Sensitivity and specificity of digital retinal imaging for screening diabetic retinopathy

Microvascular Changes Are Associated with Proteinuria and EMG Changes in Patients with Type 2 Diabetes Using Video Capillaroscopy

Objectives: Video capillaroscopy is a diagnostic method for evaluating microvascular changes in type 2 diabetes mellitus (T2DM). This study evaluated microvascular changes, including microvascular architecture, capillary distribution (morphology and density), and angiogenesis conditions in T2DM patients via video capillaroscopy. Methods: A total of 256 patients with T2DM enrolled in this study. Based on electromyography (EMG)-nerve conduction velocity results, patients were divided into patients with normal and abnormal EMG. Microalbuminuria was assessed using biochemical urine analysis. Finally, video capillaroscopy was performed to evaluate changes in microvascular architecture, capillary distribution, and angiogenesis status. Results: The differences between microalbuminuria in patients with normal and abnormal EMG were not significant. Other microvascular changes were not significant between normal and abnormal EMG groups. The patients with greater microalbuminuria were at risk of abnormal EMG 2.8 times higher than those with fewer microalbuminuria (odds ratio = 2.804; 1.034-7.601). However, EMG is not a risk factor for microvascular architecture alternation in T2DM (odds ratio = 1.069; 0.323-3.546). Conclusions: Microvascular alternations are common in T2DM and early detection of these changes could help to avoid the progress of nephropathic complications. Also, video capillaroscopy provides a promising diagnostic method for the detection of microvascular alternations in T2DM.

Two-field non-mydriatic fundus photography for diabetic retinopathy screening: a protocol for a systematic review and meta-analysis

INTRODUCTION

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes mellitus. Guidelines for DR screening in different countries vary greatly, including fundus photography, slit-lamp biomicroscopy, indirect ophthalmoscopy, Optical Coherence Tomography (OCT), OCT-A and Fundus Fluorescein Angiography (FFA). Two-field non-mydriatic fundus photography (NMFP) is an effective screening method due to its low cost and less time-consuming process. However, it is controversial due to the sensitivity and specificity of two-field NMFP. This review intends to evaluate the performance of the two-field NMFP in diagnosing DR and helps clinicians determine the most optimal screening method.

METHODS AND ANALYSIS

Two reviewers will independently search on the Medline, Embase, Cochrane databases, ProQuest, Opengrey, Chinese National Knowledge Infrastructure, Wanfang Data, VIP China Science and Technology Journal Database, Chinese BioMedical Literature Database, ISRCTN, ClinicalTrials.gov and the WHO ICTRP to identify relevant studies. There is no restriction posed on the language of the study. Included studies focus on the performance of two-field NMFP in detecting DR in diabetes patients. Analysis and evaluation of the studies will be examined by two reviewers independently using the Quality Assessment for Diagnostic Accuracy Studies-2 tool and later evaluated using the Population, Intervention, Comparison, Outcome, Study design criteria. A random-effect model will calculate the diagnostic indicators, including the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic OR, area under the curve and 95% CIs. We will also develop a summary receiver operating characteristic curve. We anticipate analysing subgroups according to the factors, which may lead to heterogeneity, including DR levels of patients, the reference standards, camera models, the interpretation criteria. The data will be analysed by STATA software. This study was registered with PROSPERO.

ETHICS AND DISSEMINATION

This review will analyse the published data. Patients/the public were not involved in this research. The results of this study will be published in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42020203608.

Imaging Modalities Employed in Diabetic Retinopathy Screening: A Review and Meta-Analysis

INTRODUCTION

Urbanization has caused dramatic changes in lifestyle, and these rapid transitions have led to an increased risk of noncommunicable diseases, such as type 2 diabetes. In terms of cost-effectiveness, screening for diabetic retinopathy is a critical aspect in diabetes management. The aim of this study was to review the imaging modalities employed for retinal examination in diabetic retinopathy screening.

METHODS

The PubMed and Web of Science databases were the main sources used to investigate the medical literature. An extensive search was performed to identify relevant articles concerning "imaging", "diabetic retinopathy" and "screening" up to 1 June 2021. Imaging techniques were divided into the following: (i) mydriatic fundus photography, (ii) non-mydriatic fundus photography, (iii) smartphone-based imaging, and (iv) ultrawide-field imaging. A meta-analysis was performed to analyze the performance and technical failure rate of each method.

RESULTS

The technical failure rates for mydriatic and non-mydriatic digital fundus photography, smartphone-based and ultrawide-field imaging were 3.4% (95% CI: 2.3-4.6%), 12.1% (95% CI: 5.4-18.7%), 5.3% (95% CI: 1.5-9.0%) and 2.2% (95% CI: 0.3-4.0%), respectively. The rate was significantly different between all analyzed techniques (p < 0.001), and the overall failure rate was 6.6% (4.9-8.3%; I² = 97.2%). The publication bias factor for smartphone-based imaging was significantly higher than for mydriatic digital fundus photography and non-mydriatic digital fundus photography (b = -8.61, b = -2.59 and b = -7.03, respectively; p < 0.001). Ultrawide-field imaging studies were excluded from the final sensitivity/specificity analysis, as the total number of patients included was too small.

CONCLUSIONS

Regardless of the type of the device used, retinal photographs should be taken on eyes with dilated pupils, unless contraindicated, as this setting decreases the rate of ungradable images. Smartphone-based and ultrawide-field imaging may become potential alternative methods for optimized DR screening; however, there is not yet enough evidence for these techniques to displace mydriatic fundus photography.

