Peter H Scanlon

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

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

Comparison of two reference standards in validating two field mydriatic digital photography as a method of screening for diabetic retinopathy

Aim: To compare two reference standards when evaluating a method of screening for referable diabetic retinopathy. Method: Clinics at Oxford and Norwich Hospitals were used in a two centre prospective study of 239 people with diabetes receiving an ophthalmologist’s examination using slit lamp biomicroscopy, seven field 35 mm stereophotography and two field mydriatic digital photography. Patients were selected from those attending clinics when the ophthalmologist and ophthalmic photographer were able to attend. The main outcome measures were the detection of referable diabetic retinopathy as defined by the Gloucestershire adaptation of the European Working Party guidelines. Results: In comparison with seven field stereophotography, the ophthalmologist’s examination gave a sensitivity of 87.4% (confidence interval 83.5 to 91.5), a specificity of 94.9% (91.5 to 98.3), and a kappa statistic of 0.80. Two field mydriatic digital photography gave a sensitivity of 80.2% (75.2 to 85.2), specificity of 96.2% (93.2 to 99.2), and a kappa statistic of 0.73. In comparison with the ophthalmologist’s examination, two field mydriatic digital photography gave a sensitivity of 82.8% (78.0 to 87.6), specificity of 92.9% (89.6 to 96.2), and a kappa statistic of 0.76. Seven field stereo gave a sensitivity of 96.4% (94.0 to 98.8), a specificity of 82.9% (77.4 to 88.4), and a kappa statistic of 0.80. 15.3% of seven field sets, 1.5% of the two field digital photographs, and none of the ophthalmologist’s examinations were ungradeable. Conclusion: An ophthalmologist’s examination compares favourably with seven field stereophotography, and two field digital photography performs well against both reference standards.

The English national screening programme for sight-threatening diabetic retinopathy

Objectives The main objective of the national screening programme is to reduce the risk of sight loss among people with diabetes due to diabetic retinopathy (DR). Methods Offering two-field mydriatic digital photographic screening to all people with diabetes in England over the age of 12 years. Stage of development The programme is in its infancy, receiving the first years annual reports from approximately 96 screening programmes, each of which have developed to offer screening to a minimum number of 12,000 people with diabetes, which would cover a population of 350,000 people with 3.4% diabetes prevalence. The national programme has commenced the External quality assurance (QA) programme in order to achieve and sustain the highest possible standards. Potential benefits England has a population of two million people with diabetes over the age of 12 and it is believed that there is a prevalence of blindness of 4200 and an annual incidence of blindness of 1280 people with diabetes. This programme has the potential to reduce the prevalence of blindness in England from 4200 people to 1000 people and a conservative estimate of reducing the annual incidence of DR blindness by one-third would save 427 people per annum from blindness. These figures are based on the UK certification of blindness but if World Health Organization (WHO) definitions are used the prevalence, incidence and potential reductions in blindness are much greater.

Diabetic retinopathy and socioeconomic deprivation in Gloucestershire

Objectives To investigate socioeconomic variations in diabetes prevalence, uptake of screening for diabetic retinopathy, and prevalence of diabetic retinopathy. Methods The County of Gloucestershire formed the setting of the study. A cross-sectional study of people with diabetes was done on a countywide retinopathy-screening database. Diabetes prevalence with odds ratios, uptake of screening, prevalence of any retinopathy and prevalence of sight-threatening retinopathy at screening were compared for different area deprivation quintiles. Logistic regression was used to adjust for confounding. Results With each increasing quintile of deprivation, diabetes prevalence increased (odds ratio 0.84), the probability of having been screened for diabetic retinopathy decreased (odds ratio 1.11), and the prevalence of sight-threatening diabetic retinopathy among screened patients increased (odds ratio of 0.98), while the prevalence of non-sight-threatening diabetic retinopathy remained unchanged with each increasing quintile of deprivation. Conclusion Sight-threatening diabetic retinopathy was associated with socioeconomic deprivation, but non-sight-threatening diabetic retinopathy was not. Uptake of screening was inversely related to socioeconomic deprivation.

