Comparison of non-mydriatic retinal photography with ophthalmoscopy in 2159 patients: mobile retinal camera study

Comparative analysis of two retinal fractures with ultrabroad‑angle fundus photography systems

The aim of the present study was to compare the performance of the Opel Panorama 200 and Zeiss Clarus 500 (Carl Zeiss AG) systems in diagnosing retinal fractures. Human subjects were selected from 298 fundus examinations (531 eyes) in ophthalmology from February 2021 to June 2021, including 68 patients with retinal fissures (95 eyes). All fundus tests were performed with Opel Panoramic 200. Zeiss Clarus 500 (Carl Zeiss AG) fundus photography, slit-lamp full retinal lens (Ocular Mainster Wide Field; Ocular Instruments), and retinal laser photocoagulation was performed for all affected eyes. The diagnostic sensitivity of the two examination methods was compared, and their sensitivities for posterior retina, peripheral nose, crystal eye, cataract, positive experiment, and myopia testing were compared. In all, 68 patients (95 eyes) were clinically examined and treated 112 laser times. For retinal fractures, the Opel Panorama 200 used a check sensitivity of 89.5%, and the Clarus 500 check had a sensitivity of 94.7%, with the difference being non-significant (P=0.358). Moreover, Clarus 500 diagnosed the sensitivity of the temporal periphery significantly higher than that of Opel Panorama 200 (P=0.048). Opel Panorama 200 displayed statistically significant sensitivity compared with Clarus 500 diagnosis with crystalline and crystal fewer eyes (P>0.05); Clarus 500 sensitivity for cataract diagnosis (crystal turbidity level 3 and above) was significantly higher than that of Opel Panorama 200 (P=0.033). Opel Panoramic 200 displayed significant sensitivity to ocular myopia and medium to moderate myopia (P>0.05). Clarus 500 diagnosed high myopia with a significantly higher sensitivity than Opel Panorama 200 (P=0.045). Opel Panorama 200 and Zeiss Clarus 500 displayed the same level of sensitivity to retinal fissures, with improved sensitivity in refractive turbidity and for retinal fissures located in the far periphery of the temporal side.

Imaging Modalities Employed in Diabetic Retinopathy Screening: A Review and Meta-Analysis

INTRODUCTION

Urbanization has caused dramatic changes in lifestyle, and these rapid transitions have led to an increased risk of noncommunicable diseases, such as type 2 diabetes. In terms of cost-effectiveness, screening for diabetic retinopathy is a critical aspect in diabetes management. The aim of this study was to review the imaging modalities employed for retinal examination in diabetic retinopathy screening.

METHODS

The PubMed and Web of Science databases were the main sources used to investigate the medical literature. An extensive search was performed to identify relevant articles concerning "imaging", "diabetic retinopathy" and "screening" up to 1 June 2021. Imaging techniques were divided into the following: (i) mydriatic fundus photography, (ii) non-mydriatic fundus photography, (iii) smartphone-based imaging, and (iv) ultrawide-field imaging. A meta-analysis was performed to analyze the performance and technical failure rate of each method.

RESULTS

The technical failure rates for mydriatic and non-mydriatic digital fundus photography, smartphone-based and ultrawide-field imaging were 3.4% (95% CI: 2.3-4.6%), 12.1% (95% CI: 5.4-18.7%), 5.3% (95% CI: 1.5-9.0%) and 2.2% (95% CI: 0.3-4.0%), respectively. The rate was significantly different between all analyzed techniques (p < 0.001), and the overall failure rate was 6.6% (4.9-8.3%; I2 = 97.2%). The publication bias factor for smartphone-based imaging was significantly higher than for mydriatic digital fundus photography and non-mydriatic digital fundus photography (b = -8.61, b = -2.59 and b = -7.03, respectively; p < 0.001). Ultrawide-field imaging studies were excluded from the final sensitivity/specificity analysis, as the total number of patients included was too small.

CONCLUSIONS

Regardless of the type of the device used, retinal photographs should be taken on eyes with dilated pupils, unless contraindicated, as this setting decreases the rate of ungradable images. Smartphone-based and ultrawide-field imaging may become potential alternative methods for optimized DR screening; however, there is not yet enough evidence for these techniques to displace mydriatic fundus photography.

Nomogram Prediction Model for Diabetic Retinopathy Development in Type 2 Diabetes Mellitus Patients: A Retrospective Cohort Study

BACKGROUND

This study is aimed at investigating the systemic risk factors of diabetic retinopathy and further establishing a risk prediction model for DR development in T2DM patients.

METHODS

This is a retrospective cohort study including 330 type 2 diabetes mellitus (T2DM) patients who were followed up from December 2012 to November 2020. Multivariable cox regression analysis identifying factors associated with the hazard of developing diabetic retinopathy (DR) was used to construct the DR risk prediction model in the form of nomogram.

RESULTS

50.6% of participants (mean age: 58.60 ± 10.55) were female, and mean duration of diabetes was 7.09 ± 5.36 years. After multivariate cox regression, the risk factors for developing DR were age (HR 1.068, 95%Cl 1.021-1.118, P = 0.005), diabetes duration (HR 1.094, 95%Cl 1.018-1.177, P = 0.015), HbA1c (HR 1.411, 95%Cl 1.113-1.788, P = 0.004), albuminuria (HR 6.908, 95%Cl 1.794-26.599, P = 0.005), and triglyceride (HR 1.554, 95%Cl 1.037-2.330, P = 0.033). The AUC values of the nomogram for predicting developing DR at 3-, 4-, and 5-year were 0.854, 0.845, and 0.798.

CONCLUSION

Combining age, diabetes duration, HbA1c, albuminuria, and triglyceride, the nomogram model is effective for early recognition and intervention of individuals at high risk of DR development.

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.

[Performance of ultra-wide field retinophotography for screening of diabetic retinopathy]

INTRODUCTION

Early diagnosis of diabetic retinopathy is a public health issue. Fundus retinophotography (FRP) is widely used for the detection of the disease. Recently, ultra-wide field retinophotography (WFRP) device allows imaging of approximately 80% of the retinal surface in a single image. The goal of the present study was to evaluate the efficacy of WFRP in the diagnosis and gradation of diabetic retinopathy compared to the gold standard of FRP.

METHODS

The non-mydriatic Optos P200Tx was used for WFRP imaging. FRP in the 9 positions of gaze was then acquired with the Topcon TRC-NW6S after pupillary dilation. The processing time for each imaging modality was recorded.

RESULTS

One hundred and sixteen eyes of 58 patients were included in this study. Fourteen eyes were excluded from the analysis due to insufficient imaging quality. WFRP sensitivity was 96% and specificity was 92%. Only 6 eyes received a higher severity grade of diabetic retinopathy by WFRP compared to FRP. In these cases, when the WFRP was analyzed in the same field as the FRP, the severity grade was similar for 5 of the 6 eyes. The mean time of acquisition was significantly lower for WFRP compared to FRP.

CONCLUSION

WFRP is fast and effective in screening for diabetic retinopathy. The severity grade of the disease was similar to the gold standard of FRP in most cases. WFRP could thus be used in mass screening for diabetic retinopathy.

Non-Mydriatic Fundus Retinography in Screening for Diabetic Retinopathy: Agreement Between Family Physicians, General Ophthalmologists, and a Retinal Specialist

PURPOSE

To determine the level of agreement between trained family physicians (FPs), general ophthalmologists (GOs), and a retinal specialist (RS) in the assessment of non-mydriatic fundus retinography in screening for diabetic retinopathy (DR) in the primary health-care setting.

METHODS

200 Diabetic patients were submitted to two-field non-mydriatic digital fundus camera. The images were examined by four trained FPs, two GOs, and one RS with regard to the diagnosis and severity of DR and the diagnosis of macular edema. The RS served as gold standard. Reliability and accuracy were determined with the kappa test and diagnostic measures.

