Comparative study of the polaroid and digital non-mydriatic cameras in the detection of referrable diabetic retinopathy in Australia

Application of non-mydriatic fundus photography-assisted telemedicine in diabetic retinopathy screening

BACKGROUND

Early screening and accurate staging of diabetic retinopathy (DR) can reduce blindness risk in type 2 diabetes patients. DR's complex pathogenesis involves many factors, making ophthalmologist screening alone insufficient for prevention and treatment. Often, endocrinologists are the first to see diabetic patients and thus should screen for retinopathy for early intervention.

AIM

To explore the efficacy of non-mydriatic fundus photography (NMFP)-enhanced telemedicine in assessing DR and its various stages.

METHODS

This retrospective study incorporated findings from an analysis of 93 diabetic patients, examining both NMFP-assisted telemedicine and fundus fluorescein angiography (FFA). It focused on assessing the concordance in DR detection between these two methodologies. Additionally, receiver operating characteristic (ROC) curves were generated to determine the optimal sensitivity and specificity of NMFP-assisted telemedicine, using FFA outcomes as the standard benchmark.

RESULTS

In the context of DR diagnosis and staging, the kappa coefficients for NMFP-assisted telemedicine and FFA were recorded at 0.775 and 0.689 respectively, indicating substantial intermethod agreement. Moreover, the NMFP-assisted telemedicine's predictive accuracy for positive FFA outcomes, as denoted by the area under the ROC curve, was remarkably high at 0.955, within a confidence interval of 0.914 to 0.995 and a statistically significant P-value of less than 0.001. This predictive model exhibited a specificity of 100%, a sensitivity of 90.9%, and a Youden index of 0.909.

CONCLUSION

NMFP-assisted telemedicine represents a pragmatic, objective, and precise modality for fundus examination, particularly applicable in the context of endocrinology inpatient care and primary healthcare settings for diabetic patients. Its implementation in these scenarios is of paramount significance, enhancing the clinical accuracy in the diagnosis and therapeutic management of DR. This methodology not only streamlines patient evaluation but also contributes substantially to the optimization of clinical outcomes in DR management.

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.

The diagnostic accuracy of an intelligent and automated fundus disease image assessment system with lesion quantitative function (SmartEye) in diabetic patients

BACKGROUND

With the diabetes mellitus (DM) prevalence increasing annually, the human grading of retinal images to evaluate DR has posed a substantial burden worldwide. SmartEye is a recently developed fundus image processing and analysis system with lesion quantification function for DR screening. It is sensitive to the lesion area and can automatically identify the lesion position and size. We reported the diabetic retinopathy (DR) grading results of SmartEye versus ophthalmologists in analyzing images captured with non-mydriatic fundus cameras in community healthcare centers, as well as DR lesion quantitative analysis results on different disease stages.

METHODS

This is a cross-sectional study. All the fundus images were collected from the Shanghai Diabetic Eye Study in Diabetics (SDES) program from Apr 2016 to Aug 2017. 19,904 fundus images were acquired from 6013 diabetic patients. The grading results of ophthalmologists and SmartEye are compared. Lesion quantification of several images at different DR stages is also presented.

RESULTS

The sensitivity for diagnosing no DR, mild NPDR (non-proliferative diabetic retinopathy), moderate NPDR, severe NPDR, PDR (proliferative diabetic retinopathy) are 86.19, 83.18, 88.64, 89.59, and 85.02%. The specificity are 63.07, 70.96, 64.16, 70.38, and 74.79%, respectively. The AUC are PDR, 0.80 (0.79, 0.81); severe NPDR, 0.80 (0.79, 0.80); moderate NPDR, 0.77 (0.76, 0.77); and mild NPDR, 0.78 (0.77, 0.79). Lesion quantification results showed that the total hemorrhage area, maximum hemorrhage area, total exudation area, and maximum exudation area increase with DR severity.

CONCLUSIONS

SmartEye has a high diagnostic accuracy in DR screening program using non-mydriatic fundus cameras. SmartEye quantitative analysis may be an innovative and promising method of DR diagnosis and grading.

Single-Field Non-Mydriatic Fundus Photography for Diabetic Retinopathy Screening: A Systematic Review and Meta-Analysis

PURPOSE

Single-field non-mydriatic fundus photography (NMFP) has been used to detect diabetic retinopathy (DR) in many studies; however, its value in a general clinical setting has not been established. Here we performed a meta-analysis to evaluate its diagnostic effectiveness.

