Retinal abnormalities, although relatively common in sleep clinic patients referred for polysomnography, are largely unrelated to sleep-disordered breathing.

STUDY OBJECTIVES: There has been long-standing interest in potential links between obstructive sleep apnea (OSA) and eye disease. This study used retinal photography to identify undiagnosed retinal abnormalities in a cohort of sleep clinic patients referred for polysomnography (PSG) and then determined associations with PSG-quantified sleep-disordered breathing (SDB) severity. METHODS: Retinal photographs (n = 396 patients) were taken of each eye prior to polysomnography and graded according to validated, standardized, grading scales. SDB was quantified via in-laboratory polysomnography (PSG; n = 385) using standard metrics. A questionnaire (n = 259) documented patient-identified pre-existing eye disease. Within-group prevalence rates were calculated on a per patient basis. Data were analyzed using multivariate logistic regression models to determine independent predictors for retinal abnormalities. P < 0.05 was considered significant. RESULTS: Main findings were (1) 76% of patients reported no pre-existing "eye problems"; (2) however, 93% of patients had at least one undiagnosed retinal photograph-identified abnormality; (3) most common abnormalities were drusen (72%) and peripapillary atrophy (PPA; 47%); (4) age was the most common risk factor; (5) diabetes history was an expected risk factor for retinopathy; (6) patients with very severe levels of SDB (apnea hypopnea index ≥ 50 events/h) were nearly three times more likely to have PPA. CONCLUSION: Retinal photography in sleep clinic settings will likely detect a range of undiagnosed retinal abnormalities, most related to patient demographics and comorbidities and, except for PPA, not associated with SDB. PPA may be indicative of glaucoma, and any association with severe SDB should be confirmed in larger prospective studies.

VAMPIRE® fundus image analysis algorithms: Validation and diagnostic relevance in hypertensive cats.

OBJECTIVES: To validate a retinal imaging software named VAMPIRE® (Vascular Assay and Measurement Platform for Images of the Retina) in feline patients and test the clinical utility in hypertensive cats. ANIMALS STUDIED: One hundred and five healthy cats were enrolled. They represented the normal dataset used in the validation (group 1). Forty-three hypertensive cats with no noticeable retinal abnormalities were enrolled for the clinical validity of the software (group 2). PROCEDURES: Eleven points (4 veins, 4 arteries, and 3 arterial bifurcations) were measured for each digital image. Repeatability and reproducibility of measurements were assessed using two independent operators. Data were statistically analyzed by the Mann-Whiney and Tukey box plot. Significance was considered when P < 0.05. RESULTS: Two hundred and ten retinal images were analyzed for a total of 2310 measurements. Total mean was 9.1 and 6.1 pixels for veins and arteries, respectively. First, second, and third arteriolar bifurcations angles were 73.6°, 76.9°, and 85.4°, respectively. A comparison between groups 1 and 2 showed a statistically significant reduction in arteriolar diameter (mean 3.3 pixels) and branch angle (55°, 47.8° and 59.9°) associated with increasing vein diameter (mean 24.15 pixels). CONCLUSIONS: Current image analysis techniques used in human medicine were investigated in terms of extending their use to veterinary medicine. The VAMPIRE® algorithm proved useful for an objective diagnosis of retinal vasculature changes secondary to systemic hypertension in cats, and could be an additional diagnostic test for feline systemic hypertension.

Clinical uses of autofluorescence in ophthalmology.

Although it has been around for many years, historically autofluorescence has been difficult to capture. Developments in technology and camera sensors have made the process much easier and there is increasing research exploring autofluorescence patterns and how they can be used. This article explores the clinical uses of this technology in monitoring certain retinal conditions.

Fundus Photography in the 21st Century--A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare.

BACKGROUND: The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly. LITERATURE REVIEW: Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera. RESULTS: Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer. CONCLUSIONS: In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

Addressing Technical Failures in a Diabetic Retinopathy Screening Program.

