Wide-field imaging of sickle retinopathy

The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications

PURPOSE

To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans.

METHODS

Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D).

RESULTS

The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions.

CONCLUSION

Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

Comparative analysis of two retinal fractures with ultrabroad‑angle fundus photography systems

The aim of the present study was to compare the performance of the Opel Panorama 200 and Zeiss Clarus 500 (Carl Zeiss AG) systems in diagnosing retinal fractures. Human subjects were selected from 298 fundus examinations (531 eyes) in ophthalmology from February 2021 to June 2021, including 68 patients with retinal fissures (95 eyes). All fundus tests were performed with Opel Panoramic 200. Zeiss Clarus 500 (Carl Zeiss AG) fundus photography, slit-lamp full retinal lens (Ocular Mainster Wide Field; Ocular Instruments), and retinal laser photocoagulation was performed for all affected eyes. The diagnostic sensitivity of the two examination methods was compared, and their sensitivities for posterior retina, peripheral nose, crystal eye, cataract, positive experiment, and myopia testing were compared. In all, 68 patients (95 eyes) were clinically examined and treated 112 laser times. For retinal fractures, the Opel Panorama 200 used a check sensitivity of 89.5%, and the Clarus 500 check had a sensitivity of 94.7%, with the difference being non-significant (P=0.358). Moreover, Clarus 500 diagnosed the sensitivity of the temporal periphery significantly higher than that of Opel Panorama 200 (P=0.048). Opel Panorama 200 displayed statistically significant sensitivity compared with Clarus 500 diagnosis with crystalline and crystal fewer eyes (P>0.05); Clarus 500 sensitivity for cataract diagnosis (crystal turbidity level 3 and above) was significantly higher than that of Opel Panorama 200 (P=0.033). Opel Panoramic 200 displayed significant sensitivity to ocular myopia and medium to moderate myopia (P>0.05). Clarus 500 diagnosed high myopia with a significantly higher sensitivity than Opel Panorama 200 (P=0.045). Opel Panorama 200 and Zeiss Clarus 500 displayed the same level of sensitivity to retinal fissures, with improved sensitivity in refractive turbidity and for retinal fissures located in the far periphery of the temporal side.

Variability of Vascular Reactivity in the Retina and Choriocapillaris to Oxygen and Carbon Dioxide Using Optical Coherence Tomography Angiography

Purpose

To investigate the regional and layer-specific vascular reactivity of the healthy human retina and choriocapillaris to changes in systemic carbon dioxide or oxygen.

Methods

High-resolution 3 × 3-mm2 optical coherence tomography angiography (OCTA) images were acquired from the central macula, temporal macula, and peripapillary retina while participants were exposed to three gas breathing conditions-room air, 5%CO2, and 100% O2. OCTA from all three regions were extracted and the apparent skeletonized vessel density (VSD) was assessed. The mean flow deficit sizes (MFDSs) of the choriocapillaris were also assessed. Repeated-measures analysis of variance was used to compare the ratio of intrasubject VSD change induced by the gas conditions from baseline in the superficial retinal layer (SRL) and deep retinal layer (DRL) for each retinal region independently, as well as the MFDS of the choriocapillaris. We also compared the vessel reactivity between the retinal capillaries and the choriocapillaris.

Results

The cumulative intrasubject response to the gas conditions differed significantly among regions of the SRL (F(2, 7) = 28.22, P < 0.001), with the temporal macula showing the largest response (15%) compared to the macula (8%) and radial peripapillary capillaries (7%). A similar trend was found in the DRL. The choriocapillaris reactivity was similar between the macula (5.8%) and temporal macula (5.6%). There was also a significant heterogeneity in the layer-specific gas responses, with the DRL showing the largest response (28.2%) and the choriocapillaris showing the smallest response (2.8%).

Conclusions

Capillary reactivity to changes in inhaled O2 and CO2 is spatially heterogeneous across the retina but not choriocapillaris.

