Use of offline artificial intelligence in a smartphone-based fundus camera for community screening of diabetic retinopathy

Purpose:The aim of the study was to analyse the reliability of an offline artificial intelligence (AI) algorithm for community screening of diabetic retinopathy.Methods:A total of 1378 patients with diabetes visiting public dispensaries under the administration of the Municipal Corporation of Greater Mumbai between August 2018 and September 2019 were enrolled for the study. Fundus images were captured by non-specialist operators using a smartphone-based camera covering the posterior pole, including the disc and macula, and the nasal and temporal fields. The offline AI algorithm on the smartphone marked the images as referable diabetic retinopathy (RDR) or non-RDR, which were then compared against the grading by two vitreoretinal surgeons to derive upon the sensitivity and specificity of the algorithm.Results:Out of 1378 patients, gradable fundus images were obtained and analysed for 1294 patients. The sensitivity and specificity of diagnosing RDR were 100% (95% CI: 94.72–100.00%) and 89.55% (95% CI: 87.76–91.16%), respectively; the same values for any diabetic retinopathy (DR) were 89.13% (95% CI: 82.71–93.79%) and 94.43% (95% CI: 91.89–94.74%), respectively, with no false-negative results.Conclusion:The robustness of the offline AI algorithm was established in this study making it a reliable tool for community-based DR screening.     

Comparison of automated and expert human grading of diabetic retinopathy using smartphone-based retinal photography

PurposeThe aim of this study is to investigate the efficacy of a mobile platform that combines smartphone-based retinal imaging with automated grading for determining the presence of referral-warranted diabetic retinopathy (RWDR).MethodsA smartphone-based camera (RetinaScope) was used by non-ophthalmic personnel to image the retina of patients with diabetes. Images were analyzed with the Eyenuk EyeArt® system, which generated referral recommendations based on presence of diabetic retinopathy (DR) and/or markers for clinically significant macular oedema. Images were independently evaluated by two masked readers and categorized as refer/no refer. The accuracies of the graders and automated interpretation were determined by comparing results to gold standard clinical diagnoses.ResultsA total of 119 eyes from 69 patients were included. RWDR was present in 88 eyes (73.9%) and in 54 patients (78.3%). At the patient-level, automated interpretation had a sensitivity of 87.0% and specificity of 78.6%; grader 1 had a sensitivity of 96.3% and specificity of 42.9%; grader 2 had a sensitivity of 92.5% and specificity of 50.0%. At the eye-level, automated interpretation had a sensitivity of 77.8% and specificity of 71.5%; grader 1 had a sensitivity of 94.0% and specificity of 52.2%; grader 2 had a sensitivity of 89.5% and specificity of 66.9%.DiscussionRetinal photography with RetinaScope combined with automated interpretation by EyeArt achieved a lower sensitivity but higher specificity than trained expert graders. Feasibility testing was performed using non-ophthalmic personnel in a retina clinic with high disease burden. Additional studies are needed to assess efficacy of screening diabetic patients from general population.Subject terms: Medical imaging, Prognostic markers, Retinal diseases, Medical research     

Capturing the clinical decision-making processes of expert and novice diabetic retinal graders using a ‘think-aloud’ approach

BackgroundDiabetic eye screening programmes have been developed worldwide based on evidence that early detection and treatment of diabetic retinopathy are crucial to preventing sight loss. However, little is known about the decision-making processes and training needs of diabetic retinal graders, particularly in low- and middle-income countries.ObjectivesTo provide data for improving evidence-based diabetic retinopathy training to help novice graders process fundus images more like experts.Subjects/methodsThis is a mixed-methods qualitative study conducted in southern Vietnam and Northern Ireland. Novice diabetic retinal graders in Vietnam (n = 18) and expert graders in Northern Ireland (n = 5) were selected through a purposive sampling technique. Data were collected from 21st February to 3rd September 2019. The interviewer used neutral prompts during think-aloud sessions to encourage participants to verbalise their thought processes while grading fundus images from anonymised patients, followed by semi-structured interviews. Thematic framework analysis was used to identify themes, supported by illustrative quotes from interviews. Mann–Whitney U tests were used to compare graders’ performance.ResultsExpert graders used a more systematic approach when grading images, considered all four images per patient and used available software tools such as red-free filters prior to making a decision on management. The most challenging features for novice graders were intra-retinal microvascular abnormalities and new vessels, which were more accurately identified by experts.ConclusionTaking more time to grade fundus images and adopting a protocol-driven “checklist” approach may help novice graders to function more like experts.Subject terms: Retinal diseases, Medical imaging, Health occupations     

