Screening for diabetic retinopathy in France

Deep Learning for Diabetic Retinopathy Analysis: A Review, Research Challenges, and Future Directions

Deep learning (DL) enables the creation of computational models comprising multiple processing layers that learn data representations at multiple levels of abstraction. In the recent past, the use of deep learning has been proliferating, yielding promising results in applications across a growing number of fields, most notably in image processing, medical image analysis, data analysis, and bioinformatics. DL algorithms have also had a significant positive impact through yielding improvements in screening, recognition, segmentation, prediction, and classification applications across different domains of healthcare, such as those concerning the abdomen, cardiac, pathology, and retina. Given the extensive body of recent scientific contributions in this discipline, a comprehensive review of deep learning developments in the domain of diabetic retinopathy (DR) analysis, viz., screening, segmentation, prediction, classification, and validation, is presented here. A critical analysis of the relevant reported techniques is carried out, and the associated advantages and limitations highlighted, culminating in the identification of research gaps and future challenges that help to inform the research community to develop more efficient, robust, and accurate DL models for the various challenges in the monitoring and diagnosis of DR.

Capturing the clinical decision-making processes of expert and novice diabetic retinal graders using a 'think-aloud' approach

BACKGROUND

Diabetic eye screening programmes have been developed worldwide based on evidence that early detection and treatment of diabetic retinopathy are crucial to preventing sight loss. However, little is known about the decision-making processes and training needs of diabetic retinal graders, particularly in low- and middle-income countries.

OBJECTIVES

To provide data for improving evidence-based diabetic retinopathy training to help novice graders process fundus images more like experts.

SUBJECTS/METHODS

This is a mixed-methods qualitative study conducted in southern Vietnam and Northern Ireland. Novice diabetic retinal graders in Vietnam (n = 18) and expert graders in Northern Ireland (n = 5) were selected through a purposive sampling technique. Data were collected from 21st February to 3rd September 2019. The interviewer used neutral prompts during think-aloud sessions to encourage participants to verbalise their thought processes while grading fundus images from anonymised patients, followed by semi-structured interviews. Thematic framework analysis was used to identify themes, supported by illustrative quotes from interviews. Mann-Whitney U tests were used to compare graders' performance.

RESULTS

Expert graders used a more systematic approach when grading images, considered all four images per patient and used available software tools such as red-free filters prior to making a decision on management. The most challenging features for novice graders were intra-retinal microvascular abnormalities and new vessels, which were more accurately identified by experts.

CONCLUSION

Taking more time to grade fundus images and adopting a protocol-driven "checklist" approach may help novice graders to function more like experts.

Automatic Screening for Ocular Anomalies Using Fundus Photographs

SIGNIFICANCE

Screening for ocular anomalies using fundus photography is key to prevent vision impairment and blindness. With the growing and aging population, automated algorithms that can triage fundus photographs and provide instant referral decisions are relevant to scale-up screening and face the shortage of ophthalmic expertise.

PURPOSE

This study aimed to develop a deep learning algorithm that detects any ocular anomaly in fundus photographs and to evaluate this algorithm for "normal versus anomalous" eye examination classification in the diabetic and general populations.

METHODS

The deep learning algorithm was developed and evaluated in two populations: the diabetic and general populations. Our patient cohorts consist of 37,129 diabetic patients from the OPHDIAT diabetic retinopathy screening network in Paris, France, and 7356 general patients from the OphtaMaine private screening network, in Le Mans, France. Each data set was divided into a development subset and a test subset of more than 4000 examinations each. For ophthalmologist/algorithm comparison, a subset of 2014 examinations from the OphtaMaine test subset was labeled by a second ophthalmologist. First, the algorithm was trained on the OPHDIAT development subset. Then, it was fine-tuned on the OphtaMaine development subset.

RESULTS

On the OPHDIAT test subset, the area under the receiver operating characteristic curve for normal versus anomalous classification was 0.9592. On the OphtaMaine test subset, the area under the receiver operating characteristic curve was 0.8347 before fine-tuning and 0.9108 after fine-tuning. On the ophthalmologist/algorithm comparison subset, the second ophthalmologist achieved a specificity of 0.8648 and a sensitivity of 0.6682. For the same specificity, the fine-tuned algorithm achieved a sensitivity of 0.8248.