RESULTS

A total of 397 eyes of 200 patients were included. The mean age was 55.1 (±11.7) years, and 182 (91%) had type 2 diabetes. The mean levels of serum glucose and glycosylated hemoglobin A1c were 195.6 (±87.3) mg/dL and 8.9% (±2.1), respectively. DR was diagnosed in 166 eyes by the RS and in 114 and 182 eyes by GO₁ and GO₂, respectively. For severity, DR was graded as proliferative in 8 eyes by the RS vs. 15 and 9 eyes by GO₁ and GO₂, respectively. The agreement between the RS and the GOs was substantial for both DR diagnosis (GO₁k = 0.65; GO₂k = 0.74) and severity (GO₁k = 0.60; GO₂k = 0.71), and fair or moderate for macular edema (GO₁k = 0.27; GO₂k = 0.43). FP₁, FP₂, FP₃, and FP₄ diagnosed DR in 108, 119, 163, and 117 eyes, respectively. The agreement between the RS and the FPs with regard to DR diagnosis was substantial (FP₂k = 0.69; FP₃k = 0.73; FP₄k = 0.71) or moderate (FP₁k = 0.56). As for DR severity, the agreement between the FPs and the RS was substantial (FP₂k = 0.66; FP₃k = 069; FP₄k = 0.64) or moderate (FP₁k = 0.51). Agreement between the FPs and the RS with regard to macular edema was fair (FP₁k = 0.33; FP₂k = 0.39; FP₃k = 0.37) or moderate (FP₄k = 0.51).

CONCLUSION

Non-mydriatic fundus retinography was shown to be useful in DR screening in the primary health-care setting. FPs made assessments with good levels of agreement with an RS. Non-mydriatic fundus retinography associated with appropriate general physicians training is essential for the DR screening.

Parafoveal OCT Angiography Features in Diabetic Patients without Clinical Diabetic Retinopathy: A Qualitative and Quantitative Analysis

Purpose

To evaluate the capacity of OCT angiography (OCTA) for detecting infraclinical lesions in parafoveal capillaries in diabetic patients without diabetic retinopathy (DR).

Methods

This prospective observational cross-sectional case-control study analyzed the superficial and deep capillary plexuses (SCP and DCP) on macular OCTA scans (3 × 3 mm) centered on the fovea. We compared 22 diabetic patients (34 eyes included) without DR diagnosis on color fundus photographs, with 22 age- and gender-matched nondiabetic controls (40 eyes included). Qualitative analysis concerned morphological ischemic capillary alterations. Quantitative analysis measured foveal avascular zone (FAZ) size, parafoveal capillary density, and enlargement coefficient of FAZ between SCP and DCP.

Results

Neither the qualitative nor quantitative parameters were significantly different between both groups. No microaneurysms or venous tortuosity was observed in any of the analyzed images. On the SCP, the mean FAZ area was 0.322 ± 0.125 mm² in diabetic patients and 0.285 ± 0.150 mm² in controls, P = 0.31. On the DCP, the mean FAZ area was 0.444 ± 0.153 mm² in cases and 0.398 ± 0.138 mm² in controls, P = 0.20.

Conclusion

OCTA did not detect infraclinical qualitative or quantitative differences in parafoveal capillaries of diabetic patients without DR in comparison with nondiabetic controls.

Sensitivity and specificity of nonmydriatic digital imaging in screening diabetic retinopathy in Indian eyes

Background:

Nonmydriatic digital imaging (NMDI) is ideal for screening diabetic retinopathy (DR), but its use in Indian eyes has not been evaluated.

Aim:

The aim was to evaluate the sensitivity and specificity of NMDI as a screening tool in detecting DR in Indian eyes.

Design:

A prospective, nonrandomized, noncomparative, noninterventional study.

Materials and Methods:

A total of 500 diabetic patients visiting the endocrinology clinic (September 2008-June 2010) underwent NMDI (Zeiss Procam), followed by routine dilated fundus photography (FP; Zeiss Visupac 450+) of 345° retinal fields (1) optic disc and macula, (2) superotemporal, and (3) nasal to optic disc. Two-masked retina specialists graded the images for quality and severity of DR, and compared between NMDI and dilated FP.

Statistical Analysis:

SPSS Windows 17 for version.

Results:

Mean age was 52.97 ± 13.46 years (306 males: 194 females). The rate of ungradable images was 30.6% and 31% by the two observers. By observer 1, the sensitivity and specificity of detecting any DR was 58.8% and 69.1%, respectively, (κ = 0.608) and sight-threatening DR (STDR) was 63.1% and 68.9%, respectively, (κ = 0.641). By observer 2, the sensitivity and specificity was 57.3% and 68.3%, respectively, for any DR (κ = 0.593) and 62.8% and 68.3%, respectively, for STDR (κ = 0.637). The level of agreement between two observers was high (κ = 0.96).

Conclusion:

A high rate of poor quality photographs and low sensitivity limited the use of NMDI as a perfect screening system, particularly in dark iris population with diabetes as seen in Indian eyes.

Wide-field imaging and OCT vs clinical evaluation of patients referred from diabetic retinopathy screening

Purpose

Compare wide-field Optomap imaging and optical coherence tomography (OCT) with clinical examination in diabetic retinopathy (DR).

Methods

Patients referred from Diabetic Eye Screening Programmes to three centres underwent dilated ophthalmoscopy and were assigned a DR grade. Wide-field colour imaging and OCT were then examined by the same clinician at that visit and a combined grade was assigned. Independent graders later reviewed the images and assigned an imaging-only grade. These three grades (clinical, combined, and imaging) were compared. The method that detected the highest grade of retinopathy, including neovascularisation, was determined.

Results

Two thousand and forty eyes of 1023 patients were assessed. Wide-field imaging compared with clinical examination had a sensitivity and specificity of 73% and 96%, respectively, for detecting proliferative DR, 84% and 69% for sight-threatening DR, and 64% and 90% for diabetic macular oedema. Imaging alone found 35 more eyes with new vessels (19% of eyes with new vessels) and the combined grade found 14 more eyes than clinical examination alone.

Conclusions

Assessment of wide-field images and OCT alone detected more eyes with higher grades of DR compared with clinical examination alone or when combined with imaging in a clinical setting. The sensitivity was not higher as the techniques were not the same, with imaging alone being more sensitive. Wide-field imaging with OCT could be used to assess referrals from DR screening to determine management, to enhance the quality of assessment in clinics, and to follow-up patients whose DR is above the screening referral threshold but does not actually require treatment.

25th RCOphth Congress, President's Session paper: 25 years of progress in medical retina

The quarter century since the foundation of the Royal College of Ophthalmologists has coincided with immense change in the subspecialty of medical retina, which has moved from being the province of a few dedicated enthusiasts to being an integral, core part of ophthalmology in every eye department. In age-related macular degeneration, there has been a move away from targeted, destructive laser therapy, dependent on fluorescein angiography to intravitreal injection therapy of anti-growth factor agents, largely guided by optical coherence tomography. As a result of these changes, ophthalmologists have witnessed a marked improvement in visual outcomes for their patients with wet age-related macular degeneration (AMD), while at the same time developing and enacting entirely novel ways of delivering care. In the field of diabetic retinopathy, this period also saw advances in laser technology and a move away from highly destructive laser photocoagulation treatment to gentler retinal laser treatments. The introduction of intravitreal therapies, both steroids and anti-growth factor agents, has further advanced the treatment of diabetic macular oedema. This era has also seen in the United Kingdom the introduction of a coordinated national diabetic retinopathy screening programme, which offers an increasing hope that the burden of blindness from diabetic eye disease can be lessened. Exciting future advances in retinal imaging, genetics, and pharmacology will allow us to further improve outcomes for our patients and for ophthalmologists specialising in medical retina, the future looks very exciting but increasingly busy.

Screening and Referral of Diabetic Retinopathy: A Comparative Review of the Practice Guidelines

Diabetic retinopathy (DR) is a leading cause of preventable visual impairment in the working age group. The major risk factors for development and progression are duration of disease and the severity of hyperglycemia. The Global Diabetic Retinopathy Project developed a new classification system for DR and macular edema to enhance communication and coordination among the multidisciplinary team of physicians taking care of diabetic patients. Diabetic retinopathy progresses from nonproliferative DR to proliferative DR through a series of stages. Early detection and timely referral are critical for timely interventions to prevent further deterioration. Primary care physicians have an integral role in the community as they are the first point of contact for patients. Guidelines from various associations provide recommendations to physicians taking care of diabetic patients on how to screen and situations where referral to an ophthalmologist is needed. Dilated direct ophthalmoscopy is a convenient method to assess the fundus, but it does not replace retinal photography in the screening of DR. All patients with proliferative DR and diabetic macular edema should be referred to an ophthalmologist, whereas the situation for nonproliferative DR remains unclear as no consensus was drawn from the various guidelines.

