94.0%, and two-field 45 degrees colour imaging sensitivity of 88.9%. The specificity of these imaging modalities was 98.9-100%, and ungradeable images represented 1.2-1.6%. The hand-held digital colour videocamera (MediTell) showed a sensitivity of 6.9% and ungradeable images represented 92.3%.

CONCLUSION

Digital 50 degrees red-free and two-field 50 degrees or 45 degrees colour imaging were suitable for DR screening, whereas the hand-held digital videocamera did not fulfil the needs of DR screening.

A comparison of in-person examination and video otoscope imaging for tympanostomy tube follow-up

The objective of this study was to determine if video otoscope still images (640 x 480 pixel resolution) of the tympanic membrane following surgical placement of tympanostomy tubes are comparable to an in-person microscopic examination. Forty patients having undergone tympanostomy tube placement in both ears were independently examined in-person by two otolaryngologists and imaged using a video otoscope and telemedicine software package. The two physicians later reviewed images at 6 and 12 weeks. Physical examination findings and diagnosis were documented and compared for their concordance using kappa statistics. For both physicians, the intraprovider concordance between the in-person examination and the corresponding image review was high for each of the physical examination findings: Tube In 93-94% (K 0.85-0.87), Tube Patent 86-93% (K 0.74-0.85), Drainage 94-98% (K 0.42-0.66), Perforation 85-98% (K 0.40-0.84), Granulation 95-99% (K -0.01 to 0.00), Middle Ear Fluid 89-91% (K -0.03 to 0.50), and Retracted 89-94% (K 0.13-0.43). These agreement rates are similar to the normal interprovider concordance observed when two physicians independently examined the same patient in-person for physical exam findings: Tube In 96% (K 0.93), Tube Patent 94% (K 0.88), Drainage 96% (K 0.56), Perforation 90% (K 0.60), Granulation 96% (K 0.39), Middle Ear Fluid 88% (K 0.14), and Retracted 91% (K 0.43). For both physicians, the intraprovider diagnostic concordance between the in-person examination and the corresponding image review was high 79-85% (K 0.67-0.76). The interprovider diagnostic concordance for the in-person exam was 88% (K 0.81). The interprovider diagnostic concordance when two physicians independently reviewed all images was 84% (K 0.74), and 89% (K 0.80) when poor images were excluded. This study demonstrates that physician review of video otoscope images is comparable to an in-person microscopic examination. Store-and-forward video otoscopy may be an acceptable method of following patients post-tympanostomy tube placement.

Use of Telemedicine in Periodic Screening of Diabetic Retinopathy

Telemedicine was used for taking ocular fundus images of diabetic patients, which were subsequently sent by electronic mail to experienced ophthalmologists at a university hospital. The ophthalmologists provided reports on the patients to the internists. The objective of the study was to evaluate the effectiveness of this telemedicine system. A total of 279 diabetic patients were admitted to the Third Department of Internal Medicine of Yokohama City University Hospital, School of Medicine, for blood sugar control or for education on lifestyle between April, 1999, and October, 2000. The subjects did not have eye disease nor diabetic retinopathy when evaluated by an ophthalmologist (at either Yokohama City University Hospital or other facility) within 3 months before enrollment in the study. After dilation of the pupil, fundus images were taken of each eye from four angles using a nonmydriatic fundus camera. The images were transmitted by electronic mail to the Division of Ophthalmology of Tokyo University Branch Hospital along with other patient information. The ophthalmologists there evaluated the images on the screen according to Fukuda's classification of diabetic retinopathy. They sent ophthalmologic reports to the internists at the Third Department of Internal Medicine of Yokohama City University Hospital, School of Medicine, and recommended whether the patient should be seen by his/her regular ophthalmologist earlier than the next scheduled visit. Fundus images were obtained at the time of admission, at 1, 3, and 6 months after discharge, and at every 6 months thereafter. Out of the images of 1170 eyes obtained at various time points from the 279 patients, 1076 (92.0%) were successfully evaluated by the ophthalmologists at the University of Tokyo, while 60 (5.1%) could not be evaluated and there was a communication problem for the images of 34 eyes. The ophthalmologists determined that 5 eyes of 3 patients required further evaluation by the patient's regular ophthalmologist based on the images transferred by telemedicine. No patient dropped out during the study period.

