Incidence of sight-threatening retinopathy in Type 1 diabetes in a systematic screening programme.

AIM: To measure the cumulative incidence of any retinopathy, maculopathy and sight-threatening diabetic retinopathy (STDR), and calculate optimal screening intervals by retinopathy grade at baseline for patients with Type 1 diabetes attending an established systematic retinal screening programme. METHODS: All patients with Type 1 diabetes registered with enrolled general practitioners, excluding only those attending an ophthalmologist, were studied if retinopathy data was available at baseline and at least one further screen event. Screening utilized non-stereoscopic 3-field mydriatic photography and modified Wisconsin grading. STDR was defined as moderate pre-proliferative retinopathy or greater and/or significant maculopathy in any eye. RESULTS: Patients (n=501) underwent 2742 screen events. Cumulative incidence of STDR in patients without baseline retinopathy was 0.3% (95% CI 0.0-0.9) at 1 year, rising to 3.9% (1.4-5.4) at 5 years. Rates of progression to STDR in patients with background and mild pre-proliferative retinopathy at 1 year were 3.6% (0.5-6.6) and 13.5% (4.2-22.7), respectively. Progression to STDR was greater in patients with a higher grade of baseline retinopathy (P=0.001) or a longer disease duration (P=0.003). For a 95% likelihood of remaining free of STDR, mean screening intervals by baseline status were: no retinopathy 5.7 (95% CI 3.5-7.6) years, background 1.3 (0.4-2.0) years and mild pre-proliferative 0.4 (0-0.8) years. CONCLUSIONS: Screening at 2-3 year intervals, rather than annually, for patients without retinopathy in Type 1 diabetes is feasible because of the low risk of progression to STDR, and may result in significant cost savings for a screening programme. Patients with higher grades of retinopathy require screening at least annually or more frequent.     

Trends in yield and effects of screening intervals during 17 years of a large UK community‐based diabetic retinopathy screening programme

Aims To describe changes in risk profiles and yield in a screening programme and to investigate relationships between retinopathy prevalence, screening interval and risk factors. Methods We analysed a population of predominantly Type 2 diabetic patients, managed in general practice, and screened between 1990 and 2006, with up to 17 years’ follow‐up and up to 14 screening episodes each. We investigated associations between referable or sight‐threatening diabetic retinopathy (STDR), screening interval and frequency of repeated screening, whilst adjusting for age, duration and treatment of diabetes, hypertension treatment and period. Results Of 63 622 screening episodes among 20 788 people, 16 094 (25%) identified any retinopathy, 3136 (4.9%) identified referable retinopathy and 384 (0.60%) identified STDR. The prevalence of screening‐detected STDR decreased by 91%, from 1.7% in 1991–1993 to 0.16% in 2006. The prevalence of referable retinopathy increased from 2.0% in 1991–1993 to 6.7% in 1998–2001, then decreased to 4.7% in 2006. Compared with screening intervals of 12–18 months, screening intervals of 19–24 months were not associated with increased risk of referable retinopathy [adjusted odds ratio 0.93, 94% confidence interval (CI) 0.82–1.05], but screening intervals of more than 24 months were associated with increased risk (odds ratio 1.56, 95% CI 1.41–1.75). Screening intervals of < 12 months were associated with high risks of referable retinopathy and STDR. Conclusions Over time the risk of late diagnosis of STDR decreased, possibly attributable to earlier diagnosis of less severe retinopathy, decreasing risk factors and systematic screening. Screening intervals of up to 24 months should be considered for lower risk patients.     

Six-Year Retrospective Follow-Up Study of Safe Screening Intervals for Sight-Threatening Retinopathy in Patients with Diabetes Mellitus

Background

We estimate safe screening intervals for sight-threatening diabetic retinopathy (STDR).

Methods

A 6-year retrospective follow-up study to review screening results of two cohorts of patients with diabetes mellitus (DM) was conducted; a cohort free of diabetic retinopathy (DR) and a cohort with mild nonproliferative diabetic retinopathy (NPDR) at baseline. Patients had been screened by means of a nonmydriatic retinal camera. Baseline age, sex, and diabetes characteristics were also collected. Statistical analysis was based on life-table method of risk estimation.