Comparison of early diabetic retinopathy staging in asymptomatic patients between autonomous AI-based screening and human-graded ultra-widefield colour fundus images

IntroductionComparison of diabetic retinopathy (DR) severity between autonomous Artificial Intelligence (AI)-based outputs from an FDA-approved screening system and human retina specialists’ gradings from ultra-widefield (UWF) colour images.MethodsAsymptomatic diabetics without a previous diagnosis of DR were included in this prospective observational pilot study. Patients were imaged with autonomous AI (IDx-DR, Digital Diagnostics). For each eye, two 45° colour fundus images were analysed by a secure server-based AI algorithm. UWF colour fundus imaging was performed using Optomap (Daytona, Optos). The International Clinical DR severity score was assessed both on a 7-field area projection (7F-mask) according to the early treatment diabetic retinopathy study (ETDRS) and on the total gradable area (UWF full-field) up to the far periphery on UWF images.ResultsOf 54 patients included (n = 107 eyes), 32 were type 2 diabetics (11 females). Mean BCVA was 0.99 ± 0.25. Autonomous AI diagnosed 16 patients as negative, 28 for moderate DR and 10 for having a vision-threatening disease (severe DR, proliferative DR, diabetic macular oedema). Based on the 7F-mask grading with the eye with the worse grading defining the DR stage 23 patients were negative for DR, 11 showed mild, 19 moderate and 1 severe DR. When UWF full-field was analysed, 20 patients were negative for DR, while the number of mild, moderate and severe DR patients were 12, 21, and 1, respectively.ConclusionsThe autonomous AI-based DR examination demonstrates sufficient accuracy in diagnosing asymptomatic non-proliferative diabetic patients with referable DR even compared to UWF imaging evaluated by human experts offering a suitable method for DR screening.Subject terms: Retinal diseases, Medical imaging     

Ophthalmic image acquired by ophthalmologists and by allied health personnel as part of a telemedicine strategy: a comparative study of image quality

ObjectivesThis study evaluates the quality of ophthalmic images acquired by a nurse technician trained in teleophthalmology as compared with images acquired by an ophthalmologist, in order to provide a better understanding of the workforce necessary to operate remote care programs.MethodsA cross-sectional study was performed on 2044 images obtained from 118 participants of the TeleOftalmo project, in Brazil. Fundus and slit-lamp photography were performed on site by an ophthalmologist and by a nurse technician under the supervision of a remote ophthalmologist. Image quality was then evaluated by masked ophthalmologists. Proportion of suitable images in each group was compared.ResultsThe proportion of concordant classification regarding quality was 94.8%, with a corrected kappa agreement of 0.94. When analyzing each type of photo separately, there was no significant difference in the proportion of suitable images between on-site ophthalmologist and nurse technician with remote ophthalmologist assistance for the following: slit-lamp views of the anterior segment and anterior chamber periphery, and fundus photographs centered on the macula and on the optic disc (P = 0.825, P = 0.997, P = 0.194, and P = 0.449, respectively). For slit-lamp views of the lens, the proportion of suitable images was higher among those obtained by an ophthalmologist (99.6%) than by a technician (93.8%, P < 0.01).ConclusionsOphthalmic photographs acquired by a trained technician consistently achieved >90% adequacy for remote reading. Compared with ophthalmologist-acquired photos, the proportion of images deemed suitable achieved a high overall agreement. These findings provide favorable evidence of the adequacy of teleophthalmological imaging by nurse technicians.Subject terms: Physical examination, Outcomes research     

Assessing diabetic retinopathy using two-field digital photography and the influence of JPEG-compression

