Evaluation of a portable fundus camera for use in the teleophthalmologic diagnosis of glaucoma.

PURPOSE: The digital images of the optic disk from a portable fundus camera were evaluated for suitability in teleophthalmologic screening for glaucoma. METHODS: Fifty-one eyes of 27 consecutive patients from our glaucoma clinic were dilated and photographed with a Zeiss FF retinal camera (Carl Zeiss, Oberkochen, Germany) and a portable Nidek NM-100 (Nidek, Tokyo, Japan) fundus camera. Digital images from the portable fundus camera were digitized, compressed and stored in a Fujix DF-10M (Fuji, Tokyo, Japan) digitizer. Lossy compressed digital images and photographs from the Zeiss camera were presented separately in random order to three ophthalmologists for estimation of vertical cup:disk ratios (VCDR) and to evaluate image quality as good, acceptable, or unacceptable for screening glaucoma. Gold standard VCDRs were measured from monoscopic photographic slides obtained using the Zeiss camera by a fourth ophthalmologist. RESULTS: Measurement of agreement (Kappa values) between estimated VCDR of digital images and photographs by the three ophthalmologists were 0.52, 0.38, and 0.50 respectively. Agreement between gold standard and estimated VCDR from photographs were 0.87, 0.45, and 0.84 respectively (specificity between 79% and 97%, sensitivity between 70% and 95%). Kappa values obtained between gold standard and estimated VCDR from digital images were 0.52, 0.49, and 0.49, respectively (specificity between 68% and 79%, sensitivity between 67% and 87%. CONCLUSION: Moderate to good agreement indicates that the digital images from the portable fundus camera may be suitable for optic disk assessment in the current configuration. This easy to use Nidek hand-held camera could be a viable instrument for teleophthalmology if a better digitizing system is incorporated to improve the quality of the images.     

Novel approach towards colour imaging using a scanning laser ophthalmoscope

AIMS—Conventional fundus imaging using a fundus camera produces colour fundus pictures. The scanning laser ophthalmoscope (SLO) has the advantages of lower levels of light exposure, improved contrast, and direct digital imaging but until now has produced monochromatic images as a laser of single wavelength is used. True representation of the fundus is possible by combining images taken using blue, green, and red lasers.
METHODS—A custom built SLO was used to capture blue, green, and red fundus images from suitable volunteers and patients with fundus disease. Images were corrected for eye movement and combined to form a colour image. Colour fundus photographs were taken using a fundus camera for comparison with the SLO image.
RESULTS—The background fundus and retinal vasculature had similar appearances with the two imaging modalities. Internal limiting membrane reflections were prominent with the SLO. Identification of new vessels in the diabetic fundus was easier with the SLO than the colour fundus photographs.
CONCLUSION—A colour SLO offers all the advantages of the present monochromatic imaging system with the added advantage of true colour representation of the fundus.

Keywords: scanning laser ophthalmoscope; fundus imaging; digital colour fundus images     

七方位彩色眼底照像法对糖尿病视网膜病变的诊断价值

目的 筛选经济、简便、有效地糖尿病视网膜病变检查法.方法 分别采用散瞳50度眼底后极部彩色照像法、美国早期糖尿病性视网膜病变治疗研究小组确立的散瞳30度眼底七方位彩色照像法和FFA法对164例(308只眼)糖尿病患者进行检查,由有经验的眼底医生按照糖尿病视网膜病变国际临床分类法对图片进行分析给出分期,对三种方法所得结果进行比较.结果 散瞳50度眼底后极部彩色照像法和FFA法在DR诊断分期中一致性一般(k=0.488),七方位彩色眼底照像法和FFA法在DR诊断分期中有比较好的一致性(k=0.873).结论 七方位彩色眼底照像法可作为糖尿病视网膜病变筛查和指导治疗的一种比较可靠的方法,而散瞳50度眼底后极部彩色照像法的可靠性一般.     

