Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): five years of screening with telemedicine

Vision on wheels: Technician-assisted retinopathy of prematurity screening in rural Tamil Nadu and Andhra Pradesh: 2018-2021 Project Report

AIM

To analyze the incidence of sight-threatening retinopathy of prematurity (ROP) in premature infants in rural Tamil Nadu and Andhra Pradesh from 2018 to 2021, and to analyze its association with birthweight (BW), gestational age (GA), and postconceptional age (PCA).

METHODS

Project Vision on Wheels is a free ROP screening and treatment program initiated by a tertiary eye care center in South India in June 2018 to screen preterm infants in rural areas in 11 centers in Tamil Nadu and Andhra Pradesh by trained technicians. Infants with sight-threatening ROP were immediately shifted for vision-preserving laser.

RESULTS

Of the 18,117 infants screened from 2018 to 2021, 1046 infants underwent laser, with the majority being bigger and more mature when compared to Western data. There was a yearly increase in the number of infants with sight-threatening ROP in the lower BW, GA, and PCA categories. The timely detection of the condition by committed screening led to salvage of vision by timely laser in 100% of the treated babies in all the years. The incidence of sight-threatening ROP had a yearly decrease in higher BW, GA, and PCA categories. These trends were statistically significant ( P = 0.001 for ROP and BW, P = 0.037 for ROP and GA, and P = 0.001 for ROP and PCA).

CONCLUSION

The statistically significant trend of decreasing sight-threatening ROP in babies with higher BW, GA, and PCA and increasing treatable ROP in younger and smaller babies (with lower BWs, GAs, and PCAs) in rural India, over time, is a hitherto unreported finding. This is the first such study in rural Tamil Nadu and Andhra Pradesh combined, with the largest data to date (as per MEDLINE search) to document this healthier trend.

Evaluation of a telemedicine-enabled universal eye health delivery model in rural southern India

OBJECTIVES

To evaluate the accuracy of tele-ophthalmic examination (TOE) for common ocular conditions in comparison with the gold-standard in-person examination (IPE) for diagnosis and treatment advice.

METHODS

In a prospective, diagnostic accuracy validation study, we recruited 339 consecutive new patients, aged ≥16 years, visiting a vision centre (VC) associated with Aravind Eye Hospital in south India during January and February, 2020. All participants underwent the TOE, followed by IPE on the same visit. The in-person ophthalmologist was masked to the TOE diagnosis and treatment advice. Data were analysed via the sensitivity specificity of TOE versus the gold-standard IPE.

RESULTS

TOE achieved high sensitivity and specificity for identifying normal eyes with 87.4% and 93.5%, respectively. TOE had high sensitivity for cataracts (91.7%), infective conjunctivitis (72.2%), and moderate sensitivity for pterygium (62.5%), DR (57.1%), non-serious injury (41.7%), but low sensitivity for glaucoma (12.5%). TOE had high specificity ranging from 93.5% to 99.8% for all diagnoses. The sensitivity for treatment advice ranged from 58.1% to 77.2% and specificity from 96.9% to 100%.

CONCLUSIONS

The TOE in VCs has acceptable accuracy to an IPE by an ophthalmologist for correctly identifying and treating major eye ailments. Through providing universal eye care to rural populations, this model may contribute to work toward achieving Universal Health Coverage, which is a linchpin of the health-related U.N. Sustainable Development Goals (SDG).

Multinational External Validation of Autonomous Retinopathy of Prematurity Screening

Importance

Retinopathy of prematurity (ROP) is a leading cause of blindness in children, with significant disparities in outcomes between high-income and low-income countries, due in part to insufficient access to ROP screening.

Objective

To evaluate how well autonomous artificial intelligence (AI)-based ROP screening can detect more-than-mild ROP (mtmROP) and type 1 ROP.

Design, Setting, and Participants

This diagnostic study evaluated the performance of an AI algorithm, trained and calibrated using 2530 examinations from 843 infants in the Imaging and Informatics in Retinopathy of Prematurity (i-ROP) study, on 2 external datasets (6245 examinations from 1545 infants in the Stanford University Network for Diagnosis of ROP [SUNDROP] and 5635 examinations from 2699 infants in the Aravind Eye Care Systems [AECS] telemedicine programs). Data were taken from 11 and 48 neonatal care units in the US and India, respectively. Data were collected from January 2012 to July 2021, and data were analyzed from July to December 2023.

Exposures

An imaging processing pipeline was created using deep learning to autonomously identify mtmROP and type 1 ROP in eye examinations performed via telemedicine.

Main Outcomes and Measures

The area under the receiver operating characteristics curve (AUROC) as well as sensitivity and specificity for detection of mtmROP and type 1 ROP at the eye examination and patient levels.

Results

The prevalence of mtmROP and type 1 ROP were 5.9% (91 of 1545) and 1.2% (18 of 1545), respectively, in the SUNDROP dataset and 6.2% (168 of 2699) and 2.5% (68 of 2699) in the AECS dataset. Examination-level AUROCs for mtmROP and type 1 ROP were 0.896 and 0.985, respectively, in the SUNDROP dataset and 0.920 and 0.982 in the AECS dataset. At the cross-sectional examination level, mtmROP detection had high sensitivity (SUNDROP: mtmROP, 83.5%; 95% CI, 76.6-87.7; type 1 ROP, 82.2%; 95% CI, 81.2-83.1; AECS: mtmROP, 80.8%; 95% CI, 76.2-84.9; type 1 ROP, 87.8%; 95% CI, 86.8-88.7). At the patient level, all infants who developed type 1 ROP screened positive (SUNDROP: 100%; 95% CI, 81.4-100; AECS: 100%; 95% CI, 94.7-100) prior to diagnosis.

Conclusions and Relevance

Where and when ROP telemedicine programs can be implemented, autonomous ROP screening may be an effective force multiplier for secondary prevention of ROP.