Results

A total of 286 patients with DM free of DR and 144 patients with mild NPDR at baseline were included in the study. For patients free of DR, the probability of remaining free of STDR was 97% (95% confidence interval [CI] 94–99%) at the end of the fourth year. In this cohort of patients, those with type 2 DM were more likely to progress to STDR than those who had type 1 DM (p < .01). For patients with mild NPDR, the probability of remaining free of STDR dropped to 94% (95% CI 88–97%) at the end of the second year, and it was still 100% at the end of the second year for those with a glycated hemoglobin level ≤7.5% at baseline (p < .05).

Conclusions

Screening at a 3–4 year interval for diabetes patients free of DR is safe because of their low risk of developing STDR. Patients with mild NPDR require screening at a 1 year interval, or at a 2 year interval with good metabolic control.     

Compliance with the quality standards of National Diabetic Retinopathy Screening Committee

AimsThe National Diabetic Retinopathy Screening Committee has recommended 19 standards for quality assurance of screening programmes in the United Kingdom. Five of the standards apply to the care provided by ophthalmology departments. This study assesses the quality assurance of the eye care provided by the Wakefield and North Kirklees Screening programme.MethodsA retrospective audit of case notes of patients for 12 consecutive months in 2007. The outcomes were compared with the five quality standards.ResultsOut of a total number of 15,080 patients screened for diabetic retinopathy (DR), 479 (3.17%) required referral to ophthalmology department (screen-positive). Of these, 352 (2.33% of total screened) were referred for diabetic retinopathy. Forty-three patients (13%) were referred for proliferative retinopathy (R3), 279 (79%) for maculopathy (M1), 24 (7%) for non-proliferative retinopathy (R2), and 4 (1%) for a history of previous photo-coagulation (P1). Fifty-eight patients (16%) failed to attend. A timely consultation was achieved in 33% of R3 and 77% of M1 patients. Only 31% of R3 and 8% of M1 at screening were listed at their first visit to ophthalmology clinic and received laser treatment in stipulated time.ConclusionSignificant progress is required for timely consultation and management of screen-positive patients. In order to achieve these targets efficiently, it may be appropriate to re-define M1 so that a significant proportion of patients with M1 may be referred to and better managed by primary care physicians or diabetologists.     

A comparison of digital retinal images and 35 mm colour transparencies in detecting and grading diabetic retinopathy

We compared digital retinal images and 35 mm colour transparencies taken with the Canon CR5 retinal camera for the detection and grading of diabetic retinopathy in a clinical setting, in a randomized, blinded study of diabetic patients with a spectrum of severity of diabetic retinopathy. Forty patients were photographed, giving a total of 75 eyes including non-diabetic eyes as controls. Images were graded according to the validated European guidelines. There was exact agreement between grades obtained from both the 2 field 45° 35 mm colour transparencies and digital images in 93.3 % (70/75) of eyes, with Cohen’s Kappa statistic for the comparison being 0.92. Overall, when grading from the digital images 5.3 % (4/75) eyes were undergraded with three cases of sight threatening diabetic retinopathy (STDR) graded as non-sight threatening (NSTDR) (3/48, 6.3 %). One eye was overgraded (1/75, 1.3 %). Two of the three cases of STDR undergraded as NSTDR had small numbers of intra-retinal microvascular abnormalities (IRMA) discernible on the colour transparencies but which were not visible from the digital image. The third had multiple small cotton wool spots graded as laser photocoagulation scars from the digital images. In conclusion there is good to excellent agreement between retinopathy grades using the Canon CR5 digital retinal imaging system compared to 35 mm colour transparencies. © 1998 John Wiley & Sons, Ltd.     

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.     