Objective: To study the effectiveness of two digital 50° photographic fields per eye, stored compressed or integrally, in the grading of diabetic retinopathy, in comparison to 35-mm colour slides. Subjects and methods: Two-field digital non-stereoscopic retinal photographs and two-field 35-mm retinal photographs were made at the same time from patients visiting a diabetic retinopathy outpatient clinic. The digital images were stored integrally (TIFF-file) and in a compressed way (JPEG-file). Two ophthalmologists assessed the photographs in a masked fashion. The results were compared. The sensitivity and specificity for the detection of vision-threatening diabetic retinopathy were calculated, using only the grading of the most affected eye. The differences between the retinopathy gradings of the two kinds of photographs were analysed. Results: The agreement for the grading of DR compared to slides was good, both for the compressed and for the integrally stored images (kappa 0.63–0.68). The sensitivity for the detection of vision-threatening diabetic retinopathy using the JPEG-stored images was 0.72–0.74, specificity 0.93–0.98. The sensitivity for vision-threatening retinopathy detection using the integrally stored images was 0.86–0.92, specificity 0.93. Conclusions: Two-field digital retinal photography is effective in diabetic retinopathy grading and it can replace 35-mm retinal photography. Vision-threatening retinopathy can be detected on the images with reasonable to good sensitivity and specificity. An experienced grader should assess the images. The compression of the digital images seems to have some adverse effect on the detection of diabetic retinopathy.     

Smartphone fundoscopy for retinopathy of prematurity

PurposeThe utility of digital fundus images in retinopathy of prematurity (ROP) screening has been established. A smartphone can be a device available to most ophthalmologists to capture digital fundus photographs. In this study, fundus images were captured with original camera settings for ROP documentation.MethodsThe examination was performed under topical anesthesia. An assistant held a glass stick against the eye movement if infants moved their eyes too frequently. A hand-held smartphone and a 30D lens were used to record the fundus in video mode. A continuous flash was turned on to provide almost constant coaxial illumination. Fundus photographs were captured from the video film.ResultsFundus photographs can be captured successfully with a smartphone and a 30D lens under original camera settings.ConclusionFundus photographs of acceptable diagnostic quality can be obtained in ROP patients conveniently and inexpensively using a portable hand-held smartphone. It might be a useful tool in documentation, education, consultation, and telemedicine in ROP.     

Review of retinal cameras for global coverage of diabetic retinopathy screening

The global burden of diabetes has resulted in an increase in the prevalence of diabetic retinopathy (DR), a microvascular complication of diabetes. Lifelong repetitive screening for DR is essential for early detection and timely management to prevent visual impairment due to the silent sight-threatening disorder. Colour fundus photography (CFP) is helpful for documentation of the retinopathy as well as for counselling the patient. CFP has established roles in DR screening, detection, progression and monitoring of treatment response. DR screening programmes use validated mydriatic or non-mydriatic fundus cameras for retinal imaging and trained image graders identify referable DR. Smartphone-based fundus cameras and handheld fundus cameras that are cost-effective, portable and easy to handle in remote places are gaining popularity in recent years. The images captured with these low-cost devices can be immediately sent to trained ophthalmologists for grading of DR. Recent increase in numbers of telemedicine programmes based on imaging with digital fundus cameras and remote interpretation has facilitated larger population coverage of DR screening and timely referral of those with sight-threatening DR to ophthalmologists. Good-quality retinal imaging and accurate diagnosis are essential to reduce inappropriate referrals. Advances in digital imaging such as ultra-wide field imaging and multi-modal imaging have opened new avenues for assessing DR. Fundus cameras with integrated artificial intelligence (AI)-based automated algorithms can also provide instant DR diagnosis and reduce the burden of healthcare systems. We review the different types of fundus cameras currently used in DR screening and management around the world.Subject terms: Retinal diseases, Outcomes research, Medical imaging     

Assessment of diabetic retinopathy using two-field 60 degrees fundus photography. A comparison between red-free, black-and-white prints and colour transparencies

PURPOSE: To assess the severity of diabetic retinopathy and maculopathy by comparing two different photographic methods; two-field 60 degrees photography using red-free, black-and-white prints and colour transparencies. METHODS: Two ophthalmologists independently graded the photographs of 74 patients using grading scales for retinopathy and maculopathy designed for 60 degrees photography. A set of nine 60 degrees red-free, black-and-white standard photographs were chosen to represent the severity of principal diabetic retinopathy and maculopathy abnormalities. RESULTS: The inter-observer agreement for five pooled retinopathy severity levels was 88% (kappa 0.83, weighted kappa 0.96) and 81% (kappa 0.73, weighted kappa 0.89) using red-free, black-and-white prints and colour transparencies respectively. The corresponding figures for six pooled maculopathy levels were 96% (kappa 0.84, weighted kappa 0.97) and 93% (kappa 0.67, weighted kappa 0.86). The analyses revealed that red-free, black-and-white prints disclosed a higher severity level of retinopathy in 83% (Grader 1) and 76% (Grader 2) in those eyes for which the grading was discordant. CONCLUSION: High-quality monochrome, red-free, wide-angle fundus photographs may be useful for the detection of early and advanced diabetic retinopathy.     