Purpose: Diabetic retinopathy (DR) is a preventable cause of blindness detectable through screening using retinal digital photography. The Irish National Diabetic Retina Screening (DRS) programme, Diabetic RetinaScreen, provides free screening services to patients with diabetes from aged 12 years and older. A technical failure (TF) occurs when digital retinal imaging is ungradable, resulting in delays in the diagnosis and treatment of sight-threatening disease. Despite their impact, the causes of TFs, and indeed the utility of interventions to prevent them, have not been extensively examined. Aim: Primary analysis aimed to identify factors associated with TF. Secondary analysis examined a subset of cases, assessing patient data from five time points between 2019 and 2021 to identify photographer/patient factors associated with TF. Methods: Patient data from the DRS database for one provider were extracted for analysis between 2018 and 2022. Information on patient demographics, screening results, and other factors previously associated with TF were analyzed. Primary analysis involved using mixed-effects logistic regression models with nested patient-eye random effects. Secondary analysis reviewed a subset of cases in detail, checking for causes of TF. Results: The primary analysis included a total of 366,528 appointments from 104,407 patients over 5 years. Most patients had Type 2 diabetes (89.2%), and the overall TF rate was 4.9%. Diabetes type and duration, dilate pupil status, and the presence of lens artefacts on the camera were significantly associated with TF. The Secondary analysis identified the primary cause of TF was found to be optically dense cataracts, accounting for over half of the TFs. Conclusion: This study provides insight into the causes of TF within the Irish DRS program, highlighting cataracts as the primary contributing factor. The identification of patient-level factors associated with TF facilitates appropriate interventions that can be put in place to improve patient outcomes and minimize delays in treatment and diagnosis.

Evaluating the potential of retinal photography in chronic kidney disease detection: a review.

Background: Chronic kidney disease (CKD) is a significant global health concern, emphasizing the necessity of early detection to facilitate prompt clinical intervention. Leveraging the unique ability of the retina to offer insights into systemic vascular health, it emerges as an interesting, non-invasive option for early CKD detection. Integrating this approach with existing invasive methods could provide a comprehensive understanding of patient health, enhancing diagnostic accuracy and treatment effectiveness. Objectives: The purpose of this review is to critically assess the potential of retinal imaging to serve as a diagnostic tool for CKD detection based on retinal vascular changes. The review tracks the evolution from conventional manual evaluations to the latest state-of-the-art in deep learning. Survey Methodology: A comprehensive examination of the literature was carried out, using targeted database searches and a three-step methodology for article evaluation: identification, screening, and inclusion based on Prisma guidelines. Priority was given to unique and new research concerning the detection of CKD with retinal imaging. A total of 70 publications from 457 that were initially discovered satisfied our inclusion criteria and were thus subjected to analysis. Out of the 70 studies included, 35 investigated the correlation between diabetic retinopathy and CKD, 23 centered on the detection of CKD via retinal imaging, and four attempted to automate the detection through the combination of artificial intelligence and retinal imaging. Results: Significant retinal features such as arteriolar narrowing, venular widening, specific retinopathy markers (like microaneurysms, hemorrhages, and exudates), and changes in arteriovenous ratio (AVR) have shown strong correlations with CKD progression. We also found that the combination of deep learning with retinal imaging for CKD detection could provide a very promising pathway. Accordingly, leveraging retinal imaging through this technique is expected to enhance the precision and prognostic capacity of the CKD detection system, offering a non-invasive diagnostic alternative that could transform patient care practices. Conclusion: In summary, retinal imaging holds high potential as a diagnostic tool for CKD because it is non-invasive, facilitates early detection through observable microvascular changes, offers predictive insights into renal health, and, when paired with deep learning algorithms, enhances the accuracy and effectiveness of CKD screening.

Association between retinal microvascular abnormalities and late-life brain amyloid-ß deposition: the ARIC-PET study.

BACKGROUND: Retinal microvascular signs are accessible measures of early alterations in microvascular dysregulation and have been associated with dementia; it is unclear if they are associated with AD (Alzheimer's disease) pathogenesis as a potential mechanistic link. This study aimed to test the association of retinal microvascular abnormalities in mid and late life and late life cerebral amyloid. METHODS: Participants from the ARIC-PET (Atherosclerosis Risk in Communities-Positron Emission Tomography) study with a valid retinal measure (N = 285) were included. The associations of mid- and late-life retinal signs with late-life amyloid-ß (Aß) by florbetapir PET were tested. Two different measures of Aß burden were included: (1) elevated amyloid (SUVR > 1.2) and (2) continuous amyloid SUVR. The retinal measures' association with Aß burden was assessed using logistic and robust linear regression models. A newly created retinal score, incorporating multiple markers of retinal abnormalities, was also evaluated in association with greater Aß burden. RESULTS: Retinopathy in midlife (OR (95% CI) = 0.36 (0.08, 1.40)) was not significantly associated with elevated amyloid burden. In late life, retinopathy was associated with increased continuous amyloid standardized value uptake ratio (SUVR) (ß (95%CI) = 0.16 (0.02, 0.32)) but not elevated amyloid burden (OR (95%CI) = 2.37 (0.66, 9.88)) when accounting for demographic, genetic and clinical risk factors. A high retinal score in late life, indicating a higher burden of retinal abnormalities, was also significantly associated with increased continuous amyloid SUVR (ß (95% CI) = 0.16 (0.04, 0.32)) independent of vascular risk factors. CONCLUSIONS: Retinopathy in late life may be an easily obtainable marker to help evaluate the mechanistic vascular pathway between retinal measures and dementia, perhaps acting via AD pathogenesis. Well-powered future studies with a greater number of retinal features and other microvascular signs are needed to test these findings.