Diagnostic accuracy of direct ophthalmoscopy for detection of diabetic retinopathy using fundus photographs as a reference standard

AimsTo determine the diagnostic accuracy of direct ophthalmoscopy for the presence and severity of diabetic retinopathy (DR) using fundus photographs as a reference standard.MethodsPatients with type 2 diabetes attending the outpatient department (OPD) of a tertiary care diabetes center, from October 2009 to March 2010 were recruited in the study after obtaining signed informed consent. Patients with type 1 diabetes and gestational diabetes or having eye problems were excluded. After checking visual acuity, direct ophthalmoscopy of each eye was done by diabetologist, followed by photography of two fields of retina by fundus camera. DR was graded by a retinal specialist, according to International Diabetic Retinopathy Disease Severity Scale. According to severity, patients with DR were grouped into non-sight threatening diabetic retinopathy (NSTDR) and sight threatening diabetic retinopathy (STDR). Sensitivity and specificity of direct ophthalmoscopy for detection of any retinopathy, NSTDR and STDR was calculated.ResultsA total of 728 eyes were examined by direct ophthalmoscopy as well as fundus photography. Sensitivity (95% CI) of direct ophthalmoscopy for any retinopathy, NSTDR and STDR was found to be 55.67% (50.58–60.78), 37.63% (32.67–42.59) and 68.25% (63.48–73.02) respectively. Whereas, specificity of direct ophthalmoscopy was found to be 76.78% (72.45–81.11), 71.27% (CI: 66.63–75.91) and 90.0% (86.93–93.07) for any retinopathy, NSTDR and STDR respectively.ConclusionThe sensitivity and specificity of direct ophthalmoscopy performed by the diabetologist for the presence and severity of DR was lower compared to the recommended level of sensitivity and specificity of a screening test of DR.     

Affluence is not related to delay in diagnosis of Type 2 diabetes as judged by the development of diabetic retinopathy.

AIM: To determine the relationship between affluence and the presence of diabetic retinopathy at time of diagnosis of Type 2 diabetes. METHODS: Records of patients held by Southampton Retinal Screening Programme were examined. Patients (n = 1844) newly diagnosed with Type 2 diabetes and subsequently receiving photographic retinal screening within 24 months were selected. Townsend scores for social deprivation were calculated and the patients with and without retinopathy at first screening were then compared. RESULTS: No significant difference was found in the median Townsend score of those people with (-0.2, interquartile range (IQR) -3.7 to 3.8) and those without (-0.5, IQR -3.3 to 3.6) diabetic retinopathy at first screening after diagnosis of Type 2 diabetes (P = 0.6). CONCLUSION: The relative affluence of the area in which a person lives, as judged by postcode, does not appear to predict likelihood of diabetic retinopathy at diagnosis of Type 2 diabetes.     

Grading and disease management in national screening for diabetic retinopathy in England and Wales.

AIMS: A National Screening Programme for diabetic eye disease in the UK is in development. We propose a grading and early disease management protocol to detect sight-threatening diabetic retinopathy and any retinopathy, which will allow precise quality assurance at all steps while minimizing false-positive referral to the hospital eye service. METHODS: Expert panel structured discussions between 2000 and 2002 with review of existing evidence and grading classifications. PROPOSALS: Principles of the protocol include: separate grading of retinopathy and maculopathy, minimum number of steps, compatible with central monitoring, expandable for established more complex systems and for research, no lesion counting, no 'questionable' lesions, attempt to detect focal exudative, diffuse and ischaemic maculopathy and fast track referral from primary or secondary graders. Sight-threatening diabetic retinopathy is defined as: preproliferative retinopathy or worse, sight-threatening maculopathy and/or the presence of photocoagulation. In the centrally reported minimum data set retinopathy is graded into four levels: none (R0), background (R1), preproliferative (R2), proliferative (R3). Maculopathy and photocoagulation are graded as absent (M0, P0) or present (M1, P1). DISCUSSION: The protocol developed by the Diabetic Retinopathy Grading and Disease Management Working Party represents a new consensus upon which national guidelines can be based leading to the introduction of quality-assured screening for people with diabetes.     

Screening for diabetic retinopathy.