METHOD

We systematically searched PubMed, EMBASE, and Cochrane databases for candidate studies published through May 19, 2018. A random-effect model was used to calculate the diagnostic indicators including the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the curve (AUC), and 95% confidence intervals.

RESULTS

Ten prospective studies were ultimately included. The pooled sensitivity, specificity, PLR, NLR, and DOR were 0.68, 0.94, 11.2, 0.34 and 33, respectively. The AUC was 0.88. Subgroup analysis showed that single-field NMFP had a respective sensitivity and specificity of 0.73 and 0.91 when compared to standard 7-field mydriatic stereoscopic photography (7SF), and 0.54 and 0.98 when compared to slit-lamp biomicroscopy as reference standard.

CONCLUSIONS

Single-field NMFP is inadequate to detect DR. Additionally, it showed higher sensitivity and lower specificity when 7SF was used as reference standard, as compared to slit-lamp biomicroscopy, suggesting that different reference standards used in DR screening might have affected the diagnostic results.

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.

Racial disparity of eye examinations among the U.S. working-age population with diabetes: 2002-2009

OBJECTIVE

Diabetes care differs across racial and ethnic groups. This study aimed to assess the racial disparity of eye examinations among U.S. adults with diabetes.

RESEARCH DESIGN AND METHODS

Working-age adults (age 18-64 years) with diabetes were studied using data from the Medical Expenditure Panel Survey Household Component (2002-2009) including the Diabetes Care Survey. Racial and ethnic groups were classified as non-Hispanic whites and minorities. People reporting one or more dilated eye examination were considered to have received an eye examination in a particular year. Eye examination rates were compared between racial/ethnic groups for each year, and were weighted to national estimates. Multivariate adjusted odds ratios (aORs) and 95% CIs for racial/ethnic difference were assessed annually using logistic regression models. Other influencing factors associated with eye examination were also explored.

RESULTS

Whites had consistently higher unadjusted eye examination rates than minority populations across all 8 years. The unadjusted rates increased from 56% in 2002 to 59% in 2009 among whites, while the rates in minorities decreased from 56% in 2002 to 49% in 2009. The largest significant racial gap of 15% was observed in 2008, followed by 11%, 10%, and 7% in 2006, 2009, and 2005, respectively (P < 0.05). Minorities were less likely to receive eye examination (2006: aOR 0.75 [95% CI 0.57-0.99]; 2008: 0.61 [0.45-0.84]).

CONCLUSIONS

The racial/ethnic differences in eye examinations for patients with diabetes have persisted over the last decade. National programs to improve screening and monitoring of diabetic retinopathy are needed to target minority populations.

Telemedicine and ocular health in diabetes mellitus

Teleretinal/teleophthalmological programs that use existing health information technology infrastructure solutions for people with diabetes increase access to and adherence to appropriate eye care. Teleophthalmological studies indicate that the single act of patients viewing their own retinal images improves self-management behaviour and clinical outcomes. In some settings this can be done at lower cost and with improved visual outcomes compared with standard eye care. Cost-effective and sustainable teleretinal surveillance for detection of diabetic retinopathy requires a combination of an inexpensive portable device for taking low light-level retinal images without the use of pharmacological dilation of the pupil and a computer-assisted methodology for rapidly detecting and diagnosing diabetic retinopathy. A more holistic telehealth-care paradigm augmented with the use of health information technology, medical devices, mobile phone and mobile health applications and software applications to improve health-care co-ordination, self-care management and education can significantly impact a broad range of health outcomes, including prevention of diabetes-associated visual loss. This approach will require a collaborative, transformational, patient-centred health-care program that integrates data from medical record systems with remote monitoring of data and a longitudinal health record. This includes data associated with social media applications and personal mobile health technology and should support continuous interactions between the patient, health-care team and the patient's social environment. Taken together, this system will deliver contextually and temporally relevant decision support to patients to facilitate their well-being and to reduce the risk of diabetic complications.

Systematic review of the diagnostic accuracy of the single, two and three field digital retinal photography for screening diabetic retinopathy

BACKGROUND

Regular eye examinations are important to aid in early detection of diabetic retinopathy. Screening methods include ophthalmoscopy, retinal photography and variations of both. Digital retinal photography (DRP) is being increasingly adopted. The gold standard is to photograph seven visual fields, in practice, however, fewer fields such as single, two or three fields are used, to reduce cost and time. There is no existing review comparing the diagnostic accuracy of the single, two and three-field DRP.