Ultra-wide field retinal imaging in detection, classification, and management of diabetic retinopathy

Current ultra-wide field (UWF) retinal imaging systems utilize scanning laser ophthalmoscope technology combined with an ellipsoidal mirror to capture up to 200 degrees of the retina in a single image. When compared with mydriatic ETDRS-protocol, 7 standard field photographs and clinical examination, nonmydriatic UWF images appear to have excellent agreement in allowing the detection and classification of diabetic retinopathy (DR), although larger, definitive validation studies are still forthcoming. UWF imaging and angiography allow visualization of peripheral retinal nonperfusion, vascular leakage and neovascularization in patients with DR that may not be captured on 7 standard fields. Prospective randomized controlled trials are needed to evaluate whether modified laser treatment algorithms based on improved visualization of the retinal periphery might improve patient outcomes. Nonmydriatic UWF imaging has potential applications for ocular diabetic telehealth programs, but validation of newer, more portable, and more affordable UWF imaging models is needed.

Comparison of image-assisted versus traditional fundus examination

BACKGROUND

The purpose of this study was to evaluate the ability of image-assisted fundus examination to detect retinal lesions compared with traditional fundus examination.

METHODS

Subjects were imaged using a nonmydriatic ultrawide field scanning laser ophthalmoscope. After imaging, subjects underwent both a traditional and an image-assisted fundus examination, in random order. During the image-assisted method, ultrawide field scanning laser ophthalmoscopic images were reviewed in conjunction with a dilated fundus examination. Lesions detected by each method were assigned to one of three regions, ie, optic disc, posterior pole/macula, or mid-to-peripheral retina. Discrepancies between the image-assisted and the traditional examination methods were adjudicated by a retinal ophthalmologist.

RESULTS

In total, 170 subjects (339 eyes) were recruited. Agreement between image-assisted and traditional fundus examination varied by lesion type and was excellent for staphyloma (kappa 0.76), fair for suspicious cupping (kappa 0.66), drusen in the posterior pole/macula and mid-to-peripheral retina (0.45, 0.41), retinal pigment epithelial changes in the posterior pole/macula (0.54), peripheral retinal degeneration (0.50), cobblestone (0.69), vitreoretinal interface abnormalities (0.40), and vitreous lesions (0.53). Agreement was poor for hemorrhage in the mid-to-peripheral retina (kappa 0.33), and nevi in the mid-to-peripheral retina (0.34). When the methods disagreed, the results indicated a statistically significant advantage for the image-assisted examination in detecting suspicious cupping (P = 0.04), drusen in the posterior pole/macula and mid-to-peripheral retina (P = 0.004, P < 0.001), retinal pigment epithelial changes in the posterior pole/macula (P = 0.04), nevi in the posterior pole/macula and mid-to-peripheral retina (P = 0.01, P = 0.007), peripheral retinal degeneration (P < 0.001), hemorrhage in the mid-to-peripheral retina (P = 0.01), and vitreous lesions (P < 0.001).

CONCLUSION

Image-assisted fundus examination may enhance detection of retinal lesions compared with traditional fundus examination alone.

Nonmydriatic ultrawide field retinal imaging compared with dilated standard 7-field 35-mm photography and retinal specialist examination for evaluation of diabetic retinopathy

PURPOSE

To compare nonmydriatic stereoscopic Optomap ultrawide field images with dilated stereoscopic Early Treatment Diabetic Retinopathy Study 7-standard field 35-mm color 30-degree fundus photographs (ETDRS photography) and clinical examination for determining diabetic retinopathy (DR) and diabetic macular edema (DME) severity.

DESIGN

Single-site, prospective, comparative, instrument validation study.

METHODS

One hundred three diabetic patients (206 eyes) representing the full spectrum of DR severity underwent nonmydriatic ultrawide field 100-degree and 200-degree imaging, dilated ETDRS photography, and dilated fundus examination by a retina specialist. Two independent readers graded images to determine DR and DME severity. A third masked retina specialist adjudicated discrepancies.

RESULTS

Based on ETDRS photography (n = 200), the results were as follows: no DR (n = 25 eyes [12.5%]), mild nonproliferative DR (NPDR; 47 [23.5%]), moderate NPDR (61 [30.5%]), severe NPDR (11 [5.5%]), very severe NPDR (3 [1.5%]), and proliferative DR (52 [2.5%]). One (0.5%) eye was ungradable and 6 eyes did not complete ETDRS photography. No DME was found in 114 eyes (57.0%), DME was found in 28 eyes (14.0%), and clinically significant DME was found in 47 eyes (23.5%), and 11 (5.5%) eyes were ungradable. Exact DR severity agreement between ultrawide field 100-degree imaging and ETDRS photography occurred in 84%, with agreement within 1 level in 91% (K(W) = 0.85; K = 0.79). Nonmydriatic ultrawide field images exactly matched clinical examination results for DR in 70% and were within 1 level in 93% (K(W) = 0.71; K = 0.61). Nonmydriatic ultrawide field imaging acquisition time was less than half that of dilated ETDRS photography (P < .0001).

CONCLUSIONS

Nonmydriatic ultrawide field images compare favorably with dilated ETDRS photography and dilated fundus examination in determining DR and DME severity; however, they are acquired more rapidly. If confirmed in broader diabetic populations, nonmydriatic ultrawide field imaging may prove to be beneficial in DR evaluation in research and clinical settings.

Quality of nonmydriatic digital fundus photography obtained by nurse practitioners in the emergency department: the FOTO-ED study

OBJECTIVE

Nonmydriatic fundus photography by non-ophthalmic-trained personnel has recently been shown to be a potential alternative to direct ophthalmoscopy in the emergency department (ED). We evaluated the reliability of a novel quality rating scale and applied this scale to nonmydriatic fundus photographs taken during routine ED patient encounters to determine factors associated with diminished photograph quality.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

We included 350 patients enrolled in the Fundus photography versus Ophthalmoscopy Trials Outcomes in the Emergency Department study who were photographed by nurse practitioners after <30 minutes of training followed by supervision.

METHODS

Photographs of both eyes were graded for quality on 2 occasions by 2 neuro-ophthalmologists. Four regions were independently evaluated for quality: Optic disc, macula, and superior and inferior vascular arcades. Quality as a function of the number of photographs taken was evaluated by Kaplan-Meier analysis. Mixed effects ordinal logistic regression was used to evaluate for predictors of image quality while accounting for the repeated measures design.

MAIN OUTCOME MEASURES

Overall photographic quality (1-5 scale; 5 best).

RESULTS

We evaluated 1734 photographs. Inter- and intraobserver agreements between neuro-ophthalmologists were very good (weighted kappa, 0.84-0.87). Quality of the optic disc area was better than those of other retinal areas (P<0.002). Kaplan-Meier analysis showed that if a high-quality photograph of an eye was not obtained by the third attempt, it was unlikely that one would be obtained at all. A 10-second increase in the interphotograph interval before a total of 40 seconds increased the odds of a 1-unit higher quality rating by 1.81 times (95% confidence interval [CI], 1.68-1.98), and a 10-year increase in age decreased the odds by 0.76 times (95% CI, 0.69-0.85). Black patients had 0.42 times (95% CI, 0.28-0.63) the odds of a 1-unit higher quality rating compared with whites.

CONCLUSIONS

Our 5-point scale is a reliable measure of nonmydriatic photograph quality. The region of interest, interphotograph interval, and patient age and race are significant predictors of image quality for nonmydriatic photographs taken by nurse practitioners in the ED. Addressing these factors may have a direct impact on the successful implementation of nonmydriatic fundus photography into the ED.

Long-term impact of retinal screening on significant diabetes-related visual impairment in the working age population

AIMS

Diabetic retinopathy has long been regarded as the commonest preventable cause of blindness in the working age population. The aim was to determine if consistent annual screening for treatable retinopathy decreased the incidence of new blindness.

METHODS

We collated the causes of blindness for a 5-year period between 2001 and 2005 for the 16- to 64-year age group in a district that had operated systematic retinal screening in diabetes since 1986.

RESULTS

Diabetic retinopathy was found to be the second commonest cause of blindness, with optic atrophy being the commonest cause in Newcastle District. This differs from national data showing diabetic retinopathy to be the commonest cause. Diabetic retinopathy was also the second commonest cause of partial sightedness registrations, with stroke being the commonest cause. Overall, stroke disease accounted for 16.2% and diabetic retinopathy for 15.4% of registrations. The annual incidence of blindness was 0.22 per 1000 with diabetes and of partial sightedness 0.43 per 1000 with diabetes.

CONCLUSIONS

In a district that has operated retinal screening since 1986, diabetic retinopathy was not the commonest cause of blindness in the working age population, consistent with an effect of systematic annual screening.

Influence of pregnancy on long-term progression of retinopathy in patients with type 1 diabetes

AIMS/HYPOTHESIS

Pregnancy in type 1 diabetic women is associated with risk of worsening of retinopathy. It has been reported that deterioration continues in the months after delivery, but direct data are lacking. It is also unclear what impact pregnancy has on the long-term progression of retinopathy.

