Photographic Screening Research Articles

Screening for sight-threatening diabetic retinopathy: comparison of fundus photography with automated color contrast threshold test

PurposeTo compare tritan contrast threshold (TCT) with fundus photography in screening for sight-threatening diabetic retinopathy (STDR), before significant visual loss. DesignProspective, comparative study. MethodsA total of 510 consenting diabetic patients attending a hospital-based photographic screening clinic were recruited over a 2-year period. Exclusion criteria included visual acuity of worse than 6/9, previous photocoagulation, and a history of previous eye disease known to affect color vision. The automated TCT test was performed using a computerized cathode ray tube-based technique. Retinal photography was performed using a Polaroid mydriatic fundus camera with a 45 degrees field. Grading of diabetic retinopathy was carried out by an ophthalmologist using slit-lamp biomicroscopy and a 78-diopters lens. Assessments of sensitivity, specificity, and predictive values for both fundus photography and the TCT test were made. ResultsBoth the fundus photography and TCT test correlated significantly with the presence of STDR (P < .0001, χ2 test). The TCT test yielded a sensitivity of 94% (95% confidence interval [CI], 73%– 100%) and a specificity of 95% (95% CI, 92%– 96%) for detection of STDR compared with a sensitivity of 88% (95% CI, 66%–97%) and a specificity of 95% (95% CI, 93%–97%) with fundus photography. Combined modality improved overall screening performance. ConclusionThe TCT assessment is an effective and clinically viable technique, in comparison with fundus photography, to screen for STDR among a diabetic population. Additionally, our results also showed that combining the TCT test with fundus photography greatly increases the performance of screening for STDR.

HLA-DRB1, -DQA1, and -DQB1 subtypes or ACE gene polymorphisms do not seem to be risk markers for severe retinopathy in younger Type 1 diabetic patients

The aim of this study was to test the hypothesis that HLA-DRB1, -DQA1, and -DQB1 subgroups or angiotensin-converting enzyme (ACE) gene polymorphisms are associated with severe retinopathy in younger Type 1 diabetic patients. Twenty-four Type 1 diabetic patients who had received panretinal photocoagulation for severe nonproliferative or proliferative diabetic retinopathy were compared with 24 Type 1 diabetic patients (participating in a photographic screening program with regular fundus examinations) with no or minimal retinopathy, matched for age at onset and duration of diabetes. The HLA-DRB1–DQA1–B1 haplotype 04–03–0302 represented 22/48 (46%) in the severe and 21/48 (44%) in the no/minimal retinopathy group, respectively (n.s.). The most common genotype, 03–0501–0201/04–03–0302, occurred in 8/24 (33%) with severe and 10/24 (42%) with no/minimal retinopathy, respectively (n.s.). There were no statistical differences between patients with severe and no/minimal retinopathy whether DRB1, DQA1, or DQB1 alleles, haplotypes, or genotypes were analysed. The ACE gene polymorphism was almost identical between patients with severe and no/minimal retinopathy, and serum ACE levels did not differ. Thus, in the present study on a small group with carefully characterised diabetic retinopathy phenotypes, there was no indication that HLA-DRB1, -DQA1, and -DQB1 subtypes or ACE gene polymorphisms were associated with severe retinopathy in younger Type 1 diabetic patients.

Comparison of optometry vs digital photography screening for diabetic retinopathy in a single district.

To compare (a). the clinical effectiveness and (b). cost effectiveness of the two models in screening for diabetic retinopathy. (a). Retrospective analysis of referral diagnoses of each screening model in their first respective years of operation and an audit of screen positive patients and a sample of screen negatives referred to the hospital eye service from both screening programmes. (b). Cost effectiveness study. (1). A total of 1643 patients screened in the community and in digital photography clinics; (2). 109 consecutive patients referred to the Diabetic Eye Clinic through the two existing models of diabetic retinopathy screening; (3). 55 screen negative patients from the optometry model; (4). 68 screen negative patients audited from the digital photography model. The compliance rate was 45% for optometry (O) vs 50% for the digital imaging system (I). Background retinopathy was recorded at screening in 22% (O) vs 17% (I) (P=0.03) and maculopathy in 3.8% (O) vs 1.7% (I) (P=0.02). Hospital referral rates were 3.8% (O) vs 4.2% (I) Sensitivity (75% for optometry, 80% for digital photography) and specificity (98% for optometry and digital photography) were similar in both models. The cost of screening each patient was pound 23.99 (O) vs pound 29.29 (I). The cost effectiveness was pound 832 (O) vs pound 853(I) in the first year. The imaging system was not always able to detect early retinopathy and maculopathy; it was equally specific in identifying sight-threatening disease. Cost effectiveness was poor in both models, in their first operational year largely as a result of poor compliance rates in the newly introduced screening programme. Cost effectiveness of the imaging model should further improve with falling costs of imaging systems. Until then, it is essential to continue any existing well-coordinated optometry model.