Proliferative Sickle Cell Retinopathy in the Retinal Periphery Detected by Ultra-Widefield Imaging: A Case Report

Sickle cell proliferative retinopathy usually presents first in the peripheral retina and the ability to extend and enhance our visualization of the peripheral retina would allow for superior clinical decision-making. In our practice, we had a 28-year-old patient diagnosed with major sickle cell disease of the homozygous type SS (HbSS) that presented with sickle cell proliferative retinopathy detected by ultra-widefield imaging in the nasal side of the left fundus. At follow-up, neovascularization was detected in the extreme nasal periphery of the left eye by ultra-widefield imaging fluorescein angiography with right gaze. The case was graded as Goldberg stage 3, and the patient was administered photocoagulation treatment. With further advancements in the quality and modality of peripheral retinal imaging, novel proliferative lesions can be detected and appropriately managed much earlier than was previously possible. Ultra-widefield imaging allows for the visualization of the central 200 degrees of the retina but, with gaze view, peripheral retina beyond 200 degrees can be reached.

Sensitivity and specificity of pseudocolor ultrawide field imaging in comparison to wide field fundus fluorescein angiography in detecting retinal neovascularization in diabetic retinopathy

OBJECTIVE

To evaluate the diagnostic accuracy of ultrawide pseudocolor retinal photography (pseudocolor UWF) compared to wide field fundus fluorescein angiography (WFFFA) in the detection of retinal neovascularization (NV) and NV of the disc (NVD) in patients with diabetic retinopathy (DR).

DESIGN

Diagnostic accuracy observational study evaluating pseudocolor UWF as the index test. The reference standard was WFFFA.

SETTING

Single retinal centre in India.

PARTICIPANTS

People with severe non-proliferative DR (sNPDR), early proliferative DR (ePDR) or high-risk proliferative DR (HR PDR).

MAIN OUTCOME MEASURES

Sensitivity and specificity of pseudocolor UWF in the detection of NV.

RESULTS

A total of 176 eyes of 94 subjects with sNPDR, ePDR or HR PDR underwent pseudocolor UWF and WFFFA. The sensitivity and specificity of pseudocolor UWF in detecting NVE were 92.5% (95% CI 86.2-96.5) and 81% (95% CI 64.8-92.0), respectively, with moderate interobserver agreement of 0.722 (p value 0.001). The positive predictive value and negative predictive value were 83.0 (71.4-90.5) and 91.5 (84.9-95.3), respectively.

CONCLUSION

Compared to WFFFA as the gold standard, pseudocolor UWF has high sensitivity and specificity in detection of NV in all retinal quadrants and NVD. Therefore, pseudocolor UWF may be used as a non-invasive tool for screening and managing DR.

Comparison of Ultra-Wide Field Photography to Ultra-Wide Field Angiography for the Staging of Sickle Cell Retinopathy

Sickle cell retinopathy (SCR) is classified by Goldberg based on peripheral vascular changes. Ultra-wide field (UWF) imaging has enhanced visualization of the peripheral retina. However, there is no consensus on the optimal imaging technique for the screening of SCR. We performed a monocentric observational cross-sectional study to compare UWF fundus photography (UWF-FP) with UWF angiography (UWF-FA). All patients who underwent UWF-imaging (Optos, PLC, Scotland, UK) for screening of sickle cell retinopathy between January 2016 and December 2019 were retrospectively included. Eyes with previous laser treatment or concomitant retinal disease were excluded. UWF-FP images were graded based on the Goldberg classification by four graders with various degrees of experience. UWF-FA pictures were reviewed by an independent retina specialist. Differences in Goldberg staging across UWF-FP and UWF-FA were assessed. A total of 84 eyes of 44 patients were included. Based on UWF-FA, most eyes were stage 2 (77.4%) and 19 were stage 3 (22.6%). The pre-retinal neovascularization detection sensitivity on UWF-FP was 52.6 to 78.9%, depending on the graders. UWF-FA led to a later Goldberg stage of retinopathy, in most cases from stage 1 to stage 2. Neovascularization (stage 3) was not detected by our graders on UWF-FP in 21.1 to 57.9% of eyes. UWP-FP tends to underestimate Goldberg stages of retinopathy compared with UWF-FA and is less accurate when detecting neovascularization in sickle cell retinopathy, which has a direct impact on therapeutic management and prognosis.

Deep learning-based classification of retinal vascular diseases using ultra-widefield colour fundus photographs

Objective

To assess the ability of a deep learning model to distinguish between diabetic retinopathy (DR), sickle cell retinopathy (SCR), retinal vein occlusions (RVOs) and healthy eyes using ultra-widefield colour fundus photography (UWF-CFP).