METHODS

We studied 59 women with type 1 diabetes who had retinal photographs before pregnancy and yearly for 5 years post pregnancy. These photographs were graded using the EURODIAB retinopathy grading system.

RESULTS

The mean duration of diabetes was 14.4+/-8.2 years and mean age at pregnancy was 29.8+/-5.5 years. Mean HbA(1c) was 8.2+/-2.0% before pregnancy with tighter control during pregnancy itself. This value was high despite efforts to improve take-up of pre-conception care. Mean HbA(1c) was 8.6+/-1.5 during the follow-up period. At baseline, 43 (72.9%) women were free of retinopathy, 15 had non-proliferative retinopathy and one woman had previously had laser therapy. During pregnancy four women required laser therapy. Over the next 5 years none required laser therapy, although retinopathy worsened in 14 women. Ten-year follow-up data were available on 22 women, one of whom required laser therapy 8 years after pregnancy. Baseline retinopathy status was the only independent risk factor which predicted progression of retinopathy.

CONCLUSIONS/INTERPRETATION

Pregnancy is not associated with post-partum worsening of retinopathy.

Comparative study of the polaroid and digital non-mydriatic cameras in the detection of referrable diabetic retinopathy in Australia

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.

Establishing ongoing quality assurance in a retinal screening programme

AIM

To establish a clinically efficient, cost-effective quality assurance programme as part of a routine retinopathy screening service.

METHODS

The operation of a quality assurance system as part of an ongoing retinal screening service is described. A random selection of 12% of images of all people reported to have retinopathy and of 2% reported to have no retinopathy are re-graded by a consultant ophthalmologist. Entry of the two sets of data into a purpose-designed excel spreadsheet allows automated calculation of sensitivity and specificity.

RESULTS

The results of quality assurance from August 2001 to July 2003 are reported. Out of 8351 screening episodes, 498 were re-examined. Of the 62 cases identified by the ophthalmologist as having referable retinopathy, four false negatives for detection were identified. Three of these had been assigned to early re-screening by the retinal screener but were still regarded as false negative by the parameters of the quality assurance system. The sensitivity and specificity for detection of sight-threatening retinopathy were 93.5% (95% CI = 84.3-98.2%) and 97.8% (95% CI = 95.8-98.9%), respectively.

CONCLUSION

A robust and cost-effective system has been developed to allow monitoring of performance of routine retinal screening which may be extended to meet current national recommendations.

Detecting cataract causing visual impairment using a nonmydriatic fundus camera

PURPOSE

To assess the validity of a digital nonmydriatic fundus camera in detecting cataract as a cause of visual impairment.

DESIGN

Diagnostic test comparison.

METHODS

Photos of the anterior segment of 72 eyes were taken with a nonmydriatic fundus camera and assessed for cataract by two graders. Dilated biomicroscopy examination of the anterior segment of the same 72 eyes was then performed and cataract graded using the Wilmer scale.

RESULTS

Grader 1 and 2 reported 90% and 94% sensitivity and 82% and 77% specificity, respectively, when the digital photos were compared with slit-lamp biomicroscopy in determining visually significant cataract. In addition, both graders showed similar substantial agreement between the digital photos and slit-lamp biomicroscopy when assessed for cataract (unweighted kappa 0.87 and 0.92, respectively, for graders 1 and 2).

CONCLUSION

The nonmydriatic fundus camera may be an alternative method for screening for visually significant cataract in the community.

Evaluation of a screening program for diabetic retinopathy in a primary care setting Dodia (Dépistage ophtalmologique du diabète) study

OBJECTIVES

The aim of this observational study was to evaluate the screening for diabetic retinopathy (DR) using eye fundus photography taken by a nonmydriatic camera and transmitted trough the Internet to an ophthalmological reading centre, as compared to a dilated eye examination performed by an ophthalmologist.

METHODS

A total of 456 and 426 diabetic patients were included by two different groups of primary care physicians (PCPs), 358 being screened with the non-mydriatic camera (experimental group) and 320 with dilated eye fundus exam (control group).

RESULTS

The proportion of screened patients for whom PCPs received a screening report within the 6-month follow-up period was 74,1% for the experimental group and 71,5% for the control group. Screening for DR was negative in 77,6% of patients with eye fundus photographs vs 89,6% with dilated eye examination. DR was diagnosed in 62 patients (17,3%) with eye fundus photographs versus 31 with dilated eye examination (10,4%). Referral to an ophthalmologist was required in 59 reports of patients with photographs (16.5%), 23 of them due to high grade DR. Finally, the non-mydriatic camera was found of little inconvenience by patients.

CONCLUSION

The telemedical approach to DR screening proved to be effective in providing primary care practitioners with information about their patient's eye status. This screening method allowed to identify patients requiring prompt referral to the ophthalmologist for further complete eye examination. In conclusion, this study provided successful results of DR screening using fundus photography in primary care patients, and strongly supports the need to further extend this screening program in a larger number of French sites.

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.

Effect of mydriasis and different field strategies on digital image screening of diabetic eye disease

AIMS

To assess the effects of (1) mydriasis and (2) single versus three field photography on screening for diabetic eye disease using digital photography

METHOD

Slit lamp examination findings were compared to digital fundal photographs for the detection of any retinopathy and for referable retinopathy in 398 patients (794 eyes). A Topcon TRC-NW6S digital non-mydriatic fundus camera was used. Three photographic strategies were used: undilated single field, dilated single field, and dilated multiple fields. The photographs were presented in random order to one of two retinal screeners. For the single field photographs the screeners were masked to the use of mydriatics. In 13% of fundal photographs, grading was performed by both, rather than just one grader.

RESULTS

Mydriasis reduced the proportion of ungradable photographs from 26% to 5% (p<0.001). Neither mydriasis nor three field photography improved the sensitivity or specificity for the detection of any retinopathy or of referable retinopathy when compared with undilated single field photography. The sensitivity and specificity for detecting referable retinopathy using undilated single field photography was 77% (95% CI 71 to 84) and 95 % (95% CI 93 to 97) respectively. Using dilated single field photography the figures were 81% (95% CI 76 to 87) and 92% (95% CI 90 to 94) respectively. Using dilated three field photography the figures were 83% (95% CI 78 to 88) and 93% (95% CI 91 to 96) respectively. Intergrader reliability for the detection of referable retinopathy in gradable photographs was excellent (Kappa values 0.86-1.00).

CONCLUSIONS

Mydriasis reduces the technical failure rate. Mydriasis and the three field photography as used in this study do not increase the sensitivity or specificity of detecting diabetic retinopathy.

Single-field fundus photography for diabetic retinopathy screening: a report by the American Academy of Ophthalmology

OBJECTIVE

To evaluate whether single-field fundus photography can be used as a screening tool to identify diabetic retinopathy for referral for further ophthalmic care.

METHODS

A MEDLINE search of the peer-reviewed literature was conducted in June 2001 for the years 1968 to 2001 and updated in September 2003, yielding 145 articles. The search was limited to articles published in English. The Cochrane Library of clinical trials was also investigated. The authors reviewed the abstracts of these articles and selected 63 of possible clinical relevance for review by the panel. Of these 63 articles, the panel selected 32 for the panel methodologist to review and rate according to the strength of evidence.

RESULTS

Three of the 32 articles reviewed were classified as level I evidence, and 4 were classified as level II evidence. Evidence from level I studies demonstrates that as a tool to detect vision-threatening retinopathy, single-field fundus photography interpreted by trained readers has sensitivity ranging from 61% to 90% and specificity ranging from 85% to 97% when compared with the gold standard reference of stereophotographs of 7 standard fields. When compared with dilated ophthalmoscopy by an ophthalmologist, single-field fundus photography has sensitivity ranging from 38% to 100% and specificity ranging from 75% to 100%.

CONCLUSIONS

Single-field fundus photography is not a substitute for a comprehensive ophthalmic examination, but there is level I evidence that it can serve as a screening tool for diabetic retinopathy to identify patients with retinopathy for referral for ophthalmic evaluation and management. The advantages of single-field fundus photography interpreted by trained readers are ease of use (only one photograph is required), convenience, and ability to detect retinopathy. Further studies will be required to assess the implementation of single-field photography-based programs to confirm the clinical and cost-effectiveness of these techniques in improving population visual outcomes. Future research also should include establishing standardized protocols and satisfactory performance standards for diabetic retinopathy screening programs.