Automated diagnosis of plus disease in retinopathy of prematurity using quantification of vessels characteristics

The condition known as Plus disease is distinguished by atypical alterations in the retinal vasculature of neonates born prematurely. It has been demonstrated that the diagnosis of Plus disease is subjective and qualitative in nature. The utilization of quantitative methods and computer-based image analysis to enhance the objectivity of Plus disease diagnosis has been extensively established in the literature. This study presents the development of a computer-based image analysis method aimed at automatically distinguishing Plus images from non-Plus images. The proposed methodology conducts a quantitative analysis of the vascular characteristics linked to Plus disease, thereby aiding physicians in making informed judgments. A collection of 76 posterior retinal images from a diverse group of infants who underwent screening for Retinopathy of Prematurity (ROP) was obtained. A reference standard diagnosis was established as the majority of the labeling performed by three experts in ROP during two separate sessions. The process of segmenting retinal vessels was carried out using a semi-automatic methodology. Computer algorithms were developed to compute the tortuosity, dilation, and density of vessels in various retinal regions as potential discriminative characteristics. A classifier was provided with a set of selected features in order to distinguish between Plus images and non-Plus images. This study included 76 infants (49 [64.5%] boys) with mean birth weight of 1305 ± 427 g and mean gestational age of 29.3 ± 3 weeks. The average level of agreement among experts for the diagnosis of plus disease was found to be 79% with a standard deviation of 5.3%. In terms of intra-expert agreement, the average was 85% with a standard deviation of 3%. Furthermore, the average tortuosity of the five most tortuous vessels was significantly higher in Plus images compared to non-Plus images (p ≤ 0.0001). The curvature values based on points were found to be significantly higher in Plus images compared to non-Plus images (p ≤ 0.0001). The maximum diameter of vessels within a region extending 5-disc diameters away from the border of the optic disc (referred to as 5DD) exhibited a statistically significant increase in Plus images compared to non-Plus images (p ≤ 0.0001). The density of vessels in Plus images was found to be significantly higher compared to non-Plus images (p ≤ 0.0001). The classifier's accuracy in distinguishing between Plus and non-Plus images, as determined through tenfold cross-validation, was found to be 0.86 ± 0.01. This accuracy was observed to be higher than the diagnostic accuracy of one out of three experts when compared to the reference standard. The implemented algorithm in the current study demonstrated a commendable level of accuracy in detecting Plus disease in cases of retinopathy of prematurity, exhibiting comparable performance to that of expert diagnoses. By engaging in an objective analysis of the characteristics of vessels, there exists the possibility of conducting a quantitative assessment of the disease progression's features. The utilization of this automated system has the potential to enhance physicians' ability to diagnose Plus disease, thereby offering valuable contributions to the management of ROP through the integration of traditional ophthalmoscopy and image-based telemedicine methodologies.

Effective field of view of wide-field fundus photography in the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP)

Five-field 130° wide-angle imaging is the standard of care for retinopathy of prematurity (ROP) screening with an ideal hypothetical composite field-of-view (FOV) of 180°. We hypothesized that in many real-world scenarios the effective composite FOV is considerably less than ideal. This observational retrospective study analyzed the effective FOV of fundus photos of patients screened for ROP as part of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) initiative. Five fundus photos were selected from each eye per image session. Effective FOV was defined as the largest circular area centered on the optic disc that encompassed retina in each of the four cardinal views. Seventy-three subjects were analyzed, 35 without ROP and 34 with ROP. Mean effective FOV was 144.55 ± 6.62° ranging from 130.00 to 153.71°. Effective FOV was not correlated with the presence or absence of ROP, gestational age, birth weight, or postmenstrual age. Mean effective FOV was wider in males compared to females. Standard five-field 130° fundus photos yielded an average effective FOV of 144.54° in the SUNDROP cohort. This implies that an imaging FOV during ROP screening considerably less than the hypothetical ideal of 180° is sufficient for detecting treatment warranted ROP.

Modeling absolute zone size in retinopathy of prematurity in relation to axial length

Treatment outcomes in retinopathy of prematurity (ROP) are closely correlated with the location (i.e. zone) of disease, with more posterior zones having poorer outcomes. The most posterior zone, Zone I, is defined as a circle centered on the optic nerve with radius twice the distance from nerve to fovea, or subtending an angle of 30 degrees. Because the eye enlarges and undergoes refractive changes during the period of ROP screening, the absolute area of Zone I according to these definitions may likewise change. It is possible that these differences may confound accurate assessment of risk in patients with ROP. In this study, we estimated the area of Zone I in relation to different ocular parameters to determine how variability in the size and refractive power of the eye may affect zoning. Using Gaussian optics, a model was constructed to calculate the absolute area of Zone I as a function of corneal power, anterior chamber depth, lens power, lens thickness, and axial length (AL), with Zone I defined as a circle with radius set by a 30-degree visual angle. Our model predicted Zone I area to be most sensitive to changes in AL; for example, an increase of AL from 14.20 to 16.58 mm at postmenstrual age 32 weeks was calculated to expand the area of Zone I by up to 72%. These findings motivate several hypotheses which upon future testing may help optimize treatment decisions for ROP.

Utilizing near infra-red spectroscopy to identify physiologic variations during digital retinal imaging in preterm infants

OBJECTIVE

Evaluate physiologic changes during digital retinal imaging (DRI) using near infra-red spectroscopy (NIRS).

STUDY DESIGN

Prospective observational study of preterm infants undergoing retinopathy of prematurity screening via DRI using wide-field retinal camera. Cardiorespiratory (CR) and NIRS data were collected, trends correlated for changes and coefficient representing "slopes" of outcomes were plotted over time. The p value associated with each slope coefficient was tested to assess for slope differences from time of intervention (time = 0/or no slope).

RESULTS

Thirty-one preterm infants were included in the study. There were no significant changes in pre- and post-slopes for cerebral or mesenteric oxygenation, or CR indices with eye drop administration compared to baseline. DRI resulted in significant increase in post exam slope in cerebral oxygenation, mesenteric oxygenation and respiratory rate.

CONCLUSION

ROP examination using DRI was well tolerated with slight improvements in cerebral and mesenteric perfusion without significant safety concerns.

A brief history of telemedicine and the evolution of teleneonatology

Over a century of innovations in technology and medical care have led to the current day capabilities in telemedicine. In this chapter, we discuss the evolution of telemedicine over the last century and highlight various applications in neonatal care. We hope this chapter demonstrates the exponential adoption of telemedicine, particularly in neonatology, and the breadth and depth of the technology being used.