Effect of digital image compression on screening for diabetic retinopathy

BACKGROUND/AIMS: Digital imaging is widely used for diabetic retinopathy screening. The storage and transmission of digital images can be facilitated by image compression. The authors aimed to assess the effect of image compression on the accuracy of grading diabetic retinopathy. METHODS: Forty nine 35 mm transparencies (17 with no retinopathy, eight with background, five with preproliferative, and 19 with proliferative retinopathy) were digitised and subjected to JPEG compression by 90%, 80%, 70%, and 0%. The 196 images were randomised and graded on a portable computer. Two masked graders assessed the images for grade of retinopathy and image quality (0-10). The sensitivity and specificity of retinopathy grading were calculated with a weighted kappa for grading agreement between levels of compression. RESULTS: The sensitivity of retinopathy grading was reduced by JPEG compression. At 90%, 80%, 70%, and 0% compression the sensitivities were 0.38, 0.50, 0.65, and 0.72, respectively; the specificity results were 1.00, 1.00, 0.83, and 0.84, respectively; and the weighted kappa scores were 0.60, 0.75, 0.77, and 0.84, respectively. The quality scores for 90%, 80%, 70%, 0% compression were 2.9 (SD 1.1, 95% CI; 2.7-3.2), 4.6 (SD 1.1, 95% CI; 3.0-5.6), 5.8 (SD1.5, 95% CI 5.0-6.6), 6.3 (SD1.4, 95% CI; 5.4-7.2) (p<0.01 for each intergroup comparison). CONCLUSION: The results demonstrate significant loss of sensitivity to the features of diabetic retinopathy with JPEG compression; this was compounded by the thin film transistor (TFT) screen. The authors found the quality of uncompressed images on TFT screens too poor to give grading sensitivities which reach current guidelines for diabetic retinopathy screening.     

Light and portable novel device for diabetic retinopathy screening

Background: To validate the use of an economical portable multipurpose ophthalmic imaging device, EyeScan (Ophthalmic Imaging System, Sacramento, CA, USA), for diabetic retinopathy screening. Design: Evaluation of a diagnostic device. Participants: One hundred thirty‐six (272 eyes) were recruited from diabetic retinopathy screening clinic of Royal Perth Hospital, Western Australia, Australia. Methods: All patients underwent three‐field (optic disc, macular and temporal view) mydriatic retinal digital still photography captured by EyeScan and FF450 plus (Carl Zeiss Meditec, North America) and were subsequently examined by a senior consultant ophthalmologist using the slit‐lamp biomicroscopy (reference standard). All retinal images were interpreted by a consultant ophthalmologist and a medical officer. Main Outcome Measures: The sensitivity, specificity and kappa statistics of EyeScan and FF450 plus with reference to the slit‐lamp examination findings by a senior consultant ophthalmologist. Results: For detection of any grade of diabetic retinopathy, EyeScan had a sensitivity and specificity of 93 and 98%, respectively (ophthalmologist), and 92 and 95%, respectively (medical officer). In contrast, FF450 plus images had a sensitivity and specificity of 95 and 99%, respectively (ophthalmologist), and 92 and 96%, respectively (medical officer). The overall kappa statistics for diabetic retinopathy grading for EyeScan and FF450 plus were 0.93 and 0.95 for ophthalmologist and 0.88 and 0.90 for medical officer, respectively. Conclusions: Given that the EyeScan requires minimal training to use and has excellent diagnostic accuracy in screening for diabetic retinopathy, it could be potentially utilized by the primary eye care providers to widely screen for diabetic retinopathy in the community.     