Nordic research in ophthalmology.

To provide an overview of some of the current activities in eye research in the Nordic countries. The presentations at the biannual Nordic Congress of Ophthalmology, held in Tampere, Finland in 2002, were reviewed and the contributions found most noteworthy are included in this article along with a limited discussion of each research field. However, space requirements prevented the inclusion of many interesting scientific contributions. Important contributions in various subfields of eye research and ophthalmology are reviewed. These include cornea, cataract, paediatric ophthalmology, glaucoma, diabetic eye disease, age-related macular degeneration, physiology and pharmacology and oncology. Eye research is very active in the Nordic countries and significant contributions are being made to ophthalmology in several fields on a world scale. We hope to continue to review Nordic contributions to eye research after each Nordic Congress of Ophthalmology and plan to make the reviews more systematic and comprehensive in the future.

Ambulatory photographic screening for diabetic retinopathy in nursing homes.

To evaluate the feasibility and cost of screening for diabetic eye disease in homebound nursing home residents not attending a systematic screening programme. Postal survey identification of residents with diabetes in all nursing homes in Liverpool. An ophthalmologist and nurse performed Bailey-Lovie logmar visual acuity (VA), portable slit-lamp examination, fundus photography, and subjective assessment of ability to cooperate with treatment in a sample of homes. Modified Wisconsin photographic grading was performed. Screen-positive patients were invited to a dedicated assessment clinic. Sight-threatening diabetic eye disease (STED) was defined as any of: moderate preproliferative retinopathy or worse, circinate maculopathy, or exudate within 1 disc diameter of fixation. A total of 54 (78%) nursing homes responded reporting 199/2427 (8.2%) residents with diabetes. Of these, 64/80 (80%) residents in 17 homes were examined: VA possible in 50 (78%); slit-lamp examination in 56 (88%); gradable photographs in at least one eye in 34 (53%); STED in 12 (35%) patients. In all, 35 (70%) patients had Snellen-equivalent VA worse than 6/12 in the better eye, of whom 13 (26%) were worse than 6/60. Of 29 screen positive patients, 12 attended the assessment clinic: one was unable to cooperate outside the home; 11 continue under ophthalmic review, four for previously undetected STED of which one listed for laser photocoagulation. Total cost pound 16,980; cost per screen event pound 60.30. Systematic eye screening in homebound patients with diabetes detects disease but follow-up and treatment is only feasible in a small proportion and at high cost. Alternative targeted assessment is recommended.

Automated detection of diabetic retinopathy in a fundus photographic screening population.

To evaluate the performance of an automated fundus photographic image-analysis algorithm in high-sensitivity and/or high-specificity segregation of patients with diabetes with untreated diabetic retinopathy from those without retinopathy. This was a retrospective cross-sectional study of 260 consecutive nonphotocoagulated eyes in 137 diabetic patients attending routine photographic retinopathy screening. Mydriatic 60 degrees fundus photography on 35-mm color transparency film was used, with a single fovea-centered field. Routine grading was based on visual examination of slide-mounted transparencies. Reference grading was performed with specific emphasis on achieving high sensitivity. Computer-assisted automated red lesion detection was performed on digitized transparencies. When applied in a screening population comprising patients with diabetes with untreated diabetic retinopathy in any eye and patients with diabetes without retinopathy, the automated lesion detection correctly identified 90.1% of patients with retinopathy and 81.3% of patients without retinopathy. A per-eye analysis for methodological purposes demonstrated that the automated lesion detection could be adapted to simulate various visual evaluation strategies. When adapted at high sensitivity, the automated system demonstrated sensitivity at 93.1% and specificity at 71.6%. When adapted at high specificity the automated system demonstrated sensitivity at 76.4% and specificity at 96.6%, closely matching routine visual grading at sensitivity 76.4% and specificity 98.3%. Automated detection of untreated diabetic retinopathy in fundus photographs from a screening population of patients with diabetes can be made with adjustable priority settings, emphasizing high-sensitivity identification of diabetic retinopathy or high-specificity identification of absence of retinopathy, covering opposing extremes of visual evaluation strategies demonstrated by human observers.