Digital technology, tele-medicine and artificial intelligence in ophthalmology: A global perspective

The simultaneous maturation of multiple digital and telecommunications technologies in 2020 has created an unprecedented opportunity for ophthalmology to adapt to new models of care using tele-health supported by digital innovations. These digital innovations include artificial intelligence (AI), 5th generation (5G) telecommunication networks and the Internet of Things (IoT), creating an inter-dependent ecosystem offering opportunities to develop new models of eye care addressing the challenges of COVID-19 and beyond. Ophthalmology has thrived in some of these areas partly due to its many image-based investigations. Tele-health and AI provide synchronous solutions to challenges facing ophthalmologists and healthcare providers worldwide. This article reviews how countries across the world have utilised these digital innovations to tackle diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, glaucoma, refractive error correction, cataract and other anterior segment disorders. The review summarises the digital strategies that countries are developing and discusses technologies that may increasingly enter the clinical workflow and processes of ophthalmologists. Furthermore as countries around the world have initiated a series of escalating containment and mitigation measures during the COVID-19 pandemic, the delivery of eye care services globally has been significantly impacted. As ophthalmic services adapt and form a "new normal", the rapid adoption of some of telehealth and digital innovation during the pandemic is also discussed. Finally, challenges for validation and clinical implementation are considered, as well as recommendations on future directions.

Key factors in a rigorous longitudinal image-based assessment of retinopathy of prematurity

To describe a database of longitudinally graded telemedicine retinal images to be used as a comparator for future studies assessing grader recall bias and ability to detect typical progression (e.g. International Classification of Retinopathy of Prematurity (ICROP) stages) as well as incremental changes in retinopathy of prematurity (ROP). Cohort comprised of retinal images from 84 eyes of 42 patients who were sequentially screened for ROP over 6 consecutive weeks in a telemedicine program and then followed to vascular maturation or treatment, and then disease stabilization. De-identified retinal images across the 6 weekly exams (2520 total images) were graded by an ROP expert based on whether ROP had improved, worsened, or stayed the same compared to the prior week’s images, corresponding to an overall clinical “gestalt” score. Subsequently, we examined which parameters might have influenced the examiner’s ability to detect longitudinal change; images were graded by the same ROP expert by image view (central, inferior, nasal, superior, temporal) and by retinal components (vascular tortuosity, vascular dilation, stage, hemorrhage, vessel growth), again determining if each particular retinal component or ROP in each image view had improved, worsened, or stayed the same compared to the prior week’s images. Agreement between gestalt scores and view, component, and component by view scores was assessed using percent agreement, absolute agreement, and Cohen’s weighted kappa statistic to determine if any of the hypothesized image features correlated with the ability to predict ROP disease trajectory in patients. The central view showed substantial agreement with gestalt scores (κ = 0.63), with moderate agreement in the remaining views. Of retinal components, vascular tortuosity showed the most overall agreement with gestalt (κ = 0.42–0.61), with only slight to fair agreement for all other components. This is a well-defined ROP database graded by one expert in a real-world setting in a masked fashion that correlated with the actual (remote in time) exams and known outcomes. This provides a foundation for subsequent study of telemedicine’s ability to longitudinally assess ROP disease trajectory, as well as for potential artificial intelligence approaches to retinal image grading, in order to expand patient access to timely, accurate ROP screening.

Retinopathy of Prematurity: How to Prevent the Third Epidemics in Developing Countries

Retinopathy of prematurity (ROP) is vasoproliferative disease affecting preterm infants and is a leading cause of avoidable childhood blindness worldwide. The world is currently experiencing the third epidemic of ROP, where majority of the cases are from middle-income countries. Over 40% of the world's premature infants were born in India, China, Bangladesh, Pakistan, and Indonesia. Together with other neighboring nations, this region has unique challenges in ROP management. Key aspects of the challenges including heavier and more mature infants developing severe ROP. Current strategies include adoption of national screening guidelines, telemedicine, integrating vision rehabilitation and software innovations in the form of artificial intelligence. This review overviews some of these aspects.

Artificial Intelligence in Retinopathy of Prematurity Diagnosis

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness worldwide. The diagnosis of ROP is subclassified by zone, stage, and plus disease, with each area demonstrating significant intra- and interexpert subjectivity and disagreement. In addition to improved efficiencies for ROP screening, artificial intelligence may lead to automated, quantifiable, and objective diagnosis in ROP. This review focuses on the development of artificial intelligence for automated diagnosis of plus disease in ROP and highlights the clinical and technical challenges of both the development and implementation of artificial intelligence in the real world.

Telemedicine in the Management of Exudative Age-Related Macular Degeneration within an Integrated health care System

PURPOSE

To investigate the outcomes of patients with exudative age-related macular degeneration (AMD) treated with intravitreal antivascular endothelial growth factors (VEGF) using a telemedicine system.

DESIGN

Interventional case series.

METHODS

This study examined all patients with exudative AMD who were receiving intravitreal anti-VEGF injections from September 1, 2015, through August 31, 2017, using electronic consultations at a single academic center and health system. Patients were managed initially by a retinal specialist and then allowed to receive further care with their local ophthalmologist. There were 200 electronic consultations placed during this time period for 83 eyes of 59 patients. Data collected included the retina specialist's recommendations: intravitreal agent, interval between injections, number of injections, and when the patient was to follow-up. All occurrences of recommendations that were not completed were reported.

RESULTS

The mean age of the patients at the time of electronic consultations was 82.3 ± 7.3 years with a mean follow-up time of 2.4 ± 0.81 years. The mean distance from the home of the patient to the retina specialist was 70 ± 44 miles. There were 14 consultations (7.1%) that did not comply with the recommendations of the retina specialist. Most of these were due to other medical comorbidities leading to missed appointments or scheduling errors.

CONCLUSIONS

In an integrated health care setting, 59 patients with exudative AMD were identified who were able to be effectively managed using a telemedicine system. In the appropriate setting, telemedicine may be able to assist in the management of patients with wet AMD.