PURPOSE: To determine the appropriate patients, methods, and timing for screening for diabetic retinopathy. DATA SOURCES: Relevant articles were identified through prominent review articles, the authors' files, recommendations from experts, and a MEDLINE search (1986 to the present); additional references were selected from the bibliographies of identified articles. STUDY SELECTION: Selection of articles on the natural history of retinopathy was limited to large clinical series and formal epidemiologic studies of defined populations. Selection of articles on the therapeutic effect of photocoagulation and of glycemic control was limited to randomized trials. Sources bearing on the accuracy of screening modalities were necessarily more varied. DATA EXTRACTION: For important variables, individual estimates from multiple studies are presented rather than a single meta-analytic summary estimate. RESULTS: Screening for retinopathy is justifiable if early detection leads to less vision loss at an acceptable cost. The evidence shows that 1) laser therapy reduces the rate of vision loss by 50% among patients with proliferative retinopathy and macular edema, conditions that are often asymptomatic; 2) duration of diabetes is the main risk factor for retinopathy; and 3) standard ophthalmoscopic examination has only moderate sensitivity (about 80% in research settings) and specificity (greater than 90% for proliferative retinopathy but lower for macular edema), making seven-field stereophotography a more accurate method. Estimates of cost effectiveness indicate that screening for retinopathy not only saves years of vision but may be cost saving from a societal perspective. CONCLUSIONS: Screening for retinopathy in patients with diabetes, and subsequent photocoagulation therapy for those who have high risk macular edema or proliferative retinopathy, is clearly beneficial.     

A pilot quality assurance scheme for diabetic retinopathy risk reduction programmes.

AIMS: We describe a pilot study of measurement of quality assurance targets for diabetic retinopathy screening and performance comparison between 10 existing services, in preparation for the roll-out of the national programme. BACKGROUND: In 1999 the UK National Screening Committee approved proposals for a national diabetic retinopathy risk reduction programme, including recommendations for quality assurance, but implementation was held pending publication of the National Service Framework for Diabetes. Existing services requested the authors to perform a pilot study of a QA scheme, indicating willingness to contribute data for comparison. METHODS: Objectives and quality standards were developed, following consultation with diabetologists, ophthalmologists and retinal screeners. Services submitted 2001/2 performance data, in response to a questionnaire, for anonymization, central analysis and comparison. RESULTS: The 17 quality standards encompass all aspects of the programme from identification of patients to timeliness of treatment. Ten programmes took part, submitting all the data available. All returns were incomplete, but especially so from the optometry-based schemes. Eight or more services demonstrated they could reach the minimum level in only five of the 17 standards. Thirty per cent could not provide coverage data. All were running behind. Reasons for difficulties in obtaining data and/or failing to achieve standards included severe under-funding and little previous experience of QA. Information systems were limited and incompatible between diabetes and eye units, and there was a lack of co-ordinated management of the whole programme. CONCLUSION: Quality assurance is time-consuming, expensive and inadequately resourced. The pilot study identified priorities for local action. National programme implementation must involve integral quality assurance mechanisms from the outset.     

Causes of preventable visual loss in type 2 diabetes mellitus

To examine circumstances surrounding suboptimally timed retinal photocoagulation, we reviewed the medical records of 238 patients who had received photocoagulation for diabetic retinopathy at one of three large referral centers. Forty-three percent (95% confidence interval, 36% to 49%) of cases were rated as probably or definitely suboptimally timed (i.e., patient could have benefited from earlier photocoagulation). About one third of cases were due to patients going many years without screening (> 3 years), and two thirds were associated with surveillance problems (failures to achieve close follow-up for known retinopathy). We found that suboptimal timing of photocoagulation was common but was not due to patients going between 13 and 36 months between screening visits, suggesting that current performance measures, which focus on annual retinal examinations, may be requiring wasteful care while not addressing a major quality problem.     

Screening for diabetic retinopathy by general practitioners: ophthalmoscopy or retinal photography as 35 mm colour transparencies?