Prevalence of diabetic eye disease in patients entering a systematic primary care-based eye screening programme.

Large-scale, baseline prevalence measurements in a population at the institution of systematic retinal screening are currently unavailable. We report the prevalence of all grades of retinopathy at entry into a systematic primary care-based diabetic eye screening programme. Primary care-based photographic screening utilizing mydriasis and three-field non-stereoscopic photography for all patients with diabetes (except those under continuing care of an ophthalmologist) in Liverpool. Sight-threatening diabetic eye disease (STED) was defined as any of: moderate preproliferative retinopathy or worse, circinate maculopathy or exudates within one disc diameter of the centre of fovea. Type 1 diabetes mellitus (DM) (n = 831): baseline prevalence (95% confidence interval (CI)) of any retinopathy, proliferative diabetic retinopathy (PDR) and STED was 45.7% (42.3-49.1), 3.7% (2.4-5.0) and 16.4% (13.9-18.9), respectively. Presence of STED was associated with increased disease duration (odds ratio (OR) 1.09 per year; P < 0.0001) and higher in men (OR 2.15; P = 0.001). Type 2 DM (n = 7231): baseline prevalence (95% CI) of any retinopathy, PDR and STED was 25.3% (24.3-26.3), 0.5% (0.3-0.7) and 6.0% (5.5-6.5), respectively. Presence of STED was associated with longer time since diagnosis of DM (OR 1.03; P < 0.0001) and insulin use (OR 2.46; P < 0.0001). This study provides baseline information for health providers on prevalence of all grades of retinopathy and STED in a large population at the establishment of systematic screening. Baseline prevalence of STED was high and highest in patients with a longer disease duration in both Type 1 and Type 2 DM.

Application of the fetal alcohol syndrome facial photographic screening tool in a foster care population

We determined the prevalence of fetal alcohol syndrome (FAS) in a foster care population and evaluated the performance of the FAS Facial Photographic Screening Tool. All children enrolled in a Washington State Foster Care Passport Program were screened for three conditions: (1) the FAS facial phenotype from a photograph, (2) evidence of brain damage with prenatal alcohol exposure from their Health and Education passport, and/or (3) other syndromes identifiable from a facial photograph. Screen-positives received diagnostic evaluations at a FAS Diagnostic and Prevention Network clinic. The prevalence of FAS in this foster care population was 10 to 15/1000, or 10 to 15 times greater than in the general population. The screening tool performed with 100% sensitivity, 99.8% specificity, 85.7% predictive value positive, and 100% predictive value negative. We conclude that the foster care population is a high-risk population for FAS. The screening tool performed with very high accuracy and could be used to track FAS prevalence over time in foster care to accurately assess the effectiveness of primary prevention efforts. (J Pediatr 2002;141:712-7)

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

To determine the relationship between affluence and the presence of diabetic retinopathy at time of diagnosis of Type 2 diabetes. 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. 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). 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.

A small number of older type 2 diabetic patients end up visually impaired despite regular photographic screening and laser treatment for diabetic retinopathy

The present study describes the prevalence of visual impairment and blindness in a geographically defined population 8 years after the introduction of a screening programme in 1987 for early detection of sight-threatening diabetic retinopathy. Of 374 patients with diabetes, comprising 2.6% of the population in the study community, 72% were examined with fundus photography or biomicroscopy during 1994-95. These patients form the basis of this study. The screening programme was fulfilled by 93% of subjects, all of whom underwent ophthalmic examinations at least every other year. A total of 79 eyes in 52 patients received photocoagulation for macular oedema alone or in combination with severe non-proliferative or proliferative retinopathy. Eight years after the implementation of the programme, only three patients, all with type 2 diabetes (diabetes diagnosed at or after 30 years of age), had visual acuity < or = 0.1. The total number of eyes with visual acuity < or = 0.5 was higher in insulin-treated type 2 diabetic patients (n = 20) than in those on oral treatment (n = 5) or diet treatment only (n = 1) (p = 0.006 in both cases). The only independent risk factor for visual impairment in eyes with sight-threatening retinopathy was age. A small number of older type 2 diabetic patients end up with visual impairment due to unsuccessful photocoagulation of macular oedema.