The role of retinal photography and telemedicine in ROP screening

Until advances in retinal imaging over recent decades, detection of retinopathy of prematurity requiring treatment depended largely on indirect ophthalmoscopy by ophthalmologists with experience in examination of low birth weight, often fragile infants. Recent studies have added to our understanding of the pros and cons of using this technology to provide timely care for the increasing number of infants at risk for ROP blindness worldwide.

Smartphone-based fundus photography for screening of plus-disease retinopathy of prematurity

BACKGROUND

Inadequate screening of treatment-warranted retinopathy of prematurity (ROP) can lead to devastating visual outcomes. Especially in resource-poor communities, the use of an affordable, portable, and easy to use smartphone-based non-contact fundus photography device may prove useful for screening for high-risk ROP. This study evaluates the feasibility of screening for high-risk ROP using a novel smartphone-based fundus photography device, RetinaScope.

METHODS

Retinal images were obtained using RetinaScope on a cohort of prematurely born infants during routine examinations for ROP. Images were reviewed by two masked graders who determined the image quality, the presence or absence of plus disease, and whether there was retinopathy that met predefined criteria for referral. The agreement between image-based assessments was compared to the gold standard indirect ophthalmoscopic assessment.

RESULTS

Fifty-four eyes of 27 infants were included. A wide-field fundus photograph was obtained using RetinaScope. Image quality was acceptable or excellent in 98% and 95% of cases. There was substantial agreement between the gold standard and photographic assessment of presence or absence of plus disease (Cohen's κ = 0.85). Intergrader agreement on the presence of any retinopathy in photographs was also high (κ = 0.92).

CONCLUSIONS

RetinaScope can capture digital retinal photographs of prematurely born infants with good image quality for grading of plus disease.

Retinal immaturity at first screening and retinopathy of prematurity: Image-based validation of 1202 eyes of premature infants to predict disease progression

Purpose:

To use the extent of retinal immaturity at the first visit to predict progression to any stage and treatment-requiring retinopathy of prematurity (ROP).

Methods:

Retrospective, multicenter, nonrandomized, observational, clinical, validation study. In all, 601 Asian Indian preterm infants born < 2000 g and/or < 34 weeks of gestation completing ROP screening with RetCam images taken during each visit were included. A total of 1202 eyes of these infants were classified into three groups based on the retinal immaturity at the first screening visit into “mild” (Group 1), vessels reaching the posterior boundary of zone 3; “moderate” (Group 2), vessels entering zone 2 anterior; and “severe” (Group 3), vessels in zone 1 or zone 2 posterior. RetCam images at each subsequent visit were evaluated and the proportion of eyes that progressed to Type 1 or Type 2 ROP was correlated with the degree of retinal immaturity.

Results:

Of the 958 eyes in Group 1, 200 eyes in Group 2, and 44 eyes in Group 3, any stage ROP developed in 15% of eyes in Group 1, 46.5% of eyes in Group 2, and 100% of eyes in Group 3 (P < 0.001). Sixteen of 128 eyes (12.5%), 12 of 72 (16.6%), and 28 of 44 of eyes (63.6%) in Groups 1, 2, and 3, respectively, required treatment (P < 0.001).

Conclusion:

Retinal immaturity at first screening visit predicts Type 1 and Type 2 ROP. “Severe” immaturity is more likely to progress to “treatment-requiring” disease. This could be a useful tool for prognostication, counseling, and scheduling follow-up.

A Novel, Low-Cost, Wide-Field, Infant Retinal Camera, "Neo": Technical and Safety Report for the Use on Premature Infants

Purpose

To report the technical aspects, systemic, and ocular safety of a novel, low-cost, wide-field, infant retinal camera for use on premature infants.

Methods

The device, the “3nethra Neo” (Neo) is a 120° portable, contact, wide-field, unibody camera, with a CMOS sensor (2040 × 2040 resolution) and a warm light-emitting diode (LED) illumination source. The Neo was used to image 140 awake, preterm infants between postmenstrual age (PMA) of 28 to 37 weeks, undergoing retinopathy of prematurity (ROP) screening. Baseline, ‘during procedure', at 5 minutes, and for 60 minutes postprocedure, readings of oxygen saturation and heart rate were recorded. The device design, optics, illumination, and software specifications were compared with the RetCam 3.

Results

Study defined bradycardia (9 infants, 6.4%), tachycardia (3 infants, 2.1%), and hypoxia (2 infants, 1.4%) were observed but there were no clinically significant systemic changes that required intervention during or following any of the study time intervals. There was a transient increase in heart rate by 9.68 (7.53–11.83; P < 0.0001) and marginal decrease in oxygen saturation (−1.94 [−1.60 to −2.28], P < 0.0001), which started to return to baseline 5 minutes after the procedure. Transient redness was seen in two eyes (0.7%) of two infants. No other ocular adverse effects were observed.

Conclusions

The Neo is easy to use in preterm infants and being compact was readily portable. There were no significant ocular or systemic adverse effects, potentially allowing it to be a viable low-cost device for ROP screening in low resource settings.

Translational Relevance

The camera provides a safe and affordable alternative to image the retina of infants by using novel illumination and lens mechanics and has the potential of worldwide acceptance.

A national telemedicine network for retinopathy of prematurity screening

PURPOSE

To report the results of retinopathy of prematurity (ROP) screening by a telemedicine system in Chile and evaluate its usefulness for referring patients who require treatment.

METHODS

Premature infants at risk of developing ROP from 11 neonatal intensive care units were included. Screening was performed on all infants born at a gestational age of <32 weeks and/or birth weight of <1500 g. A trained nonphysician operator used an imaging system to capture retinal images, which were reviewed by two independent ROP experts. All infants that required treatment were referred for further evaluation.

RESULTS

The study included 2,048 eyes of 1,024 premature infants. Mean gestational age was 28.8 ± 2.2 weeks, and mean birth weight was 1128 ± 279 g. A total of 5,263 telemedicine examinations were performed and reported. The average number of image sets per patient was 2.6 ± 2.5. Of the 5,263 images, 4,903 (93%) were recorded to at least the end of zone II; 5,172 (98%) were graded as having good quality, allowing for staging of ROP disease. Forty-two infants (4%) were referred for treatment. Discharged patients with ROP type 2 that regressed did not present with any complications or adverse effects during 6 months' follow-up.