Methods and Analysis

In this retrospective study, UWF-CFP images of patients with retinal vascular disease (DR, RVO, and SCR) and healthy controls were included. The images were used to train a multilayer deep convolutional neural network to differentiate on UWF-CFP between different vascular diseases and healthy controls. A total of 224 UWF-CFP images were included, of which 169 images were of retinal vascular diseases and 55 were healthy controls. A cross-validation technique was used to ensure that every image from the dataset was tested once. Established augmentation techniques were applied to enhance performances, along with an Adam optimiser for training. The visualisation method was integrated gradient visualisation.

Results

The best performance of the model was obtained using 10 epochs, with an overall accuracy of 88.4%. For DR, the area under the receiver operating characteristics (ROC) curve (AUC) was 90.5% and the accuracy was 85.2%. For RVO, the AUC was 91.2% and the accuracy 88.4%. For SCR, the AUC was 96.7% and the accuracy 93.8%. For healthy controls, the ROC was 88.5% with an accuracy that reached 86.2%.

Conclusion

Deep learning algorithms can classify several retinal vascular diseases on UWF-CPF with good accuracy. This technology may be a useful tool for telemedicine and areas with a shortage of ophthalmic care.

Developing portable widefield fundus camera for teleophthalmology: Technical challenges and potential solutions

A portable, low cost, widefield fundus camera is essential for developing affordable teleophthalmology. However, conventional trans-pupillary illumination used in traditional fundus cameras limits the field of view (FOV) in a snapshot image, and frequently requires pharmacologically pupillary dilation for reliable examination of eye conditions. This minireview summarizes recent developments in alternative illumination approaches for widefield fundus photography. Miniaturized indirect illumination has been used to enable compact design for developing low cost, portable, widefield fundus camera. Contact mode trans-pars-planar illumination has been validated for ultra-widefield fundus imaging of infant eyes. Contact-free trans-pars-planar illumination has been explored for widefield imaging of adult eyes. Trans-palpebral illumination has been also demonstrated in a smartphone-based widefield fundus imager to foster affordable teleophthalmology.

Artificial intelligence for improving sickle cell retinopathy diagnosis and management

Sickle cell retinopathy is often initially asymptomatic even in proliferative stages, but can progress to cause vision loss due to vitreous haemorrhages or tractional retinal detachments. Challenges with access and adherence to screening dilated fundus examinations, particularly in medically underserved areas where the burden of sickle cell disease is highest, highlight the need for novel approaches to screening for patients with vision-threatening sickle cell retinopathy. This article reviews the existing literature on and suggests future research directions for coupling artificial intelligence with multimodal retinal imaging to expand access to automated, accurate, imaging-based screening for sickle cell retinopathy. Given the variability in retinal specialist practice patterns with regards to monitoring and treatment of sickle cell retinopathy, we also discuss recent progress toward development of machine learning models that can quantitatively track disease progression over time. These artificial intelligence-based applications have great potential for informing evidence-based and resource-efficient clinical diagnosis and management of sickle cell retinopathy.

Deep Learning Detection of Sea Fan Neovascularization From Ultra-Widefield Color Fundus Photographs of Patients With Sickle Cell Hemoglobinopathy

Importance

Adherence to screening for vision-threatening proliferative sickle cell retinopathy is limited among patients with sickle cell hemoglobinopathy despite guidelines recommending dilated fundus examinations beginning in childhood. An automated algorithm for detecting sea fan neovascularization from ultra-widefield color fundus photographs could expand access to rapid retinal evaluations to identify patients at risk of vision loss from proliferative sickle cell retinopathy.

Objective

To develop a deep learning system for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy.

Design, Setting, and Participants

In a cross-sectional study conducted at a single-institution, tertiary academic referral center, deidentified, retrospectively collected, ultra-widefield color fundus photographs from 190 adults with sickle cell hemoglobinopathy were independently graded by 2 masked retinal specialists for presence or absence of sea fan neovascularization. A third masked retinal specialist regraded images with discordant or indeterminate grades. Consensus retinal specialist reference standard grades were used to train a convolutional neural network to classify images for presence or absence of sea fan neovascularization. Participants included nondiabetic adults with sickle cell hemoglobinopathy receiving care from a Wilmer Eye Institute retinal specialist; the patients had received no previous laser or surgical treatment for sickle cell retinopathy and underwent imaging with ultra-widefield color fundus photographs between January 1, 2012, and January 30, 2019.