In order to assess the relative ability of general practitioners (GPs) to detect diabetic retinopathy (DR), especially sight-threatening diabetic retinopathy (STDR) by direct ophthalmoscopy or by examining, on a separate occasion, retinal images as 35 mm colour transparencies, a South and Mid Wales primary care-based study was performed in four general practices (six GPs). The participating GPs were provided with standardized training and equipment. Both methods were compared to the ‘reference’ grade of DR provided by the Diabetic Retinopathy Reading Centre (London), based on the same retinal images. Ophthalmoscopy and retinal photography (Canon CR4 45NM) with mydriasis were all practice based. The clinical assessments were based on a protocol developed for screening for DR in Europe. A total of 996 people with diabetes were identified, representing a prevalence of known diabetes of 2.1 %. After exclusions on medical grounds, 897 patients were available for screening, of whom 605 (68 %) were photographed. Based on the retinal images, the reference centre identified DR in 43 % and STDR in 14.4 %. In total, 597 valid comparisons between GPs and the reference centre were obtained; of these, 462 (77 %) were high quality photographs which were used in subsequent analysis. The sensitivity for detecting any DR increased from 62.6 % (95 % CI 55.9–69.4) with ophthalmoscopy to 79.2 % (95 % CI 73.6–84.9) using retinal photographs, specificity remaining essentially unchanged at 75.0 (95 % CI 69.5–80.5) and 73.5 % (95 % CI 68.0–79.1) with the positive predictive value (PPV) increasing from 67.2 (95 % CI 60.4–74.0) to 71.0 % (95 % CI 65.0–77.0), respectively. The detection of STDR sensitivity increased from 65.7 (95 % CI 54.4–77.1) with ophthalmoscopy alone to 87.3 % (95 % CI 79.4–95.2) based on retinal photographs with specificity falling from 93.8 (95 % CI 91.4–96.3) to 84.8 % (95 % CI 81.2–88.5) and PPV from 65.7 (95 % CI 54.4–77.1) to 51.2 % (95 % CI 42.1–60.3), respectively. We conclude that the use of standardized 35 mm colour transparency retinal photographs for screening by trained GPs in a primary care setting achieves an acceptable detection rate (>87 %) for STDR, contrasting with ophthalmoscopy alone (66 %), which was below the proposed UK standard of 80 %. © 1998 John Wiley & Sons, Ltd.     

Sensitivity and specificity of digital retinal imaging for screening diabetic retinopathy.

AIMS: To assess the effectiveness of a non-mydriatic digital camera (45 degrees -30 degrees photographs) compared with the reference method for screening diabetic retinopathy. METHODS: Type 1 and 2 diabetic patients (n = 773; 1546 eyes) underwent screening for diabetic retinopathy in a prospective observational study. Hospital-based non-mydriatic digital retinal imaging by a consultant specialist in retinal diseases was compared with slit-lamp biomicroscopy and indirect ophthalmoscopy through dilated pupils, as a gold standard, previously performed in a community health centre by another consultant specialist in retinal diseases. The main outcome measures were sensitivity and specificity of screening methods and prevalence of diabetic retinopathy. RESULTS: The prevalence of any form of diabetic retinopathy was 42.4% (n = 328); the prevalence of sight-threatening including macular oedema and proliferative retinopathy was 9.6% (n = 74). Sensitivity of detection of any diabetic retinopathy by digital imaging was 92% (95% confidence interval 90, 94). Specificity of detection of any diabetic retinopathy was 96% (95, 98). The predictive value of the negative tests was 94% and of a positive test 95%. For sight-threatening retinopathy digital imaging had a sensitivity of 100%. CONCLUSIONS: A high sensitivity and specificity are essential for an effective screening programme. These results confirm digital retinal imaging with a non-mydriatic camera as an effective option in community-based screening programmes for diabetic retinopathy.     

Fundus photography for the screening for diabetic retinopathy

Despite the efficacy of laser photocoagulation to prevent complications of diabetic retinopathy, diabetic retinopathy remains a major cause of visual impairment and blindness in France. This is mainly due to a too late diagnosis of diabetic retinopathy. In an effort to detect diabetic retinopathy at an early stage before visual loss, international and national guidelines for the screening for diabetic retinopathy have been developed, which recommend annual fundus examination for all diabetic patients. In France, a recent survey showed that less than 50% of diabetic patients had had an eye examination during the previous year. With the increasing number of diabetic patients and the decreasing number of ophthalmologists, this situation should not improve by the next 15 years. Fundus photography is a method at least as sensitive as ophthalmoscopy in the screening for diabetic retinopathy. New nonmydriatic cameras and digital photography may allow a network organization of several screening centers around a central ophthalmological reading center where digital images could be transmitted. This organization should improve the screening for diabetic retinopathy, while saving medical time.     