Accuracy of Low-Cost, Smartphone-Based Retinal Photography for Diabetic Retinopathy Screening: A Systematic Review.

Purpose: Diabetic retinopathy (DR) is a leading cause of blindness. Early DR screening is essential, but the infrastructure can be less affordable in low resource countries. This study aims to review the accuracy of low-cost smartphone-based fundus cameras for DR screening in adult patients with diabetes. Methods: We performed a systematic literature search to find studies that reported the sensitivity and specificity of low-cost smartphone-based devices for fundus photography in adult patients with diabetes. We searched three databases (MEDLINE, Google Scholar, Scopus) and one register (Cochrane CENTRAL). We presented the accuracy values by grouping the diagnosis into three: any DR, referrable DR, and diabetic macular oedema (DMO). Risk of bias and applicability of the studies were assessed using QUADAS-2. Results: Five out of 294 retrieved records were included with a total of six smartphone-based devices reviewed. All of the reference diagnostic methods used in the included studies were either indirect ophthalmoscopy or slit-lamp examinations and all smartphone-based devices' imaging protocols used mydriatic drops. The reported sensitivity and specificity for any DR were 52-92.2% and 73.3-99%; for referral DR were 21-91.4% and 64.9-100%; and for DMO were 29.4-81% and 95-100%, respectively. Conclusion: Sensitivity available low-cost smartphone-based devices for DR screening were acceptable and their specificity particularly for detecting referrable DR and DMO were considerably good. These findings support their potential utilization for DR screening in a low resources setting.

Smartphone for retinal imaging - Case series in resource-limited rural settings.

Purpose: There is a clinical need for a cost-effective, reliable, easy-to-use, and portable retinal photography. The use of smartphone fundus photography for documentation of retinal changes in resource-limited settings, where retinal imaging was not previously possible, is studied here. The introduction of smartphone-based retinal imaging has resulted in the increase in available technologies for fundus photography. On account of the cost, fundus cameras are not readily available in ophthalmic practice in developing countries. Because smartphones are readily available, easy to use, and also portable, they present a low-cost alternative method in resource-limited settings. The aim is to explore the use of smartphones (iphones) for retinal imaging in resource-limited settings. Methods: A smartphone (iphone) was used to acquire retinal images with the use of +20 D lens in patients with dilated pupils by activating the video mode of the camera. Results: Clear retinal images were obtained in different clinical conditions in adults and children, including branch retinal vein occlusion with fibro-vascular proliferation, choroidal neo-vascular membranes, presumed ocular toxoplasmosis, diabetic retinopathy, retinoblastoma, ocular albinism, and hypertensive retinopathy. Conclusion: New inexpensive, portable, easy-to-operate cameras have revolutionized retinal imaging and screening programs and play an innovative role in research, education, and information sharing.

A cost-minimisation analysis comparing alternative telemedicine screening approaches for retinopathy of prematurity.

