Accuracy and Reliability of a Handheld, Nonmydriatic Fundus Camera for the Remote Detection of Optic Disc Edema

Clinical utility of handheld fundus and smartphone-based camera for monitoring diabetic retinal diseases: a review study

Diabetic retinopathy (DR) is the leading global cause of vision loss, accounting for 4.8% of global blindness cases as estimated by the World Health Organization (WHO). Fundus photography is crucial in ophthalmology as a diagnostic tool for capturing retinal images. However, resource and infrastructure constraints limit access to traditional tabletop fundus cameras in developing countries. Additionally, these conventional cameras are expensive, bulky, and not easily transportable. In contrast, the newer generation of handheld and smartphone-based fundus cameras offers portability, user-friendliness, and affordability. Despite their potential, there is a lack of comprehensive review studies examining the clinical utilities of these handheld (e.g. Zeiss Visuscout 100, Volk Pictor Plus, Volk Pictor Prestige, Remidio NMFOP, FC161) and smartphone-based (e.g. D-EYE, iExaminer, Peek Retina, Volk iNview, Volk Vistaview, oDocs visoScope, oDocs Nun, oDocs Nun IR) fundus cameras. This review study aims to evaluate the feasibility and practicality of these available handheld and smartphone-based cameras in medical settings, emphasizing their advantages over traditional tabletop fundus cameras. By highlighting various clinical settings and use scenarios, this review aims to fill this gap by evaluating the efficiency, feasibility, cost-effectiveness, and remote capabilities of handheld and smartphone fundus cameras, ultimately enhancing the accessibility of ophthalmic services.

Ultrasound in ocular oncology: Technical advances, clinical applications, and limitations

Due to its accessibility and ability for real-time image acquisition of ocular structures, ultrasound has high utility in the visualization of the eye, especially in ocular oncology. In this minireview, we summarize the technical rationale and applications of ultrasound modalities, A-scan, B-scan, high-frequency ultrasound biomicroscopy (UBM), and Doppler measurement. A-scan ultrasound uses a transducer of 7-11 MHz, making it useful for determining the echogenicity of ocular tumors (7-8 MHz) and measuring the axial length of the eye (10-11 MHz). B-scan ultrasound operates at 10-20 MHz, which can be used for measuring posterior ocular tumors while UBM operates at 40-100 MHz to evaluate anterior ocular structures. Doppler ultrasonography allows for the detection of tumor vascularization. While ultrasonography has numerous clinical applications due to its favorable penetration compared with optical coherence tomography, it is still limited by its relatively lower resolution. Ultrasound also requires an experienced sonographer due to the need for accurate probe localization to areas of interest.

Diagnostic accuracy of handheld fundus photography: A comparative study of three commercially available cameras

The objective of this study was to compare the sensitivity and specificity of handheld fundus cameras in detecting diabetic retinopathy (DR), diabetic macular edema (DME), and macular degeneration. Participants in the study, conducted at Maharaj Nakorn Hospital in Northern Thailand between September 2018 and May 2019, underwent an ophthalmologist examination as well as mydriatic fundus photography with three handheld fundus cameras (iNview, Peek Retina, Pictor Plus). Photographs were graded and adjudicated by masked ophthalmologists. Outcome measures included the sensitivity and specificity of each fundus camera for detecting DR, DME, and macular degeneration, relative to ophthalmologist examination. Fundus photographs of 355 eyes from 185 participants were captured with each of the three retinal cameras. Of the 355 eyes, 102 had DR, 71 had DME, and 89 had macular degeneration on ophthalmologist examination. The Pictor Plus was the most sensitive camera for each of the diseases (73-77%) and also achieved relatively high specificity (77-91%). The Peek Retina was the most specific (96-99%), although in part due to its low sensitivity (6-18%). The iNview had slightly lower estimates of sensitivity (55-72%) and specificity (86-90%) compared to the Pictor Plus. These findings demonstrated that the handheld cameras achieved high specificity but variable sensitivities in detecting DR, DME, and macular degeneration. The Pictor Plus, iNview, and Peek Retina would have distinct advantages and disadvantages when applied for utilization in tele-ophthalmology retinal screening programs.

Evaluation of a remote telemedicine platform using a novel handheld fundus camera: Physician and patient perceptions from real-world experience

BACKGROUND

Although teleophthalmology has gained traction in recent years, it is at the center of the coronavirus disease pandemic. However, most hospitals are not ready owing to a severe lack of real-world experience. Furthermore, a limited number of studies have evaluated telemedicine applications on remote islands. This study aimed to evaluate real-world clinical and referral accuracy, image quality, physician-perceived diagnostic certainty, and patient satisfaction with telemedicine eye screening using a novel handheld fundus camera in a rural and medically underserved population.