CONCLUSIONS

The proposed algorithm compares favorably with human performance for normal versus anomalous eye examination classification using fundus photography. Artificial intelligence, which previously targeted a few retinal pathologies, can be used to screen for ocular anomalies comprehensively.

[Screening for diabetic retinopathy by non-mydriatic fundus photography: First national campaign in Lebanon]

INTRODUCTION

Diabetic retinopathy (DR) is a leading cause of blindness worldwide. Non-mydriatic fundus photography (NMFP) has been adopted as a screening tool for this disease. We aim to determine the prevalence of DR through this method in Lebanese diabetic patients and to evaluate the impact of such screening in this population.

MATERIALS AND METHODS

This study explores data from an awareness and screening campaign conducted in Lebanon. Diabetic patients from multiple regions were referred by their endocrinologists to undergo NMFP using the Optomed SmartScope^® handheld fundus camera. Photographs were interpreted by a remote observer, and recommendations were given accordingly. The prevalence of DR was calculated, and statistical analyses were performed on the clinical characteristics, fundus findings and number of referrals to ophthalmologists.

RESULTS

The campaign lasted 11 months, during which 2205 patients were examined in 37 screening locations. Out of the 97.41% of patients with type 2 diabetes mellitus, 12.56% had signs of DR, with no significant difference between the regions. 6.28% of the photos were uninterpretable. Positive results were associated with a longer duration of diabetes (P<0.01), treatment with insulin (P<0.01), as well as the presence and chronicity of systemic hypertension (P=0.01). 25% of patients with positive testing were retrospectively asked about their follow-up; only one third had an ophthalmologic examination as per the recommendation, among whom 68.18% underwent treatment for proliferative DR and/or diabetic macular edema.

CONCLUSION

Tele-ophthalmology is useful in mass screening for DR. The importance of dilated fundus examinations still needs to be highlighted for diabetic patients, and better collaboration between endocrinologists and ophthalmologists is required to improve screening outcomes.

Advances in Retinal Imaging and Applications in Diabetic Retinopathy Screening: A Review

Rising prevalence of diabetes worldwide has necessitated the implementation of population-based diabetic retinopathy (DR) screening programs that can perform retinal imaging and interpretation for extremely large patient cohorts in a rapid and sensitive manner while minimizing inappropriate referrals to retina specialists. While most current screening programs employ mydriatic or nonmydriatic color fundus photography and trained image graders to identify referable DR, new imaging modalities offer significant improvements in diagnostic accuracy, throughput, and affordability. Smartphone-based fundus photography, macular optical coherence tomography, ultrawide-field imaging, and artificial intelligence-based image reading address limitations of current approaches and will likely become necessary as DR becomes more prevalent. Here we review current trends in imaging for DR screening and emerging technologies that show potential for improving upon current screening approaches.

A Remote Operating Slit Lamp Microscope System

Objectives: To develop a remote-operating slit lamp microscope system (the remote slit lamp) as the core for highly specialized ophthalmology diagnoses, and to compare the utility of this system with the conventional slit lamp microscope system (the conventional slit lamp) in making a diagnosis.

Methods: The remote slit lamp system was developed. Three factors were evaluated in comparison to the conventional slit lamp. The ability to acquire skills was investigated using a task loading system among specialists and residents in ophthalmology. Participants repeated a task up to ten times and the time required for each task was analyzed. The consistency of the two systems in making a diagnosis was investigated using eyes of patients with ocular diseases as well as healthy volunteers.

Results: The remote slit lamp is composed of a patient’s unit and ophthalmologist’s unit connected by high-speed internet. The two units share images acquired by the slit lamp in addition to the images and voices of patients and ophthalmologists. Both ophthalmology specialists and residents could minimize the completion times after several trials. The remote slit lamp took more time than the conventional slit lamp. Both systems showed a high consistency in evaluations among eyes with healthy eyes or those with ocular diseases.