Effectiveness and safety of screening for diabetic retinopathy with two nonmydriatic digital images compared with the seven standard stereoscopic photographic fields

BACKGROUND

The use of nonmydriatic cameras, which offer ease of screening and 45 degrees immediate imaging of the fundus, is gaining increasing acceptance for screening programs tailored to diverse conditions. We performed a study to evaluate the effectiveness and safety of screening for diabetic retinopathy with two nonmydriatic camera images compared with the seven standard stereoscopic 30 degrees fields (7SF). We also wished to determine whether safe screening guidelines could be established to identify patients needing referral to an ophthalmologist.

METHODS

In this prospective masked cross-sectional study, we evaluated agreement in the assessment of the severity of diabetic retinopathy by means of two 45 degrees images centred on the optic disc and on the macula obtained with the Topcon CRW6 nonmydriatic camera and by means of 7SF photography and ophthalmologic slit-lamp biomicroscopy, both performed with pupil dilation. Between November 2000 and June 2001, 98 adult patients known to have type 1 or 2 diabetes mellitus who presented for the first time to the diabetic retinopathy clinic of a tertiary care centre in Montreal were enrolled consecutively. Thus, patient recruitment was weighted toward more severe retinopathy to ensure sufficient representation of less frequent but more severe levels. Each patient underwent nonmydriatic fundus photography of both eyes, followed by a complete ophthalmologic examination with pupil dilation by a single retina specialist and 7SF photography of both eyes with pupil dilation. The level of retinopathy was graded independently in each eye from the 7SF photographs according to the Early Treatment Diabetic Retinopathy Study (ETDRS) scale by two graders; an independent retina specialist adjudicated the rare instances of interreader disagreement in a masked fashion. Two months later, two graders independently graded the nonmydriatic images in a blinded fashion according to the ETDRS scale; a third observer adjudicated the rare instances of interreader disagreement. We measured concordance between grading results with the various screening techniques using the weighted and unweighted kappa statistic. We used sensitivity and specificity indices to determine safe screening guidelines to identify patients needing referral to an ophthalmologist.

RESULTS

There was substantial agreement in the grading of retinopathy with nonmydriatic camera imaging and with 7SF photography, both for all eyes (kappa = 0.626 [standard deviation (SD) 0.045]) and for the eye with more severe disease (kappa = 0.654 [SD 0.063]). With nonmydriatic camera imaging, screening thresholds for patient referral to an ophthalmologist of very mild retinopathy (ETDRS grade 20), mild retinopathy (ETDRS grade 35) and moderate retinopathy (EDTRS grade 43) had sensitivity values of 97.9%, 97.1% and 53.3% respectively and specificity values of 81.3%, 95.5% and 96.9% respectively. Screening thresholds of very mild or mild retinopathy both correctly identified 100% of eyes with severe nonproliferative or proliferative retinopathy. With a screening threshold of mild retinopathy, screening with the nonmydriatic camera would lead to referral to an ophthalmologist of 37.8% of patients because of detected disease and of an additional 17.3% because of insufficient image quality in at least one eye, for a total of 55.1%. The overall sensitivity and specificity of a two-field nonmydriatic screening strategy with a threshold of mild retinopathy for referral of patients with insufficient image quality in at least one eye are 97.7% and 84.0% respectively.

INTERPRETATION

Our results suggest that two-field nonmydriatic camera imaging is a safe screening strategy that may identify the patients with diabetes most in need of ophthalmologic care.

Comparison of two, three and four 45° image fields obtained with the Topcon CRW6 nonmydriatic camera for screening for diabetic retinopathy

BACKGROUND

The use of the nonmydriatic camera is gaining increasing acceptance for the detection of diabetic retinopathy when integrated into a community-tailored program. We performed a study to evaluate the optimal number and positioning of photographic fields necessary to screen for diabetic retinopathy with the Topcon CRW6 nonmydriatic camera.

METHODS

In this prospective masked cross-sectional comparative study, we compared the assessment of diabetic retinopathy using two, three or four 45 degrees fundus images (centred respectively on the disc and the macula; on the disc, on the macula and temporal to the macula; and on the disc, on the macula, temporal to the macula and superotemporal to the macula, including the superior temporal vein) acquired with the Topcon CRW6 nonmydriatic camera, with the grading of the seven standard stereoscopic 30 degrees field photographs (7SF). The study population consisted of 98 consecutive adult patients known to have type 1 or 2 diabetes mellitus who presented for the first time to the diabetic retinopathy clinic of a tertiary care centre in Montreal. All patients underwent four nonmydriatic fundus photography sessions of both eyes, 7SF photography with pupil dilation and a complete ophthalmologic examination with pupil dilation by a retina specialist.

RESULTS

Compared to the 7SF, the sensitivity and specificity of screening for any retinopathy (Early Treatment Diabetic Retinopathy Study [ETDRS] grade greater than 10) using the two central fields were 95.7% and 78.1% respectively. The corresponding values with three image fields were 97.6% and 71.9%, and with four image fields, 97.6% and 65.6%. The sensitivity and specificity of screening for mild or worse disease (ETDRS grade 35 or greater) using the two central fields were 87.5% and 92.3%. The corresponding values with three image fields were 88.9% and 94.6%, and with four image fields, 88.9% and 91.9%. Poor image quality occurring with the addition of extra fields resulted in an increase of 6.2% in the rate of referral to an ophthalmologist. The use of two image fields missed no cases of retinopathy.

INTERPRETATION

The use of image fields in addition to the two 45 degrees images centred on the disc and the macula on imaging with the Topcon CRW6 nonmydriatic camera did not significantly increase the sensitivity or specificity of screening for diabetic retinopathy. Contrary to the desired effect, the addition of fields resulted in diminished utility and cost-effectiveness of this screening approach.

Use of telemedicine in screening for diabetic retinopathy

BACKGROUND

A diabetic retinopathy screening program was introduced in September 2000 at a university-affiliated hospital in Montreal to meet the demands of an overburdened health care system. In this article we describe our initial experience with this program.

METHODS

A Canon CR6-45NM nonmydriatic 45 degrees camera was installed in the outpatient endocrinology clinic of the hospital. All patients who visited the clinic between September 2000 and January 2001 agreed to participate in the program. For each patient, a short questionnaire (age, sex, type of diabetes mellitus, time since diagnosis, prior retinal laser therapy and presence of end-organ involvement) was filled in. Subsequently at least two photographs were obtained of each eye. The photographs were sent via the hospital intranet to a retinal specialist within the hospital. The specialist reviewed the images unchanged and sent a report (grading of the level of diabetic retinopathy, presence or absence of macular hard exudates, quality of the images obtained and follow-up recommendations) via the hospital intranet to the endocrinology service. If the images were judged to be of poor quality and could not be read by the retina specialist, the patient was asked to see his or her regular ophthalmologist.

RESULTS

Images of 830 eyes of 415 patients (211 men and 204 women with a mean age of 57.5 years) were obtained. Most (83.6%) had type 2 diabetes. The average duration of disease was 13.3 years. Macular hard exudates were observed in 50 eyes (6.0%). Nonproliferative diabetic retinopathy was noted in 117 eyes (14.1%) and proliferative diabetic retinopathy in 15 eyes (1.8%). Unexpected findings included epiretinal membranes (in three eyes), macular holes (in two), bilateral cotton-wool spots (in one patient) and central retinal vein occlusion (in one eye). Overall, 10% of the patients were referred to a retina specialist based on the screening photographs. The main difficulty encountered with the screening program was image inconsistency. Overall, 35% of the images graded were felt to be of poor quality, the most common reason being poor exposure (84.4%). The quality of the images improved significantly over the study period (p < 0.01). Images obtained from patients aged 65 years or more were consistently poorer than those obtained from patients less than 65 years of age (p < 0.001).

INTERPRETATION

Despite the imperfections of such a system, our experience was favourable, allowing us to screen large numbers of patients in a cost-effective, reliable manner.

Evaluation of a new non-mydriatic digital camera for detection of diabetic retinopathy

AIMS

To compare the results of fundus photography using a new non-mydriatic digital camera with the results of reference standard of Early Treatment Diabetic Retinopathy Study (ETDRS) retinal photographs, for the detection of diabetic retinopathy (DR).

METHODS

Fundus colour photographs were taken with a Topcon non-mydriatic camera of 147 eyes of 74 diabetic patients, without pupillary dilation (five overlapping fields of 45 degrees; posterior pole, nasal, temporal, superior and inferior). Three retinal specialists classified the photographs in a masked fashion, as showing no DR or mild non-proliferative DR (NPDR) not requiring referral, moderate or more severe NPDR and/or macular oedema, or as non-gradable image requiring referral. ETDRS 35-mm colour slides served as reference images for DR detection.