A national survey of the current state of screening services for diabetic retinopathy: ABCD–Diabetes UK survey of specialist diabetes services 2006

The main aims were to ascertain the progress made in the implementation of retinal screening services and to explore any barriers or difficulties faced by the programmes. The survey focused on all the essential elements for retinal screening, including assessment and treatment of screen‐positive cases. Eighty‐five per cent of screening programmes have a coordinated screening service and 73% of these felt that they have made significant progress. Eighty‐five per cent of screening units use ‘call and recall’ for appointments and 73.5% of programmes follow the National Screening Committee (NSC) guidance. Although many units worked closely with ophthalmology, further assessment and management of screen‐positive patients was a cause for concern. The fast‐track referral system, to ensure timely and appropriate care, has been difficult to engineer by several programmes. This is demonstrated by 48% of programmes having waiting lists for patients identified as needing further assessment and treatment for retinopathy. Ophthalmology service for people with diabetic retinopathy was provided by a dedicated ophthalmologist in 89.4% of the programmes. Sixty‐six per cent of the programmes reported inadequate resources to sustain a high‐quality service, while 26% highlighted the lack of infrastructure and 49% lacked information technology (IT) support. In conclusion, progress has been made towards establishing a national screening programme for diabetic retinopathy by individual screening units, with a number of programmes providing a structured retinal screening service. However, programmes face difficulties with resource allocation and compliance with Quality Assurance (QA) standards, especially those which apply to ophthalmology and IT support. Screening programmes need to be resourced adequately to ensure comprehensive coverage and compliance with QA.     

Non-attendance at diabetic eye screening and risk of sight-threatening diabetic retinopathy: a population-based cohort study

Aims/hypothesis

This study evaluated whether repeated non-attendance for diabetic eye screening is associated with the risk of sight-threatening diabetic retinopathy (STDR).

Methods

This was a cohort study of 6,556 residents with diabetes who were invited for screening between 2008 and 2011 in a population-based eye screening programme in inner London and who attended for their first-ever screen in 2008. The proportion of participants with STDR was evaluated in relation to the number of years in which screening was missed.

Results

The proportion of participants who did not attend screening decreased between 2009 and 2011 (annual reduction 1.6% [95% CI 0.9%, 2.3%]). The adjusted relative odds of STDR for 210 participants who did not attend two consecutive years of screening were 3.76 (95% CI 2.14, 6.61; p?<?0.001), compared with participants who were screened annually. In 605 participants with mild non-proliferative retinopathy at the first screen, the adjusted relative odds of developing proliferative or moderate to severe non-proliferative retinopathy were 5.72 (95% CI 7.43, 22.83; p?=?0.013) for 53 participants who missed two screens.

Conclusions/interpretation

Patients who do not attend diabetic eye screening are at increased risk of developing STDR. Tracing of non-attenders with evidence of established retinopathy should be an important fail-safe procedure.     

Beyond retinal screening: digital imaging in the assessment and follow-up of patients with diabetic retinopathy