The effectiveness of screening for diabetic retinopathy by digital imaging photography and technician ophthalmoscopy

AIMS

To evaluate the introduction of a community-based non-mydriatic and mydriatic digital photographic screening programme by measuring the sensitivity and specificity compared with a reference standard and assessing the added value of technician direct ophthalmoscopy.

METHODS

Study patients had one-field, non-mydriatic, 45 degrees digital imaging photography prior to mydriatic two-field digital imaging photography followed by technician ophthalmoscopy. Of these patients, 1549 were then examined by an experienced ophthalmologist using slit lamp biomicroscopy as a reference standard. The setting was general practices in Gloucestershire. Patients were selected by randomizing groups of patients (from within individual general practices) and 3611 patients were included in the study. Patients for reference standard examination were recruited from groups of patients on days when the ophthalmologist was able to attend. The main outcome measure was detection of referable diabetic retinopathy (DR) as defined by the Gloucestershire adaptation of the European Working Party guidelines.

RESULTS

For mydriatic digital photography, the sensitivity was 87.8%, specificity was 86.1% and technical failure rate was 3.7%. Technician ophthalmoscopy did not alter these figures. For non-mydriatic photography, the sensitivity was 86.0%, specificity was 76.7% and technical failure rate was 19.7%.

CONCLUSIONS

Two-field mydriatic digital photography is an effective method of screening for referable diabetic retinopathy. Non-mydriatic digital photography has an unacceptable technical failure rate and low specificity.

Online eye care in prisons in Western Australia

In prisons, prison medical officers provide general medical care. However, if specialist care is needed then the prisoner is transported to a specialist medical centre. This is a costly procedure and prison escapes occur during transportation. We have tested our Internet-based eye care system in prisons in Western Australia. Medical and ophthalmic history, visual acuity and intraocular pressure were stored in a browser-based multimedia database. Digital images of the retina and the external eye were recorded and transmitted to a central server. Based on the medical data and the digital images, the specialist ophthalmologist could provide a diagnosis within 24 h. Eleven patients (mean age 48, range 30-82 years) were reviewed during two separate visits to a maximum-security prison in Western Australia. Our main aim was to train prison medical officers and nurses to operate the portable ophthalmic imaging instruments and to use the Internet-based eye care system. The outcome of the pilot study indicated that considerable savings could be made in transport costs and the security risk could be reduced. The Ministry of Justice in Western Australia has decided to implement telemedicine services to provide regular ophthalmic consultation to its prisons.

Telemedical devices in diabetes management

This paper reviews telemedicine and its recent expansions within diabetes management. Diabetes mellitus continues to be one of the major chronic diseases with up to 11% of national health care expenditure, when all late complications are taken into account. Over and above this, the incidence of diabetes is increasing in pandemic fashion. Diabetes has been the focus of telemedicine and information technology over the past two decades. Useful applications supporting high quality treatment exist in clinical management, education, decision support and modelling. Development of high-speed networks enables transmission of good quality photographs making consultations from distant locations possible. Databases and data analysis are fundamental to diabetes outcome research. Less successful has been the development of electronic medical records although this is a dream of many. Evidence of improved clinical outcome using telemedical applications still awaits the breakthrough.

Working toward a portable tele-ophthalmic system for use in maximum-security prisons: a pilot study

The medical care of prisoners is a difficult and often costly process. Basic medical needs are serviced by prison medical officers. However, specialized care often means transport to specialist centers with the attendant cost and safety. We examined portable ophthalmic equipment in a prison environment to screen 11 prisoners who were scheduled for specialist ophthalmic assessment. Medical and ophthalmic histories were documented, visual acuity was tested, digital images were taken of the external eye and retina, and intraocular pressures taken. The data were sent via modem to a specialist ophthalmologist, and the reports were dictated via e-mail at the end of each session. Of the 11 patients who were scheduled to travel for ophthalmic assessment, only 2 were still required to travel to a specialist ophthalmic center. This pilot study showed that there were considerable cost savings to be made by this screening process with the attendant increase in community safety. The prototype equipment requires refinement by further experimentation, but showed the potential as an adjunct to current examination and assessment techniques when applied to a prison population.