A Simple Risk Stratification for Time to Development of Sight-Threatening Diabetic Retinopathy

OBJECTIVE The American Diabetes Association and the English NHS Diabetic Eye Screening Program recommend annual screening for diabetic retinopathy (DR) with referral to ophthalmology clinics of patients with sight-threatening DR (STDR). Using only longitudinal data from retinal photographs in the population-based NHS Diabetic Eye Screening Program in Gloucestershire, we developed a simple means to estimate risk of STDR. RESEARCH DESIGN AND METHODS From 2005, 14,554 patients with no DR or mild nonproliferative DR only at two consecutive annual digital photographic screenings were categorized by the presence of DR in neither, one, or both eyes at each screening and were followed for a further median 2.8 years. RESULTS Of 7,246 with no DR at either screening, 120 progressed to STDR, equivalent to an annual rate of 0.7%. Of 1,778 with no DR in either eye at first screening and in one eye at second screening, 80 progressed to STDR, equivalent to an annual rate of 1.9% and to a hazard ratio (HR) of 2.9 (95% CI 2.2–3.8) compared with those with no DR. Of 1,159 with background DR in both eyes at both screenings, 299 progressed to STDR equivalent to an annual rate of 11% and an HR of 18.2 (14.7–22.5) compared with individuals with no DR. CONCLUSIONS Combining the results from 2 consecutive years of photographic screening enables estimation of the risk of future development of STDR. In countries with systematic screening programs, these results could inform decisions about screening frequency.

United Kingdom National Ophthalmology Database Study: Diabetic Retinopathy; Report 1: prevalence of centre-involving diabetic macular oedema and other grades of maculopathy and retinopathy in hospital eye services

AimsTo report estimates of the prevalence of diabetic retinopathy (DR) and maculopathy grades for a large cohort of patients managed by the UK hospital eye service (HES).MethodsAnonymised data were extracted from 30 UK NHS hospital trusts using a single ophthalmic electronic medical record (EMR) for the period from April 2000 to November 2010 to create the National Ophthalmology Database (NOD). From 2007, the EMR facilitated capture of a nationally agreed-upon standardised data set (DR Structured Assessment) relating to the presence or absence of clinical signs of DR and maculopathy. An algorithm in the software automatically calculated the Early Treatment of Diabetic Retinopathy Study grades of retinopathy and maculopathy.ResultsBetween 2007 and 2010, 307 538 patients had data on the NOD, with 76 127 (24.8%) patients having been recorded as having diabetes. The proportion of patients with diabetes who had a structured assessment increased from 50.7% (2007) to 86.8% (2010). In each NHS year, 12.6–20.6% of eyes with structured assessments had no DR; 59.6–67.3% had non-proliferative DR; and 18.3–20.9% had active or regressed proliferative DR. Clinically significant macular oedema was present in 15.8–18.1% of eyes, and in 8.7–10.0% of eyes, this involved the central macula.ConclusionThis study provides contemporary estimates of the prevalence of retinopathy and maculopathy grades in a large cohort of patients with diabetes managed by the UK HES. Centre-involving diabetic macular oedema, potentially amenable to anti-VEGF therapy, is present in the eyes of almost 10% of these patients. This information is useful for clinicians, health-care economists, and commissioners involved in planning and delivering diabetic eye services.