CONCLUSIONS

Our study demonstrates the utility of telemedicine screening for ROP with ophthalmologist readers in a developing country. Telemedicine screening was able to detect treatment-requiring ROP. Most of the images had good quality and showed the end of zone II, two variables sufficient to discharge patients.

Single grading vs double grading with adjudication in the telemedicine approaches to evaluating acute-phase retinopathy of prematurity (e-ROP) study

PURPOSE

To evaluate the sensitivity and specificity of single, independent, nonphysician trained reader (TR) gradings in the Telemedicine Approaches to Evaluating Acute-phase Retinopathy of Prematurity (e-ROP) study.

METHODS

Secondary analyses of image grading results from 1,235 infants of birth weights <1251 g. Two of three TRs independently graded image sets; discrepancies were adjudicated by the reading center director (an ophthalmologist) to reach final grading. Sensitivity and specificity of each TR grading and final grading was calculated by comparing gradings to clinical examination results.

RESULTS

Of 7,808 double graded image sets, TR1 graded 5,165; TR2, 3,787; and TR3, 6,664. Compared to final grading for referral warranted retinopathy of prematurity (RW-ROP), two TRs had relatively lower sensitivity (TR1, 75% vs 79% [P = 0.03]; TR2, 73% vs 77% [P = 0.02]) and specificity (TR1, 80% vs 83% [P < 0.001]; TR2, 82% vs 83% [P = 0.09]). TR3 had similar sensitivity (83% vs 83% [P = 0.78]) and specificity (83% vs 84% [P = 0.02]). Compared to final grading, TR1 had lower sensitivity for zone I ROP (47% vs 56% [P = 0.04]) and stage ≥3 ROP (71% vs 77% [P = 0.002]); TR2 had lower sensitivity for stage ≥3 ROP (69% vs 77% [P < 0.001]) and lower specificity for all three components (P < 0.001); TR3 had lower sensitivity for detecting plus disease (23% vs 35% [P < 0.001]) and similar sensitivity for zone I ROP and stage ≥3 ROP.

CONCLUSIONS

There is a small but significant decrease in the sensitivity and specificity for RW-ROP when single-reader grading is compared to double adjudicated grading.

Non-Mydriatic Ultra-Widefield Imaging Compared With Single-Field Imaging in the Evaluation of Peripheral Retinal Pathology

BACKGROUND AND OBJECTIVE

To report clinical feasibility of non-mydriatic ultra-widefield (NMUWF) imaging and determine the prevalence of peripheral retinal pathology in comparison to standard single-field imaging in a primary care setting.

PATIENTS AND METHODS

Six hundred and thirty-two subjects (1,260 eyes) who underwent NMUWF imaging during annual health screening from October 2015 through March 2016 were retrospectively identified. An automated algorithm processed the raw images into: (1) NMUWF image with mask/grid outline that delineates the center 45° field simulating standard single-field photograph and (2) single-field image comprising 45° posterior pole extracted from the corresponding NMUWF image.

RESULTS

Mean age of patients was 59.6 years ± 7.5 years. Of the 1,260 eyes, 1,238 eyes (98.3%) were considered optimum for grading. NMUWF images detected peripheral retinal pathology in 228 eyes (18.4%) that were not visible on corresponding single-field images.

CONCLUSIONS

NMUWF imaging is feasible in a primary care setting, allows improved visualization of peripheral retinal pathology, and may therefore be useful for telemedicine screening. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:962-968.].

Telemedicine for ROP

With the increasing survival of preterm babies in the Asia-Pacific region, there has been an increase in the incidence of retinopathy of prematurity (ROP). There is also a lack of trained ophthalmologists to screen for this disease. New strategies for screening of ROP are required, wherein the load on the ophthalmologist can be reduced. Telemedicine is an excellent tool to address this need. This paper reviews the initial studies comparing digital imaging with indirect ophthalmoscopy, the current active ROP telescreening programs in the world, and ends with studies dealing with automated diagnosis of ROP.

Telemedical Diagnosis of Stage 4 and Stage 5 Retinopathy of Prematurity

PURPOSE

To determine the accuracy of image-based diagnosis for stage 4 or worse retinopathy of prematurity (ROP) disease.

DESIGN

Prospective cohort study.

PARTICIPANTS

We prospectively obtained data, from 8 major ROP centers, for 1220 eye examinations from 230 infants.

METHODS

An ophthalmologist at each center provided a clinical diagnosis using indirect ophthalmoscopy. Wide-angle retinal images (RetCam; Clarity Medical Systems, Pleasanton, CA) were then obtained, and these were independently read by 2 ROP experts using a web-based system for an image-based diagnosis.

MAIN OUTCOME MEASURES

Sensitivity and specificity of image-based diagnosis from the ROP experts were calculated using the clinical diagnosis as the reference standard.

RESULTS

Of 1220 examinations, 28 (2%) had a clinical diagnosis of stage 4 or worse. Sensitivity and specificity for stage 4 or worse disease were 75% and 99% for expert 1, and 86% and 99% for expert 2. Sensitivity and specificity for the detection of stage 5 disease were 69% and 99% for both experts.

CONCLUSIONS

There are inconsistencies in the accuracy of image-based diagnosis of stage 4 and stage 5 ROP when compared with the clinical diagnosis.

Advances in understanding and management of retinopathy of prematurity

The understanding, diagnosis, and treatment of retinopathy of prematurity have changed in the 70 years since the original description of retrolental fibroplasia associated with high oxygenation. It is now recognized that retinopathy of prematurity differs in appearance worldwide and as ever smaller and younger premature infants survive. New methods are being evaluated to image the retina, diagnose severe retinopathy of prematurity, and determine windows of time for treatment to save eyes and improve visual and neural outcomes. New treatments to promote physiologic retinal vascular development, vascular repair, and inhibit vasoproliferation by regulating proteins involved in vascular endothelial growth factor, insulin-like growth factor, or erythropoietin signaling. Reducing excessive oxidative/nitrosative stress and understanding progenitor cells and neurovascular and glial vascular interactions are being studied.