INTRODUCTION: Screening for retinopathy of prematurity (ROP) is an important procedure in the prevention of blindness in high-risk preterm infants. In the regionalised healthcare system of Queensland (Australia), outside of the major centres, some preterm infants are cared for in special care nurseries (SCNs). When necessary, infants in these nurseries who are at risk of ROP are transferred to a tertiary hospital for screening by paediatric ophthalmologists. The transport of preterm infants for eye examinations adds risk and incurs significant costs to the health system. Using a cost-minimisation approach, we aimed to compare the costs of the current ROP screening practice with two alternative telemedicine approaches. METHODS: We constructed a decision analytic model to estimate costs from a health service perspective with a five-year analysis horizon; activity data from a tertiary ROP screening service were used to inform the models. The three models assessed were: (a) a digital retinal photography (DRP)-equipped travelling nurse, (b) equipping SCNs with DRP, and providing training to local nurses, and (c) current practice of infant transfer. In all cases, the tertiary centre provides specialist ophthalmologic review. RESULTS: Of the three models, we estimated the most expensive option to be equipping SCNs with DRP and providing training to local nurses (AUD$4114/infant). We found that the current practice of transferring infants was the second most expensive (AUD$1021/infant). The most economical model was the specialist nurse travelling to each SCN with a portable DRP (AUD$363/infant). A sensitivity analysis, which assessed uncertainty and variability around the cost estimates, found that the ranking for the expected costs of the alternative models of care did not change. DISCUSSION: This is the first economic and cost-minimisation analysis in Australia to compare the costs of the current screening programme with two alternative telemedicine approaches for screening ROP. Telemedicine programmes that facilitate non-physician screening may improve the cost efficiency of the health system while maintaining the health outcomes for children, and reducing the risk associated with infant transport.

Prevalence and risk factors for diabetic retinopathy in prediabetes in Asian Indians.

AIM: To assess the prevalence of diabetic retinopathy (DR) and associated risk factors in Asian Indians with prediabetes. METHODS: In a cross-sectional study conducted at two tertiary care diabetes centres in Chennai, India, clinical and biochemical assessment and nonmydriatic ultra-wide field fundus photography was performed in individuals with prediabetes (impaired fasting glucose [IFG] and/or impaired glucose tolerance [IGT]) based on oral glucose tolerance test (OGTT) and/or glycated hemoglobin (HbA1c) between 5.7% and 6.4% in 2019. The retinal photographs were graded by certified ophthalmologists. Systemic risk factors associated with DR in prediabetes were assessed. RESULTS: The mean age of the 192 individuals with prediabetes was 48 ± 13 years (55.2% were males). DR was present in 12 (6.3%) individuals of which nine (4.7%) had mild non-proliferative DR (NPDR) and three (1.6%) had moderate NPDR. None had severe sight-threatening DR. The Poisson multiple regression analysis showed that after adjusting for other systemic covariates, HbA1c values ≥ 6% (6-6.4%) was associated with 2 times higher relative risk of DR (Risk ratio 1.95 (95% CI 1.07-3.545, p = 0.028) in comparison to HbA1c < 6%). CONCLUSION: DR was present in about 6% of the Asian Indians with prediabetes. Higher HbA1c values among individuals with prediabetes was associated with twice the relative risk for DR. Robust control of HbA1c should be encouraged even before the diagnosis of diabetes is established.

Noninvasive Instrument-based Tests for Detecting and Measuring Vitreous Inflammation in Uveitis: A Systematic Review.

PURPOSE: This systematic review aims to identify instrument-based tests for quantifying vitreous inflammation in uveitis, report the test reliability and the level of correlation with clinician grading. METHODS: Studies describing instrument-based tests for detecting vitreous inflammation were identified by searching bibliographic databases and trials registers. Test reliability measures and level of correlation with clinician vitreous haze grading are extracted. RESULTS: Twelve studies describing ultrasound, optical coherence tomography (OCT), and retinal photography for detecting vitreous inflammation were included: Ultrasound was used for detection of disease features, whereas OCT and retinal photography provided quantifiable measurements. Correlation with clinician grading for OCT was 0.53-0.60 (three studies) and for retinal photography was 0.51 (1 study). Both instruments showed high inter- and intra-observer reliability (>0.70 intraclass correlation and Cohen's kappa), where reported in four studies. CONCLUSION: Retinal photography and OCT are able to detect and measure vitreous inflammation. Both techniques are reliable, automatable, and warrant further evaluation.

Mild Hypertensive Retinopathy and Risk of Cardiovascular Disease: The Suita Study.