METHODS

This prospective study included 176 eyes from a remote island. All participants underwent a comprehensive ophthalmic examination. Nonmydriatic retinal images obtained using a handheld fundus camera were reviewed by two retinal specialists to determine image quality, diagnosis, and need for referrals. The agreement of diagnosis between image-based assessments was compared with that of binocular indirect ophthalmoscopic assessments.

RESULTS

Image quality of fundus photographs was considered acceptable or ideal in 97.7% and 95.5% of eyes assessed by two reviewers, respectively. There was considerable agreement in diagnosis between the indirect ophthalmoscopic assessment and image-based assessment by two reviewers (Cohen's kappa = 0.80 and 0.78, respectively). Likewise, substantial agreement was achieved in the referrals. The sensitivity for referable retinopathy from the two reviewers was 78% (95% confidence interval [CI], 57%-91%) and 78% (95% CI, 57%-91%), whereas specificity was 99% (95% CI, 95%-99%] and 98% (95% CI, 93%-99%), respectively. For physicians' perceived certainty of diagnosis, 93.8% and 90.3% were considered either certain or reliable. Overall, 97.4% of participants were satisfied with their experiences and greatly valued the telemedicine services.

CONCLUSION

Novel fundus camera-based telemedicine screening demonstrated high accuracy in detecting clinically significant retinopathy in real-world settings. It achieved high patient satisfaction and physician-perceived certainty in diagnosis with reliable image quality, which may be scaled internationally to overcome geographical barriers under the global pandemic.

Fundoscopy Use in Neurology Departments and the Utility of Smartphone photography ( FUNDUS ): A prospective prevalence and crossover diagnostic accuracy study amongst neurology inpatients

Background and purpose

Although fundoscopy is a crucial part of the neurological examination, it is challenging, under‐utilized and unreliably performed. The aim was to determine the prevalence of fundus pathology amongst neurology inpatients and the diagnostic accuracy of current fundoscopy practice compared with systematic screening with smartphone fundoscopy (SF) and portable non‐mydriatic fundus photography (NMFP).

Methods

This was a prospective cross‐sectional surveillance and diagnostic accuracy study on adult patients admitted under neurology in an Australian hospital. Inpatients were randomized to initial NMFP (RetinaVue 100, Welch Allyn) or SF (D‐EYE) followed by a crossover to the alternative modality. Images were graded by neurology doctors, using telemedicine consensus neuro‐ophthalmology NMFP grading as the reference standard. Feasibility parameters included ease, comfort and speed.

Results

Of 79 enrolled patients, 14.1% had neurologically relevant pathology (seven, disc pallor; one, hypertensive retinopathy; three, disc swelling). The neurology team performed direct ophthalmoscopy in 6.6% of cases and missed all abnormalities. SF had a sensitivity of 30%–40% compared with NMFP (45.5%); however, it had a lower rate of screening failure (1% vs. 13%, p < 0.001), a shorter examination time (1.10 vs. 2.25 min, p < 0.001) and a slightly higher patient comfort rating (9.2 vs. 8/10, p < 0.001).

Conclusion

Our study demonstrates a clinically significant prevalence of fundus pathology amongst neurology inpatients which was missed by current fundoscopy practices. Portable NMFP screening appears more accurate than SF, whilst both are diagnostically superior to routine fundoscopic practice, feasible and well tolerated by patients.

Diagnostic Error in Neuro-ophthalmology: Avenues to Improve

Purpose of Review

To highlight potential avenues to reduce preventable diagnostic error of neuro-ophthalmic conditions and avoid patient harm.

Recent Findings

Recent prospective studies and studies of patient harm have advanced our understanding. Additionally, recent studies of fundus photography, telemedicine, and artificial intelligence highlight potential avenues for diagnostic improvement.

Summary

Diagnostic error of neuro-ophthalmic conditions can often be traced to failure to gather an adequate history, perform a complete physical exam, obtain adequate/appropriate neuroimaging, and generate a complete, appropriate differential diagnosis. Improving triage and identification of neuro-ophthalmic conditions by other providers and increasing access to subspecialty neuro-ophthalmology evaluation are essential avenues to reduce diagnostic error. Further research should evaluate the relationship between misdiagnosis and patient harm, and help identify the most impactful potential targets for improvement.