Assessment of a Tele-education System to Enhance Retinopathy of Prematurity Training by International Ophthalmologists-in-Training in Mexico

PURPOSE

To evaluate a tele-education system developed to improve diagnostic competency in retinopathy of prematurity (ROP) by ophthalmologists-in-training in Mexico.

DESIGN

Prospective, randomized cohort study.

PARTICIPANTS

Fifty-eight ophthalmology residents and fellows from a training program in Mexico consented to participate. Twenty-nine of 58 trainees (50%) were randomized to the educational intervention (pretest, ROP tutorial, ROP educational chapters, and posttest), and 29 of 58 trainees (50%) were randomized to a control group (pretest and posttest only).

METHODS

A secure web-based educational system was created using clinical cases (20 pretest, 20 posttest, and 25 training chapter-based) developed from a repository of over 2500 unique image sets of ROP. For each image set used, a reference standard ROP diagnosis was established by combining the clinical diagnosis by indirect ophthalmoscope examination and image-based diagnosis by multiple experts. Trainees were presented with image-based clinical cases of ROP during a pretest, posttest, and training chapters.

MAIN OUTCOME MEASURES

The accuracy of ROP diagnosis (e.g., plus disease, zone, stage, category) was determined using sensitivity and specificity calculations from the pretest and posttest results of the educational intervention group versus control group. The unweighted kappa statistic was used to analyze the intragrader agreement for ROP diagnosis by the ophthalmologists-in-training during the pretest and posttest for both groups.

RESULTS

Trainees completing the tele-education system had statistically significant improvements (P < 0.01) in the accuracy of ROP diagnosis for plus disease, zone, stage, category, and aggressive posterior ROP (AP-ROP). Compared with the control group, trainees who completed the ROP tele-education system performed better on the posttest for accurately diagnosing plus disease (67% vs. 48%; P = 0.04) and the presence of ROP (96% vs. 91%; P < 0.01). The specificity for diagnosing AP-ROP (94% vs. 78%; P < 0.01), type 2 ROP or worse (92% vs. 84%; P = 0.04), and ROP requiring treatment (89% vs. 79%; P < 0.01) was better for the trainees completing the tele-education system compared with the control group. Intragrader agreement improved for identification of plus disease, zone, stage, and category of ROP after completion of the educational intervention.

CONCLUSIONS

A tele-education system for ROP education was effective in improving the diagnostic accuracy of ROP by ophthalmologists-in-training in Mexico. This system has the potential to increase competency in ROP diagnosis and management for ophthalmologists-in-training from middle-income nations.

Comparison of strategies for grading retinal images of premature infants for referral warranted retinopathy of prematurity

PURPOSE

To determine the accuracy of identifying referral-warranted retinopathy of prematurity (RW-ROP, defined as any zone I ROP, stage 3 or worse, or plus disease) from retinal image sets using three grading protocols: a single optic disk-centered image, a set of 3 horizontal images, and a 5-image set.

METHODS

In this secondary analysis of images from the e-ROP study, a weighted sample of 250 image sets from 250 infants (125 with RW-ROP and 125 without RW-ROP) was randomly selected. The sensitivities and specificities for detecting RW-ROP and its components from a single disk center image, along with nasal and temporal retinal images, were calculated and compared with the e-ROP grading of RW-ROP of all 5 retinal images (disk center and nasal, temporal, superior, and inferior retinal images).

RESULTS

RW-ROP was identified with a sensitivity of 11.2% (95% CI, 6.79%-17.9%) using a single disk center image, with a sensitivity of 70.4% (95% CI, 61.9%-77.9%) using 3 horizontal images, and a statistically higher sensitivity of 82.4% (95% CI, 75.0%-89.0%) using all 5 images (P = 0.002). The specificities were 100%, 86.4%, and 90.4%, respectively. For grading using 3 horizontal images, sensitivity was 14.3% for plus disease, 25% for zone I ROP, and 71.2% for stage 3 or worse compared to 40.8%, 50%, and 79.8% for grading using 5-image sets, respectively.

CONCLUSIONS

Both a single, disk-centered, posterior pole image and 3 horizontal images were less effective than a 5-image set in determining the presence of RW-ROP on qualitative grading by trained readers.

Bedside ROP screening and telemedicine interpretation integrated to a neonatal transport system: Economic aspects and return on investment analysis

BACKGROUND AND AIM

Peter Cerny Ambulance Service - Premature Eye Rescue Program (PCA-PERP) uses digital retinal imaging (DRI) with remote interpretation in bedside ROP screening, which has advantages over binocular indirect ophthalmoscopy (BIO) in screening of premature newborns. We aimed to demonstrate that PCA-PERP provides good value for the money and to model the cost ramifications of a similar newly launched system.

METHODS

As DRI was demonstrated to have high diagnostic performance, only the costs of bedside DRI-based screening were compared to those of traditional transport and BIO-based screening (cost-minimization analysis). The total costs of investment and maintenance were analyzed with micro-costing method. A ten-year analysis time-horizon and service provider's perspective were applied.

RESULTS

From the launch of PCA-PERP up to the end of 2014, 3722 bedside examinations were performed in the PCA covered central region of Hungary. From 2009 to 2014, PCA-PERP saved 92,248km and 3633 staff working hours, with an annual nominal cost-savings ranging from 17,435 to 35,140 Euro. The net present value was 127,847 Euro at the end of 2014, with a payback period of 4.1years and an internal rate of return of 20.8%. Our model presented the NPVs of different scenarios with different initial investments, annual number of transports and average transport distances.

CONCLUSIONS

PCA-PERP as bedside screening with remote interpretation, when compared to a transport-based screening with BIO, produced better cost-savings from the perspective of the service provider and provided a return on initial investment within five years after the project initiation.