Digital photographic screening for diabetic retinopathy in the James Bay Cree

This study evaluates a single, 45-degree fundus image from a non-mydriatic camera for the triage of subjects at risk for diabetic retinopathy. A complete retinal assessment by a retina specialist was the main comparator for the camera. Inter-observer agreements were calculated for the reading of digital images with different grades of retinopathy. Two hundred eyes of 100 consecutive subjects were evaluated as part of the James Bay diabetic retinopathy screening project; 62% of subjects had no retinopathy, 12% had microaneurysms only, 24% had non-proliferative retinopathy, 5% had clinically significant macular edema (CSME), and 2% had proliferative disease (PDR). The Kappa statistic for two independent observers was 0.85 (p < 0.001) for the identification of retinopathy from the digital images. The sensitivity of the digital camera for the evaluation of any retinopathy was 84.4%, for CSME and/or PDR it was over 90%. The use of a single digital retinal image for the evaluation of diabetic retinopathy was performed with a high degree of inter-observer concordance and a high degree of sensitivity.

Screening and prevention of diabetic blindness.

Diabetic eye disease remains a major cause of blindness in the world. Laser treatment for proliferative diabetic retinopathy and diabetic macular edema became available more than two decades ago. The outcome of treatment depends on the timing of laser treatment. The laser treatment is optimally delivered when high-risk characteristics have developed in proliferative retinopathy or diabetic macular edema and before this has significantly affected vision. Laser treatment is usually successful if applied during this optimal period whereas the treatment benefit falls sharply if the treatment is applied too late. In order to optimize the timing of laser treatment in diabetic eye disease screening programs have been established. The oldest screening program is 20 years old and several programs have been established during the last decade. In this paper the organisation and methods of screening programs are described including direct and photographic screening. The incidence and prevalence of blindness is much lower in populations where screening for diabetic eye disease has been established compared to diabetic populations without screening. Technical advantages may allow increased efficiency and telescreening. From a public health standpoint screening for diabetic eye disease is one of the most cost effective health procedures available. Diabetic eye disease can be prevented using existing technology and the cost involved is many times less than the cost of diabetic blindness.

Cost effectiveness analysis of screening for sight threatening diabetic eye disease

Objective: To measure the cost effectiveness of systematic photographic screening for sight threatening diabetic eye disease compared with existing practice.Design: Cost effectiveness analysisSetting: Liverpool.Subjects: A target population of 5000 diabetic...

Screening for diabetic retinopathy by digital imaging photography and technician ophthalmoscopy.

283 D IABETES AFFECTS MORE THAN 2% of the U.K. population. Diabetic retinopathy is the leading cause of blindness in the working age group.1 Screening for diabetic retinopathy has been shown to be both effective in preventing visual impairment2–5 and cost-effective.6,7 There is inconsistency in service provision for diabetic retinopathy screening in the U.K. ranging from organized services with high uptake and recorded program outcomes to ad hoc services with no recording of service outcomes.8 I have been asked to write this commentary article because I am one of a small group who has helped to set up the Gloucestershire Diabetic Eye Screening Programme, which is the first county-wide digital screening program for diabetic retinopathy in the U.K. A Gloucestershire county-wide audit in 1996 discovered 9,566 diabetic subjects over 16 years of age (2.1% of the adult population). Of these subjects with diabetes 5,666 were under the sole care of their general practitioner. This audit showed 25% had no record of an eye examination in the previous 15 months and a further 7% had no record of the results of their eye examination. In those who had been examined evidence of any retinopathy had only been recorded in 18% (suggesting under reporting). A mobile digital photographic screening programme with technician direct ophthalmoscopy was introduced in 1998. This program combines two 45° field digital retinal photography with technician direct ophthalmoscopy. This would clearly be included within the many different definitions of telemedicine. There is remote consultation with the subject with diabetes and transfer of digital images between locations both on the hard drive of laptops and via a hospital Intranet and ISDN lines between two hospitals. A formal prospective evaluation of the benefits and costs of the service has been set up in the following way:

