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Scanlon, Peter H
Biography
Professor Peter Scanlon has been Clinical Lead/Advisor for the English NHS Diabetic Eye Screening Programme since 2003. He holds appointments as a Consultant Ophthalmologist in the Gloucester Eye Unit, Associate Professor and Senior Research Fellow at the University of Oxford and Visiting Professor at the University of Gloucestershire. Professor Scanlon’s research interests lie in the screening, epidemiology, assessment and treatment of diabetic retinopathy.
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Publication Open Access Fundamental principles of an effective diabetic retinopathy screening program(Springer, 2020-03-28) Lanzetta, Paolo; Sarao, Valentina; Scanlon, Peter; Barratt, Jane; Porta, Massimo; Bandello, Francesco; Lowenstein, Anat; Vision Academy; Scanlon, Peter H; Scanlon, Peter; Medical and DentalBackground Diabetic retinopathy (DR) is the leading cause of blindness among working-age adults worldwide. Early detection and treatment are necessary to forestall vision loss from DR. Methods A working group of ophthalmic and diabetes experts was established to develop a consensus on the key principles of an effective DR screening program. Recommendations are based on analysis of a structured literature review. Results The recommendations for implementing an effective DR screening program are: (1) Examination methods must be suitable for the screening region, and DR classification/grading systems must be systematic and uniformly applied. Two-field retinal imaging is sufficient for DR screening and is preferable to seven-field imaging, and referable DR should be well defined and reliably identifiable by qualified screening staff; (2) in many countries/regions, screening can and should take place outside the ophthalmology clinic; (3) screening staff should be accredited and show evidence of ongoing training; (4) screening programs should adhere to relevant national quality assurance standards; (5) studies that use uniform definitions of risk to determine optimum risk-based screening intervals are required; (6) technology infrastructure should be in place to ensure that high-quality images can be stored securely to protect patient information; (7) although screening for diabetic macular edema (DME) in conjunction with DR evaluations may have merit, there is currently insufficient evidence to support implementation of programs solely for DME screening. Conclusion Use of these recommendations may yield more effective DR screening programs that reduce the risk of vision loss worldwide.Publication Open Access Generating evidence to support the role of AI in diabetic eye screening: considerations from the UK National Screening Committee(Elsevier, 2025-04-03) Macdonald, Trystan; Zhelev, Zhivko; Liu, Xiaoxuan; Hyde, Christopher; Fajtl, Jiri; Egan, Catherine; Tufail, Adnan; Rudnicka, Alicja; Shinkins, Bethany; Given-Wilson, Rosalind; Dunbar, Kevin; Halligan, Steve; Scanlon, Peter; Mackie, Anne; Taylor-Philips, Sian; Denniston, Alastair; Scanlon, Peter H; Scanlon, Peter; Medical and DentalScreening for diabetic retinopathy has been shown to reduce the risk of sight loss in people with diabetes, because of early detection and treatment of sight-threatening disease. There is long-standing interest in the possibility of automating parts of this process through artificial intelligence, commonly known as automated retinal imaging analysis software (ARIAS). A number of such products are now on the market. In the UK, Scotland has used a rulesbased autograder since 2011, but the diabetic eye screening programmes in the rest of the UK rely solely on human graders. With more sophisticated machine learning-based ARIAS now available and greater challenges in terms of human grader capacity, in 2019 the UK’s National Screening Committee (NSC) was asked to consider the modification of diabetic eye screening in England with ARIAS. Following up on a review of ARIAS research highlighting the strengths and limitations of existing evidence, the NSC here sets out their considerations for evaluating evidence to support the introduction of ARIAS into the diabetic eye screening programme.Publication Open Access Improving