Sensitivity and Specificity of Handheld Fundus Cameras for Eye Disease: A Systematic Review and Pooled Analysis

In order to evaluate the accuracy of commercially available handheld fundus cameras for a variety of ophthalmic diagnoses, we conducted a systematic review, searching PubMed and PubMed Central and performing a bivariate analysis to determine the pooled sensitivity and specificity of handheld fundus cameras. Eleven studies validating handheld fundus cameras against a gold-standard method for disease diagnosis were included. For non-mydriatic images, pooled sensitivity was 83% (95% CI: 77-88%) and specificity was 92% (95% CI: 79-97%). For mydriatic images, pooled sensitivity was 87% (95% CI: 79-92%) and specificity was 90% (95% CI: 78-96%). Overall pooled sensitivity was 85% (95% CI: 80-89%) and specificity was 91% (95% CI: 83-95%). Of the 11 studies included, 5 assessed the diagnosis of diabetic retinopathy, for which sensitivity was 87% (95% CI: 80-92%) and specificity was 95% (95% CI: 85-98%). For all other diagnoses combined, sensitivity was 81% (95% CI: 74-87%) and specificity was 83% (95% CI: 76-89%). These findings suggest that handheld fundus cameras are capable of achieving acceptable sensitivity and specificity values for eye disease, with mydriatic images being more sensitive for disease. Diabetic retinopathy was the single diagnosis with the strongest data to support the use of handheld fundus cameras for disease screening.

Utilizing Advanced Technology to Facilitate Diagnosis of Rare Retinal Disorders: A Case of Bietti Crystalline Dystrophy

SIGNIFICANCE

Optometrists, as primary eye care providers, encounter patients with rare ocular disease such as Bietti crystalline dystrophy from time to time. Using advanced technologies, which are also useful in managing common ocular conditions, to facilitate a prompt diagnosis is highly recommended.

PURPOSE

This report describes a patient with clinically diagnosed Bietti crystalline dystrophy with findings on funduscopy, multimodal imaging, and visual electrophysiology.

CASE REPORT

A 41-year-old Chinese woman who had subjectively progressing dimmed vision (especially in the left eye) for 9 months was referred to our clinic to test for retinitis pigmentosa. Best-corrected visual acuities were 6/6 and 6/7.6 in the right and left eyes, respectively. Funduscopy revealed multiple crystalline deposits on the posterior pole in both eyes. The 30-2 perimetry displayed bi-inferotemporal scotoma (left > right eye). Scotopic flash electroretinogram (ERG) yielded a normal result, whereas photopic ERG was slightly attenuated. Electro-oculogram showed an abnormal adaptation time course of the retinal pigmented epithelium (RPE). Multifocal ERG revealed a decreased central retinal response, but paracentral responses were relatively better preserved. Optical coherence tomography showed multiple patches of RPE atrophy, with disruption of the left ellipsoid zone. Outer retinal tubulations, hyperreflective dots on RPE-Bruch's membrane interface, and intraretinal bright spots were also identified.

CONCLUSIONS

Rare ocular diseases like Bietti crystalline dystrophy can be encountered by optometrists. This case report shows the ophthalmic findings of a rare chorioretinal dystrophy and provides insight on how to better use advanced equipment in an optometric practice to facilitate prompt diagnoses.

Predicting Glaucoma Development With Longitudinal Deep Learning Predictions From Fundus Photographs

PURPOSE

To assess whether longitudinal changes in a deep learning algorithm's predictions of retinal nerve fiber layer (RNFL) thickness based on fundus photographs can predict future development of glaucomatous visual field defects.

DESIGN

Retrospective cohort study.

METHODS

This study included 1,072 eyes of 827 glaucoma-suspect patients with an average follow-up of 5.9 ± 3.8 years. All eyes had normal standard automated perimetry (SAP) at baseline. Additional SAP and fundus photographs were acquired throughout follow-up. Conversion to glaucoma was defined as repeatable glaucomatous defects on SAP. An OCT-trained deep learning algorithm (machine to machine, M2M) was used to predict RNFL thicknesses from fundus photographs. Joint longitudinal survival models were used to assess whether baseline and longitudinal change in M2M's RNFL thickness estimates could predict development of visual field defects.