Epidemiological issues in diabetic retinopathy

There is currently an epidemic of diabetes in the world, principally type 2 diabetes that is linked to changing lifestyle, obesity, and increasing age of the population. Latest estimates from the International Diabetes Federation (IDF) forecasts a rise from 366 million people worldwide to 552 million by 2030. Type 1 diabetes is more common in the Northern hemisphere with the highest rates in Finland and there is evidence of a rise in some central European countries, particularly in the younger children under 5 years of age. Modifiable risk factors for progression of diabetic retinopathy (DR) are blood glucose, blood pressure, serum lipids, and smoking. Nonmodifiable risk factors are duration, age, genetic predisposition, and ethnicity. Other risk factors are pregnancy, microaneurysm count in an eye, microaneurysm formation rate, and the presence of any DR in the second eye. DR, macular edema (ME), and proliferative DR (PDR) develop with increased duration of diabetes and the rates are dependent on the above risk factors. In one study of type 1 diabetes, the median individual risk for the development of early retinal changes was 9.1 years of diabetes duration. Another study reported the 25 year incidence of proliferative retinopathy among population-based cohort of type 1 patients with diabetes was 42.9%. In recent years, people with diabetes have lower rates of progression than historically to PDR and severe visual loss, which may reflect better control of glucose, blood pressure, and serum lipids, and earlier diagnosis.

Visual acuity measurement and ocular co-morbidity in diabetic retinopathy screening

Aims: To evaluate the relationship between best corrected visual acuity (BCVA), age, type of diabetes, sight-threatening diabetic retinopathy (STDR) and ocular co-morbidity. Methods: 1549 randomly selected people with diabetes mellitus (DM) from a countywide digital photographic screening programme had standardised logarithm of minimum angle of resolution (logMAR) BCVA measurement, followed by slit-lamp biomicroscopy examination by an experienced ophthalmologist. Results: Subnormal vision (logMAR ⩾0.3, Snellen ⩽6/12) and blindness (logMAR >1.3, Snellen <3/60) in the better-seeing eye were found in 9.0% and 0.45%. The sensitivity, specificity and positive and negative predictive values of using subnormal vision to screen for STDR in an individual eye were 33.4%, 85.9%, 18.6% and 93.0%, respectively. Important contributory causes of moderate visual loss (logMAR 0.50 to 0.98, Snellen 6/18 or worse but better than 6/60) and of Acuity Blindness (logMAR ⩾1.0, Snellen 6/60 or worse) in an individual eye were lenticular opacity (including capsular opacification) 49%, macular degeneration (including myopic degeneration) 29%, diabetic maculopathy 15%, other media causes (including corneal opacity) 13% and amblyopia 10%. Conclusion: The majority of visual loss in a population with diabetes is due to causes other than diabetic retinopathy. BCVA alone is not a reliable criterion in predicting STDR.

Reported symptoms and quality-of-life impacts in patients having laser treatment for sight-threatening diabetic retinopathy

Aims  To explore the patient experience of symptoms of eye disease related to diabetes and its treatment, including increase of symptoms over time and their relation to severity of the condition and the effect of multiple treatments and symptoms on quality of life.

Influence of primary care practices on patients’ uptake of diabetic retinopathy screening: a qualitative case study

Background The NHS Diabetic Eye Screening Programme aims to reduce the risk of sight loss among people with diabetes in England by enabling prompt diagnosis of sight-threatening retinopathy. However, the rate of screening uptake between practices can vary from 55% to 95%. Existing research focuses on the impact of patient demographics but little is known about GP practice-related factors that can make a difference. Aim To identify factors contributing to high or low patient uptake of retinopathy screening. Design and setting Qualitative case-based study; nine purposively selected GP practices (deprived/affluent; high/low screening uptake) in three retinopathy screening programme areas. Methods Semi-structured interviews were conducted with patients, primary care professionals, and screeners. A comparative case-based analysis was carried out to identify factors related to high or low screening uptake. Results Eight possible factors that influenced uptake were identified. Five modifiable factors related to service and staff interactions: communication with screening services; contacting patients; integration of screening with other care; focus on the newly diagnosed; and perception of non-attenders. Three factors were non-modifiable challenges related to practice location: level of deprivation; diversity of ethnicities and languages; and transport and access. All practices adopted strategies to improve uptake, but the presence of two or more major barriers made it very hard for practices to achieve higher uptake levels. Conclusions A range of service-level opportunities to improve screening attendance were identified that are available to practices and screening teams. More research is needed into the complex interfaces of care that make up retinopathy screening.