MultiColor imaging to detect different subtypes of retinal microaneurysms in diabetic retinopathy

BackgroundRetinal microaneurysms (MAs) are among the earliest signs of diabetic retinopathy (DR) and are typically detected by fluorescein angiography (FA). Confocal MultiColor is a noninvasive-imaging technique able to analyze different retinal features by capturing three simultaneous reflectance images. The main aim of the present study was to characterize morphological features of MAs by means of MultiColor images and to compare these with spectral domain optical coherence tomography (SD-OCT) and FA findings.MethodsA cross-sectional, observational study setting was chosen. Multimodal imaging included MultiColor, SD-OCT and FA images. We performed a qualitative analysis in order to assess the relationship between MultiColor and its green- and red-reflectance components, SD-OCT (hyperreflective, hyporeflective and mixed reflectivity) and FA findings. MAs detected on our MultiColor images were then categorized in accordance with a previously published histological classification.ResultsIn our study FA images were used to detect 153 MAs in 30 eyes displaying DR. MultiColor was able to distinguish 122 MAs (80%). We identified green (16%), red (19%), and mixed (65%) MAs, corresponding to different reflectivity features detected by SD-OCT. MAs not visualized on MultiColor images corresponded to tiny hyperreflective lesions on SD-OCT. We compared our imaging findings with a histological MA classification reported in the literature. Our findings showed a strict relationship between MA subtypes and SD-OCT, suggesting that the composition of MAs (cells + endothelium + fibrosis) may influence the signal detected in MultiColor images.ConclusionsMultiColor appears to be a useful technique for investigating MA features in patients with DR.Subject terms: Retinal diseases, Anatomy, Biomarkers     

Ophthalmoscopy versus fundus photographs for detecting and grading diabetic retinopathy.

Reported here is the agreement between three examination methods chosen to detect and grade diabetic retinopathy in 124 subjects with type II (noninsulin-dependent) diabetes mellitus. These three examination methods include ophthalmoscopy (indirect and direct) by a retina specialist, seven standard field fundus photographs read by the same retina specialist, and the same photographs read by a trained photographic grader at the Fundus Photograph Reading Center. For the 59 subjects examined with all three methods, these results indicated fair to good (kappas, 0.69-0.84) agreement between the retina specialist's and trained grader's reading of photographs, fair to good (kappas, 0.58-0.79) agreement between the retina specialist's ophthalmoscopic findings and the specialist's reading of photographs, and fair (kappas, 0.49-0.62) agreement between the retina specialist's ophthalmoscopic findings and the trained grader's reading of fundus photographs. Analysis of the disagreements confirmed earlier reports that ophthalmoscopy misses approximately 50% of eyes with microaneurysms only. Other disagreements resulted from the trained grader's overreading photographs of eyes with lesions simulating diabetic retinopathy. Of the 393 total subjects (diabetic and nondiabetic) in this study, such lesions were seen with ophthalmoscopy in six eyes of six subjects (2.4% of diabetic patients and 1.1% of nondiabetic subjects). The authors believe at least one definite retinal microaneurysm should be present in one eye before establishing the diagnosis of diabetic retinopathy in diabetic patients.     

Agreement between clinician and reading center gradings of diabetic retinopathy severity level at baseline in a phase 2 study of intravitreal bevacizumab for diabetic macular edema

PURPOSE: To evaluate agreement in diabetic retinopathy severity classification by retina specialists performing ophthalmoscopy versus reading center (RC) grading of seven-field stereoscopic fundus photographs in a phase 2 clinical trial of intravitreal bevacizumab for center-involved diabetic macular edema. METHODS: Clinicians' grading scale used four levels: microaneurysms only, mild/moderate nonproliferative diabetic retinopathy (NPDR), severe NPDR, and proliferative diabetic retinopathy (PDR) or prior panretinal photocoagulation (PRP) or both. The RC scale used eight levels: microaneurysms only, mild NPDR, moderate NPDR, moderately severe NPDR, severe NPDR, mild PDR, moderate PDR, and high-risk PDR. Percent agreement and kappa statistic were defined by collapsing RC categories to match those used by clinicians. RESULTS: There was agreement in 89/118 eyes (75%) with kappa = 0.55 (95% confidence interval [0.41, 0.68]). In six eyes, disagreements were of potential substantial clinical importance: five eyes with subtle retinal neovascularization and one with a small preretinal hemorrhage identified only in photographs. CONCLUSIONS: Clinician grading of retinopathy severity had moderate agreement with RC grading and might be useful for placing eyes into broad baseline categories.     

