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

The oxygen saturation and vascular morphology of branch retinal vein occlusion by a dual-model fundus camera based on deep learning / 中华眼底病杂志

Objective:To study a deep learning-based dual-modality fundus camera which was used to study retinal blood oxygen saturation and vascular morphology changes in eyes with branch retinal vein occlusion (BRVO).Methods:A prospective study. From May to October 2020, 31 patients (31 eyes) of BRVO (BRVO group) and 20 healthy volunteers (20 eyes) with matched gender and age (control group) were included in the study. Among 31 patients (31 eyes) in BRVO group, 20 patients (20 eyes) received one intravitreal injection of anti-vascular endothelial growth factor drugs before, and 11 patients (11 eyes) did not receive any treatment. They were divided into treatment group and untreated group accordingly. Retinal images were collected with a dual-modality fundus camera; arterial and vein segments were segmented in the macular region of interest (MROI) using deep learning; the optical density ratio was used to calculate retinal blood oxygen saturation (SO 2) on the affected and non-involved sides of the eyes in the control group and patients in the BRVO group, and calculated the diameter, curvature, fractal dimension and density of arteriovenous in MROI. Quantitative data were compared between groups using one-way analysis of variance. Results:There was a statistically significant difference in arterial SO 2 (SO 2 -A) in the MROI between the affected eyes, the fellow eyes in the BRVO group and the control group ( F=4.925, P<0.001), but there was no difference in the venous SO 2 (SO 2-V) ( F=0.607, P=0.178). Compared with the control group, the SO 2-A in the MROI of the affected side and the non-involved side of the untreated group was increased, and the difference was statistically significant ( F=4.925, P=0.012); there was no significant difference in SO 2-V ( F=0.607, P=0.550). There was no significant difference in SO 2-A and SO 2-V in the MROI between the affected side, the non-involved side in the treatment group and the control group ( F=0.159, 1.701; P=0.854, 0.197). There was no significant difference in SO 2-A and SO 2-V in MROI between the affected side of the treatment group, the untreated group and the control group ( F=2.553, 0.265; P=0.088, 0.546). The ophthalmic artery diameter, arterial curvature, arterial fractal dimension, vein fractal dimension, arterial density, and vein density were compared in the untreated group, the treatment group, and the control group, and the differences were statistically significant ( F=3.527, 3.322, 7.251, 26.128, 4.782, 5.612; P=0.047, 0.044, 0.002, <0.001, 0.013, 0.006); there was no significant difference in vein diameter and vein curvature ( F=2.132, 1.199; P=0.143, 0.321). Conclusion:Arterial SO 2 in BRVO patients is higher than that in healthy eyes, it decreases after anti-anti-vascular endothelial growth factor drugs treatment, SO 2-V is unchanged.

Uso de retinógrafo portátil como ferramenta no rastreamento de retinopatia diabética / Use of a handheld fundus camera as a screening tool for diabetic retinopathy

Resumo Objetivo: Determinar a concordância do retinógrafo portátil Pictor Plus, na ausência de midríase, com a retinografia digital e avaliar a sua acurácia como método de rastreio da retinopatia diabética (RD). Métodos: Estudo transversal, mascarado para o observador, avaliando 100 olhos de 51 pacientes diabéticos. Foram realizadas retinografias com o Pictor Plus com e sem midríase, seguidos de retinografia convencional com o retinógrafo IMAGEnet por técnico treinado. As imagens obtidas foram analisadas por oftalmologista especialista em retina e classificadas normais, presença de edema macular diabético, retinopatia não proliferativa (inicial, moderada e grave) e retinopatia proliferativa, além de análise inviável. A concordância entre os resultados foi avaliada via coeficiente Kappa. As imagens foram agrupadas em normais e alteradas e estas em RD de alto risco e RD de baixo risco. Avaliou-se ainda a sensibilidade, especificidade, valores preditivos positivos e negativos, em relação à retinografia convencional. Resultados: Oitenta e nove por cento das imagens foram consideradas viáveis para classificação. Pouco mais de 31% dos olhos avaliados foram considerados como normais pelas três tecnologias. O exame com Pictor na ausência de midríase apresentou altos índices de sensibilidade e especificidade para a classificação normal (92,9% e 93,4%) e RD de alto risco (82,9% e 97,9%) e bons resultados para RD de baixo risco (75,0% e 87,0%). Conclusão: O Pictor Plus apresentou altos níveis de concordância com a retinografia digital ao discriminar exames normais de alterados e portadores de RD de baixo e alto risco. Foram verificadas ainda altas sensibilidade e especificidade desta ferramenta, se comparados à retinografia padrão.