Comparison of stereo optic disc photographs from the Nidek 3-Dx and Zeiss retinal cameras

Objective: To compare the Zeiss retinal camera with the Nidek 3-Dx camera for photographic quality and stereo separation.
Subjects: Eleven subjects (22 eyes) were selected from patients referred for optic disc photography.
Methods: The subjects were photographed using the Nidek 3-Dx camera for simultaneous stereo photographs, and the 30° field and 15° field settings on the Zeiss retinal camera for sequential stereo photographs. Four ophthalmologists qualitatively scored the photographs on a five-point scale for stereo separation and photographic resolution and sharpness. The results from the four observers were averaged and the Friedman two-way analysis of variance used to analyse the results.
Conclusions: It was found that the stereo separation is significantly better using the Nidek camera when compared with both the 30° and 15° Zeiss results. There was no significant difference in photographic quality between the Nidek and Zeiss 30° photographs. It was also found that the Zeiss 30° images had a significantly higher quality than the Zeiss 15°, which contradicted previous results.     

Smartphone fundoscopy for retinopathy of prematurity

PurposeThe utility of digital fundus images in retinopathy of prematurity (ROP) screening has been established. A smartphone can be a device available to most ophthalmologists to capture digital fundus photographs. In this study, fundus images were captured with original camera settings for ROP documentation.MethodsThe examination was performed under topical anesthesia. An assistant held a glass stick against the eye movement if infants moved their eyes too frequently. A hand-held smartphone and a 30D lens were used to record the fundus in video mode. A continuous flash was turned on to provide almost constant coaxial illumination. Fundus photographs were captured from the video film.ResultsFundus photographs can be captured successfully with a smartphone and a 30D lens under original camera settings.ConclusionFundus photographs of acceptable diagnostic quality can be obtained in ROP patients conveniently and inexpensively using a portable hand-held smartphone. It might be a useful tool in documentation, education, consultation, and telemedicine in ROP.     

Study of the Retinal Imaging and Output in Premature Baby under a Computer-assisted Binocular Indirect Ophthalmoscope

 Purpose: To explore a clear retinal imaging and output and enhance the development of retinopathy of prematurity (ROP) screening, which is safe and effective for ROP screening in premature infants. Methods: A computer-assisted binocular indirect ophthalmoscope imaging and output system was equipped with camera and image processing hardware and connected to computers. The process of fundus examination was videotaped (photograph) and output. Simulated eyes were utilized to debug video head and acquire stable and clear fundus images by binocular indirect ophthalmoscope for premature infants. Results: Fundus imaging output technique was sucessfully established. The common reasons of unclear imaging and corresponding solutions were summarized. This technique can capture and output stable and clear fundus images of premature infants. Conclusion: Assisted by hardware and software processing, a compute assisted binocular indirect ophthalmoscope imaging and output system was established, which can be used for screening, research, treatment and follow-up of ROP in premature babies to resolve the difficulty in obtaining clear fundus photograph.     

Video indirect ophthalmoscopy using a hand-held video camera

Fundus photography in adults and cooperative children is possible with a fundus camera or by using a slit lamp-mounted digital camera. Retcam TM or a video indirect ophthalmoscope is necessary for fundus imaging in infants and young children under anesthesia. Herein, a technique of converting and using a digital video camera into a video indirect ophthalmoscope for fundus imaging is described. This device will allow anyone with a hand-held video camera to obtain fundus images. Limitations of this technique involve a learning curve and inability to perform scleral depression.     