AIMS: This study aimed to investigate the association of mild hypertensive retinopathy with cardiovascular disease (CVD) risk. METHODS: A total of 7,027 residents aged 30-79 years without a history of CVD participated in the annual health checkups and retinal photography assessments. Retinal microvascular abnormalities were graded using the standard protocols and classified according to the Keith-Wagener-Barker classification. Mild hypertensive retinopathy was defined as grades 1 and 2. Cox proportional hazard model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for total CVD and its subtypes according to the presence and absence of mild hypertensive retinopathy. RESULTS: During a median follow-up of 17 years, 351 incident stroke and 247 coronary heart disease (CHD) cases were diagnosed. After adjustment for traditional cardiovascular risk factors, mild hypertensive retinopathy was positively associated with risk of CVD (multivariable HR=1.24; 95% CI, 1.04-1.49) and stroke (1.28; 1.01-1.62) but not with risk of CHD (1.19; 0.89-1.58). Generalized arteriolar narrowing and enhanced arteriolar wall reflex were positively associated with CVD risk, the multivariable HR (95% CI) was 1.24 (1.00-1.54) and 1.33 (1.02-1.74), respectively. Moreover, mild hypertensive retinopathy was positively associated with stroke risk in normotensive participants. CONCLUSION: Mild hypertensive retinopathy was positively associated with CVD and stroke risk in the urban Japanese population. Especially, generalized arteriolar narrowing and enhanced arteriolar wall reflex were positively associated with CVD risk. These findings suggested that retinal photography could be helpful for cardiovascular risk stratification in the primary cardiovascular prevention.

An Overview of Deep-Learning-Based Methods for Cardiovascular Risk Assessment with Retinal Images.

Cardiovascular diseases (CVDs) are one of the most prevalent causes of premature death. Early detection is crucial to prevent and address CVDs in a timely manner. Recent advances in oculomics show that retina fundus imaging (RFI) can carry relevant information for the early diagnosis of several systemic diseases. There is a large corpus of RFI systematically acquired for diagnosing eye-related diseases that could be used for CVDs prevention. Nevertheless, public health systems cannot afford to dedicate expert physicians to only deal with this data, posing the need for automated diagnosis tools that can raise alarms for patients at risk. Artificial Intelligence (AI) and, particularly, deep learning models, became a strong alternative to provide computerized pre-diagnosis for patient risk retrieval. This paper provides a novel review of the major achievements of the recent state-of-the-art DL approaches to automated CVDs diagnosis. This overview gathers commonly used datasets, pre-processing techniques, evaluation metrics and deep learning approaches used in 30 different studies. Based on the reviewed articles, this work proposes a classification taxonomy depending on the prediction target and summarizes future research challenges that have to be tackled to progress in this line.

Telemedical Diabetic Retinopathy Screening in a Primary Care Setting: Quality of Retinal Photographs and Accuracy of Automated Image Analysis.

BACKGROUND: Screening for diabetic eye disease (DED) and general diabetes care is often separate, which leads to delays and low adherence to DED screening recommendations. Thus, we assessed the feasibility, achieved image quality, and possible barriers of telemedical DED screening in a point-of-care general practice setting and the accuracy of an automated algorithm for detection of DED. METHODS: Patients with diabetes were recruited at general practices. Retinal images were acquired using a non-mydriatic camera (CenterVue, Italy) by medical assistants. Images were quality assessed and double graded by two graders. All images were also graded automatically using a commercially available artificial intelligence (AI) algorithm (EyeArt version 2.1.0, Eyenuk Inc.). RESULTS: A total of 75 patients (147 eyes; mean age 69 years, 96% type 2 diabetes) were included. Most of the patients (51; 68%) preferred DED screening at the general practice, but only twenty-four (32%) were willing to pay for this service. Images of 63 patients (84%) were determined to be evaluable, and DED was diagnosed in 6 patients (8.0%). The algorithm's positive/negative predictive values (95% confidence interval) were 0.80 (0.28-0.99)/1.00 (0.92-1.00) and 0.75 (0.19-0.99)/0.98 (0.88-1.00) for detection of any DED and referral-warranted DED, respectively.Overall, the number of referrals was 18 (24%) for manual telemedical assessment and 31 (41%) for the artificial intelligence (AI) algorithm, resulting in a relative increase of referrals by 72% when using AI. CONCLUSIONS: Our study shows that achieved overall image quality in a telemedical GP-based DED screening was sufficient and that it would be accepted by medical assistants and patients in most cases. However, good image quality and integration into existing workflow remain challenging. Based on these findings, a larger-scale implementation study is warranted.

Correlation Between Retinal Microvascular Abnormalities and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease in Patients With Type 2 Diabetes.