OBJECTIVES

To perform a systematic review of the diagnostic accuracy of the single, two and three field DRP for screening diabetic retinopathy.

INCLUSION CRITERIA

All patients with diabetes mellitus who attended an eye screening were included. Studies which include digital retinal imaging techniques that capture single, two or three visual images were considered.To be included, studies must have compared the technique to a reference standard, either the seven-field stereoscopic fundus photography (7SF) or indirect ophthalmoscopy.

TYPES OF OUTCOMES

The main outcomes were sensitivity and specificity of the screening technique.

SEARCH STRATEGY

Search was carried out, for the time period 1985 to December 2008, for full text papers and conference abstracts.

METHODOLOGICAL QUALITY

Methodological quality of included studies was assessed by two reviewers using an adapted version of the critical appraisal tool for diagnostic studies developed by the Critical Appraisal Skills Programme at the Public Health Resource Unit.

DATA COLLECTION

Data from included studies were extracted using a modified JBI data extraction tool.

DATA SYNTHESIS

Studies were grouped by the reference standard used and summarised using tabular and narrative formats.

RESULTS

Twenty-two primary studies met the review criteria. Fifteen studies used a single field, five applied two-field and seven applied three-field. There was great heterogeneity among the studies. Using 7SF as a reference standard, the sensitivity (for detecting any retinopathy) of the single, two and three fields ranged from: 66%-87%, 86%-98%, and 66%-98%. For indirect ophthalmoscopy, sensitivity ranged from 38%-100%, 83%-97%, and 90%-97%. The corresponding specificity for 7SF was 45%-96%, 78%-95%, 72%-86%; for indirect ophthalmoscopy was 47%-100%, 79%-100%, 90%-98%. Five studies comparing more than one field type had a general trend of higher sensitivity and lower specificity with increasing number of fields. Pupil dilation led to a lower proportion of ungradeable images.

CONCLUSIONS

The review findings are limited by the heterogeneity between studies and the number of studies comparing more than one screening type. Evidence for the optimal number of screening fields is not conclusive.

IMPLICATIONS FOR PRACTICE

Until further research is available for stronger comparisons to be made, single field DRP would be the option requiring less time and lower costs. Dilation should be applied to reduce ungradeable images. Older age, smaller pupil size, and presence of cataract are associated with ungradeable images.

IMPLICATIONS FOR RESEARCH

There is a strong recommendation for field specialists to achieve consensus on DRP methods including a standard scale for grading diabetic retinopathy and common threshold for referrable retinopathy. Future studies should consider following the Standards for Reporting of Diagnostic Accuracy (STARD). A prospective study comparing the single, two and three fields, with and without dilation will provide the required evidence for optimal number of fields.

Six-year retrospective follow-up study of safe screening intervals for sight-threatening retinopathy in patients with diabetes mellitus

BACKGROUND

We estimate safe screening intervals for sight-threatening diabetic retinopathy (STDR).

METHODS

A 6-year retrospective follow-up study to review screening results of two cohorts of patients with diabetes mellitus (DM) was conducted; a cohort free of diabetic retinopathy (DR) and a cohort with mild nonproliferative diabetic retinopathy (NPDR) at baseline. Patients had been screened by means of a nonmydriatic retinal camera. Baseline age, sex, and diabetes characteristics were also collected. Statistical analysis was based on life-table method of risk estimation.

RESULTS

A total of 286 patients with DM free of DR and 144 patients with mild NPDR at baseline were included in the study. For patients free of DR, the probability of remaining free of STDR was 97% (95% confidence interval [CI] 94-99%) at the end of the fourth year. In this cohort of patients, those with type 2 DM were more likely to progress to STDR than those who had type 1 DM (p < .01). For patients with mild NPDR, the probability of remaining free of STDR dropped to 94% (95% CI 88-97%) at the end of the second year, and it was still 100% at the end of the second year for those with a glycated hemoglobin level < or =7.5% at baseline (p < .05).

CONCLUSIONS

Screening at a 3-4 year interval for diabetes patients free of DR is safe because of their low risk of developing STDR. Patients with mild NPDR require screening at a 1 year interval, or at a 2 year interval with good metabolic control.