Performance and Limitation of Machine Learning Algorithms for Diabetic Retinopathy Screening: Meta-analysis

Background

Diabetic retinopathy (DR), whose standard diagnosis is performed by human experts, has high prevalence and requires a more efficient screening method. Although machine learning (ML)–based automated DR diagnosis has gained attention due to recent approval of IDx-DR, performance of this tool has not been examined systematically, and the best ML technique for use in a real-world setting has not been discussed.

Objective

The aim of this study was to systematically examine the overall diagnostic accuracy of ML in diagnosing DR of different categories based on color fundus photographs and to determine the state-of-the-art ML approach.

Methods

Published studies in PubMed and EMBASE were searched from inception to June 2020. Studies were screened for relevant outcomes, publication types, and data sufficiency, and a total of 60 out of 2128 (2.82%) studies were retrieved after study selection. Extraction of data was performed by 2 authors according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), and the quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis of diagnostic accuracy was pooled using a bivariate random effects model. The main outcomes included diagnostic accuracy, sensitivity, and specificity of ML in diagnosing DR based on color fundus photographs, as well as the performances of different major types of ML algorithms.

Results

The primary meta-analysis included 60 color fundus photograph studies (445,175 interpretations). Overall, ML demonstrated high accuracy in diagnosing DR of various categories, with a pooled area under the receiver operating characteristic (AUROC) ranging from 0.97 (95% CI 0.96-0.99) to 0.99 (95% CI 0.98-1.00). The performance of ML in detecting more-than-mild DR was robust (sensitivity 0.95; AUROC 0.97), and by subgroup analyses, we observed that robust performance of ML was not limited to benchmark data sets (sensitivity 0.92; AUROC 0.96) but could be generalized to images collected in clinical practice (sensitivity 0.97; AUROC 0.97). Neural network was the most widely used method, and the subgroup analysis revealed a pooled AUROC of 0.98 (95% CI 0.96-0.99) for studies that used neural networks to diagnose more-than-mild DR.

Conclusions

This meta-analysis demonstrated high diagnostic accuracy of ML algorithms in detecting DR on color fundus photographs, suggesting that state-of-the-art, ML-based DR screening algorithms are likely ready for clinical applications. However, a significant portion of the earlier published studies had methodology flaws, such as the lack of external validation and presence of spectrum bias. The results of these studies should be interpreted with caution.

Development and Validation of a Diabetic Retinopathy Screening Modality Using a Hand-Held Nonmydriatic Digital Retinal Camera by Physician Graders at a Tertiary-Level Medical Clinic: Protocol for a Validation Study

BACKGROUND

Visual impairment and blindness from diabetic retinopathy (DR), which can be reduced by early screening and treatment, is an emerging public health concern in low-income and middle-income countries (LMICs) owing to the increasing prevalence of diabetes mellitus (DM). However, no systematic screening exists in most LMIC settings. The Western province of Sri Lanka has the highest prevalence of DM (18.6%) in the country. A situational analysis identified a marked gap in DR screening (DRS) and treatment services uptake in this region; only opportunistic screening is practiced currently.

OBJECTIVE

The aim of this protocol is to describe the methods of development and validation of a DRS intervention using a hand-held nonmydriatic digital camera by physician graders in a non-ophthalmological setting at a tertiary-level medical clinic to propose a valid and feasible modality to improve uptake.

METHODS

DRS modality was developed after assessing barriers and identifying the most appropriate personnel, methods, and location for screening services, following formative research work. The validation will be conducted in a public sector tertiary care center in the Western province of Sri Lanka. The selected physicians will be trained on capturing and grading images according to a valid locally adopted protocol. Two physicians rated high on training will screen a sample of 506 people with DM at a medical clinic. They will use nonmydriatic and mydriatic 2-field imaging strategy. The validity of the proposed screening procedure will be assessed and compared with the mydriatic indirect biomicroscopic examination by a senior retinologist.

RESULTS

The validity of screening by physician graders will be analyzed and the sensitivity, specificity, and predictive values (with 95% CIs) calculated by the dilation status and for each grader. The diagnostic accuracy at each level of severity of DR will be assessed to define the most appropriate referable criteria. Data is currently being collected.

CONCLUSIONS

The outcome of this study will be useful for the detection of a defined level of DR at non-ophthalmological setting to filter the people with DM before referral to an eye clinic. This will be helpful to improve the uptake and identify risk groups in advance to prevent sight-threatening DR. Furthermore, evidence from this study will be useful for the implementation of a DRS program in this region and in similar communities.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/10900.

Systematic review and meta-analysis of diagnostic accuracy of detection of any level of diabetic retinopathy using digital retinal imaging

BACKGROUND

Visual impairment from diabetic retinopathy (DR) is an increasing global public health concern, which is preventable with screening and early treatment. Digital retinal imaging has become a preferred choice as it enables higher coverage of screening. The aim of this review is to evaluate how different characteristics of the DR screening (DRS) test impact on diagnostic test accuracy (DTA) and its relevance to a low-income setting.

METHODS

We conducted a systematic literature search to identify clinic-based studies on DRS using digital retinal imaging of people with DM (PwDM). Summary estimates of different sub-groups were calculated using DTA values weighted according to the sample size. The DTA of each screening method was derived after exclusion of ungradable images and considering the eye as the unit of analysis. The meta-analysis included studies which measured DTA of detecting any level of DR. We also examined the effect on detection from using different combinations of retinal fields, pupil status, index test graders and setting.