the screening of risk factors in diabetic retinopathy(Taylor and Francis Group, 2022-05) Scanlon, Peter; Scanlon, Peter H; Scanlon, Peter; Medical and DentalIntroduction: In 2002, Diabetic Retinopathy was reported as the leading cause of blindness in the working age group. The introduction of systematic screening programs in the UK has reduced visual loss and blindness due to diabetic retinopathy, but it does still occur with catastrophic consequences for the individual. Areas covered: The author conducted an ongoing search for articles relating to diabetic retinopathy since 2000 utilizing Zetoc Alert with keywords and contents page lists from relevant journals. This review covers the risk factors for loss of vision due to diabetic retinopathy and discusses ways in which the awareness of these risk factors can be used to further reduce visual loss. Some risk factors such as glycemic and B/P control are well known from landmark trials. This review has included these factors but concentrated more on the evidence behind those risk factors that are not so clearly defined or so well known. Expert opinion: The major risk factors are well known, but one continues to find that people with diabetes lose vision in situations in which a better awareness of the risks by both the individual with diabetes and the health workers involved may have prevented the visual loss.Publication Open Access Prospective evaluation of an artificial intelligence-enabled algorithm for automated diabetic retinopathy screening of 30 000 patients(BMJ Publishing Group, 2020-06-30) Heydon, Peter; Egan, Catherine; Bolter, Louis; Chambers, Ryan; Anderson, John; Aldington, Steve; Stratton, Irene; Scanlon, Peter; Webster, Laura; Mann, Samantha; du Chemin, Alain; Owen, Christopher; Tufail, Adnan; Rudnicka, Alicja; Scanlon, Peter H; Aldington, Steve; Stratton, Irene; Scanlon, Peter; Admin and Clerical; Additional Clinical Services; Medical and DentalBackground/aims Human grading of digital images from diabetic retinopathy (DR) screening programmes represents a significant challenge, due to the increasing prevalence of diabetes. We evaluate the performance of an automated artificial intelligence (AI) algorithm to triage retinal images from the English Diabetic Eye Screening Programme (DESP) into test-positive/technical failure versus test-negative, using human grading following a standard national protocol as the reference standard. Methods Retinal images from 30 405 consecutive screening episodes from three English DESPs were manually graded following a standard national protocol and by an automated process with machine learning enabled software, EyeArt v2.1. Screening performance (sensitivity, specificity) and diagnostic accuracy (95% CIs) were determined using human grades as the reference standard. Results Sensitivity (95% CIs) of EyeArt was 95.7% (94.8% to 96.5%) for referable retinopathy (human graded ungradable, referable maculopathy, moderate-to-severe non-proliferative or proliferative). This comprises sensitivities of 98.3% (97.3% to 98.9%) for mild-to-moderate non-proliferative retinopathy with referable maculopathy, 100% (98.7%,100%) for moderate-to-severe non-proliferative retinopathy and 100% (97.9%,100%) for proliferative disease. EyeArt agreed with the human grade of no retinopathy (specificity) in 68% (67% to 69%), with a specificity of 54.0% (53.4% to 54.5%) when combined with non-referable retinopathy. Conclusion The algorithm demonstrated safe levels of sensitivity for high-risk retinopathy in a real-world screening service, with specificity that could halve the workload for human graders. AI machine learning and deep learning algorithms such as this can provide clinically equivalent, rapid detection of retinopathy, particularly in settings where a trained workforce is unavailable or where large-scale and rapid results are needed.Publication Open Access Evaluation of standard of care intravitreal aflibercept treatment of diabetic macular oedema treatment-naive patients in the UK: DRAKO study 12-month outcomes(Springer Nature, 2021-07-09) Sivaprasad, Sobha; Ghanchi, Faruque; Kelly, Simon; Kotagiri, Ajay; Talks, James; Scanlon, Peter; McGoey, Hellen; Nolan, Andrew; Saddiq, Moneeb; Napier, Jackie; Scanlon, Peter