12.3Historical Perspective in England

In 1990, Taylor [14] reported results from the mobile retinal camera study in which 2,159 patients from the outpatient diabetic clinics of six hospital diabetic clinics were photographed using 1 × 45¡ Þeld non-mydriatic Polaroid retinal photography and demonstrated that this was more effective than direct ophthalmoscopy by the clinic physicians.

In 1995, Harding [6] demonstrated the effectiveness of 35-mm Þlm in screening for sightthreatening diabetic retinopathy in the Liverpool Diabetic Eye Study. In 1996, non-mydriatic digital cameras were being introduced in England that were of a size that were more portable and provided the opportunity for mobile screening using digital photography. This lead to the introduction of the Þrst digital screening programmes in England and the publication of the Þrst results of sensitivity and speciÞcity of screening for sight-threatening diabetic retinopathy [13]. The sensitivity of detection of STDR using 2 × 45¡ Þeld mydriatic photography was 87.8% (95% CI, 83.0Ð92.6%), the speciÞcity was 86.1% (95% CI, 84.2Ð87.8%) and the ungradable image rate was 3.7%. The sensitivity of detection of STDR using 1 × 45¡ Þeld non-mydriatic photography was 86.0% (95% CI, 80.9Ð91.1%); the speciÞcity was 76.7% (95% CI, 74.5Ð78.9%), and the ungradable image rate was 19.7%. The reference

standard was slit-lamp biomicroscopy by an experiencedophthalmologistwhoseexamination technique was tested against seven-Þeld stereophotography in a separate study [12]. In 2000/2001, Garvican [3] and Gillow [5] reported the Þndings of a group commissioned by the National Screening Committee to develop a model for a comprehensive national risk-reduc- tion programme in the UK. The group proposed the introduction of a systematic national programme based on digital photography.

The Department of Health in England announced [8] the introduction of a National Screening Programme for sight-threatening diabetic retinopathy in 2003 with a target of offering annual digital photographic screening to all people with diabetes (estimate 1.5 million) by the end of 2007.

12.4Methodology

The National Screening Programme in England recommends the measurement of visual acuity with distance spectacles and a pinhole followed by mydriatic two-Þeld digital photography. The recommended Þelds are a macular-centred Þeld and a disc-centred Þeld (Fig. 12.1a,b).

12.4.1 The Aim of the Programme

The aim of the programme is to reduce the risk of sight loss among people with diabetes by the