RESULTS

Six thousand six hundred forty-six titles and abstracts were retrieved, and data were extracted from 122 potentially eligible full reports. Twenty-six studies were included in the review, and 21 studies, mostly from high-income settings (18/21, 85.7%), were included in the meta-analysis. The highest sensitivity was observed in the mydriatic greater than two field strategy (92%, 95% CI 90-94%). The highest specificity was observed in greater than two field methods (94%, 95% CI 93-96%) where mydriasis did not affect specificity. Overall, there was no difference in sensitivity between non-mydriatic and mydriatic methods (86%, 95% CI 85-87) after exclusion of ungradable images. The highest DTA (sensitivity 90%, 95% CI 88-91%; specificity 95%, 95% CI 94-96%) was observed when screening was delivered at secondary/tertiary level clinics.

CONCLUSIONS

Non-mydriatic two-field strategy could be a more pragmatic approach in starting DRS programmes for facility-based PwDM in low-income settings, with dilatation of the pupils of those who have ungradable images. There was insufficient evidence in primary studies to draw firm conclusions on how graders' background influences DTA. Conducting more context-specific DRS validation studies in low-income and non-ophthalmic settings can be recommended.

Multicolor Scanning Laser Imaging in Diabetic Retinopathy

SIGNIFICANCE

Diabetic retinopathy is a common cause of blindness in individuals younger than 60 years. Screening for retinopathy is undertaken using conventional color fundus photography and relies on the identification of hemorrhages, vascular abnormalities, exudates, and cotton-wool spots. These can sometimes be difficult to identify.

PURPOSE

Multicolor scanning laser imaging, a new imaging modality, may have a role in improving screening outcomes, as well as facilitating treatment decisions.

METHODS

Observational case series comprising two patients with known diabetes who were referred for further examination after color fundus photography revealed abnormal findings. Multicolor scanning laser imaging was undertaken. Features of retinal disease from each modality were compared.

RESULTS

Multicolor scanning laser imaging provides superior visualization of retinal anatomy and pathology, thereby facilitating risk stratification and treatment decisions.

CONCLUSIONS

Multicolor scanning laser imaging is a novel imaging technique offering the potential for improving the reliability of screening for diabetic retinopathy. Validation studies are warranted.

Telemedicine for diabetic retinopathy screening using an ultra-widefield fundus camera

OBJECTIVE

Telemedicine reporting of diabetic retinopathy (DR) screening using ultra-widefield (UWF) fundus camera.

MATERIALS AND METHODS

Cross-sectional study of diabetic patients who visited the endocrinology department of a private multi-specialty hospital in United Arab Emirates between April 2015 and January 2017 who underwent UWF fundus imaging. Fundus pictures are then accessed at the Retina Clinic in the Department of Ophthalmology. Primary outcome measure was incidence of any form of DR detected. The secondary outcome measure was failure to take good image and inability to grade.

RESULTS

A total of 1,024 diabetic individuals were screened for DR from April 2015 to January 2017 in the department of Endocrinology. Rate of DR was 9.27%; 165 eyes of 95 individuals were diagnosed to have some form of DR. Mild non-proliferative DR (NPDR) was seen in 114 of 165 eyes (69.09%), moderate NPDR in 32 eyes (19.39%), severe NPDR in six eyes (3.64%), and proliferative DR (PDR) in 13 eyes (7.88%). The secondary outcome measure of poor image acquisition was seen in one individual who had an image acquired in one eye that could not be graded due to bad picture quality.

CONCLUSIONS

The present study has shown the effectiveness of DR screening using UWF fundus camera. It has shown the effectiveness of trained nursing personnel taking fundus images. This model can be replicated in any private multi-specialty hospital and reduce the burden of DR screening in the retina clinic and enhance early detection of treatable DR.

Early short-term intensive multidisciplinary diabetes care: A ten-year follow-up of outcomes

OBJECTIVES

To evaluate the outcome of an early short-term intensive diabetic care program followed by a regular out-patient shared-care education program.

METHODS

We retrospectively reviewed the medical charts of 196 patients newly diagnosed with type 2 diabetes mellitus (DM) who were admitted to the hospital for intensive multidisciplinary interventions. For comparison, we also enrolled 206 patients with type 2 DM newly diagnosed but not receiving short-term intensive program. Both groups all attended an out-patient shared-care education program for more than one year. Outcome measure included average and standard deviation (SD) of glycated hemoglobin (HbA1c) over ten years, serum creatinine (Cr), lipid profile, urine albumin/Cr (UACR), and chronic diabetic complications after 10years later. The Kaplan-Meier event happening rates were used to compare the event rate of two samples. Multivariate Cox proportional-hazards models were used to investigate the influence of different variables on chronic complications.

RESULTS

Patients who received short-term intensive diabetic education had less SD of HbA1cs: (0.7±0.7% vs. 1.0±0.8% (5.3±5.3mmol/mol vs 9.2±6.4mmol/mol), p<0.001), less new-onset coronary heart disease (CHD) (8.2% vs. 13.7%, p=0.005), lower serum Cr (1.4±0.7mg/dL vs. 1.5±0.9mg/dL, p=0.005), less progression of nephropathy was also revealed (13.5% vs. 21.2%, p=0.009) and lower UACR (4.7±1.4mg/g vs. 5.3±1.0mg/g, p<0.001). There were no group differences in age, gender distribution, average HbA1c, lipid profile, and new-onset of neuropathy and retinopathy. The independent predictors of CHD and nephropathy were short-term intensive diabetic education and SD of HbA1cs.