Two years’ experience of screening for hydroxychloroquine retinopathy

BackgroundThe Royal College of Ophthalmologists (RCOphth) recently produced new guidelines for the screening of hydroxychloroquine (HCQ) retinopathy. New imaging techniques have suggested an increased prevalence of retinopathy (7.5%) compared with previous studies (0.5%).MethodsWe collected prospective data from all patients referred to Sunderland Eye Infirmary, Sunderland for HCQ screening. Patients were screened according to RCOphth guidelines. In addition to retinal images, the data recorded included visual acuity, visual fields and multifocal electroretinography as appropriate, the patient’s age, diagnosis, weight, renal function and use of tamoxifen.ResultsOf the 678 patients screened, 333 were categorised to be at risk (251 patients had been on HCQ >5 years, 117 had an estimated glomerular function rate <60 ml/min/1.73 m², and 46 were on a dose >5 mg/kg/day). Eighty patients had multiple risk factors, 31 had been on doses of >5 mg/kg/day for >5 years. One hundred and sixty-eight of these patients have now been screened twice. The prevalence of HCQ retinopathy was 2/678 (0.3%) of all screened, 2/333 (0.6%) of patients at risk.ConclusionsOur results show a far lower rate of retinopathy compared to the widely reported figure taken as standard by the RCOphth. This may be multifactorial: this prospective analysis has fewer patients taking higher doses of HCQ and shorter follow up, the comparison of serial images may highlight more cases and in addition, there are significant numbers of patients yet to be referred. Finally, the RCOphth’s diagnostic criteria is more exacting than that of the recent literature.Subject terms: Retinal diseases, Epidemiology     

Clinical validation of an artificial intelligence-based diabetic retinopathy screening tool for a national health system

ObjectiveTo evaluate the accuracy and validity of an automated diabetic retinopathy (DR) screening tool (DART, TeleDx, Santiago, Chile) that uses artificial intelligence to analyze ocular fundus photographs for potential implementation in the national Chilean DR screening programme.MethodThis was an observational study of 1123 diabetic eye exams using a validation protocol designed by the commission of the Chilean Ministry of Health personnel and retina specialists.ResultsReceiver operating characteristic (ROC) analysis indicated a sensitivity of 94.6% (95% CI: 90.9–96.9%), specificity of 74.3% (95% CI: 73.3–75%), and negative predictive value of 98.1% (95% CI: 96.8–98.9%) for the automated tool at the optimal operating point for DR screening. The area under the ROC curve was 0.915.ConclusionsThe results of this study suggest that DART is a valid tool that could be implemented in a heterogeneous health network such as the Chilean system.Subject terms: Public health, Retinal diseases     

Clinical biomicroscopy versus fluorescein angiography: effectiveness and sensitivity in detecting diabetic retinopathy

PURPOSE: To compare diagnostic effectiveness and sensitivity of the two methods of screening for diabetic retinopathy. METHODS: Prospective analytic study comparing diabetic retinopathy grading obtained from clinical slit lamp biomicroscopy and fundus fluorescein angiography (FFA). A total of 189 consecutive patients were examined in the ophthalmology department at Jordan University Hospital. RESULTS: A total of 376 eyes were reviewed by consultant ophthalmologist for diabetic retinopathy grading on FFA. The sensitivity of ophthalmoscopy in diagnosing diabetic retinopathy grading was 91.2%, with a specificity of 97.9%. The degree of agreement kappa was 0.87. CONCLUSIONS: Slit-lamp biomicroscopy is highly sensitive for screening diabetic retinopathy grading in diabetic patients and ophthalmologists do not need to confirm a suspected clinical diagnosis of proliferative diabetic retinopathy using FFA as ophthalmoscopy proved to be comparable to angiography.     