Screening for diabetic retinopathy using a digital non-mydriatic camera compared with standard 35-mm stereo colour transparencies

PURPOSE: To investigate the use of a digital non-mydriatic camera for determining the ETDRS clinical level of diabetic retinopathy, and to evaluate its use in a screening setting to appropriately determine the need for referral to an ophthalmologist (ETDRS level > or = 35). METHODS: A total of 83 patients with diabetes were photographed with and without pharmacological pupil dilation at an ophthalmology department using a digital non-mydriatic camera, obtaining two sets of five non-stereoscopic, 45 degree field images of each eye. ETDRS seven standard field, 35-mm stereoscopic colour fundus photographs were also obtained. A subgroup of 59 patients was photographed at an optician's shop using the digital non-mydriatic camera without pupil dilation. RESULTS: There was substantial agreement between the clinical level of diabetic retinopathy assessed from the 35-mm photographs and the digital images: the ophthalmology department (kappa = 0.76) with pupil dilation and (kappa = 0.66) without pupil dilation, respectively, and at the optician's (kappa = 0.60 without pupil dilation). With respect to the need for referral to an ophthalmologist, there was almost perfect agreement in the ophthalmology department (kappa = 0.88) with pupil dilation and (kappa = 0.84) without pupil dilation, respectively, and those taken at the optician's (kappa = 0.87 without pupil dilation). CONCLUSION: A digital non-mydriatic camera may be used in a screening situation to appropriately determine the need for referral to an ophthalmologist (ETDRS level > or = 35).     

Selfie fundus imaging for diabetic retinopathy screening

BackgroundRegular screening for retinopathy and timely intervention reduces blindness from diabetes by 90%. Screening is currently dependent on the interpretation of images captured by trained technicians. Inherent barriers of accessibility and affordability with this approach impede widespread success of retinopathy screening programs. Herein, we report our observations on the potential of a novel approach, Selfie Fundus Imaging (SFI), to enhance diabetic retinopathy screening.MethodsThe study was undertaken over a two-month period during COVID 19 lockdown. 60 diabetic patients participated in the study. Retinal images were captured using three different approaches, handheld smartphone-based photographs captured by patients themselves after a short video-assisted training session (SFI group), and smartphone-based photographs captured by a trained technician and photographs taken on desktop conventional digital fundus camera (Gold standard). Sensitivity and kappa statistics was determined for retinopathy and macular oedema grading.FindingsMean age of the study participants was 52.4 years ± 9.8 years and 78% were men. Of 120 images captured using SFI, 90% were centred-gradable, 8% were decentred-gradable and 2% were ungradable. 82% patients captured the image within a minute (majority by 31–45 s). The sensitivity of SFI to detect diabetic retinopathy was 88.39%. Agreement between SFI grading and standard fundus photograph grading was 85.86% with substantial kappa (0.77). For the detection of diabetic macular oedema, the agreement between SFI images and standard images was 93.67, with almost perfect kappa (0.91).ConclusionFundus images were captured by patients using SFI without major difficulty and were comparable to images taken by trained specialist. With greater penetrance, advances, and availability of mobile photographic technology, we believe that SFI would positively impact the success of diabetic retinopathy screening programs by breaking the barriers of availability, accessibility, and affordability. SFI could ensure continuation of screening schedules for diabetic retinopathy, even in the face a highly contagious pandemic.Subject terms: Outcomes research, Retinal diseases, Physical examination     

Digital photographic screening for diabetic retinopathy in the James Bay Cree

This study evaluates a single, 45-degree fundus image from a non-mydriatic camera for the triage of subjects at risk for diabetic retinopathy. A complete retinal assessment by a retina specialist was the main comparator for the camera. Inter-observer agreements were calculated for the reading of digital images with different grades of retinopathy. Two hundred eyes of 100 consecutive subjects were evaluated as part of the James Bay diabetic retinopathy screening project; 62% of subjects had no retinopathy, 12% had microaneurysms only, 24% had non-proliferative retinopathy, 5% had clinically significant macular edema (CSME), and 2% had proliferative disease (PDR). The Kappa statistic for two independent observers was 0.85 (p < 0.001) for the identification of retinopathy from the digital images. The sensitivity of the digital camera for the evaluation of any retinopathy was 84.4%, for CSME and/or PDR it was over 90%. The use of a single digital retinal image for the evaluation of diabetic retinopathy was performed with a high degree of inter-observer concordance and a high degree of sensitivity.     