CONCLUSION

Initiation of earlier intensive short-term multidisciplinary interventions in patients with newly diagnosed DM may decrease coronary heart disease and nephropathy. These better outcomes may be related to less fluctuation in blood glucose levels.

Availability and variability in guidelines on diabetic retinopathy screening in Asian countries

BACKGROUND

Diabetic retinopathy (DR) is a blinding yet treatable complication of diabetes. DR screening is highly cost-effective at reducing blindness. Amidst the rapidly growing diabetic population in Asia, the prevalence of DR in the region is relatively less well known.

AIMS

To review existing national DR screening guidelines of 50 countries in Asia, compare them against the International Council of Ophthalmology (ICO) guideline, and summarise the prevalence rates of DR and sight-threatening DR (STDR) in these countries.

METHODS

We systematically searched for published guidelines from the National Guideline Clearinghouse and other databases, and contacted local diabetic and ophthalmological associations of all 50 Asian countries.

RESULTS

Eleven Asian countries have published relevant guidelines, nine of which pertain to general diabetes care and two are DR-specific, covering less than half of Asia's population. The median DR prevalence among patients with diabetes is 30.5% (IQR: 23.2%-36.8%), similar to the USA and the UK. However, rates of STDR are consistently higher. All guidelines from the 11 Asian countries fulfil the ICO standard on when to start and repeat screening, except for screening interval for pregnant patients. However, only 2 of the 11 guidelines fulfil the ICO referral criteria and 6 partially fulfil. A third of the recommendations on screening process, equipment and personnel is either unavailable or incomplete.

CONCLUSIONS

Countries in Asia need to establish more comprehensive and evidence-based DR screening guidelines to facilitate the execution of robust screening programmes that could help reduce DR-related blindness, improve patient outcomes and reduce healthcare costs.

Integrated sensor-augmented pump therapy systems [the MiniMed® Paradigm™ Veo system and the Vibe™ and G4® PLATINUM CGM (continuous glucose monitoring) system] for managing blood glucose levels in type 1 diabetes: a systematic review and economic evaluation

BACKGROUND

In recent years, meters for continuous monitoring of interstitial fluid glucose have been introduced to help people with type 1 diabetes mellitus (T1DM) to achieve better control of their disease.

OBJECTIVE

The objective of this project was to summarise the evidence on the clinical effectiveness and cost-effectiveness of the MiniMed(®) Paradigm™ Veo system (Medtronic Inc., Northridge, CA, USA) and the Vibe™ (Animas(®) Corporation, West Chester, PA, USA) and G4(®) PLATINUM CGM (continuous glucose monitoring) system (Dexcom Inc., San Diego, CA, USA) in comparison with multiple daily insulin injections (MDIs) or continuous subcutaneous insulin infusion (CSII), both with either self-monitoring of blood glucose (SMBG) or CGM, for the management of T1DM in adults and children.

DATA SOURCES

A systematic review was conducted in accordance with the principles of the Centre for Reviews and Dissemination guidance and the National Institute for Health and Care Excellence Diagnostic Assessment Programme manual. We searched 14 databases, three trial registries and two conference proceedings from study inception up to September 2014. In addition, reference lists of relevant systematic reviews were checked. In the absence of randomised controlled trials directly comparing Veo or an integrated CSII + CGM system, such as Vibe, with comparator interventions, indirect treatment comparisons were performed if possible.

METHODS

A commercially available cost-effectiveness model, the IMS Centre for Outcomes Research and Effectiveness diabetes model version 8.5 (IMS Health, Danbury, CT, USA), was used for this assessment. This model is an internet-based, interactive simulation model that predicts the long-term health outcomes and costs associated with the management of T1DM and type 2 diabetes. The model consists of 15 submodels designed to simulate diabetes-related complications, non-specific mortality and costs over time. As the model simulates individual patients over time, it updates risk factors and complications to account for disease progression.

RESULTS

Fifty-four publications resulting from 19 studies were included in the review. Overall, the evidence suggests that the Veo system reduces hypoglycaemic events more than other treatments, without any differences in other outcomes, including glycated haemoglobin (HbA1c) levels. We also found significant results in favour of the integrated CSII + CGM system over MDIs with SMBG with regard to HbA1c levels and quality of life. However, the evidence base was poor. The quality of the included studies was generally low, often with only one study comparing treatments in a specific population at a specific follow-up time. In particular, there was only one study comparing Veo with an integrated CSII + CGM system and only one study comparing Veo with a CSII + SMBG system in a mixed population. Cost-effectiveness analyses indicated that MDI + SMBG is the option most likely to be cost-effective, given the current threshold of £30,000 per quality-adjusted life-year gained, whereas integrated CSII + CGM systems and Veo are dominated and extendedly dominated, respectively, by stand-alone, non-integrated CSII with CGM. Scenario analyses did not alter these conclusions. No cost-effectiveness modelling was conducted for children or pregnant women.

CONCLUSIONS

The Veo system does appear to be better than the other systems considered at reducing hypoglycaemic events. However, in adults, it is unlikely to be cost-effective. Integrated systems are also generally unlikely to be cost-effective given that stand-alone systems are cheaper and, possibly, no less effective. However, evidence in this regard is generally lacking, in particular for children. Future trials in specific child, adolescent and adult populations should include longer term follow-up and ratings on the European Quality of Life-5 Dimensions scale at various time points with a view to informing improved cost-effectiveness modelling.