Knowledge levels of diabetic eye disease in people with diabetes: results of a descriptive survey

An epidemiological questionnaire delivered to patients attending a mobile community based photographic screening unit for detection of diabetic eye disease (n=2386) has yielded demographic, prevalence and knowledge data. The main results of this report focus on the knowledge of eye complications, which show that there is a considerable lack of knowledge in people with diabetes in this area. This paper presents the results of two questions pertaining to knowledge of effects of diabetic eye disease and control of blood glucose levels. Results show that 1021 (42.8%) of responders were aware that diabetes can cause blindness and 1439 (60.3%) were aware that good control of diabetes was very important. Health education strategies need to be developed in order that people with diabetes have the correct information, necessary to make positive cognitive decisions regarding their diabetes management and lifestyle.Trained workers delivered the closed response questions via a structured interview. The coded responses were entered onto an Epi-Info database with measures to limit unreliability and ensure validity. Data were then analysed to present descriptive data and broad recommendations were made on potential effective health education strategies.

Diabetic retinopathy in people aged 70 years or older. The Oulu Eye Study

AIMSTo evaluate the presence and severity of diabetic retinopathy and the value of retinopathy screening in people aged 70 years or older.METHODSIn a population based study on 500 of 560...

A case definition and photographic screening tool for the facial phenotype of fetal alcohol syndrome

OBJECTIVES: The purpose of this study was to demonstrate that a quantitative, multivariate case definition of the fetal alcohol syndrome (FAS) facial phenotype could be derived from photographs of individuals with FAS and to demonstrate how this case definition and photographic approach could be used to develop efficient, accurate, and precise screening tools, diagnostic aids, and possibly surveillance tools. STUDY DESIGN: Frontal facial photographs of 42 subjects (from birth to 27 years of age) with FAS were matched to 84 subjects without FAS. The study population was randomly divided in half. Group 1 was used to identify the facial features that best differentiated individuals with and without FAS. Group 2 was used for cross validation. RESULTS: In group 1, stepwise discriminant analysis identified three facial features (reduced palpebral fissure length/inner canthal distance ratio, smooth philtrum, and thin upper lip) as the cluster of features that differentiated individuals with and without FAS in groups 1 and 2 with 100% accuracy. Sensitivity and specificity were unaffected by race, gender, and age. CONCLUSIONS: The phenotypic case definition derived from photographs accurately distinguished between individuals with and without FAS, demonstrating the potential of this approach for developing screening, diagnostic, and surveillance tools. Further evaluation of the validity and generalizability of this method will be needed. (J P EDIATR 1996;129:33-41)

Cost effectiveness of screening modalities must be determined

EDITOR,—S P Harding and colleagues recommend a three field photographic screening protocol with use of mydriatics to detect diabetic retinopathy.1 Despite the relatively high sensitivity (89%) reported for the detection of sight threatening eye disease with this method, the sensitivities …

Photographic screening for retinopathy.

A photographic method for detecting diabetic eye disease should be the preferred option in national, community based screening programmes, Liverpool researchers report.

Photography of the peripheral retina: Assessment of its value in screening for diabetic retinopathy

The diagnostic value of peripheral retinal photography in screening for retinopathy was assessed in 100 eyes from 95 diabetic patients following pharmacological mydriasis. Polaroid prints of the central 45° field and of 4 peripheral fields were assessed by a consultant ophthalmologist. There were 45 eyes judged to have no retinopathy centrally. Of the 55 eyes with retinopathy, 21 were referred: 3 for pre-proliferative retinopathy and 18 for maculopathy. The 4 Polaroids of the peripheral retina were assessed at a second reviewing session. There was significant agreement in diagnosing the presence or absence of retinopathy from the central versus the peripheral review. No proliferative retinopathy was identified from any of the photographs. There were 7 eyes judged to have clear central fields in which the peripheral photographs revealed retinopathy, though none of these required referral. It is concluded that additional peripheral photographs are not essential for routine screening.