Assessing the natural course of diabetic retinopathy: a population-based study in Kinmen, Taiwan

PURPOSE: To explore the natural course of diabetic retinopathy among type 2 diabetics using the indirect ophthalmoscope and single-field fundus photographs in Kinmen, Taiwan. METHODS: A screening program for diabetic retinopathy was carried out by a panel of ophthalmologists, who employed the ophthalmoscope and 45-degree retinal color photographs to examine the fundus after pupil dilation. Screening, which was conducted between 1999 and 2002, involved 971 patients diagnosed with type 2 diabetes. A multi-state Markov model was used to assess the natural course of diabetic retinopathy among type 2 diabetics. RESULTS: Among the 725 diabetes patients who attended at least two ophthalmological fundus check-ups and were screened, the overall response rate was about 75%. The mean duration of the disease states mild nonproliferative diabetic retinopathy, moderate nonproliferative diabetic retinopathy, severe nonproliferative diabetic retinopathy, and proliferative diabetic retinopathy were 4.05 [95% confidence interval (CI): 3.28-5.32], 4.18 (95% CI: 3.18-6.06), 2.52 (95% CI: 1.78-4.27), and 4.22 (95% CI: 2.88-7.81) years, respectively. Compared to controls, the incidence of blindness reduction for annual, biennial, 3-year, 4-year, and 5-year screenings of diabetic retinopathy were approximately 94.4% (95% CI: 91.6%-96.3%), 83.9% (95% CI: 83.6%-84.2%), 70.2% (95% CI: 69.8%-70.7%), 57.2% (95% CI: 56.7%-57.7%), and 45.6% (95% CI: 45.0%-46.1%), respectively. CONCLUSIONS: In conclusion, the average time for the development of diabetic retinopathy from nonexistence to blindness was approximately 26.5 years. The present recommendation for annual screening in type 2 diabetics with nonproliferative diabetic retinopathy should be retained only for the mild form, not for the moderate or severe forms.     

Automatic detection of diabetic retinopathy using an artificial neural network: a screening tool.

AIMS: To determine if neural networks can detect diabetic features in fundus images and compare the network against an ophthalmologist screening a set of fundus images. METHODS: 147 diabetic and 32 normal images were captured from a fundus camera, stored on computer, and analysed using a back propagation neural network. The network was trained to recognise features in the retinal image. The effects of digital filtering techniques and different network variables were assessed. 200 diabetic and 101 normal images were then randomised and used to evaluate the network's performance for the detection of diabetic retinopathy against an ophthalmologist. RESULTS: Detection rates for the recognition of vessels, exudates, and haemorrhages were 91.7%, 93.1%, and 73.8% respectively. When compared with the results of the ophthalmologist, the network achieved a sensitivity of 88.4% and a specificity of 83.5% for the detection of diabetic retinopathy. CONCLUSIONS: Detection of vessels, exudates, and haemorrhages was possible, with success rates dependent upon preprocessing and the number of images used in training. When compared with the ophthalmologist, the network achieved good accuracy for the detection of diabetic retinopathy. The system could be used as an aid to the screening of diabetic patients for retinopathy.     

Comparison of a digital retinal imaging system and seven-field stereo color fundus photography to detect diabetic retinopathy in the primary care environment.

BACKGROUND AND OBJECTIVE: Because patients with diabetes mellitus may visit their primary care physician regularly but not their ophthalmologist, a retinal risk assessment in the primary care setting could improve the screening rate for diabetic retinopathy. An imaging system for use in the primary care setting to identify diabetic retinopathy requiring referral to an ophthalmologist was evaluated. PATIENTS AND METHODS: In a masked prospective study, images were obtained from 11 patients with diabetes mellitus using both the digital retinal imaging system and seven-field stereo color fundus photography. The ability to obtain gradable images and to identify diabetic retinal lesions was compared. RESULTS: Of all images, 85% of digital retinal imaging system images and 88% of seven-field images were gradable. Agreement based on "no retinopathy" versus "any retinopathy" was excellent (Kappa = 0.96). Agreement based on "microaneurysms or less retinopathy" versus "retinal hemorrhages or worse retinopathy" was very good (Kappa = 0.83). CONCLUSIONS: The agreement between the digital retinal imaging system and seven-field photography indicates that the digital retinal imaging system may be useful to screen for diabetic retinopathy.     