Conclusions: The remote slit lamp has a similar diagnostic ability, but required more examination time in comparison to the conventional slit lamp. The currently developed remote slit lamp has the potential to be employed for telemedicine purposes in the field of ophthalmology.

Diabetic Retinopathy Screening Ratio Is Improved When Using a Digital, Nonmydriatic Fundus Camera Onsite in a Diabetes Outpatient Clinic

OBJECTIVE

To evaluate the effect of onsite screening with a nonmydriatic, digital fundus camera for diabetic retinopathy (DR) at a diabetes outpatient clinic.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 502 patients, 112 with type 1 and 390 with type 2 diabetes. Patients attended screenings for microvascular complications, including diabetic nephropathy (DN), diabetic polyneuropathy (DP), and DR. Single-field retinal imaging with a digital, nonmydriatic fundus camera was used to assess DR. Prevalence and incidence of microvascular complications were analyzed and the ratio of newly diagnosed to preexisting complications for all entities was calculated in order to differentiate natural progress from missed DRs.

RESULTS

For both types of diabetes, prevalence of DR was 25.0% (n = 126) and incidence 6.4% (n = 32) (T1DM versus T2DM: prevalence: 35.7% versus 22.1%, incidence 5.4% versus 6.7%). 25.4% of all DRs were newly diagnosed. Furthermore, the ratio of newly diagnosed to preexisting DR was higher than those for DN (p = 0.12) and DP (p = 0.03) representing at least 13 patients with missed DR.

CONCLUSIONS

The results indicate that implementing nonmydriatic, digital fundus imaging in a diabetes outpatient clinic can contribute to improved early diagnosis of diabetic retinopathy.

The burden and treatment of diabetes in France

BACKGROUND

The objective of this review was to describe and situate the burden and treatment of diabetes within the broader context of the French health care system.

METHODS

Literature review on the burden, treatment and outcomes of diabetes in France, complemented by personal communication with with diabetes experts in the Paris public hospital system.

RESULTS

Prevalence of diabetes in the French population is estimated at 6%. Diabetes has the highest prevalence among all chronic conditions covered 100% by France's statutory health insurance (SHI), and the number of covered patients has doubled in the past 10 years. In 2010, the SHI cost for pharmacologically-treated diabetes patients amounted to €17.7 billion, including an estimated €2.5 billion directly related to diabetes treatment and prevention and €4.2 billion for treatment of diabetes-related complications. In 2007, the average annual SHI cost was €6 930 for patients with type 1 diabetes and €4 890 for patients with type 2 diabetes. Complications are associated with significantly increased costs. Diabetes is a leading cause of adult blindness, amputation and dialysis in France, which also has one of the highest rates of end-stage renal disease in Europe. Cardiovascular disease is the leading cause of death among people with diabetes. Historically, the French health care system has been more oriented to curative acute care rather than preventive medicine and management of long-term chronic diseases. More recently, the government has focused on primary prevention as part of its national nutrition and health program, with the goal of reducing overweight and obesity in adults and children. It has also recognized the critical role of the patient in managing chronic diseases such as diabetes and has put into place a free patient support program called "sophia". Additional initiatives focus on therapeutic patient education (TPE) and the development of personalized patient pathways.

CONCLUSIONS

While France has been successful in protecting patients from the financial consequences of diabetes through its SHI coverage, improvements are necessary in the areas of prevention, monitoring and reducing the incidence of complications. Systemic changes must be made to improve the coordination and delivery of chronic care.