STUDY REGISTRATION

PROSPERO Registration Number CRD42014013764.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Sensitivity and specificity of nonmydriatic digital imaging in screening diabetic retinopathy in Indian eyes

Background:

Nonmydriatic digital imaging (NMDI) is ideal for screening diabetic retinopathy (DR), but its use in Indian eyes has not been evaluated.

Aim:

The aim was to evaluate the sensitivity and specificity of NMDI as a screening tool in detecting DR in Indian eyes.

Design:

A prospective, nonrandomized, noncomparative, noninterventional study.

Materials and Methods:

A total of 500 diabetic patients visiting the endocrinology clinic (September 2008-June 2010) underwent NMDI (Zeiss Procam), followed by routine dilated fundus photography (FP; Zeiss Visupac 450+) of 345° retinal fields (1) optic disc and macula, (2) superotemporal, and (3) nasal to optic disc. Two-masked retina specialists graded the images for quality and severity of DR, and compared between NMDI and dilated FP.

Statistical Analysis:

SPSS Windows 17 for version.

Results:

Mean age was 52.97 ± 13.46 years (306 males: 194 females). The rate of ungradable images was 30.6% and 31% by the two observers. By observer 1, the sensitivity and specificity of detecting any DR was 58.8% and 69.1%, respectively, (κ = 0.608) and sight-threatening DR (STDR) was 63.1% and 68.9%, respectively, (κ = 0.641). By observer 2, the sensitivity and specificity was 57.3% and 68.3%, respectively, for any DR (κ = 0.593) and 62.8% and 68.3%, respectively, for STDR (κ = 0.637). The level of agreement between two observers was high (κ = 0.96).

Conclusion:

A high rate of poor quality photographs and low sensitivity limited the use of NMDI as a perfect screening system, particularly in dark iris population with diabetes as seen in Indian eyes.

Tele-ophthalmology for diabetic retinopathy screening: 8 years of experience

PURPOSE

To describe the results of a diabetic retinopathy screening program implemented in a primary care area.

METHODS

A retrospective study was conducted using data automatically collected since the program began on 1 January 2007 until 31 December 2015.

RESULTS

The number of screened diabetic patients has progressively increased, from 7,173 patients in 2007 to 42,339 diabetic patients in 2015. Furthermore, the ability of family doctors to correctly interpret retinographies has improved, with the proportion of retinal images classified as normal having increased from 55% in 2007 to 68% at the end of the study period. The proportion of non-evaluable retinographies decreased to 7% in 2015, having peaked at 15% during the program. This was partly due to a change in the screening program policy that allowed the use of tropicamide. The number of severe cases detected has declined, from 14% with severe non-proliferative and proliferativediabetic retinopathy in the initial phase of the program to 3% in 2015.

CONCLUSIONS

Diabetic eye disease screening by tele-ophthalmology has shown to be a valuable method in a growing population of diabetics. It leads to a regular medical examination of patients, helps ease the workload of specialised care services and favours the early detection of treatable cases. However, the results of implementing a program of this type are not immediate, achieving only modest results in the early years of the project that have improved over subsequent years.

Ultra-wide field imaging system and traditional retinal examinations for screening fundus changes after cataract surgery

AIM

To compare the results of non-mydriatic ultra-wide field imaging system, mydriatic slit-lamp lens (Volk +90 D) and mydriatic Goldmann three-mirror contact lens examinations in screening fundus lesions among patients after cataract surgery.

METHODS

Non-mydriatic images were obtained with an Optomap panoramic 200Tx (Optomap 200Tx) 3d after surgery and graded by a blinded ophthalmologist. A mydriatic slit-lamp lens examination was performed by another blinded retinal specialist on the same day. A third blinded retinal specialist examined patients two weeks after surgery using a Goldmann three-mirror contact lens.

RESULTS

In total, 160 patients (184 eyes) were examined, and 66, 69, and 75 cases of retinal lesion(s) were identified using the Optomap 200Tx, slit-lamp lens, and Goldmann three-mirror contact lens, respectively. In 13 cases, fundus changes were sight-threatening. The results obtained by Optomap 200Tx examination and by mydriatic slit-lamp lens examination have good consistency (P=0.375, Kappa=0.942). The mydriatic Goldmann three-mirror lens examination revealed more fundus lesions but are consistent with Optomap 200Tx (P=0.004, Kappa=0.897) and mydriatic slit-lamp lens examination (P=0.031, Kappa=0.932).

CONCLUSION

Early post-operative fundus screening in cataract patients is extremely important and necessary to prevent further vision loss. Wide-field imaging is a feasible and convenient tool for fundus examination that can be used as a primary screening method among patients after cataract surgery.

Outpatient services and primary care: scoping review, substudies and international comparisons

Aim

This study updates a previous scoping review published by the National Institute for Health Research (NIHR) in 2006 (Roland M, McDonald R, Sibbald B.Outpatient Services and Primary Care: A Scoping Review of Research Into Strategies For Improving Outpatient Effectiveness and Efficiency. Southampton: NIHR Trials and Studies Coordinating Centre; 2006) and focuses on strategies to improve the effectiveness and efficiency of outpatient services.