Many screening methods are available for detecting diabetic retinopathy. However, once patients develop retinopathy, it is unclear as to what method should be used for their review. We describe a novel and integrated system for the screening and treatment of diabetic retinopathy using high street optometrists for primary screening and digital imaging as a secondary screening tool, with referral to a joint retinal clinic only where ophthalmological intervention may be required. Of 3586 patients screened by optometrists, 328 were classified as having moderate/severe pre-proliferative retinopathy or diabetic maculopathy. Patients with proliferative retinopathy (1 % of the total) were recalled directly to the joint retinal clinic. A consecutive sample (281) of these patients, together with a further 100 classified by the optometrists as having no or background retinopathy were compared using digital images and standard 35 mm colour transparencies. These, together with the original optometrist reports, were reviewed independently and individually by an opthalmologist. A further sample of 124 patients who had undergone both digital imaging and ophthalmologist slit-lamp examination were also compared. Comparison of 35 mm colour transparencies with optometrist reports showed the latter had a sensitivity for detecting sight-threatening retinopathy (STR) of 62 %, a specificity of 84 %, and a kappa score of 0.62. The results for digital images were 90 %, 97 %, and 0.90, respectively, although the extent of retinopathy was under-reported in 10 patients. With opthalmologist slit-lamp examination as the gold standard, the sensitivity of digital imaging was 90 % with a substantial level of agreement between them (kappa 0.61). We conclude that digital images provide an efficient method for the follow-up of patients with established or previously treated retinopathy. © 1998 John Wiley & Sons, Ltd.     

Coverage in screening for diabetic retinopathy according to screening provision: results from a national survey in England and Wales.

AIM: To assess the proportion of people with diabetes screened for retinopathy according to provision of screening services. METHODS: Twenty-five health authorities in England and Wales were sampled after stratification by type of screening provision for diabetic retinopathy. Nine did not have a population-based screening scheme, six had an optometry scheme, six had a camera scheme and four had schemes with more than one method of screening ('mixed schemes'). Within each authority general practices were randomly sampled, 129 in total, and in each the records of a sample of diabetic patients examined. RESULTS: Of the 9200 records examined, 5812 (63.2%) had a record of one or more retinal examinations from any source in the year before the survey. This proportion did not differ significantly according to type of screening provision. The proportion of people with one or more retinal examinations by an 'expert' (defined as ophthalmologist, diabetologist, optometrist or screening scheme) in the last year was 44.7% where there was no screening scheme and 62.2%, 59.4%, and 61.6%, respectively, where optometry, camera and mixed schemes were present. Adjusted relative odds (95% confidence interval) for a retinal examination from any source in the last year compared with areas with no screening schemes were 1.19 (0.73, 1.93), 1.26 (0.80, 1.98), and 1.19 (0.77, 1.84) for camera, optometry and mixed schemes, respectively. Equivalent figures for an expert retinal examination were 2.30 (1.51, 3.49), 1.86 (1.25, 2.78) and 2.13 (1.32, 3.45). Coverage by schemes themselves did not differ according to type of scheme. Highest coverage rates, including examinations by screening schemes, were achieved in those treated with insulin, and the lowest rates found in those treated with diet alone. CONCLUSIONS: Screening schemes have had a small impact on overall retinal examinations, but a higher impact on the coverage of examinations performed by experts.     

Quality assurance for diabetic retinopathy telescreening.

AIMS: TOSCA was an EU-Commission supported international research project designed to develop telescreening services in diabetic retinopathy and glaucoma. This paper describes the quality assurance methods developed for the diabetic retinopathy telescreening service within the TOSCA project. SETTING: The study was performed in 1895 patients with diabetes between 2000 and 2002 at diabetic retinopathy screening sites in five European countries. Data were analysed centrally. METHODS: Patients attending each clinic's diabetic retinopathy screening service received standardized retinal photography. The images and associated data were transferred electronically to a remote location for grading. Each photographer uploading images and each grader downloading images for assessment was controlled by a systematic quality management approach. The quality assurance measures defined were image quality, intragrader reliability. A cockpit chart was developed for the management and presentation of relevant results and quality measures. For the intragrader reliability tests, 10% of the images were processed for a second grading. An algorithm for calculating differences between repeated gradings was developed. RESULTS: The assessment of image quality for the different sites showed that only 0-0.7% were unassessable. One hundred per cent agreement for both gradings was achieved in 50-85% of graded cases, depending on site and grader, and an agreement better than 95% in 71-100% of cases. CONCLUSIONS: A telemedicine-supported quality assurance process is practical and advantageous. The cockpit charts have proven to be useful tools when monitoring the performance of a telescreening service. Grader feedback showed high satisfaction with the quality assurance process.