RESULTS

For moderately severe to severe DR, the sensitivities of detection reported by the three observers were 92, 100 and 92%, respectively, and the specificities, 87, 85, and 88%. For four levels of DR severity (none or mild NPDR, moderate NPDR, severe NPDR and proliferative DR), the percentages of exact agreement between the three observers on the retinopathy grades assigned to the non-mydriatic photographs and to the ETDRS reference slides were 94.6, 93 and 87.6%, respectively (kappa 0.60-0.80). Sixteen eyes of nine patients (11%) were judged ungradable by at least one observer. In a second series of 110 patients, evaluated in the setting of a screening procedure, fewer photographs were ungradable (< 6%).

CONCLUSION

These results suggest that fundus photographs taken by the Topcon TRC-NW6S non-mydriatic camera, without pupillary dilation, are suitable for DR screening.

[Application of a method for the early detection of diabetic retinopathy in Primary Health Care]

PATIENTS AND METHODS

An ophthalmic examination was performed in 1,495 diabetic patients by means of a photographic method with a non-mydriatic retinal (Ffo-CNM) camera (with inclusion of 81.5% of the total diabetic population in our area attended in three primary care centers in Terrasa, Barcelona.

RESULTS

The prevalence of diabetic retinopathy known prior to the study was 15% (n = 218). With the application of the Ffo-CNM method the prevalence increased up to 28% (p = 0.0001). The diagnoses obtained were: normal fundoscopic appearance (bilateral), 61% (n = 908), DR without maculopathy, 22% (n = 334); DR with maculopathy, 5% (n = 75); severe DR or preproliferative DR, 0.1% (n = 1), and proliferative DR, 0.7% (n = 10). The fundus was not visible in 11% (n = 167) of patients, mainly because of darkness refractory miosis (48%) and media opacity (43%). Thirty-nine percent of examined patients were referred to the referral Ophthalmology department either because DR or non-visible eye fundus.

CONCLUSIONS

The use of Ffo-CNM enhances the ophthalmoscopic examination in the diabetic population given the simplicity of the technique and its accessibility with the corresponding increase in the number of diagnoses of DR. Likewise, it improves the care quality to the diabetic patient and also the reationalization of patient referral to the ophthalmologic centers.

Effectiveness of screening in preventing blindness due to diabetic retinopathy

AIMS

Diabetes remains the commonest cause of blindness in the working age population of the UK, but little information exists about the individuals who are currently losing sight from this cause. We determined the current blindness incidence (1998-2000) in Newcastle Health District and the clinical characteristics of these patients.

METHODS

Data were collected for 1998-2000 from the Royal National Institute for the Blind Liaison Office of the Newcastle Ophthalmology Department. The Ophthalmology Clinic notes on each individual were retrieved to verify clinical details, including previous eye diagnosis, dates of previous laser photocoagulation and eye surgery. The diabetes clinical records were studied to obtain information on type and duration of diabetes, blood pressure, HbA1c and other biochemical parameters. To ensure completeness of data, details of all patients registered blind attending the Newcastle Diabetic Centre were examined.

RESULTS

Twenty-eight patients were registered blind due to diabetes and 26 partially sighted during this period. The annual incidence of blindness and partial sightedness due to diabetes in the Newcastle district were 0.35 and 0.56 per 1000, respectively. The average ages in the two groups were 65.9 +/- 12.5 and 67.2 +/- 12.3 years and duration of diabetes 15.5 +/- 13.9 and 15.3 +/- 10.6 years, respectively. Proliferative retinopathy accounted for 30 and maculopathy for 24 registrations. The times from ophthalmology referral to registration were 6.2 +/- 3.5 and 4.4 +/- 3.3 years in these groups, respectively. No cases resulted from false-negative screening.

CONCLUSIONS

In Newcastle district, where the retinal screening programme has been running since 1986, the rates of blindness and partial sightedness are less than one-third of those reported in the surveys prior to 1997, confirming that objectives of the St Vincent's declarations are being achieved.

Fundus imaging and the telemedical management of diabetes

Diabetes is the major preventable form of blindness among people of working age in the Western world, despite the improvements in laser photocoagulation treatments. It is known that regular glycaemic control and annual retinal screening of people with diabetes can reduce its incidence. Effective treatment needs to be available but also screening methods which are simple to perform and cost-effective should be implemented. It will be important in future to integrate digital images of the fundus into the health records of diabetic patients. Screening programmes for the detection of diabetic retinopathy aided by image-processing software for processing fundus images will save manpower and increase quality. Before this can happen, we need more clinical studies of store-and-forward techniques, so that they can be standardized and their effectiveness established against that of traditional analogue screening.

Evaluation of a district-wide screening programme for diabetic retinopathy utilizing trained optometrists using slit-lamp and Volk lenses

BACKGROUND

Debate exists about the optimum way to screen for diabetic retinopathy. Cameras produce a permanent record, but offer patients less choice about when and where to be screened. Optometrists offer flexibility but sensitivity and specificity of schemes have varied considerably, perhaps because of variability in screening methodology and that there is frequently no quality assurance programme.

AIMS

To audit our district-wide (population 340000) screening programme for diabetic retinopathy against national targets: sensitivity > 80%, specificity > 95% and referral to review < 3 months.

METHODS

Trained optometrists performed slit-lamp examination with Volk lenses (78 dioptre) with standardized reporting. Audit was by ophthalmologist with slit-lamp and Volk lenses through dilated pupils.

RESULTS

We examined 872 eyes of 439 patients; 64% were normal, 29% background diabetic retinopathy, 7% sight-threatening eye disease (STED). Sixty-three percent of patients were seen within 6 months of the original screen. Of these, sensitivity for any retinopathy was 72%, specificity 77%, positive predictive value (PPV) 53%, negative predictive value (NPV) 88%. For STED, in this group, sensitivity was 87% and specificity 91%, PPV 30%, NPV 99%. Median interval referral to ophthalmological review was 11.5 weeks with 73% reviewed in under the 13-week target. Of those referred 25% received laser therapy. Eleven patients found to have referable eye disease at their initial screen were not referred to an ophthalmologist by their GP.

CONCLUSIONS

We conclude that effective district-wide screening for diabetic retinopathy by optometrists using slit-lamp and Volk lenses is possible; however, only 36% of identified people with diabetes in the district were screened over a 4-year period.

The sensitivity and specificity of single-field nonmydriatic monochromatic digital fundus photography with remote image interpretation for diabetic retinopathy screening: a comparison with ophthalmoscopy and standardized mydriatic color photography

PURPOSE

To evaluate single-field digital monochromatic nonmydriatic fundus photography as an adjunct in the screening of diabetic retinopathy.

DESIGN

Prospective, comparative, observational case series.

METHODS

Patients with type I and type II diabetes mellitus (n = 197) were sequentially evaluated by three different techniques: single-field digital monochromatic nonmydriatic photography; dilated ophthalmoscopy by an ophthalmologist; and seven Early Treatment Diabetic Retinopathy Study (ETDRS) standardized 35-mm color stereoscopic mydriatic images. The seven stereoscopic color photographs served as the reference standard and were compared with either ophthalmoscopy or a single digital photograph transmitted electronically to a reading site. Levels of agreement were determined by kappa analyses. The sensitivity and specificity of the three methods were compared based on a threshold for referral to further ophthalmologic evaluation (ETDRS level > or =35).

RESULTS

There was highly significant agreement (kappa = 0.97, P =.0001) between the degree of retinopathy detected by a single nonmydriatic monochromatic digital photograph and that seen in seven standard 35-mm color stereoscopic mydriatic fields. The sensitivity of digital photography compared with color photography was 78%, with a specificity of 86%. Agreement was poor (kappa = 0.40, P =.0001) between mydriatic ophthalmoscopy and the seven-field standard 35-mm color photographs. Sensitivity of ophthalmoscopy compared with color photography was 34%, with a specificity of 100%.

CONCLUSION

A single nonmydriatic monochromatic wide-field digital photograph of the disk and macula was more sensitive for diabetic retinopathy screening than mydriatic ophthalmoscopy, the currently accepted screening method. When adjudicated by standard seven-field color photographs, the higher sensitivity of digital photography primarily reflected the reduced sensitivity of ophthalmoscopy in detecting early retinopathy.