H; Scanlon, Peter; Medical and DentalObjectives: DRAKO (NCT02850263) is a 24-month, prospective, non-interventional, multi-centre cohort study which enroled patients diagnosed with centre-involving diabetic macular oedema (DMO). The study aims to evaluate standard of care with intravitreal aflibercept (IVT-AFL) treatment in the UK. This analysis describes the anti-vascular endothelial growth factor (anti-VEGF) treatment-naive patient cohort after 12-month follow-up. Methods: Study eyes were treated with IVT-AFL as per local standard of care. The mean change in best-corrected visual acuity (BCVA) and central subfield thickness (CST) from baseline at 12 months were measured and stratified by baseline factors. The number of injections and safety data were also evaluated. Results: A total of 507 patients were enroled from 35 centres. Mean (SD) baseline BCVA was 71.4 (12.0) letters and CST was 448.7 (88.7) µm, with 63.1% of patients presenting with baseline BCVA ≥ 70 letters (mean 78.1). Mean (SD) change in BCVA of 2.5 (12.2) letters and CST of -119.1 (116.4) µm was observed at month 12. A 7.3 letter gain was observed in patients with baseline BCVA < 70 letters. Mean number (SD) of injections in year one was 6.4 (2.1). No significant adverse events were recorded. Conclusion: Year one results indicated that IVT-AFL was an effective treatment for DMO in standard of care UK clinical practice, maintaining or improving visual acuity in treatment-naive patients with good baseline visual acuity, despite some patients being undertreated versus the summary of product characteristics. These results also demonstrated the clinical importance and meaningful impact of diabetic retinopathy screening in the UK.Publication Open Access Evaluation of care with intravitreal aflibercept treatment for UK patients with diabetic macular oedema: DRAKO study 24-month real-world outcomes(Springer Nature, 2023-03-20) Sivaprasad, Sobha; Ghanchi, Faruque; Kelly, Simon; Kotagiri, Ajay; Talks, James; Scanlon, Peter; McGoey, Hellen; Nolan, Andrew; Saddiq, Moneeb; Napier, Jackie; Scanlon, Peter H; Scanlon, Peter; Medical and DentalBackground/ objectives: DRAKO (NCT02850263) was a 24-month, prospective, observational, multi-centre cohort study that enrolled patients diagnosed with diabetic macular oedema (DMO) including central involvement. The study aimed to evaluate standard of care intravitreal aflibercept (IVT-AFL) treatment in the UK. This analysis describes the 12-month outcomes for patients with prior anti-vascular endothelial growth factor (VEGF) treatment for DMO other than IVT-AFL (C2), and 2-year outcomes for both anti-VEGF treatment-naïve patients (C1) and C2 patients. Methods: Study eyes were treated with IVT-AFL as per local standard of care. Mean changes in best-corrected visual acuity (BCVA) in ETDRS letters and central subfield thickness (CST) were stratified by baseline factors. Changes in diabetic retinopathy assessments, glycated haemoglobin A1c levels and vision-related quality of life (QoL) were evaluated alongside numbers of injections administered and safety outcomes. Results: For C1, mean (SD) changes from baseline in BCVA of +0.7 (12.7) letters and CST of -123.3 (104.3) µm were observed at Month 24. For C2, mean (SD) changes from baseline for BCVA of + 0.2 (10.2) letters and -0.3 (13.0) letters, and CST of -79.1 (137.6) µm and -91.6 (132.9) µm, were observed at 12 and 24 months, respectively. In Year 2, C1 and C2 patients received a mean of 3.7 and 4.3 injections, respectively. Conclusions: Year 2 results indicate that IVT-AFL is an effective treatment for DMO in real-world UK clinical practice, despite relatively low injection numbers. The high baseline visual acuity and QoL scores were maintained and there was further improvement in anatomical outcomes.Publication Open Access The Scanning CONfoCal Ophthalmoscopy foR DIAbetic eye screening (CONCORDIA) study paper 1(Springer Nature, 2024-10-08) Scanlon, Peter; Gruszka-Goh, Marta; Javed, Ushna; Vukic, Anthony; Hapeshi, Julie; Chave, Steve; Galsworthy, Paul; Vallance, Scott; Aldington, Steve; Scanlon, Peter H; Scanlon, Peter; Gruszka-Goh, Marta; Javed, Ushna; Vukic, Anthony; Hapeshi, Julie; Chave, Steve; Galsworthy, Paul; Vallance, Scott; Aldington, Steve; Medical