Abstract Purpose: Determine the effectiveness of the use a portable handheld fundus camera as a screening method for diabetic retinopathy, compared to regular digital retinography. Methods: This is a cross-sectional, observer-masked study, evaluating 100 eyes of 51 diabetic patients undergoing a routine dilated retinography for diabetic retinopathy. Fundus images pre and post-dilation we captured by Pictor Plus (Volk Optical Inc., Mentor, USA), followed by routine digital retinography by IMAGEnet (Topcon Medical Systems, New Jersey, USA). All exams were performed by a trained technician on the same occasion. The images were analyzed and graded by a masked retina specialist and classified as normal, presence of diabetic macular edema, nonproliferative diabetic retinopathy (initial, moderate and severe) and proliferative diabetic retinopathy. The ungradable images were recorded and excluded from analyses. The agreement between results obtained by the three methods was evaluated via Kappa coefficient. Sensitivity, specificity, positive and negative predictive values in relation to IMAGEnet images were also determined. Results: Images were gradable in 89% of pre-dilation photos. Pictor Plus pre-dilation images had high sensitivity and specificity in identifying normal eyes (92.9% and 93.4%) and in vision-threatening DR (82.9% and 97.9%) both when compared to IMAGEnet results. Conclusion: Pictor can capture retinal images of sufficient quality to screen for DR with and without dilation. Single retinal images obtained using Pictor can identify eyes with vision-threatening DR with high sensitivity and specificity compared to routine IMAGEnet images.

Trash to treasure Retcam

Digital fundus imaging is being used in diagnosis, documentation, and sharing of many retinal diseases and hence forms an essential part of ophthalmology. The use of smartphones for the same has been ever increasing. There is a need for simpler devices to couple the 20D lens and smartphone so as to take fundus photographs which can help in fundus documentation. This article describes a simple inexpensive technique of preparing a smartphone fundus photography device (Trash To Treasure (T3) Retcam) from the used materials in the clinics within minutes. This article will also review the optical principles of the T3 Retcam and describe the step–by–step method to record good-quality retinal image/videos. This inexpensive device is made by recycling and modifying the plastic hand sanitizer bottle in the clinics/hospitals which can be used for documenting, diagnosing, screening, and academic purposes.

Diagnostic performance of confocal scanning laser ophthalmoscope imaging and compared with color fundus camera in retinal pigment epithelial detachment of polypoidal choroidal vasculopathy / 中华眼底病杂志

Objective To observe confocal scanning laser ophthalmoscope (cSLO) based retinal imaging and color fundus camera in pigment epithelial detachment (PED) of polypoidal choroidal vasculopathy (PCV).Methods PED of 30 patients (32 eyes) were recruited from June 2016 to June 2017 in the Beijing Tongren Hospital who were detected in high-definition OCT (HD-OCT) and diagnosed as PCV by FFA and ICGA.There were 16 males (17 eyes) and 14 females (15 eyes);aged from 50-83 years,with the mean age of 66.59 years.The photographs of ocular fundus including color fundus camera,cSLO imaging,HD-OCT,FFA and ICGA were analyzed.Multimodal imaging results were regarded as gold standard.Sensitivity and specificity were calculated in serous and hemorrhagic PED diagnosis using color fundus camera and cSLO imaging.The positive number of PED was used to compare between two modes fundus imaging by using x2 test.Results Twenty serous PED eyes,3 hemorrhagic PED eyes and 9 serous/hemorrhagic PED eyes were determined using multimodal imaging.The sensitivity and specificity of color fundus camera were 45％ and 100％ in detecting serous PED and 100％ and 91％ in detecting hemorrhagic PED.The sensitivity and specificity of cSLO imaging were 83％ and 100％ in detecting serous PED and 50％ and 86％ in detecting hemorrhagic PED.The positive number of serous PED in cSLO imaging was significantly higher than color fundus camera (x2=7.752,P=0.011).The positive number of hemorrhagic PED in cSLO imaging shows no obvious difference compared with color fundus camera (x2=1.164,P=0.419).Conclusion The sensitivity and positive number of detecting serous PED with PCV in cSLO fundus imaging were higher than the color fundus camera technology.