Current status of screening for diabetic retinopathy in the UK

This article reviews the current status of retinopathy screening schemes in the UK. There is evidence that high-quality diabetic retinopathy screening schemes are in existence but provision is patchy. Many health authorities have ad hoc screening programmes reaching only about 60% of patients, with unacceptable or undocumented efficacy and minimal quality control. Several models of screening are currently in use with the current preferred option being camera-based screening. Digital imaging systems offer the best prospects for image acquisition, although at present evidence of adequate effectiveness only exists for 35 mm film-based systems. The final report of the National Diabetic Retinopathy Screening Programme commissioned by the UK National Screening Committee for inclusion into the national service framework for diabetes, is thus eagerly awaited and should set standards for screening programmes, in order to improve the care of all those with diabetes. Quality assurance will be the main driver in the immediate future of improvements in screening programmes. Research data will provide the evidence to refine techniques and set targets in the longer term, with the emphasis on cost-effectiveness and quality of life.

Quality assurance in screening for sight-threatening diabetic retinopathy

AIMS

There is a need for continuous evaluation of screening services for diabetic retinopathy against agreed performance standards. We describe a quality assurance programme implemented in Newcastle in January 1999 and report on outcomes at 18 months.

METHODS

Annual retinal screening is performed using combined retinal photography and direct ophthalmoscopy in two streams. Diabetologists perform screening in the Hospital Screening Programme, which serves patients whose diabetes is managed in specialist clinics, and trained retinal screeners perform screening in the District Screening Programme, which serves patients whose diabetes is managed in the community. Reference standard examination of dilated fundoscopy with a slit-lamp and condensing lens was performed by an ophthalmologist at periodic sessions on consecutive patients attending for screening.

RESULTS

Six hundred and nine (6.4%) of 9468 patients screened underwent reference standard examination. The sensitivity and specificity of detection of sight-threatening diabetic retinopathy (STDR) was 82.5% and 98%, respectively, for the Hospital Screening Programme; 85.7% and 95.7%, respectively, for the District Screening Programme; and 83.3% and 96.8% for both services combined. One hundred and ten (18.1%) of 609 patients audited were referred to ophthalmology as a result of screening, and this led to 16 patients (2.6%) receiving laser photocoagulation for STDR. Reference standard examination identified a further four patients (0.7%) who required laser photocoagulation.

CONCLUSIONS

Preliminary data indicate that satisfactory performance standards are being achieved. The National Service Framework for Diabetes requires that all units institute quality assurance for retinal screening, and we report the practical implementation of this in one district.

Screening and follow-up of diabetic retinopathy using a new mosaic 9-field fundus photography system

AIM

To evaluate the clinical usefulness of a newly developed fundus photographing system and assess its applicability to telemedicine.

METHODS

Nine overlapping 45 degrees fundus photographs were taken by a new camera equipped with nine internal fixation targets to provide standardized 9-field photographs. The digitally stored images were either edited in 3x3 form or reconstructed as collage (9F) and compared to the ophthalmological examination (OP) and single-field non-mydriatic photography (SC). In telemedicine, 9-field images derived from 61 adolescent diabetics were sent to ophthalmologists over an analog phone line.

RESULTS

The sensitivities of the examinations by 9F without and with mydriasis (78 and 82%) were equivalent to OP (84%) and superior to SC (64%). The diagnosis of severity by 9F was also comparable to those by OP, whereas SC tended to underestimate the severity. An average of 1 min 19 s was required to send one edited 9-field photography (average size 259+/-30 KB) over the Internet. Twelve of these eyes were diagnosed as diabetic retinopathy on a desktop monitor whereas SC gave only seven.

CONCLUSION

This new 9-field fundus photography system can be appropriate for the screening and follow-up of diabetic retinopathy in adult and adolescent diabetic subjects, especially when applied to telemedicine over the Internet.

Effectiveness of optometrist screening for diabetic retinopathy using slit-lamp biomicroscopy

PURPOSE

To assess the effectiveness of optometrists as screeners for diabetic retinopathy using slit-lamp binocular indirect ophthalmoscopy through dilated pupils.

METHODS

Prospective study of a screening scheme. Screening was performed by 27 locally accredited optometrists in their practice. The referral protocol used a new simple grading system of retinopathy, especially designed for use in an optometrist screening programme. All positive referrals and 10% of negative referrals were reexamined by an ophthalmologist. Sensitivity, specificity, likelihood ratios and technical failure rates were calculated.

RESULTS

The optometrists screened 4904 people with diabetes in 18 months. 'Subthreshold' (screen negative) reports accounted for 4438 (90.5% of 4904); 429 (9.67%) of these were re-examined at secondary screening. There was disagreement regarding grading in 13 patients, of whom 5 (1.16% of 429) had sight-threatening retinopathy (STDR); this extrapolates to 52 patients if all the 4438 test-negatives had been examined. Of the 371 'threshold' patients, 112 (30.18%) were false positives; the commonest cause for false positive referral was drusen in patients with background diabetic retinopathy. The sensitivity for identification of STDR was 76% (95% CI 70% to 81%) and specificity 95% (95% CI 95% to 96%). The likelihood ratio of a positive test indicating STDR was 16.54 (95% CI 14.17 to 19.23) and that of a negative test 0.25 (95% CI 0.20 to 0.32). The technical failure rate was 0.2%.

CONCLUSIONS

Suitably trained and accredited community optometrists performed well when screening for diabetic retinopathy using slit-lamp biomicroscopy through a dilated pupil. This was facilitated by the use of simple grading and referral criteria. The sensitivity, positive likelihood ratio and specificity were high.

Stereo nonmydriatic digital-video color retinal imaging compared with Early Treatment Diabetic Retinopathy Study seven standard field 35-mm stereo color photos for determining level of diabetic retinopathy

OBJECTIVE

To evaluate the ability to determine clinical levels of diabetic retinopathy, timing of next appropriate retinal evaluation, and necessity of referral to ophthalmology specialists using stereoscopic nonmydriatic digital-video color retinal images as compared with Early Treatment Diabetic Retinopathy Study (ETDRS) seven standard field 35-mm stereoscopic color fundus photographs.

DESIGN

Prospective, clinic-based, comparative instrument validation study.

PARTICIPANTS

Fifty-four patients (108 eyes) with type 1 or type 2 diabetes mellitus selected after chart review from a single center to include the full spectrum of diabetic retinopathy.

METHODS

Nonsimultaneous 45 degrees -field stereoscopic digital-video color images (JVN images) were obtained from three fields with the Joslin Vision Network (JVN) system before pupil dilation. Following pupil dilation, ETDRS seven standard field 35-mm stereoscopic color 30 degrees fundus photographs (ETDRS photos) were obtained. Joslin Vision Network images and ETDRS photos were graded on a lesion-by-lesion basis by two independent, masked readers to assess ETDRS clinical level of diabetic retinopathy. An independent ophthalmology retina specialist adjudicated interreader disagreements in a masked fashion.

MAIN OUTCOME MEASURES

Determination of ETDRS clinical level of diabetic retinopathy, timing of next ophthalmic evaluation of diabetic retinopathy, and need for prompt referral to ophthalmology specialist.

RESULTS

There was substantial agreement (kappa = 0.65) between the clinical level of diabetic retinopathy assessed from the undilated JVN images and the dilated ETDRS photos. Agreement was excellent (kappa = 0.87) for suggested referral to ophthalmology specialists for eye examinations. Comparison of individual lesions between the JVN images and the ETDRS photos and for interreader comparisons were comparable to the prior ETDRS study.

CONCLUSIONS

Undilated digital-video images using the JVN system were comparable photographs for the determination of diabetic retinopathy level. The results validate the agreement between nonmydriatic JVN images and dilated ETDRS photographs and suggest that this digital technique may be an effective telemedicine tool for remotely determining the level of diabetic retinopathy, suggesting timing of next retinal evaluation and identifying the need for prompt referral to ophthalmology specialists. Thus, the JVN system would be an appropriate tool for facilitating increased access of diabetic patients into recommended eye evaluations, but should not be construed as a paradigm that would replace the need for comprehensive eye examinations.

Relationship between the severity of retinopathy and progression to photocoagulation in patients with Type 2 diabetes mellitus in the UKPDS (UKPDS 52)

AIM

to establish the degree to which the severity of retinopathy determines the risk for the need for subsequent photocoagulation in those with newly diagnosed Type 2 diabetes mellitus.

METHODS

Of 5102 patients entered into the UK Prospective Diabetes Study (UKPDS), 3709 had good quality retinal photographs that could be graded at entry. They were followed until the end of the study or until lost to follow-up, or until they received photocoagulation. Retinopathy severity was categorized as no retinopathy, microaneurysms (MA) only in one eye, MA in both eyes or more severe retinopathy features. The risk of photocoagulation was assessed in relation to severity of retinopathy at baseline, 3 and 6 years.