Evaluation of Visunex Medical's PanoCam(TM) LT and PanoCam(TM) Pro wide-field imaging systems for the screening of ROP in newborn infants

INTRODUCTION

Retinopathy of Prematurity (ROP) is a leading cause of childhood blindness. The incidence of ROP is rising, placing greater demands on the healthcare providers that serve these patients and their families. Telemedicine remote digital fundus imaging (TM-RDFI) plays a pivotal role in ROP management, and has allowed for the expansion of ROP care into previously underserved areas.

AREAS COVERED

A broad literature review through the pubmed index was undertaken with the goal of summarizing the current state of ROP and guidelines for its screening . Furthermore, all currently used telemedicine remote digital fundus imaging devices were analyzed both via the literature and the companies' websites/brochures. Finally, the PanoCam LT™ and PanoCam™ Pro created by Visunex Medical were analyzed via the company website/brochures. Expert commentary: The PanoCam LT™ and PanoCam™ Pro have recently been approved for use within the USA and CE marked for international commercialization in European Union and other countries requiring CE mark. These wide-field imaging systems have the intended use of ophthalmic imaging of all newborn babies and meet the requirements for ROP screening, thereby serving as competition within the ROP screening market previously dominated by one camera imaging system.

A store-and-forward telemedicine for retinopathy of prematurity screen: is it cost-effective in Thailand?

Background

Prompt diagnosis and treatment of retinopathy of prematurity (ROP) is crucial to prevent blindness. Telemedicine for ROP diagnosis can be applied in regions that lack an expert ophthalmologist.

Objectives

To assess the value-for-money of telemedicine in screening for ROP in high-risk infants.

Methods

A cost-utility analysis of screening and diagnosis of ROP using telemedicine was compared with the current process for ROP screening (Thai Clinical Trials Registry Identification No. TCTR20130911001). We used decision analytical models to compare costs and outcomes in terms of quality-adjusted life years (QALY) to the health provider and society. We used one-way sensitivity analysis and probabilistic sensitivity analysis to consider parameter uncertainty.

Results

The total capital cost for telemedicine to the health provider was 951,000 THB per year. With the base case analysis of 400 children screened per year per RetCam, the performance of screening and diagnosis of ROP using telemedicine (100% sensitivity and 97.8% specificity) was higher compared with the current method (88.9% sensitivity and 93.4% specificity). We therefore expect that blindness can be prevented in 3 children per 400 screening cases. The incremental cost to society of telemedicine compared with the current practice was 837 THB. Preventing just one child from becoming blind can save around 146,000 THB throughout their lifetime based on savings to welfare costs for disabled people. The incremental cost-effectiveness ratio of this telemedicine was 259 THB per case of prevented blindness and 17,397 THB per QALY saved.

Conclusions

Store and forward telemedicine for ROP screening is cost-effective.

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.

ULTRA-WIDEFIELD FUNDUS IMAGING: A Review of Clinical Applications and Future Trends

PURPOSE

To review the basic principles of ultra-widefield fundus imaging and discuss its clinical utility for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms Optos, optomap, panoramic, ultra-widefield, wide-angle, and ellipsoid mirror. This yielded 158 publications of which 128 were selected based on content and relevance.

RESULTS

A total of 128 articles pertaining to ultra-widefield imaging were cited in this review.

CONCLUSION

Optos ultra-widefield imaging has become an essential tool for the identification of peripheral retinal and vascular pathology. The high resolution and multimodal capabilities of this device are also providing new insights into a variety of disorders, even those that primarily involve the posterior pole. Although the presence of artifact and the need for clinical validation are significant hurdles to more widespread use, ultra-widefield is evolving to become the standard-of-care imaging modality for many diseases and is finding new clinical and research applications such as for screening and telemedicine.

Plus Disease in Retinopathy of Prematurity: A Continuous Spectrum of Vascular Abnormality as a Basis of Diagnostic Variability

PURPOSE

To identify patterns of interexpert discrepancy in plus disease diagnosis in retinopathy of prematurity (ROP).

DESIGN

We developed 2 datasets of clinical images as part of the Imaging and Informatics in ROP study and determined a consensus reference standard diagnosis (RSD) for each image based on 3 independent image graders and the clinical examination results. We recruited 8 expert ROP clinicians to classify these images and compared the distribution of classifications between experts and the RSD.

PARTICIPANTS

Eight participating experts with more than 10 years of clinical ROP experience and more than 5 peer-reviewed ROP publications who analyzed images obtained during routine ROP screening in neonatal intensive care units.

METHODS

Expert classification of images of plus disease in ROP.

MAIN OUTCOME MEASURES

Interexpert agreement (weighted κ statistic) and agreement and bias on ordinal classification between experts (analysis of variance [ANOVA]) and the RSD (percent agreement).

RESULTS

There was variable interexpert agreement on diagnostic classifications between the 8 experts and the RSD (weighted κ, 0-0.75; mean, 0.30). The RSD agreement ranged from 80% to 94% for the dataset of 100 images and from 29% to 79% for the dataset of 34 images. However, when images were ranked in order of disease severity (by average expert classification), the pattern of expert classification revealed a consistent systematic bias for each expert consistent with unique cut points for the diagnosis of plus disease and preplus disease. The 2-way ANOVA model suggested a highly significant effect of both image and user on the average score (dataset A: P < 0.05 and adjusted R² = 0.82; and dataset B: P < 0.05 and adjusted R² = 0.6615).

CONCLUSIONS

There is wide variability in the classification of plus disease by ROP experts, which occurs because experts have different cut points for the amounts of vascular abnormality required for presence of plus and preplus disease. This has important implications for research, teaching, and patient care for ROP and suggests that a continuous ROP plus disease severity score may reflect more accurately the behavior of expert ROP clinicians and may better standardize classification in the future.

Plus Disease in Retinopathy of Prematurity: Improving Diagnosis by Ranking Disease Severity and Using Quantitative Image Analysis

PURPOSE

To determine expert agreement on relative retinopathy of prematurity (ROP) disease severity and whether computer-based image analysis can model relative disease severity, and to propose consideration of a more continuous severity score for ROP.

DESIGN

We developed 2 databases of clinical images of varying disease severity (100 images and 34 images) as part of the Imaging and Informatics in ROP (i-ROP) cohort study and recruited expert physician, nonexpert physician, and nonphysician graders to classify and perform pairwise comparisons on both databases.