Perspectives of impaired glucose tolerance management in patients with metabolic syndrome

Aim. To assess the effectiveness of vildagliptin, its effects on visceral obesity (VO), carbohydrate and lipid metabolism parameters, and circadian profile (CP) of blood pressure (BP) in patients with metabolic syndrome (MS), Stage I arterial hypertension (AH), and impaired glucose tolerance (IGT). Material and methods. The study included 30 patients, aged 18-60 years (16 men and 14 women). All patients had IGT, VO, and Stage I AH. Previously prescribed antihypertensive therapy (AHT) was not modified after the start of the study. In all participants, carbohydrate and lipid metabolism parameters, BP CP, and body weight were measured at baseline and after 24 weeks of vildagliptin treatment. Results. Vildagliptin therapy was associated with a significant reduction in body weight, waist circumference, postprandial and fasting glucose levels, the levels of total cholesterol and low-density lipoprotein cholesterol, as well as with a sustained reduction in systolic and diastolic BP levels. Conclusion. Vildagliptin therapy resulted in weight reduction, improved carbohydrate and lipid profiles, and target BP achievement, without inducing hypoglycemia episodes.

No loss of chance of diabetic retinopathy screening by endocrinologists with a digital fundus camera

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.

[The non-mydriatic camera as a screening method in diabetics in Tarragona]

OBJECTIVE

The aim of the study is to present the results of the first year of using a non-mydriatic fundus camera. We performed an evaluation of its usefulness and problems.

METHODS

During the first year of using the non-mydriatic fundus camera we evaluated 3,272 type II diabetic patients who were not being controlled in the hospital.

RESULTS

The diabetic retinopathy was observed in 164 patients (5.01%), the mild form in 70 patients (2.14%). Diabetic macular oedema was observed in 41 patients (1.25%). In 119 patients (3.63%) the retinography could not be interpreted and were referred to the hospital; 113 patients also were referred due to other pathologies; the largest group of these patients had age-related macular disease or age-related macular degeneration (42 patients). Finally, 458 patients (13.99%) required mydriatic eye-drops.

CONCLUSIONS

The non-mydriatic fundus camera is a useful technique for assessing the presence of diabetic retinopathy, particularly in patients with poor ophthalmic control. This technique may enable us to diagnose these patients who need laser treatment.

The incorporation of family physicians in the assessment of diabetic retinopathy by non-mydriatic fundus camera

AIMS

To evaluate the inclusion of family physicians in screening for diabetic retinopathy.

METHODS

We evaluated by non-mydriatic fundus camera 2779 diabetic patients. The family physicians made an initial evaluation of the fundus and pathological images were sent to a reference ophthalmologist. An audit was taken of all the patients at the end of the study. We analysed the concordance in: diabetic retinopathy, diabetic macular edema, and lesions in the macular area.

RESULTS

Diabetic retinopathy was observed in 226 patients (8.1%) and diabetic macular edema in 40 patients (1.4%). Other retinal pathologies were diagnosed in 291 (11.0%). The sensitivity of the study was 95.2% for diabetic retinopathy, 96.0% for macular lesions and 92.9% for diabetic macular edema. The specificity was above 98% in the three studied variables. Cohen's Kappa coefficient was 0.82 for diabetic retinopathy, 0.81 for diabetic macular edema and 0.96 for macular lesions.

CONCLUSIONS

The inclusion of family physicians in the screening system seems to be effective in the diagnosis of diabetic retinopathy.

Dietary Taurine Supplementation Ameliorates Diabetic Retinopathy via Anti-excitotoxicity of Glutamate in Streptozotocin-induced Sprague-Dawley Rats

The purpose of this study was to investigate whether taurine ameliorate the diabetic retinopathy, and to further explore the underlying mechanisms. The Sprague-Dawley rats were injected with streptozotocin to establish experimental diabetic model, then fed without or with 1.2% taurine for additional 4-12 weeks. After that, the protective effects of dietary taurine supplementation on diabetic retinopathy were estimated. Our results showed that chronic taurine supplement effectively improved diabetic retinopathy as changes of histopathology and ultrastructure. The supplementation could not lower plasma glucose concentration (P > 0.05), but caused an elevation in taurine content and a decline in levels of glutamate and gamma-aminobutyric acid (GABA) in diabetic retina (P < 0.05). Moreover, chronic taurine supplementation increased glutamate transporter (GLAST) expression (P < 0.05), decreased intermediate filament glial fibrillary acidic protein (GFAP) and N-methyl-D: -aspartate receptor subunit 1 (NR1) expression in diabetic retina (P < 0.05). These results demonstrated that chronic taurine supplementation ameliorates diabetic retinopathy via anti-excitotoxicity of glutamate in rats.