Risk Factor Analysis of Diabetic Retinopathy Diagnosed with Non-mydriatic Fundus Camera: KNHANES V

PURPOSE: To clarify the relationship between various factors (sociodemographic factors, health behavioral risk factors and health status, and diabetic factors) related to diabetic retinopathy and to suggest improvements regarding the associated medical examination. METHODS: The subjects were 1,444 diabetic patients diagnosed in the 5th Korean National Health and Nutrition Examination Survey (KNHANES), aged 19 years or older, who underwent non-mydriatic fundus photography. The criteria for diagnosing diabetes were a fasting glucose level ≥ 126 mg/dL and a previous diagnosis of diabetes or currently undergoing treatment. The diagnosis of diabetic retinopathy followed the modified Airlie House classification. Univariate and multivariate analyses of diabetic retinopathy were performed. RESULTS: Among the 1,444 patients who were diagnosed with diabetes, 277 had diabetic retinopathy; the prevalence rate was 19.18%. The higher the body mass index, the lower the risk of diabetic retinopathy by 0.924 times (p = 0.001; 95% confidence interval [CI], 0.883–0.966). The longer the duration of diabetes, the greater the risk of diabetic retinopathy; the prevalence period group of more than 11 years had a 26.025-fold higher risk than the newly diagnosed group (p < 0.001; 95% CI, 10.840–62.482). The risk of diabetic retinopathy increased with the hemoglobin A1c (HbA1c) level; the risk was 5.973-fold higher in the group with HbA1c above 11.0% (p < 0.001; 95% CI, 2.984–11.956) compared with the group with HbA1c < 6.0%. The risk of diabetic retinopathy was 2.050-fold greater with insulin injections (p = 0.003; 95% CI, 1.284–3.275). CONCLUSIONS: The risk of diabetic retinopathy was higher in patients with a longer duration of diabetes, a high HbA1c level, and in those using insulin. These findings highlight the need for early education and ophthalmologic examinations for at-risk patients.

The diagnostic accuracy of single- and five-field fundus photography in diabetic retinopathy screening by primary care physicians

Purpose: The aim is to evaluate the diagnostic accuracy of digital fundus photography in diabetic retinopathy (DR) screening at a single university hospital. Methods: This was a cross-sectional hospital-based study. One hundred and ninety-eight diabetic patients were recruited for comprehensive eye examination by two ophthalmologists. Five-field fundus photographs were taken with a digital, nonmydriatic fundus camera, and trained primary care physicians then graded the severity of DR present by single-field 45° and five-field fundus photography. Sensitivity and specificity of DR grading were reported using the findings from the ophthalmologists' examinations as a gold standard. Results: When fundus photographs of the participants' 363 eyes were analyzed for the presence of DR, there was substantial agreement between the two primary care physicians, ? = 0.6226 for single-field and 0.6939 for five-field photograph interpretation. The sensitivity and specificity of DR detection with single-field photographs were 70.7% (95% Confidence interval [CI]; 60.2%–79.7%) and 99.3% (95% CI; 97.4%–99.9%), respectively. Sensitivity and specificity for five-field photographs were 84.5% (95% CI; 75.8%–91.1%) and 98.6% (95% CI; 96.5%–99.6%), respectively. The receiver operating characteristic was 0.85 (0.80–0.90) for single-field photographs and 0.92 (0.88–0.95) for five-field photographs. Conclusion: The sensitivity and specificity of fundus photographs for DR detection by primary care physicians were acceptable. Single- and five-field digital fundus photography each represent a convenient screening tool with acceptable accuracy.

A evaluation research for the optimization and utilization of medical equipment in pediatric hospital / 中国医学装备

Objective:To provide more details and guide the management and usage as well as purchasing for medical equipment, so as to realize the optimization and utilization of the medical resources and impel Precision Medicine Initiative.Methods:The cost-effective analysis and the rate of return analysis of two large-scale precision equipments (MRI and Fundus camera usage) during January 2015 and June 2016 were performed. Besides, the equipment cost was divides into several more detailed projects in the research.Results: The rate of return of MRI in the first half year of 2016 was 8.5%, which was obviously higher than the one of 2015 which was 4.1%; the rate of return of Fundus camera usage in the first half year of 2016 was 25.9%, which was also obviously higher than the one of 2015 that was 15.0%. In the analysis, the depreciation of equipment was the main cost.Conclusion: It was critical and necessary to strengthen the standardized operation and routine maintenance in operation, in order to improve their safety usage rate.

Do it yourself smartphone fundus camera – DIYretCAM.

This article describes the method to make a do it yourself smartphone‑based fundus camera which can image the central retina as well as the peripheral retina up to the pars plana. It is a cost‑effective alternative to the fundus camera.