Findings from the scoping review

Evidence from the scoping review suggests that, with appropriate safeguards, training and support, substantial parts of care given in outpatient clinics can be transferred to primary care. This includes additional evidence since our 2006 review which supports general practitioner (GP) follow-up as an alternative to outpatient follow-up appointments, primary medical care of chronic conditions and minor surgery in primary care. Relocating specialists to primary care settings is popular with patients, and increased joint working between specialists and GPs, as suggested in the NHS Five Year Forward View, can be of substantial educational value. However, for these approaches there is very limited information on cost-effectiveness; we do not know whether they increase or reduce overall demand and whether the new models cost more or less than traditional approaches. One promising development is the increasing use of e-mail between GPs and specialists, with some studies suggesting that better communication (including the transmission of results and images) could substantially reduce the need for some referrals.

Findings from the substudies

Because of the limited literature on some areas, we conducted a number of substudies in England. The first was of referral management centres, which have been established to triage and, potentially, divert referrals away from hospitals. These centres encounter practical and administrative challenges and have difficulty getting buy-in from local clinicians. Their effectiveness is uncertain, as is the effect of schemes which provide systematic review of referrals within GP practices. However, the latter appear to have more positive educational value, as shown in our second substudy. We also studied consultants who held contracts with community-based organisations rather than with hospital trusts. Although these posts offer opportunities in terms of breaking down artificial and unhelpful primary–secondary care barriers, they may be constrained by their idiosyncratic nature, a lack of clarity around roles, challenges to professional identity and a lack of opportunities for professional development. Finally, we examined the work done by other countries to reform activity at the primary–secondary care interface. Common approaches included the use of financial mechanisms and incentives, the transfer of work to primary care, the relocation of specialists and the use of guidelines and protocols. With the possible exception of financial incentives, the lack of robust evidence on the effect of these approaches and the contexts in which they were introduced limits the lessons that can be drawn for the English NHS.

Conclusions

For many conditions, high-quality care in the community can be provided and is popular with patients. There is little conclusive evidence on the cost-effectiveness of the provision of more care in the community. In developing new models of care for the NHS, it should not be assumed that community-based care will be cheaper than conventional hospital-based care. Possible reasons care in the community may be more expensive include supply-induced demand and addressing unmet need through new forms of care and through loss of efficiency gained from concentrating services in hospitals. Evidence from this study suggests that further shifts of care into the community can be justified only if (a) high value is given to patient convenience in relation to NHS costs or (b) community care can be provided in a way that reduces overall health-care costs. However, reconfigurations of services are often introduced without adequate evaluation and it is important that new NHS initiatives should collect data to show whether or not they have added value, and improved quality and patient and staff experience.

Funding

The NIHR Health Services and Delivery Research programme.

Chronic Kidney Disease and Diabetic Retinopathy in Patients with Type 2 Diabetes

Purpose

To explore the relationship between chronic kidney disease (CKD) and diabetic retinopathy (DR) in a representative population of type 2 diabetes mellitus (DM2) patients in Catalonia (Spain).

Methods

This was a population-based, cross-sectional study. A total of 28,344 patients diagnosed with DM2 who had recorded ophthalmologic and renal functional examinations were evaluated. Data were obtained from a primary healthcare electronic database of medical records. CKD was defined as an estimated glomerular filtration ratio (eGFR) of <60 ml/min/1.73m² and/or urine albumin to creatinine ratio (UACR) ≥30 mg/g. DR was categorized as non-vision threatening diabetic retinopathy and vision threatening diabetic retinopathy.

Results

CKD was associated with a higher rate of DR [OR], 95% confidence interval [CI], 1.5 (1.4–1.7). When we analyzed the association between different levels of UACR and DR prevalence observed that DR prevalence rose with the increase of UACR levels, and this association was significant from UACR values ≥10 mg/g, and increased considerably with UACR values ≥300mg/g (Odds ratio [OR], 95% confidence interval [CI], 2.0 (1.6–2.5). This association was lower in patients with eGFR levels 44 to 30 mL/min/1.73m² [OR], 95% confidence interval [CI], 1.3 (1.1–1.6).

Conclusions

These results show that CKD, high UACR and/or low eGFR, appear to be associated with DR in this DM2 population.

Teleretinal imaging for detection of referable macular degeneration

PURPOSE

The purpose of this study was to determine the sensitivity and specificity for detection of referable age-related macular degeneration (AMD) using an existing nonmydriatic telemedicine pathway for diabetic retinopathy screening with comparison to same-day face-to-face examination by a retina specialist.

METHODS

Subjects in this study underwent nonmydriatic and mydriatic digital retinal imaging on the same day as stereoscopic dilated examination of the macula by a retina specialist and the level of AMD was recorded for each eye. Images were graded by two trained readers as nonreferable or referable (AREDS [Age-Related Eye Disease Study] grading of level 3 or greater). Sensitivity and specificity were calculated by comparing referral recommendations between each reader and the retina specialist ("gold standard").

RESULTS

There were 47 subjects (94 eyes) enrolled in the study. Sensitivity for nonreferable AMD with nonmydriatic imaging was 1.0 (reader 1) and 1.0 (reader 2), whereas specificity was 0.75 (reader 1) and 0.91 (reader 2). Sensitivity for referable AMD with nonmydriatic imaging was 0.84 (reader 1) and 0.88 (reader 2), whereas specificity was 0.81 (reader 1) and 0.81 (reader 2).

CONCLUSIONS

Our study showed that nonmydriatic digital retinal imaging had excellent sensitivity and specificity in identifying referable and nonreferable AMD using an existing validated telemedicine pathway for diabetic retinopathy screening.