Background and Purpose: Diabetic retinopathy (DR) is one of the common microvascular complications in diabetes. The total magnetic resonance imaging (MRI) burden of cerebral small vessel disease (CSVD) tends to be increased in diabetic patients and is a marker of microvascular disease; however, the relationship between DR and CSVD is unclear. This study aimed to explore the relationship between retinal microvascular abnormalities and the total MRI burden of CSVD in patients with type 2 diabetes. Methods: Data were collected from patients with type 2 diabetes who were hospitalized between December 2019 and November 2020 in Changzhou Second People's Hospital affiliated to Nanjing Medical University. All patients underwent retinal photography and cerebral MRI. The central retinal artery equivalent (CRAE), the central retinal venous equivalent (CRVE), and arteriole-to-venule ratio (AVR) were calculated using Image J software to determine the retinal vascular calibers for each patient. The total MRI burden score for CSVD was determined, and the relationship between retinal microvascular abnormalities and the total MRI burden of CSVD was analyzed. Results: Of the 151 diabetic patients included in the study, 84 (55.6%) had no diabetic retinopathy (NDR), 27 (17.9%) had mild DR, and 40 (26.5%) had moderate, or severe non-proliferative DR (grouped together for this study as "more than mild DR"). In patients with more than mild DR, the proportion of moderate to severe burden of CSVD was 75%, which was higher than in patients with mild DR (48.1%) or NDR (26.2%). Patients with moderate to severe burden of CSVD were more likely than those with mild burden of CSVD to have narrowed retinal arterioles (105.24 ± 8.42 µm vs. 109.45 ± 7.93 µm), widened retinal venules (201.67 ± 16.25 µm vs. 193.95 ± 13.54 µm), and lower arteriole-to-venule ratio (0.52 ± 0.05 vs. 0.57 ± 0.04) (P < 0.05 for all). The degree of DR (r = 0.465, P < 0.001) and CRVE (r = 0.366, P < 0.001) were positively correlated with the total MRI burden of CSVD. Multivariate logistic regression analysis indicated that, after adjustments were made for age, smoking, alcohol consumption, hypertension, and other factors, more than mild DR (OR, 4.383; P = 0.028), CRAE (OR, 0.490; P = 0.031), and CRVE (OR, 1.475; P = 0.041) were independently associated with moderate to severe burden of CSVD. Conclusion: Retinal microvascular abnormalities in patients with type 2 diabetes are associated with the presence of cerebral small vessel lesions. The degree of DR and retinal vessel changes can be used as predictors of intracranial microcirculation lesions.

Prediction for the Total MRI Burden of Cerebral Small Vessel Disease With Retinal Microvascular Abnormalities in Ischemic Stroke/TIA Patients.

Background and Purpose: The association of retinal microvascular abnormalities with the total cerebral small vessel disease (cSVD) burden found on brain MRI has not been determined. In the present study, we examined whether the retinopathy score could predict the total cSVD burden in ischemic stroke/transient ischemic attack (TIA) patients. A simple practical diagnostic tool may help identify candidates for MRI screening. Methods: We consecutively collected clinical data including retinal photography and cerebral MRI of ischemic stroke/TIA patients from August 2016 to August 2017 at our stroke center. The retinopathy score was assessed by the Keith-Wagener-Barker grading system for analyzing retinal microvascular abnormalities. To evaluate the total cSVD burden, the total cSVD score was assessed by awarding one point for the presence of each marker of cSVD on MRI. The clinical characteristics and retinopathy score were analyzed across patients for each total cSVD score. The association between the retinopathy score and the total cSVD score was analyzed. Results: Among the 263 enrolled patients, the frequency of hypertension in patients with a total cSVD score of 2, 3, or 4 was higher than that in patients with a score of 0 (69.5, 71.7, and 89.2% vs. 45.2% respectively, all P < 0.05). The retinopathy score was related to the total cSVD score (r = 0.687, P < 0.001). Adjusted multivariate ordinal regression showed that the retinopathy score was independently correlated with the total cSVD score (odds ratio [OR], 4.18; 95% confidence interval [CI], 3.07-5.70) after adjustment for age, history of hypertension, previous stroke/TIA and current smoking. The c statistics were 0.30 (95% CI, 0.24-0.37; P < 0.05), 0.46 (95% CI, 0.39-0.53; P = 0.303), 0.79 (95% CI, 0.72-0.86; P < 0.001), and 0.81 (95% CI, 0.74-0.88; P < 0.001) for predicting the total cSVD score of 1, 2, 3, and 4 respectively. Conclusions: These results suggest that retinal microvascular abnormalities have predictive value for severe total cSVD burden in ischemic stroke/TIA patients.