RESULTS

A total of 196 eyes (18%) converted to glaucoma during follow-up. The mean rate of change in M2M's predicted RNFL thickness was -1.02 μm/y for converters and -0.67 μm/y for non-converters (P < .001). Baseline and rate of change of predicted RNFL thickness were significantly predictive of conversion to glaucoma, with hazard ratios in the multivariable model of 1.56 per 10 μm lower at baseline (95% CI, 1.33-1.82; P < .001) and 1.99 per 1 μm/y faster loss in thickness during follow-up (95% CI, 1.36-2.93; P < .001).

CONCLUSION

Longitudinal changes in a deep learning algorithm's predictions of RNFL thickness measurements based on fundus photographs can be used to predict risk of glaucoma conversion in eyes suspected of having the disease.

Teleophthalmology and its evolving role in a COVID-19 pandemic: A scoping review

ABSTRACT Introduction: Teleophthalmology may assist the healthcare sector in adapting to limitations imposed on clinical practice by a viral pandemic. A scoping review is performed in this study to assess the current applications of teleophthalmology for its suitability to diagnose, monitor or manage ophthalmological conditions with accuracy. Methods: A search of PubMed was conducted for teleophthalmology-related articles published from 1 January 2018 to 4 May 2020. Only articles that focused on the use of teleophthalmology in terms of diagnosis and management, as well as its benefits and detriments, were included. The Mixed Methods Appraisal Tool (MMAT) was used to assess the quality of the included articles. Results: A total of 38 articles were assessed at the full-text level. There were 2 qualitative studies and 1 quantitative randomised controlled trial, while the majority were either quantitative descriptive studies (19, 50.0%) or quantitative non-randomised studies (16, 42.1%). Overall, 8 studies described reducing manpower requirements, 4 described reducing direct patient–doctor contact, 17 described storage of medical imaging and clinical data, and 9 described real-time teleconferencing. The MMAT analysis revealed limitations in appropriate sampling strategy in both quantitative non-randomised studies (9 of 16, 56.3%) and quantitative descriptive studies (9 of 19, 47.4%). Cost-effectiveness of teleophthalmology was not performed in any included study. Conclusion: This current review of the various aspects of teleophthalmology describes how it may potentially assist the healthcare sector to cope with the limitations imposed by a viral pandemic through technology. Further research is required to evaluate the cost-effectiveness of the various strategies. Keywords: Artificial intelligence, health informatics, ophthalmology, teleconsultation, telemedicine

Characterization of the retinal vasculature in fundus photos using the PanOptic iExaminer system

BACKGROUND

The goal was to characterize retinal vasculature by quantitative analysis of arteriole-to-venule (A/V) ratio and vessel density in fundus photos taken with the PanOptic iExaminer System.

METHODS

The PanOptic ophthalmoscope equipped with a smartphone was used to acquire fundus photos centered on the optic nerve head. Two fundus photos of a total of 19 eyes from 10 subjects were imaged. Retinal vessels were analyzed to obtain the A/V ratio. In addition, the vessel tree was extracted using deep learning U-NET, and vessel density was processed by the percentage of pixels within vessels over the entire image.

RESULTS

All images were successfully processed for the A/V ratio and vessel density. There was no significant difference of averaged A/V ratio between the first (0.77 ± 0.09) and second (0.77 ± 0.10) measurements (P = 0.53). There was no significant difference of averaged vessel density (%) between the first (6.11 ± 1.39) and second (6.12 ± 1.40) measurements (P = 0.85).

CONCLUSIONS

Quantitative analysis of the retinal vasculature was feasible in fundus photos taken using the PanOptic ophthalmoscope. The device appears to provide sufficient image quality for analyzing A/V ratio and vessel density with the benefit of portability, easy data transferring, and low cost of the device, which could be used for pre-clinical screening of systemic, cerebral and ocular diseases.

Telemedicine in ophthalmology in view of the emerging COVID-19 outbreak

Purpose

Technological advances in recent years have resulted in the development and implementation of various modalities and techniques enabling medical professionals to remotely diagnose and treat numerous medical conditions in diverse medical fields, including ophthalmology. Patients who require prolonged isolation until recovery, such as those who suffer from COVID-19, present multiple therapeutic dilemmas to their caregivers. Therefore, utilizing remote care in the daily workflow would be a valuable tool for the diagnosis and treatment of acute and chronic ocular conditions in this challenging clinical setting. Our aim is to review the latest technological and methodical advances in teleophthalmology and highlight their implementation in screening and managing various ocular conditions. We present them as well as potential diagnostic and treatment applications in view of the recent SARS-CoV-2 virus outbreak.