The durability of sitagliptin in elderly patients with type 2 diabetes

AIM

To evaluate the durability of sitagliptin and to assess changes in clinical chronic complications following sitagliptin monotherapy for 48 months in elderly patients with type 2 diabetes mellitus (T2DM).

SUBJECTS AND METHODS

We enrolled 76 drug-naïve patients (40 women and 36 men; mean age: 71.3±11.7 years) with T2DM who received 25-100 mg of sitagliptin therapy from an outpatient clinic. The observational period for each patient was >48 months, beginning at the time sitagliptin therapy was initiated. The following were measured or performed at the beginning of each year: body mass index; serum total cholesterol, low-density lipoprotein, high-density lipoprotein; triglyceride levels; creatinine (Cr) levels; urine albumin and urine Cr; nonmydriatic fundusgraphy; and semiquantified neuropathy. The fasting plasma glucose and glycated hemoglobin (HbA1c) was measured every 3-6 months.

RESULTS

The change in HbA1c was significantly reduced after 6 months of therapy (7.1%±0.8% to 6.3%±0.2%). No changes in fasting plasma glucose, Cr, serum total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, body mass index, and microvascular complications were apparent. Using repeated measures to test the sequential changes in HbA1c from month 6 to month 48, the test of within-subjects effect was not significant (P=0.34).

CONCLUSION

Sitagliptin has a durable effect and stabilizes microvascular complication progression in elderly patients. This study can provide useful data for clinicians and health care professionals using sitagliptin monotherapy in the treatment of elderly patients with T2DM.

[Fundus screening by medical technicians]

Ocular fundus photography allows detection of both ocular and systemic diseases. This study investigated the efficacy of a broad screening in a department of internal medicine using nonmydriatic digital fundus photography. For 8 weeks a medical technician was trained in using the camera as well as interpreting the photographs. The medical technician and an ophthalmologist evaluated the fundus photographs separately by using a self-developed questionnaire. The fundus camera was user-friendly and after several weeks of adjustment and practical application the medical technician was able to detect the majority of pathological fundus photographs. Out of 218 patients examined 148 (68%) were identified as pathological by the medical technician and 163 (75%) by the ophthalmologist (p = 0.0003). The medical technician missed 15 (7%) patients. Furthermore the diagnoses made by the medical technician were faulty. In summary an ophthalmological screening by a medical technician is feasible but the diagnosis still remains the responsibility of ophthalmologists. Such a compromise could facilitate the examination of a large number of patients and disclose previously unrecognized diseases.

Comparison of image-assisted versus traditional fundus examination

BACKGROUND

The purpose of this study was to evaluate the ability of image-assisted fundus examination to detect retinal lesions compared with traditional fundus examination.

METHODS

Subjects were imaged using a nonmydriatic ultrawide field scanning laser ophthalmoscope. After imaging, subjects underwent both a traditional and an image-assisted fundus examination, in random order. During the image-assisted method, ultrawide field scanning laser ophthalmoscopic images were reviewed in conjunction with a dilated fundus examination. Lesions detected by each method were assigned to one of three regions, ie, optic disc, posterior pole/macula, or mid-to-peripheral retina. Discrepancies between the image-assisted and the traditional examination methods were adjudicated by a retinal ophthalmologist.

RESULTS

In total, 170 subjects (339 eyes) were recruited. Agreement between image-assisted and traditional fundus examination varied by lesion type and was excellent for staphyloma (kappa 0.76), fair for suspicious cupping (kappa 0.66), drusen in the posterior pole/macula and mid-to-peripheral retina (0.45, 0.41), retinal pigment epithelial changes in the posterior pole/macula (0.54), peripheral retinal degeneration (0.50), cobblestone (0.69), vitreoretinal interface abnormalities (0.40), and vitreous lesions (0.53). Agreement was poor for hemorrhage in the mid-to-peripheral retina (kappa 0.33), and nevi in the mid-to-peripheral retina (0.34). When the methods disagreed, the results indicated a statistically significant advantage for the image-assisted examination in detecting suspicious cupping (P = 0.04), drusen in the posterior pole/macula and mid-to-peripheral retina (P = 0.004, P < 0.001), retinal pigment epithelial changes in the posterior pole/macula (P = 0.04), nevi in the posterior pole/macula and mid-to-peripheral retina (P = 0.01, P = 0.007), peripheral retinal degeneration (P < 0.001), hemorrhage in the mid-to-peripheral retina (P = 0.01), and vitreous lesions (P < 0.001).

CONCLUSION

Image-assisted fundus examination may enhance detection of retinal lesions compared with traditional fundus examination alone.

Assessment of diabetic retinopathy using nonmydriatic ultra-widefield scanning laser ophthalmoscopy (Optomap) compared with ETDRS 7-field stereo photography

OBJECTIVE

To compare the diagnostic properties of a nonmydriatic 200° ultra-widefield scanning laser ophthalmoscope (SLO) versus mydriatic Early Treatment of Diabetic Retinopathy Study (ETDRS) 7-field photography for diabetic retinopathy (DR) screening.

RESEARCH DESIGN AND METHODS

A consecutive series of 212 eyes of 141 patients with different levels of DR were examined. Grading of DR and clinically significant macular edema (CSME) from mydriatic ETDRS 7-field stereo photography was compared with grading obtained by Optomap Panoramic 200 SLO images. All SLO scans were performed through an undilated pupil, and no additional clinical information was used for evaluation of all images by the two independent, masked, expert graders.