Diagnosed diabetic retinopathy in France, Italy, Spain, and the United Kingdom

AIM

The objective of this study was to describe the proportion and characteristics of patients diagnosed with diabetic retinopathy (DR) in France, Italy, Spain, and the United Kingdom (UK).

METHODS

To estimate the proportion of patients with type 1 and type 2 diabetes diagnosed with DR, we conducted a cross-sectional survey of general practitioners in each country using physician records. In addition, diabetes specialists were recruited in Italy and Spain. We extracted data from the medical notes of a sample of DR patients to characterize DR severity and clinical characteristics.

RESULTS

The average number of physicians per country was 41 (range: 34-49). The proportion of diagnosed DR ranged from 10.3% (95% CI, 6.7-14.0%) in Spain to 19.6% (95% CI, 16.0-23.1%) in the UK. Of 752 DR patients studied, 53.9% were male; mean age (+/-SD) was 64.2+/-12.8 years. Consistently across countries, mild non-proliferative DR was the most common severity level of diagnosed DR. Proliferative DR (PDR) ranged from 19.7% (France) to 31.5% (UK). Diabetic macular oedema was reported in approximately 10% of patients. Hypertension (73.1%), dyslipidemia (63.2%), and neuropathy (52.1%) were the most common co-morbidities.

CONCLUSIONS

Country-specific prevalence of diagnosed DR may reflect clinical management of diabetes, healthcare systems, or record-keeping accuracy. Across countries, up to 30% of DR patients had a diagnosis of PDR, which could suggest that patients are diagnosed only when their disease is advanced.

[Screening diabetic retinopathy in Burgundy with an itinerant nonmydriatic camera]

INTRODUCTION

The aim of this study was to assess the suitability of screening diabetic retinopathy (DR) with an itinerant nonmydriatic camera.

METHODS

This program required collaboration between ophthalmologists and general practitioners. Three professional organizations gave their support: L'union Professionnelle des Médecins Libéraux de Bourgogne (UPMLB), le Fonds d'Aide à la Qualité des Soins de Ville (FAQSV), et la Fédération des Associations des Diabétiques de Bourgogne (FADB). The screening programm took place from November 2004 to June 2005 throughout the Burgundy region. General practitioners, health professionals (pharmacists, nurses), local media, and health insurance offices informed patients of the DR screening. An orthoptist took photographs with a nonmydriatic digital camera. Each patient had four fundus photographs without pupillary dilatation. Photographs were analyzed in the Department of Ophthalmology of Dijon's General Hospital.

RESULTS

In this study, 676 diabetic patients were screened. Among these patients, 58 had DR, exclusively nonproliferative retinopathies. Nine percent of the photographs were ungradable. The mean age of patients with DR was 65 years. The mean onset of diabetes was 18 years before the study. Insulin therapy was followed by 27 patients (46.6%). Hemoglobin A1c was known in 26 patients (44.8%), with a mean value of 8.14%. Nearly 60% of patients with DR did not have their recommended annual consultation. After screening, 84% of patients consulted an ophthalmologist.

CONCLUSION

Screening DR with an itinerant nonmydriatic camera can improve ophthalmologic follow-up of diabetics in rural areas. This screening program has continued in 2006 with an adapted vehicle.

Systematic screening for diabetic retinopathy with a digital fundus camera following pupillary dilatation in a university diabetes department

AIMS

Screening for diabetic retinopathy (DR) is highly inadequate in France because of insufficient infrastructure and increasing disease prevalence. We describe the results of the first systematic DR screening programme established in a university diabetes department.

METHODS

In this cross-sectional study conducted over 1 year, consecutive adult patients underwent three-field retinal photography with the Topcon TRC NW6S digital fundus camera following pupillary dilatation with Tropicamide 1%. A questionnaire provided information on patients' systemic and ocular history. Glycated haemoglobin (HbA1c) was measured at the screening visit. Two ophthalmologists graded the retinal photographs in a masked fashion.