and Dental; Additional Professional Scientific and Technical; Additional Clinical Services; Admin and ClericalObjective: This project was to determine the performance of the Zeiss Clarus 700 (Clarus) and the Optos California (Optos) with staged mydriasis in a Diabetic Eye Screening Programme (DESP). Methods: Trial participants were recruited from people attending appointments in DESP or Virtual Eye clinics for delayed hospital appointments. Non-mydriatic photographs from the Clarus and Optos cameras were compared to 2-field 45 degrees mydriatic digital photography (the reference standard) and mydriatic photographs compared if the non-mydriatic photos were unassessable (staged mydriasis). Results: 1573 patients were recruited. 76 individuals were withdrawn, leaving 1497 individuals (2993 eyes). For the Clarus and the Optos, the sensitivity for any retinopathy were 94.2% (95% CI: 92.9-95.3%) and 91.9% (95% CI: 90.5-93.2%) with specificities of 87.3% (95% CI: 85.4-89.0%) and 78.1% (95% CI: 75.7-80.3%) respectively. For referable DR the sensitivities for the Clarus and Optos were 86.0% (95% CI: 82.9-88.8%) and 77.6% (95% CI: 73.9-80.9%) with specificities of 92.8% (95% CI: 91.7-93.8%) and 95.4% (95% CI: 94.5-96.2%) respectively. The Clarus and Optos without mydriasis produced 100 (3.3%) and 152 (5.1%) unassessable eyes respectively, and after staged mydriasis 51 (1.7%) and 102 (3.4%) respectively with 52 (1.7%) reference standard images unassessable. Conclusions: This study reports the performance of the Clarus and the Optos using staged mydriasis in DR screening with wider fields detecting more referable retinopathy peripherally with some reduction in sensitivity centrally for macular lesions.Publication Open Access The scanning CONfoCal Ophthalmoscopy foR DIAbetic eye screening (CONCORDIA) study paper 2(Springer Nature, 2024-10-11) Scanlon, Peter; Gruszka-Goh, Marta; Javed, Ushna; Vukic, Anthony; Hapeshi, Julie; Chave, Steve; Galsworthy, Paul; Vallance, Scott; Aldington, Steve; Scanlon, Peter H; Scanlon, Peter; Gruszka-Goh, Marta; Javed, Ushna; Vukic, Anthony; Hapeshi, Julie; Chave, Steve; Galsworthy, Paul; Vallance, Scott; Aldington, Steve; Medical and Dental; Additional Clinical Services; Additional Professional Scientific and Technical; Admin and ClericalPurpose: To determine if the Eidon white light 60-degree field Scanning Confocal Ophthalmoscope (SCO) camera was safe to use with staged mydriasis in a Diabetic Eye Screening Programme (DESP). Methods: The trial participants were recruited from people with diabetes attending appointments in DESP or Virtual Eye clinics for post-Covid delayed hospital appointments. Using staged mydriasis, the SCO images were taken before the pupils were dilated and compared to two-field 45 degrees mydriatic digital photography (the reference standard). Mydriatic SCO images were only compared to the reference standard if the non-mydriatic SCO images were unassessable. Results: 1050 patients were recruited, 35 individuals were withdrawn, the majority (18) due to an imaging protocol deviation leaving 1015 individuals (2029 eyes). Using staged mydriasis, the sensitivity and specificity for any retinopathy was 97.5% (95% CI: 96.4-98.4%) and 82.3% (95% CI: 79.6-84.7%) respectively. The sensitivity and specificity for referable retinopathy was 92.7% (95% CI: 89.9-94.9%) and 85.4% (95% CI: 83.6-87.2%) respectively. The total number of eyes that were unassessable with the Eidon without mydriasis was 85/2029 (4.2%), and after mydriasis was 34/2029 (1.7%) and, with the reference standard, 34/2029 (1.7% - not always the same images) were unassessable. Conclusions: This study provides promising early results of the performance of the Eidon camera using staged mydriasis in a DESP which needs further evidence from a non-Caucasian population and from cost-effectiveness analyses.Publication Metadata only Assessing the impact of COVID-19 on visual acuity for diabetic macular edema patients treated with aflibercept in the UK(Association for Research in Vision and Ophthalmology, 2022-06) Scanlon, Peter; Norridge, Charlotte F. E.; Mukherjee, Rajarshi; Lotery, Andrew; Peto, Tunde; Chhabra, Romi; Bailey, Clare; Eleftheriadis, Haralabos; Ghanchi, Faruque; Jones, Colin; Scanlon, Peter