Methods

A computerized search from January 2017 up to March 2020 of the online electronic database PubMed was performed, using the following search strings: “telemedicine,” “telehealth,” and “ophthalmology.” More generalized complementary contemporary research data regarding the COVID-19 pandemic was also obtained from the PubMed database.

Results

A total of 312 records, including COVID-19-focused studies, were initially identified. After exclusion of non-relevant, non-English, and duplicate studies, a total of 138 records were found eligible. Ninety records were included in the final qualitative analysis.

Conclusion

Teleophthalmology is an effective screening and management tool for a range of adult and pediatric acute and chronic ocular conditions. It is mostly utilized in screening of retinal conditions such as retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration; in diagnosing anterior segment condition; and in managing glaucoma. With improvements in image processing, and better integration of the patient’s medical record, teleophthalmology should become a more accepted modality, all the more so in circumstances where social distancing is inflicted upon us.

Ophthalmology practice during the COVID-19 pandemic

OBJECTIVE

To present an established practice protocol for safe and effective hospital-setting ophthalmic practice during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS AND ANALYSIS

Literature was reviewed to identify articles relevant to COVID-19 pandemic and ophthalmology. The following keywords were used: COVID-19, SARS-CoV-2 and telemedicine, combined with eye, ophthalmology, conjunctivitis and tears. Data were extracted from the identified manuscripts and discussed among subspecialists to obtain consensus evidence-based practice.

RESULTS

A protocol for ophthalmic practice in the era of COVID-19 pandemic was established. The protocol covered patient screening, clinic flow, required personal protective equipment and modifications of ophthalmic equipment for improved safety.

CONCLUSION

Important literature emerged with respect to the practice of ophthalmology in the era of COVID-19. An evidence-based ophthalmic practice protocol was established and should be modified in the future to accommodate new insights on the COVID-19 pandemic.

Comparison of optic disc evaluation methods in neurology emergency patients

BACKGROUND

The optic disc examination is critical for the diagnostics of several acute neurological disorders. However, dilation of the pupil is not recommended for neurological patients, which complicates ophthalmoscopy.

AIMS OF THE STUDY

Present pilot study compared a portable fundus camera to an ophthalmoscope in fundus examinations of neurological emergency patients. To our knowledge, this is the first comparative study of the subject. The fundus photographs were later reviewed with an ophthalmologist.

METHODS

The study included 60 adults, volunteer neurological emergency patients with either headache, cerebrovascular disorder, or acute confusional state (delirium). Patients' non-mydriatic fundus examination was conducted with an ophthalmoscope and a Smartscope Pro fundus camera.

RESULTS

Fundus photography succeeded in 56 (93%), partially succeeded in 2 (3%), and failed in 2 (3%) cases compared with ophthalmoscopy that succeeded in 35 (58%), partially succeeded in 14 (23%), and failed in 11 (18%) cases (P < .0005). The researcher and the ophthalmologist agreed in the findings in 54 out of 58 cases (93%). In six cases (7%), the researcher had failed to detect a non-critical ophthalmic finding.

CONCLUSIONS

The neurological fundus examination by fundus camera seems to be superior to regular ophthalmoscopy in defining the critical optic disc findings in emergency patients.

Examining the ocular fundus in neurology

PURPOSE OF REVIEW

The funduscopic examination can be a technically difficult, and often omitted, portion of the neurologic examination, despite its great potential to influence patient care.

RECENT FINDINGS

Medical practitioners are often first taught to examine the ocular fundus using a direct ophthalmoscope, however, this skill requires frequent practice. Nonmydriatic tabletop and portable fundus photography and even smartphone-based photography offer alternative and practical means for approaching examination of the ocular fundus. These alternative tools have been shown to be practical in a variety of settings including ambulatory clinics and emergency departments. Decreased retinal microvascular density detected with fundus photography has been linked to accelerated rates of cognitive decline. Research has also found optic disc pallor and retinopathy detected via fundus photography to be more prevalent in patients with recent stroke or transient ischemic attack.

SUMMARY

Alternative methods of funduscopic examination based on fundus photography have the potential to improve the ease of use, portability, and availability of funduscopy. Recognition of changes in retinal microvasculature has the potential to noninvasively identify patients at the highest risk for cognitive impairment and cerebrovascular disease. However, further research is needed to determine the specific utility of measurements of retinal microvascular changes in clinical care. Innovative funduscopy techniques offer neurologists new approaches to this essential facet of the neurological examination.