PARTICIPANTS

Six participating expert ROP clinician-scientists, each with a minimum of 10 years of clinical ROP experience and 5 ROP publications, and 5 image graders (3 physicians and 2 nonphysician graders) who analyzed images that were obtained during routine ROP screening in neonatal intensive care units.

METHODS

Images in both databases were ranked by average disease classification (classification ranking), by pairwise comparison using the Elo rating method (comparison ranking), and by correlation with the i-ROP computer-based image analysis system.

MAIN OUTCOME MEASURES

Interexpert agreement (weighted κ statistic) compared with the correlation coefficient (CC) between experts on pairwise comparisons and correlation between expert rankings and computer-based image analysis modeling.

RESULTS

There was variable interexpert agreement on diagnostic classification of disease (plus, preplus, or normal) among the 6 experts (mean weighted κ, 0.27; range, 0.06-0.63), but good correlation between experts on comparison ranking of disease severity (mean CC, 0.84; range, 0.74-0.93) on the set of 34 images. Comparison ranking provided a severity ranking that was in good agreement with ranking obtained by classification ranking (CC, 0.92). Comparison ranking on the larger dataset by both expert and nonexpert graders demonstrated good correlation (mean CC, 0.97; range, 0.95-0.98). The i-ROP system was able to model this continuous severity with good correlation (CC, 0.86).

CONCLUSIONS

Experts diagnose plus disease on a continuum, with poor absolute agreement on classification but good relative agreement on disease severity. These results suggest that the use of pairwise rankings and a continuous severity score, such as that provided by the i-ROP system, may improve agreement on disease severity in the future.

Retinopathy of prematurity: applicability and compliance of guidelines in Hong Kong

OBJECTIVE

To analyse the incidence, application and compliance to Royal College of Ophthalmologists retinopathy of prematurity (ROP) screening recommendations and subsequent treatment of ROP in a neonatal intensive care unit of a large tertiary referral centre in Hong Kong.

DESIGN

A retrospective review was performed for all eligible premature neonates screened for ROP over a 7-year period from June 2008 to December 2015 in our local tertiary neonatal intensive care unit in Prince of Wales Hospital, Hong Kong, using the Royal College of Ophthalmologists ROP screening guideline (2008). Comparison between established UK and American screening guidelines were analysed for their applicability in our locality.

RESULTS

A total of 602 infants were screened, with the incidence of ROP in 28.2% and type 1 ROP in 3.8%, and indirect diode laser performed in all type 1 ROP cases. Overall, adherence for screening criteria was 99.7%, with the average time to commence first screening at 4 weeks postnatal age. Of the 602 cases, 94 (15.6%) were early and 35 (5.8%) were later than the guidelines, of which only 5 (0.8%) of late-screened cases developed ROP requiring treatment. Subsequent treatment of ROP for all the late-screened cases was not delayed.

CONCLUSIONS

Current ROP screening using the UK guidelines (2008) is applicable, effective and safe to our predominantly Asian population in Hong Kong, with a low rate of delayed screening.

Training retinal imagers for retinopathy of prematurity (ROP) screening

PURPOSE

To report the training/certification process of nonphysician imagers, image quality, and factors that affected image quality in the National Eye Institute sponsored multicentered e-ROP study.

METHODS

Nonphysician imagers underwent rigorous training and certification in obtaining retinal images, with attention to clarity, focus, and optic disk placement. Image readers measured pupil size in pupil image and graded posterior pole, temporal, nasal, superior, and inferior retinal images and classified them as good, adequate, poor, or missing. Good and adequate images were deemed acceptable.

RESULTS

In 4,003 image sessions of 1,257 infants, 3,453 (86.8%) were complete. Of 39,550 retinal images, 91.7% had acceptable quality, 5.6% poor, and 2.7% were missing. Inadequate pupil dilation negatively affected acceptable image quality: 54% acceptable images for pupil <5 mm versus 93% for >6 mm (P < 0.0001). When ventilatory equipment obstructed access to imaged infant, the percent of acceptable image quality decreased: 94% for no support versus 66.6% for oscillatory ventilation (P < 0.0001). Acceptable image quality rates improved from 87% to 90% (P = 0.03) from first 6 months to last 6 months at low patient volume centers, while high patient volume centers remained stable at 95%.

CONCLUSIONS

Nonphysicians successfully obtained acceptable quality images for ROP evaluation. Skills improved with experience. Image quality was negatively affected by inadequate pupil dilation and the presence of obstructive ventilatory equipment.

A Comparison of Strategies for Retinopathy of Prematurity Detection

BACKGROUND AND OBJECTIVES

Delayed detection of type 1 retinopathy of prematurity (ROP) can lead to permanent visual impairment. Providing ROP examinations is challenging because of the limited ophthalmology workforce. This study compares digital imaging-based ROP detection strategies versus serial ROP examinations.

METHODS

We conducted an individual-level microsimulation study of a hypothetical cohort of 650 infants with gestational age from 23 to 30 weeks. Infants were evaluated by using strategies based on indirect ophthalmoscopy or digital imaging beginning at 32 weeks' postmenstrual age (PMA) and continuing to discharge, transfer, or 40 weeks' PMA. ROP status and the accuracy of digital imaging were based on the e-ROP (Telemedicine Approaches to Evaluating Acute-Phase ROP) study, which enrolled high-risk infants.

RESULTS

Within the hypothetical NICU, the strategy of ROP examinations identified an average of 45.8 cases of type 1 ROP by discharge, transfer, or 40 weeks' PMA, and another 1.9 cases were included in the group of infants recommended to have later follow-up. Digital imaging with an ROP examination at discharge identified all 47.7 cases of type 1 ROP. On average, the ROP examination-only strategy required 1745.7 ROP examinations, whereas digital imaging with a discharge examination required 1065.5 ROP examinations and 1786.2 digital imaging sessions.

CONCLUSIONS

Although digital imaging decreased the number of ROP examinations per infant, there was an increase in the total number of interventions (ie, ROP examinations and imaging sessions). Providing an ROP examination at the time of NICU discharge can significantly reduce the number of infants who require follow-up.