Interventions

Deidentified ultra-widefield color fundus photographs were retrospectively collected.

Main Outcomes and Measures

Sensitivity, specificity, and area under the receiver operating characteristic curve of the convolutional neural network for sea fan detection.

Results

A total of 1182 images from 190 patients were included. Of the 190 patients, 101 were women (53.2%), and the mean (SD) age at baseline was 36.2 (12.3) years; 119 patients (62.6%) had hemoglobin SS disease and 46 (24.2%) had hemoglobin SC disease. One hundred seventy-nine patients (94.2%) were of Black or African descent. Images with sea fan neovascularization were obtained in 57 patients (30.0%). The convolutional neural network had an area under the curve of 0.988 (95% CI, 0.969-0.999), with sensitivity of 97.4% (95% CI, 86.5%-99.9%) and specificity of 97.0% (95% CI, 93.5%-98.9%) for detecting sea fan neovascularization from ultra-widefield color fundus photographs.

Conclusions and Relevance

This study reports an automated system with high sensitivity and specificity for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy, with potential applications for improving screening for vision-threatening proliferative sickle cell retinopathy.

Portable ultra-widefield fundus camera for multispectral imaging of the retina and choroid

Multispectral imaging (MSI) of the retina and choroid has increasing interest for better diagnosis and treatment evaluation of eye diseases. However, currently available MSI systems have a limited field of view (FOV) to evaluate the peripheral retina. This study is to validate trans-pars-planar illumination for a contact-mode ultra-widefield MSI system. By freeing the available pupil for collecting imaging light only, the trans-pars-planar illumination enables a portable, non-mydriatic fundus camera, with 200° FOV in a single fundus image. The trans-pars-planar illumination, delivering illumination light from one side of the eye, naturally enables oblique illumination ophthalmoscopy to enhance the contrast of fundus imaging. A broadband (104 nm) 565 nm light-emitting diode (LED) is used for validating color fundus imaging first. Four narrowband (17-60 nm) 530 nm, 625 nm, 780 nm, and 970 nm LEDs are tested for MSI. With 530 nm illumination, the fundus image reveals retinal vasculature predominantly. 625 nm and 780 nm illuminations enhance the visibility of choroidal vasculature. With further increased wavelength of 970 nm, the fundus image is predominated by large veins in the choroid, with multiple vortex ampullas observed simultaneously in a single fundus image.

Comparison of two ultra-widefield imaging for detecting peripheral retinal breaks requiring treatment

AIM

To compare the sensitivity of Optomap Panoramic 200 and Clarus 500 in detecting peripheral retinal breaks that required treatment.

METHODS

This prospective study enrolled consecutive patients undergoing laser for treatment-requiring peripheral retinal breaks from May 2019 to July 2019. The patients first underwent indirect ophthalmoscopy examination with scleral indentation by a retinal consultant and then ultra-widefield imaging by a single trained technician on Optomap 200 and Clarus 500 in all nine ocular gazes. The images were analysed by two independent investigators to look for the number and location of the breaks. The sensitivity of each platform was calculated as the number of treatment-requiring breaks identified by the system divided by the number of breaks identified on clinical examination.

RESULTS

Clinical examination of 49 eyes (41 patients) showed 116 treatment-requiring breaks. Overall sensitivity for identifying such breaks for Optomap and Clarus was 80.2% (n = 93) and 74.1% (n = 86) respectively (p = 0.274). The sensitivities in superior (p = 0.665), temporal (p = 0.146) and inferior (p = 0.889) quadrants were statistically similar for both the platforms. The sensitivity of Optomap was slightly higher than Clarus in emmetropic (p = 0.046) and phakic (p = 0.061) eyes, but similar in myopic (p = 0.448) and pseudophakic (p = 0.191) eyes.

CONCLUSION

The ability to detect treatment-requiring retinal breaks is similar for both Optomap and Clarus systems.