RESULTS

Of the 3709 patients assessed at entry to the UKPDS, 2316 had no retinopathy. Of these 0.2% needed photocoagulation at 3 years, 1.1% at 6 years and 2.6% at 9 years. Those with MA in one eye only (n = 708) were similar, with 0%, 1.9% and 4.7% needing photocoagulation by 3, 6 and 9 years, respectively. Amongst those who had more retinopathy features at entry (n = 509), 15.3% required photocoagulation by 3 years, and 31.9% by 9 years. When those without retinopathy at 6 years (n = 1579) were examined 3 and 6 years later (9 and 12 years after diagnosis), 0.1% and 1.8% required photocoagulation. Those with more severe retinopathy (n = 775) needed earlier treatment, 6.6% after 3 years and 13.3% after 9 years. The commonest indication for laser therapy was maculopathy, but those with more severe retinopathy were more likely to be treated for proliferative retinopathy and to need both eyes treated.

CONCLUSION

Few type 2 diabetic patients without retinopathy progress to photocoagulation in the following 3-6 years, while patients with more severe retinopathy lesions need to be monitored closely.

Sensitivity and specificity of a new scoring system for diabetic macular oedema detection using a confocal laser imaging system

AIM

To assess the use of the Heidelberg retina tomograph (HRT) in screening for sight threatening diabetic macular oedema in a hospital diabetic clinic, using a new subjective analysis system (SCORE).

METHODS

200 eyes of 100 consecutive diabetic patients attending a diabetologist's clinic were studied, all eyes had an acuity of 6/9 or better. All patients underwent clinical examination by an ophthalmologist. Using the HRT, one good scan was obtained for each eye centred on the fovea. A System for Classification and Ordering of Retinal Edema (SCORE) was developed using subjective assessment of the colour map and the reflectivity image. The interobserver agreement of using this method to detect macular oedema was assessed by two observers (ophthalmic trainees) who were familiarized with SCORE by studying standard pictures of eyes not in the study. All scans were graded from 0-6 and test positive cases were defined as having a SCORE value of 0-2. The sensitivity of SCORE was assessed by pooling the data with an additional 88 scans of 88 eyes in order to reduce the confidence interval of the index.

RESULTS

12 eyes in eight out of the 100 patients had macular oedema clinically. Three scans in three patients could not be analysed because of poor scan quality. In the additional group of scans 76 out of 88 eyes had macular oedema clinically. The scoring system had a specificity of 99% (95% CI 96-100) and sensitivity of 67% (95% CI 57-76). The predictive value of a negative test was 87% (95% CI 82-99), and that of a positive test was 95% (95% CI 86-99). The mean difference of the SCORE value between two observers was -0.2 (95% CI -0.5 to +0.07).

CONCLUSIONS

These data suggest that SCORE is potentially useful for detecting diabetic macular oedema in hospital diabetic patients.

Telemedicine screening of glaucoma

OBJECTIVES

Glaucoma is a major cause of blindness. More than 80,000 Americans suffer permanent vision loss from the disease. Widespread screening is fundamental in limiting the incidence of glaucoma-associated blindness. This pilot study explored the use of stereo digital images taken at a primary care center for telemedicine review by an off-site specialist as a means of screening for glaucoma.

MATERIALS AND METHODS

Thirty-two diabetic patients were screened at a family medicine clinic. None had previously been diagnosed with glaucoma. A senior optometry student took stereoscopic digital and 35-mm optic disc photographs with a nonmydriatic retinal camera. The digital images were forwarded to a remote ophthalmologist for review. The conventional color stereo slide pairs of the same eyes were subsequently reviewed for comparison. Agreement on signs of glaucomatous disc changes between the two imaging systems was analyzed.

RESULTS

Twenty-six of 32 eyes' digital and 35-mm photographs were analyzed. Six of 32 eyes (18.8%) could not be compared due to lack of matching 35-mm slides or digital images. Out of 26 eyes, lamina cribosa visibility was undeterminable in 8 eyes' digital images and 3 other eyes' 35-mm slides. Agreement among digital images and 35-mm slides of the remaining eyes was: 100%-vertical elongation, barring of vessels, bayoneting of vessels, and drance hemorrhage; 96.2%-focus notching of rim and rim pallor; 93.3%-lamina cribosa visability; 92. 3%-overpass cupping; 88.5%-focal enlargement; 84.6%-parapapillary halo; 80%-nerve fiber visibility; 65.4%-parapapillary atrophy. Parapapillary halo (p = 0.046) and nerve fiber layer visibility (p = 0.18) were detected on some 35-mm slides but not seen on matching digital views.

CONCLUSION

Evaluations of cup-to-disc ratio (C/D) using both methods were in general agreement. However, some digital images were noted as too dark for assessing fine glaucomatous disc changes. Stereo digital images taken with a nonmydriatic camera by nonophthalmic photographers is a promising alternative for glaucoma screening in primary care settings. Telemedicine offers efficient communications with off-site glaucoma specialists. A larger study population is necessary to determine the overall effectiveness of using stereo digital imagery and teleophthalmology for glaucoma screening.

Diabetic retinal photographic screening: a model for introducing audit and improving general practitioner care of diabetic patients in a rural setting

This paper describes the addition of diabetic retinal screening using retinal photography to an existing immunisation audit by a General Practitioner (GP) Network in a semi-rural area 60-min drive from central Wellington, New Zealand. The employment of a nurse-facilitator who visited practices to assist the setting up of diabetic registers and the subsequent auditing of patterns of referral for retinal photography was seen as a first step in a process that would lead to audit of the care of diabetic patients by GPs in the Network. This should lead to a measurable improvement in health-care delivery to diabetic patients in this area and is a model that could be adapted by any group of rural or semirural GPs within a defined geographical area.

The use of digital cameras in a mobile retinal screening environment

AIMS

To assess how successfully digital camera technology might be incorporated into a mobile screening environment.

METHODS

One hundred and ninety-seven people had their fundi photographed using a Topcon/Imagenet digital system and 534 using a Canon CR5/Ris-Lite system in addition to concurrent 45 degrees CR4NM Polaroid photography. One hundred and eighteen randomly selected patients were also sent for 7 field stereo photography as a gold standard. An acceptability questionnaire was answered by a random sample of those photographed.

RESULTS

For the detection of any retinopathy, digital pictures had a sensitivity of 0.74 (95% confidence interval (CI) 0.68-0.80) whilst Polaroid was 0.72 (95% CI 0.66-0.78) and for referable retinopathy digital pictures had a sensitivity of 0.85 (95% CI 0.80-0.90) and Polaroid was 0.90 (95% CI 0.86-0.94). A concurrent ophthalmoscopic evaluation improved the sensitivity to 0.92 (95% CI 0.86-0.98) for detection of any retinopathy whilst the sensitivity at the referral level was improved to 0.95 (95% CI 0.91-0.99). Twenty-nine of 176 respondents experienced flash discomfort with the Polaroid system with only four of 154 describing 'some' discomfort from the digital systems which have a lower flash power (10 W vs. 300 W) and a faster recovery time.

CONCLUSIONS

This study indicates that digital systems are a feasible and acceptable alternative to Polaroid-based cameras for use in a mobile environment.

Development of a multi-field fundus photographing system using a non-mydriatic camera for diabetic retinopathy

A new fundus photographing system was developed for diabetic subjects with or without simple diabetic retinopathy using a non-mydriatic fundus camera. Eight internal fixation targets were incorporated in a non-mydriatic fundus camera (TRC-NW5S; TOPCON, Tokyo, Japan), interfaced with a 3CCD color camera. Nine 45 degrees fundus photographs were taken in 22 healthy volunteers and 16 diabetic subjects, and stored as digital images. Fundus images were reconstituted as collages on the monitor and printed out. The combined angle reached 94 degrees in collage, and the average times required for photographing with and without mydriasis were 3 min 26 s and 4 min 36 s, respectively. The concordance of fundus images between the first and second photographs of healthy volunteers with and without mydriasis was 95.4% (n = 22). The quality of the photographs, graded on a five-point scale (5, full) by three doctors, was 4.3 +/- 0.6 in the volunteers without mydriasis, 4.7 +/- 0.4 in the diabetics without mydriasis, and 4.8 +/- 0.3 in the volunteers with mydriasis. In retinas with diabetic retinopathy, the system was able to depict microaneurysms, hemorrhages, hard exudates and soft exudates. This new system was satisfactory for the screening and follow-up of diabetic retinopathy.