Retinal vasculature in glaucoma: a review.

Despite the critical impact of glaucoma on global blindness, its aetiology is not fully characterised. Elevated intraocular pressure is highly associated with glaucomatous optic neuropathy. However, visual field loss still progresses in some patients with normal or even low intraocular pressure. Vascular factors have been suggested to play a role in glaucoma development, based on numerous studies showing associations of glaucoma with blood pressure, ocular perfusion pressure, vasospasm, cardiovascular disease and ocular blood flow. As the retinal vasculature is the only part of the human circulation that readily allows non-invasive visualisation of the microcirculation, a number of quantitative retinal vascular parameters measured from retinal photographs using computer software (eg, calibre, fractal dimension, tortuosity and branching angle) are currently being explored for any association with glaucoma and its progression. Several population-based and clinical studies have reported that changes in retinal vasculature (eg, retinal arteriolar narrowing and decreased fractal dimension) are associated with optic nerve damage and glaucoma, supporting the vascular theory of glaucoma pathogenesis. This review summarises recent findings on the relationships between quantitatively measured structural retinal vascular changes with glaucoma and other markers of optic nerve head damage, including retinal nerve fibre layer thickness. Clinical implications, recent new advances in retinal vascular imaging (eg, optical coherence tomography angiography) and future research directions are also discussed.

Safety of iPhone retinal photography.

BACKGROUND: With the advancement in mobile technology, smartphone retinal photography is becoming a popular practice. However, there is limited information about the safety of the latest smartphones used for retinal photography. AIMS: This study aims to determine the photobiological risk of iPhone 6 and iPhone 6 plus when used in conjunction with a 20Diopter condensing lens for retinal photography. METHOD: iPhone 6 and iPhone 6 plus (Apple, Cupertino, CA) were used in this study. The geometrical setup of the study was similar to the indirect ophthalmoscopy technique. The phone was set up at one end of the bench with its flash turned on at maximal brightness; a 20 Dioptre lens was placed 15 cm away from the phone. The light that passes through the lens was measured with a spectroradiometer and an illuminance probe at the other end to determine the spectral profile, spatial irradiance, radiant power emitted by the phone's flash. Trigonometric and lens formula were applied to determine the field of view and retinal surface in order to determine the weighted retinal irradiance and weighted retinal radiant exposure. RESULT: Taking ocular transmission and the distribution of the beam's spatial irradiance into account, the weighted retinal irradiance is 1.40 mW/cm2 and the weighted retinal radiant exposure is 56.25 mJ/cm2. The peak weighted foveal irradiance is 1.61 mW/cm2. CONCLUSION: Our study concluded that the photobiological risk posed by iPhone 6 indirect ophthalmoscopy was at least 1 order of magnitude below the safety limits set by the ISO15004-2.2.

Systematic review: Can non-mydriatic cameras accurately detect diabetic retinopathy?

AIMS: Diabetes puts many individuals at risk for developing diabetic retinopathy (DR). Non-mydriatic (NM) retinal photography without pharmacological pupil dilation can be used to detect DR, however, its value in a general clinical setting has not been established. The objective of this review is to evaluate the validity of NM retinal photos, as compared to the reference standard of seven standard stereoscopic 30 degree field photographs (7SF), for their use of detecting DR in community-dwelling adults. METHODS: English articles were identified through MEDLINE (1992-2016), EMBASE (1992-2016), Center for Disease Control and Prevention, Food and Drug Administration, Health Canada, and Google Scholar (1992-2016). Only studies that examined the validity of NM retinal photos, without pharmacological pupil dilation, as compared to 7SF, used in a community-dwelling adult population were included. Risk of bias was assessed using the QUADAS-2. RESULTS: Of the 368 articles identified in the search, 6 articles met eligibility requirements. Sensitivities ranged from 64 to 97.9% and specificities ranged from 65.6 to 98%. Studies that used multiple field images to detect DR in a younger population generally produced higher quality photos and more valid results. CONCLUSIONS: The strongest validity indicators were reported in studies capturing multiple field images.