Assessing the Natural Course of Diabetic Retinopathy: A Population-Based Study in Kinmen,Taiwan

Purpose: To explore the natural course of diabetic retinopathy among type 2 diabetics using the indirect ophthalmoscope and single-field fundus photographs in Kinmen, Taiwan. Methods: A screening program for diabetic retinopathy was carried out by a panel of ophthalmologists, who employed the ophthalmoscope and 45-degree retinal color photographs to examine the fundus after pupil dilation. Screening, which was conducted between 1999 and 2002, involved 971 patients diagnosed with type 2 diabetes. A multi-state Markov model was used to assess the natural course of diabetic retinopathy among type 2 diabetics. Results: Among the 725 diabetes patients who attended at least two ophthalmological fundus check-ups and were screened, the overall response rate was about 75%. The mean duration of the disease states mild nonproliferative diabetic retinopathy, moderate nonproliferative diabetic retinopathy, severe nonproliferative diabetic retinopathy, and proliferative diabetic retinopathy were 4.05 [95% confidence interval (CI): 3.28–5.32], 4.18 (95% CI: 3.18–6.06), 2.52 (95% CI: 1.78–4.27), and 4.22 (95% CI: 2.88–7.81) years, respectively. Compared to controls, the incidence of blindness reduction for annual, biennial, 3-year, 4-year, and 5-year screenings of diabetic retinopathy were approximately 94.4% (95% CI: 91.6%–96.3%), 83.9% (95% CI: 83.6%–84.2%), 70.2% (95% CI: 69.8%–70.7%), 57.2% (95% CI: 56.7%–57.7%), and 45.6% (95% CI: 45.0%–46.1%), respectively. Conclusions: In conclusion, the average time for the development of diabetic retinopathy from nonexistence to blindness was approximately 26.5 years. The present recommendation for annual screening in type 2 diabetics with nonproliferative diabetic retinopathy should be retained only for the mild form, not for the moderate or severe forms.     

上海市北新泾社区糖尿病视网膜病变远程筛查系统的应用研究

目的 探讨社区糖尿病视网膜病变(DR)远程筛查系统的应用效果.方法 横断面研究.以免散瞳数码眼底照相机和计算机网络技术为基础,构建社区DR远程筛查系统.采用随机数字表法抽取109例已进入筛查系统的糖尿病居民进行系统评价.评价内容:1)经过培训的视力检查员和眼科医师对同一患者双眼远视力检查结果的一致性,采用配对t检验进行分析;不同眼病的分析人员分别按该系统中免散瞳眼底照相的读片法和散瞳后应用检眼镜、裂隙灯显微镜联合90D非接触镜检查法(传统检查法),对同一患者双眼DR诊断和分级结果的一致性进行评价,采用kappa值和组内相关系数进行分析;(2)对眼底照相获取的图像进行不同比例的压缩,通过该系统网络传输后,采用组内相关系数分析压缩后的图像质量,获得合适的压缩比例;(3)计算筛查系统运行所需的时间,并与传统检杳法进行比较.结果 109例(218只眼)受检者中,由眼科医师检查获取的视力分布情况:力<0.05者13只眼,视力0.05～0.3者61只眼,视力≥0.3者144只眼,与其他检查人员的视力检查结果比较,差异无统计学意义(t=-0.572,P=0.568).采用传统检杳法与眼底照相法诊断为DR的眼数相同,均为52只眼,两者间比较的kappa值为0.885,95%可信区间为0.807～0.963;DR不同分级诊断的一致性:内相关系数为0.91,95%可信区间为0.85～0.94,表明两者的一致性好.将眼底照相获取的图像,以最大限度压缩至原始图像的15%(526×350像素)时,图像清晰度仍不受影响.每位受检者实时远程筛查所需的时间为5～7 min,略少于传统检查法所需时间.结论 社区DR远程筛查系统可满足DR患者筛查的需求.     