The efficacy of automated "disease/no disease" grading for diabetic retinopathy in a systematic screening programme

AIM: To assess the efficacy of automated "disease/no disease" grading for diabetic retinopathy within a systematic screening programme. METHODS: Anonymised images were obtained from consecutive patients attending a regional primary care based diabetic retinopathy screening programme. A training set of 1067 images was used to develop automated grading algorithms. The final software was tested using a separate set of 14 406 images from 6722 patients. The sensitivity and specificity of manual and automated systems operating as "disease/no disease" graders (detecting poor quality images and any diabetic retinopathy) were determined relative to a clinical reference standard. RESULTS: The reference standard classified 8.2% of the patients as having ungradeable images (technical failures) and 62.5% as having no retinopathy. Detection of technical failures or any retinopathy was achieved by manual grading with 86.5% sensitivity (95% confidence interval 85.1 to 87.8) and 95.3% specificity (94.6 to 95.9) and by automated grading with 90.5% sensitivity (89.3 to 91.6) and 67.4% specificity (66.0 to 68.8). Manual and automated grading detected 99.1% and 97.9%, respectively, of patients with referable or observable retinopathy/maculopathy. Manual and automated grading detected 95.7% and 99.8%, respectively, of technical failures. CONCLUSION: Automated "disease/no disease" grading of diabetic retinopathy could safely reduce the burden of grading in diabetic retinopathy screening programmes.     

Characterisation of progression of macular oedema in the initial stages of diabetic retinopathy: a 3-year longitudinal study

Background/objectivesTo characterise the prevalence and three-year progression of centre-involving diabetic macular oedema (CI-DMO) in minimal to moderate non-proliferative diabetic retinopathy, using optical coherence tomography (OCT) and measurements of retinal fluid using tissue optical reflectivity ratios (OCT-Leakage).Methods/methodsSeventy-four eyes from 74 patients were followed in a 3-year prospective longitudinal observational cohort of type 2 diabetes (T2D) patients using spectral-domain optical coherence tomography (SD-OCT), OCT-Angiography (OCT-A) and OCT-Leakage (OCT-L). Eyes were examined four times with 1-year intervals. Sixteen eyes (17.8%) were excluded from the analysis due to quality control standards. Retinal oedema was measured by central retinal thickness and retinal fluid by using optical reflectivity ratios obtained with the OCT-L algorithm. Vessel density was measured by OCT-A. Thinning of the ganglion cell and inner plexiform layers (GCL + IPL) was examined to identify retinal neurodegenerative changes. Diabetic retinopathy ETDRS classification was performed using the seven-field ETDRS protocol.ResultsCI-DMO was identified in the first visit in 9% of eyes in ETDRS groups 10–20, 10% of eyes in ETDRS group 35 and 15% of eyes in ETDRS groups 43–47. The eyes with CI-DMO and subclinical CI-DMO showed a progressive increase in retinal extracellular fluid during the 3-year period of follow-up. The eyes with CI-DMO and increased retinal extracellular fluid accumulation were associated with vision loss.ConclusionsThe prevalence of subclinical CI-DMO and CI-DMO in the initial stages of NPDR occurs independently of severity grading of the retinopathy, showing progressive increase in retinal extracellular fluid and this increase is associated with vision loss (82% 9 out of 11 cases).Subject terms: Prognostic markers, Predictive markers     

Various models for diabetic retinopathy screening that can be applied to India

The increased burden of diabetes in India has resulted in an increase in the complications of diabetes including sight-threatening diabetic retinopathy (DR). Visual impairment and blindness due to DR can be prevented by early detection and management of sight-threatening DR. Life-long evaluation by repetitive retinal screening of people with diabetes is an essential strategy as DR has an asymptomatic presentation. Fundus examination by trained ophthalmologists and fundus photography are established modes of screening. Various modes of opportunistic screening have been followed in India. Hospital-based screening (diabetes care/eye care) and community-based screening are the common modes. Tele-ophthalmology programs based on retinal imaging, remote interpretation, and grading of DR by trained graders/ophthalmologists have facilitated greater coverage of DR screening and enabled timely referral of those with sight-threatening DR. DR screening programs use nonmydriatic or mydriatic fundus cameras for retinal photography. Hand-held/smartphone-based fundus cameras that are portable, less expensive, and easy to use in remote places are gaining popularity. Good retinal image quality and accurate diagnosis play an important role in reducing unnecessary referrals. Recent advances like nonmydriatic ultrawide field fundus photography can be used for DR screening, though likely to be more expensive. The advent of artificial intelligence and deep learning has raised the possibility of automated detection of DR. Efforts to increase the awareness regarding DR is essential to ensure compliance to regular follow-up. Cost-effective sustainable models will ensure systematic nation-wide DR screening in the country.