Use of Fundus Autofluorescence Images to Evaluate the Progression of Geographic Atrophy: Two-Year Follow-Up Study

PURPOSE: We evaluated the progression of geographic atrophy (GA) based on fundus autofluorescence (FAF) pattern and atrophy size using the fundus camera in non-exudative age-related macular degeneration (ARMD). METHODS: We acquired FAF images in non-exudative ARMD patients over a 2-year period. According to The Fundus Autofluorescence in Age-related Macular Degeneration (FAM) study, FAF patterns of geographic atrophy were classified into 5 categories. Examiners quantified the areas of GA in FAF images and analyzed the progression of atrophy based on FAF pattern and atrophy size. RESULTS: In 86 non-exudative ARMD eyes, elderly patients had faster progression rate of GA. The growth rates of GA were 1.51 mm2/year in 'Diffuse', 1.49 mm2/year in 'Banded', 1.05 mm2/year in 'Patchy', 0.59 mm2/year in 'Focal' and 0.16 mm2/year in 'None' pattern groups. In addition, the growth rate was 0.38 mm2/year in which initial the GA area was smaller than 1 disc area. This was the slowest progression rate among all categories according to initial GA area. CONCLUSIONS: As a result of evaluating the progression of geographic atrophy using FAF over a 2-year period, the growth rate of GA was the fastest in the 'Diffuse' pattern group. Additionally, as the initial GA area became smaller, the progression of GA atrophy was slower (p < 0.002). Although limitations such as short follow-up period and measurement error of GA atrophy area using fundus photography were compensated, the results in the present study were similar to the outcomes of studies on progression of GA based on FAF pattern using the scanning laser ophthalmoscope over several years and the fundus camera for 1 year. In conclusion, the fundus camera is a useful tool for the prediction of long-term progression of GA in patients with non-exudative ARMD.

Clinical significance of non - mydriatic fundus photography in screening for preschool children ocular fundus disease / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the incidence of ocular fundus disease in preschool children examined by non-mydriatic fundus camera and evaluate its effectiveness compared with direct inspection shadow mirror. METHODS: Three thousand eight hundred and ninety-six preschool children from April 2012 to October 2013 were examined by Topcon TRC-NW300 color fluorescence fundus camera and direct inspection shadow mirror, and images were saved immediately. RESULTS: Detection rate of non - mydriatic fundus photography was higher than that of direct inspection shadow mirror. In 3 896 cases, 41 eyes were detected abnormal fundus accounting for 1. 05%. The retinal myelinated nerve fibers, morning glory syndrome, retinitis pigmentosa, congenital retinoschisis were common, accounted for 24. 39%, 21. 95%, 14. 63%, 12-20% respectively. The children eye diseases were often accompanied by abnormal vision (68. 30%), ametropia (63. 41%), strabismus (19. 51%). CONCLUSION:Non-mydriatic fundus photography is a mydriatic method without medicine, so it is easy for preschool children to accept. Image results could directly display the fundus lesions. It shows important significance in the screening for preschool children eye diseases.

Early Detection of Glaucomatous Optic Nerve Abnormality by Nonmydriatic Digital Fundus Camera in a Routine Health Check-up

PURPOSE: To investigate the usefulness of the non-mydriatic digital fundus camera for detection of normal-tension glaucoma in routine health check-ups. METHODS: Among 1986 persons who received a routine health check-up in the Kangnam Health Care Center of Seoul National University Hospital (SNUH) from October to December 2003, 60 patients were referred to the Glaucoma Clinic of SNUH due to a suspicious optic nerve head or a retinal nerve fiber layer (RNFL) defect detected by a non-mydriatic digital fundus camera. The glaucoma work-up was performed, including Goldmann applanation tonometry, red free RNFL photography, Humphrey visual field (HVF), Stratus OCT and HRT II. RESULTS: Among 60 patients with a suspicious optic nerve head or suspected RNFL defect, 23 patients showed a retinal nerve fiber layer defect on red free RNFL photography. Those 23 patients had already demonstrated possible RNFL defects on photographs taken by a non-mydriatic digital fundus camera at their routine health check-up. In comparison with the normal, high PSD value of HVF (p=0.002), the narrow neuroretinal rim area shown by OCT (p=0.05) and HRT (p=0.02) were significantly different statistically. CONCLUSIONS: The non-mydriatic digital fundus camera can serve as a useful tool to screen normal-tension glaucoma in routine health check-up systems. However, the final diagnosis of glaucoma should be confirmed by red free RNFL photography and standard automated perimetry.

A new method of cataract imaging evaluation / 眼科

Photography of slit-lamp biomicroscopy combined with retro-illumination photography is the gold standard in cataract evaluation. However the application is limited due to its complexity and low efficiency. We introduce digital non-mydriatic fundus photography as a new method for cataract screening in patients with visual impairment,which might play an important role in screening low vision and blindness caused by cataract. Two distinguished benefits are found in this method including compatibility for tele-diagnosis,and integration with screening of glaucoma and diabetic retinopathy. Cautions should be made on the photographs in which media opacity derived from other than cataract or low quality photos due to small pupils.