北京市两个街道50岁以上居民免散瞳眼底照相筛查眼底病的初步研究

目的 探讨免散瞳眼底照相在社区50岁以上居民中眼底病筛查中的可行性及应用价值。设计 横断面调查。研究对象 北京市海淀区万寿路街道和田村街道通过电话通知及海报招募50岁以上的社区居民3742人。方法 对研究对象进行日常生活视力、裂隙灯检查,并使用免散瞳数码眼底相机采集眼底像。对眼底照相诊断为黄斑部疾病者,进行相干光断层扫描（OCT）。主要指标 眼底病构成比。结果 3742人参与调查,2914例（77.87%）眼底像可用于分析。筛查出视网膜动脉硬化1081例（37.1%）;可疑青光眼270例（9.27%）;年龄相关性黄斑变性178例（6.11%）;糖尿病视网膜病变65例（2.23%）;黄斑前膜38例（1.30%）;拟诊黄斑裂孔35例（1.20%）,星状玻璃体变性26例（0.89%）;视网膜有髓神经纤维17例（0.58%）;视网膜血管炎15例（0.51%）;视网膜静脉阻塞4例（0.14%）;视神经萎缩5例（0.17%）;视盘血管瘤1例（0.03%）;其他眼底病变12例（0.41%）。眼底照相诊断为黄斑变性、黄斑前膜及黄斑裂孔者的OCT诊断一致率为86.90%（219/252）。828例（22.13%）未能获得可供分析的眼底像,其比例随年龄增加而增加。结论 使用免散瞳眼底照相可对大多数50岁以上人群进行眼底病筛查,是一种客观、可行的方法。（眼科,2013,22： 230-233）     

Screening for diabetic retinopathy by one-field, non-mydriatic, 45 degrees digital photography is inadequate

PURPOSE: To evaluate the sensitivity and specificity of one-field, non-mydriatic, 45 degrees digital photography for screening for diabetic retinopathy compared to indirect ophthalmoscopy using a slit-lamp, the reference standard. METHODS: A total of 100 consecutive diabetic patients (200 eyes) who underwent digital fundus photography and ocular examinations from June 2002 to November 2002 were included in this retrospective study. The patients, recruited from a hospital-based, retina referral practice, underwent 45 degrees, non-mydriatic, digital fundus photography using a non-mydriatic fundus camera. One image was obtained focusing the mid fundus between the optic disc and the macula. The fundus images were printed and graded by endocrinologists and a retinal specialist separately. The patients also underwent complete standard ocular examinations as the reference method for determining diabetic retinopathy, including dilation of their pupils and slit-lamp biomicroscopy done by ophthalmologists. The sensitivity and specificity of the digital photographic method were calculated by comparison to the reference method. RESULTS: The sensitivity and specificity of the retinal specialist's diabetic retinopathy grades were 53.8 and 89.0%, respectively. The sensitivity and specificity of the endocrinologists' grades were 45 and 75.3%, respectively. The false negative rates were 22 and 21.5% for endocrinologists and the retinal specialist, respectively. CONCLUSIONS: Screening for diabetic retinopathy using one-field, non-mydriatic, 45 degrees digital photography is inadequate.     