RESULTS

Twenty-two eyes from ETDRS 7-field photography and 12 eyes from Optomap were not gradable by at least one grader because of poor image quality. A total of 144 eyes were analyzed regarding DR level and 155 eyes regarding CSME. For ETDRS 7-field photography, 22 eyes (18 for grader 2) had no or mild DR (ETDRS levels ≤ 20) and 117 eyes (111 for grader 2) had no CSME. A highly substantial agreement between both Optomap DR and CSME grading and ETDRS 7-field photography existed with κ = 0.79 for DR and 0.73 for CSME for grader 1, and κ = 0.77 (DR) and 0.77 (CSME) for grader 2.

CONCLUSIONS

Determination of CSME and grading of DR level from Optomap Panoramic 200 nonmydriatic images show a positive correlation with mydriatic ETDRS 7-field stereo photography. Both techniques are of sufficient quality to assess DR and CSME. Optomap Panoramic 200 images cover a larger retinal area and therefore may offer additional diagnostic properties.

Can the retinal screening interval be safely increased to 2 years for type 2 diabetic patients without retinopathy?

OBJECTIVE

In the U.K., people with diabetes are typically screened for retinopathy annually. However, diabetic retinopathy sometimes has a slow progression rate. We developed a simulation model to predict the likely impact of screening patients with type 2 diabetes, who have not been diagnosed with diabetic retinopathy, every 2 years rather than annually. We aimed to assess whether or not such a policy would increase the proportion of patients who developed retinopathy-mediated vision loss compared with the current policy, along with the potential cost savings that could be achieved.

RESEARCH DESIGN AND METHODS

We developed a model that simulates the progression of retinopathy in type 2 diabetic patients, and the screening of these patients, to predict rates of retinopathy-mediated vision loss. We populated the model with data obtained from a National Health Service Foundation Trust. We generated comparative 15-year forecasts to assess the differences between the current and proposed screening policies. RESULTS The simulation model predicts that implementing a 2-year screening interval for type 2 diabetic patients without evidence of diabetic retinopathy does not increase their risk of vision loss. Furthermore, we predict that this policy could reduce screening costs by ~25%.

CONCLUSIONS

Screening people with type 2 diabetes, who have not yet developed retinopathy, every 2 years, rather than annually, is a safe and cost-effective strategy. Our findings support those of other studies, and we therefore recommend a review of the current National Institute for Health and Clinical Excellence (NICE) guidelines for diabetic retinopathy screening implemented in the U.K.

Retinopathy screening in patients with type 1 diabetes diagnosed in young age using a non-mydriatic digital stereoscopic retinal imaging

BACKGROUND

Diabetic retinopathy seriously impairs patients' quality of life, since it represents the first cause of blindness in industrialized countries.

AIM

To estimate prevalence of retinopathy in young Type 1 diabetes patients using a non-mydriatic digital stereoscopic retinal imaging (NMDSRI), and to evaluate the impact of socio-demographic, clinical, and metabolic variables.

SUBJECTS AND METHODS

In 247 young patients glycated hemoglobin (HbA1c), gender, age, pubertal stage, presence of diabetic ketoacidosis (DKA), HLA-DQ heterodimers of susceptibility for Type 1 diabetes, and β-cell autoimmunity at clinical onset were considered. At retinopathy screening, we evaluated age, disease duration, pubertal stage, body mass index (BMI-SDS), insulin requirement, HbA1c levels, other autoimmune diseases, diabetes-related complications, serum concentrations of cholesterol and triglycerides, systolic and diastolic blood pressure.

RESULTS

Retinopathy was found in 26/247 patients: 25 showed background retinopathy, and 1 had a sight-threatening retinopathy. A significant relationship between retinopathy and female gender (p=0.01), duration of disease ≥15 yr (p<0.0001), serum triglycerides levels >65 mg/dl (p=0.012) and mean HbA1c ≥7.5% or >9% (p=0.0014) were found at the multivariate logistic analysis.

CONCLUSIONS

Metabolic control is the most important modifiable factor and promotion of continuous educational process to reach a good metabolic control is a cornerstone to prevent microangiopathic complications. Symptoms appear when the complication is already established; a screening program with an early diagnosis is mandatory to prevent an irreversible damage.

Digital ocular fundus imaging: a review

Ocular fundus imaging plays a key role in monitoring the health status of the human eye. Currently, a large number of imaging modalities allow the assessment and/or quantification of ocular changes from a healthy status. This review focuses on the main digital fundus imaging modality, color fundus photography, with a brief overview of complementary techniques, such as fluorescein angiography. While focusing on two-dimensional color fundus photography, the authors address the evolution from nondigital to digital imaging and its impact on diagnosis. They also compare several studies performed along the transitional path of this technology. Retinal image processing and analysis, automated disease detection and identification of the stage of diabetic retinopathy (DR) are addressed as well. The authors emphasize the problems of image segmentation, focusing on the major landmark structures of the ocular fundus: the vascular network, optic disk and the fovea. Several proposed approaches for the automatic detection of signs of disease onset and progression, such as microaneurysms, are surveyed. A thorough comparison is conducted among different studies with regard to the number of eyes/subjects, imaging modality, fundus camera used, field of view and image resolution to identify the large variation in characteristics from one study to another. Similarly, the main features of the proposed classifications and algorithms for the automatic detection of DR are compared, thereby addressing computer-aided diagnosis and computer-aided detection for use in screening programs.