H; Scanlon, Peter; Norridge, Charlotte; Medical and Dental; Additional Professional Scientific and TechnicalPurpose : Assessing the impact of COVID-19 on visual acuity (VA) in eyes treated for Diabetic Macular Edema. Methods : Anonymized data from 21 UK centers were extracted from Medisoft for eyes receiving treatment with aflibercept and with VA data in the pre-COVID baseline period (01/10/19 to 30/03/20, N=3,248). Comparisons for period 1 (01/04/20 to 30/09/20, N=2,077) – lockdown following RCOphth Medical Retinal Management Plan, period 2 (01/10/20 to 30/03/21, N=1,850) - intermittent lockdown and period 3 (01/04/21 to 30/09/21, N=1,111; 20 centers) - easing of COVID-19 restrictions. VA change was compared for baseline VA, <7 vs. ≥7 injections before period 1 and for eyes losing ≥5 ETDRS letters in period 1. Results : The mean change in VA for eyes with a baseline VA of ≤35 letters, was +4.9, +2.5 and +1.7 letters from baseline to period 1, period 1 to 2 and period 2 to 3, respectively. For baseline VA of 36-55 letters, +0.6, +1.7 and -0.2 letters, from baseline to period 1, period 1 to 2 and period 2 to 3, respectively. For baseline VA of 56-75 letters, +1.9, zero and -0.5 letters, from baseline to period 1, period 1 to 2 and period 2 to 3, respectively. For baseline VA of >75 letters, -4.3, -0.5 and zero letters, from baseline to period 1, period 1 to 2 and period 2 to 3, respectively. For eyes receiving <7 injections before period 1, the mean change in VA was -1.9 letters (N=1,335) from baseline to period 1, +0.5 letters (N=992) from period 1 to 2 and +0.1 letters (N=592) from period 2 to 3. For ≥7 injections before period 1, the mean change in VA was -3.4 letters (N=742) from baseline to period 1, -0.4 letters (N=515) from period 1 to 2 and -1.1 letters (N=303) from period 2 to 3. For eyes losing ≥5 letters before period 1, the mean change in VA when receiving ≥1 injection in period 2 was +3.9 letters (N=283) from period 1 to 2 and -0.1 letters (N=140) from period 2 to 3. For eyes not retreated in period 2, the mean change in VA was -2.9 letters (N=162) from period 1 to 2 and zero letters (N=73) from period 2 to 3. Conclusions : Visual gain between time periods was more likely for lower baseline vision. For eyes with <7 or ≥7 injections before period 1, the mean VA change was a loss in vision in the first period with little change in later periods. For eyes with ≥5 letter loss in period 1, subsequent visual gain was more likely if treatment continued.Publication Metadata only Screening for diabetic retinopathy: new perspectives and challenges(Elsevier, 2020-02-27) Vujosevic, Stela; Aldington, Steve; Silva, Paolo; Hernandez, Cristina; Scanlon, Peter; Peto, Tunde; Simo, Rafael; Scanlon, Peter H; Aldington, Steve; Scanlon, Peter; Admin and Clerical; Medical and DentalAlthough the prevalence of all stages of diabetic retinopathy has been declining since 1980 in populations with improved diabetes control, the crude prevalence of visual impairment and blindness caused by diabetic retinopathy worldwide increased between 1990 and 2015, largely because of the increasing prevalence of type 2 diabetes, particularly in low-income and middle-income countries. Screening for diabetic retinopathy is essential to detect referable cases that need timely full ophthalmic examination and treatment to avoid permanent visual loss. In the past few years, personalised screening intervals that take into account several risk factors have been proposed, with good cost-effectiveness ratios. However, resources for nationwide screening programmes are scarce in many countries. New technologies, such as scanning confocal ophthalmology with ultrawide field imaging and handheld mobile devices, teleophthalmology for remote grading, and artificial intelligence for automated detection and classification of diabetic retinopathy, are changing screening strategies and improving cost-effectiveness. Additionally, emerging evidence suggests that retinal imaging could be useful for identifying individuals at risk of cardiovascular disease or cognitive impairment, which could expand the role of diabetic retinopathy screening beyond the prevention of sight-threatening disease.