Grading of diabetic retinopathy from non-stereoscopic color fundus photographs--relationship to fluorescein angiography findings and three-year prognosis

PURPOSE: To evaluate the grading of diabetic retinopathy from non-stereoscopic color fundus photographs, we examined the relation of the photos to fluorescein angiography findings and to the three-year prognosis. METHODS: Fifty diabetic patients(70 eyes) who had severe non-proliferative diabetic retinopathy or early proliferative retinopathy without photocoagulation treatment were graded regarding 11 items of four-field fundus photographs using a 50-degree mydriatic camera. Fluorescein angiography was performed and the relation of the images to the grades of diabetic retinopathy were analyzed. In 51 eyes, the relation between the grading and the progression and treatment of diabetic retinopathy were evaluated. RESULTS: The grading of microaneurysms and retinal hemorrhages (p < 0.001), soft exudates (p = 0.01), intraretinal microvascular abnormalities (p < 0.001), arteriolar white threads (p = 0.003), venous loops (p = 0.01), and new vessels (p < 0.001) was significantly related to the nonperfused areas on fluorescein angiograms. The grading of diabetic retinopathy was also significantly related to the threeyear prognosis. CONCLUSION: These results indicated that the grading of diabetic retinopathy from fundus photographs may have a potential advantage over conventional classifications of diabetic retinopathy.     

Feasibility Study on Computer-Aided Screening for Diabetic Retinopathy

Purpose

To conduct a feasibility study of computer-aided screening for diabetic retinopathy by developing a computerized program to automatically detect retinal changes from digital retinal images.

Methods

The study was carried out in three steps. Step 1 was to collect baseline retinal image data of 600 eyes of normal subjects with normal fundi and data of 300 eyes of diabetic patients with diabetic retinopathy. All data were recorded by digital fundus camera. Step 2 was to analyse all retinal images for normal and abnormal features. By this method, the automated computerized screening program was developed. The program preprocesses colour retinal images and recognizes the main retinal components (optic disc, fovea, and blood vessels) and diabetic features such as exudates, haemorrhages, and microaneurysms. All of the accumulated information is interpreted as normal, abnormal, or unknown. Step 3 was to evaluate the sensitivity and specificity of the computerized screening program by testing the program on diabetic patients and comparing the program's results with the results of screening by retinal specialists.

Results

Diabetic patients (182 patients, 336 eyes) were examined by retinal specialists; 221 eyes had a normal fundus and 115 eyes had nonproliferative diabetic retinopathy. Digital retinal images were taken of these 336 eyes and interpreted by the automated screening program. The program had a sensitivity and specificity of 74.8% and 82.7%, respectively.

Conclusions

The automated screening program was able to differentiate between the normal fundus and the diabetic retinopathy fundus. The program may be beneficial for use in screening for diabetic retinopathy. Further development of the program may provide higher sensitivity.?Jpn J Ophthalmol 2006;50:361–366 © Japanese Ophthalmological Society 2006     

Review of retinal cameras for global coverage of diabetic retinopathy screening

The global burden of diabetes has resulted in an increase in the prevalence of diabetic retinopathy (DR), a microvascular complication of diabetes. Lifelong repetitive screening for DR is essential for early detection and timely management to prevent visual impairment due to the silent sight-threatening disorder. Colour fundus photography (CFP) is helpful for documentation of the retinopathy as well as for counselling the patient. CFP has established roles in DR screening, detection, progression and monitoring of treatment response. DR screening programmes use validated mydriatic or non-mydriatic fundus cameras for retinal imaging and trained image graders identify referable DR. Smartphone-based fundus cameras and handheld fundus cameras that are cost-effective, portable and easy to handle in remote places are gaining popularity in recent years. The images captured with these low-cost devices can be immediately sent to trained ophthalmologists for grading of DR. Recent increase in numbers of telemedicine programmes based on imaging with digital fundus cameras and remote interpretation has facilitated larger population coverage of DR screening and timely referral of those with sight-threatening DR to ophthalmologists. Good-quality retinal imaging and accurate diagnosis are essential to reduce inappropriate referrals. Advances in digital imaging such as ultra-wide field imaging and multi-modal imaging have opened new avenues for assessing DR. Fundus cameras with integrated artificial intelligence (AI)-based automated algorithms can also provide instant DR diagnosis and reduce the burden of healthcare systems. We review the different types of fundus cameras currently used in DR screening and management around the world.Subject terms: Retinal diseases, Outcomes research, Medical imaging