RESULTS

Of 1157 patients attending the diabetes department, 1153 (99.7%)underwent photographic screening. Images were gradable in 96% patients. Diabetic retinopathy was detected in 522 (45%) patients and sight-threatening DR in 167 (14%). Of 704 (61%) patients previously believed to have no DR,254 (34%) screened positive. The presence of DR was associated with age,insulin use and non-Caucasian ethnicity in Type 2 patients, and with duration of diabetes and HbA1c in Type 1 and Type 2 patients. Associated ocular pathologies were diagnosed in 612 (53%) patients.

CONCLUSIONS

Our photographic screening programme using pharmacological mydriasis provided a high screening coverage feasible in a hospital setting. We obtained information regarding prevalence and associated risk factors of DR inpatients attending a tertiary care centre. Screening was well accepted by patients and met with no protest from city ophthalmologists. It generated considerable interest among endocrinologists and feedback of results is expected to improve optimization of glycaemic control.

Screening for diabetic retinopathy by ophthalmologists and endocrinologists with pupillary dilation and a nonmydriatic digital camera

PURPOSE

To assess the effects of pupillary dilation on image quality and certitude of screening diabetic retinopathy by trained endocrinologists using a digital nonmydriatic camera.

DESIGN

Prospective, comparative, observational case series.

METHODS

One hundred fifty patients with diabetes attending a hospital-based photographic screening clinic had five-field (45 degree) digital retinal imaging and mosaic construction, first through dark-adapted pupils, then after a single application of tropicamide 1%. The 600 sets of images (150 patients, 300 eyes, before and after dilation) were graded independently and in a blinded manner by two endocrinologists and two ophthalmologists, with the consensual opinion on dilated images of the latter serving as the gold standard. The criteria of evaluation were assessment of image quality and certitude of detecting and grading retinopathy.

RESULTS

Of 300 eyes, pharmacological mydriasis improved image quality, with an increase in the number of eyes with five good images from seven to 160 and good-quality mosaics from 99 to 233. Dilation allowed better identification of maculopathy in the second eye because there was a decrease in ungradeable central images from 127 to 15 eyes. Dilation increased the number of eyes having retinopathy detected with certainty from 153 to 252 and graded with certainty from 173 to 277. No adverse effects were recorded.

CONCLUSIONS

Single application of tropicamide 1% significantly improves image quality and certitude of screening diabetic retinopathy with nonmydriatic camera by endocrinologists.

Screening for diabetic retinopathy: the first telemedical approach in a primary care setting in France

OBJECTIVES

Diabetic retinopathy (DR) remains a major cause of visual impairment in France, due to insufficient regular annual screening. Fundus photography is a sensitive alternative to ophthalmoscopy for DR screening. The aim of our study was to report the first telemedical approach to this screening in a primary care setting in France.

METHODS

A DR screening centre equipped with a nonmydriatic camera was opened in the 18th district of northern Paris and placed at the disposal of general practitioners (GPs) of the Réseau de Santé Paris Nord (North Paris Health Network). These GPs were invited to send their diabetic patients who had no known DR and had had no fundus examination for more than one year to this screening center. Retinal photographs were taken by an orthoptist without pupillary dilation and sent for grading through the Internet to the Lariboisière Hopital Ophthalmology Department.

RESULTS

During an 18-month period, 912 DR screening examinations were performed in 868 diabetic patients referred to the DR screening center by 240 GPs. Patients' mean +/- SD age was 59.9 +/- 11.1 years. Of these 868 patients, 260 (30%) said they never have had an ophthalmological examination. Diabetic retinopathy was detected in 197 patients (22.7%). The proportion of patients for whom fundus photographs of one or both eyes could not be assessed was 10.1%. 159 patients (18.3%) required referral to an ophthalmologist.

CONCLUSION

Nonmydriatic photography, combined with teletransmission to a reading centre, proved to be a feasible valid method for the detection of DR. This screening method allowed the identification of patients requiring prompt referral to an ophthalmologist for further complete eye examination.