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.     

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.     

计算机辅助间接检眼镜下正常早产儿眼底与早产儿视网膜病变的特征观察

目的 观察计算机辅助的双目间接检眼镜成像系统检查所见的早产儿正常眼底以及早产儿视网膜病变(ROP)图像特征，探讨计算机辅助的双目间接检眼镜成像系统在ROP筛查中 的 临床应用价值。方法 2006年1月至2006年12月期间，通过计算机辅助的 双目间接检眼镜成 像系统对150例早产儿行ROP早期筛查，首次检查的时间为早产儿出生后4~6周或其矫正胎龄 已达32周，并根据首次检查结果决定随诊时间。对检查过程进行录像，并对有意义的图像进 行拍照，以获得正常早产儿和ROP患眼的眼底图像。回顾分析时对各种图像特征进行对比分 析观察。结果 150例早产儿均通过双目间接检眼镜获得正常早产儿眼底 图像或各期典型的R OP图像。其中，正常早产儿眼底视盘色泽为较淡，周边视网膜仍未血管化呈青灰色调；ROP 各期在双目间接检眼镜下均具有不同的典型表现。结论 计算机辅助双 目间接检眼镜成像系 统可清楚地观察到早产儿正常眼底和各期ROP眼底的特征变化,真实客观的保存检查结果，在ROP筛查与治疗随访中具有一定应用价值。     

Unconventional techniques of fundus imaging: A review

The methods of fundus examination include direct and indirect ophthalmoscopy and imaging with a fundus camera are an essential part of ophthalmic practice. The usage of unconventional equipment such as a hand-held video camera, smartphone, and a nasal endoscope allows one to image the fundus with advantages and some disadvantages. The advantages of these instruments are the cost-effectiveness, ultra portability and ability to obtain images in a remote setting and share the same electronically. These instruments, however, are unlikely to replace the fundus camera but then would always be an additional arsenal in an ophthalmologist''s armamentarium.     

Retinal imaging in infants

Digital retinal imaging is at the core of a revolution that is continually improving the screening, diagnosis, documentation, monitoring, and treatment of infant retinal diseases. Historically, imaging the retina of infants had been limited and difficult to obtain. Recent advances in photographic instrumentation have significantly improved the ability to obtain high quality multimodal images of the infant retina. These include color fundus photography with different camera angles, ultrasonography, fundus fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography. We provide a summary of the current literature on retinal imaging in infants and highlight areas where further research is required.     

标准方位眼底摄像技术在早产儿视网膜病变远程筛查中的应用

目的　观察标准方位眼底摄像技术在早产儿视网膜病变（retinopathy of prematurity，ROP）远程筛查中的应用价值。方法　将2016年11月至2018年2月通过我院ROP远程筛查阅片系统筛查的早产儿1402例2804眼纳入研究，男711例1422眼，女691例1382眼。所有早产儿均使用双目间接眼底镜检查和广角数码视网膜成像系统完成眼底标准方位摄像，并将图像上传至远程阅片系统进行远程阅片。统计远程阅片系统检出ROP发病的阳性率、假阴性率、灵敏度、特异度以及ROP总发病率，评价标准方位眼底摄像技术在ROP远程筛查中的价值。结果　1402例2804眼经远程筛查系统阅片，84例168眼发病，阳性率为6.0%；因图像模糊或方位不佳导致阅片困难，可疑病变，而双目间接眼底镜检查确诊的ROP患者5例10眼，假阴性率为0.3%，灵敏度为94.4%；所有患儿总发病率为6.3%，需要激光或抗血管内皮生长因子（vascular endothelial growth factor,VEGF)治疗的重症ROP患儿28例56眼，占2.0%，其中急进型后极部ROP患儿5例10眼、阈值期患儿14例28眼、阈值前1型患儿9例18眼。重症ROP患儿中，26例52眼经一次激光或抗VEGF治疗后病情得到控制，2例4眼急进型后极部ROP患儿经抗VEGF治疗后4周病情复发，再次给予激光光凝治疗后病情稳定。所有患儿无一例漏诊、误诊、贻误最佳治疗时机者。结论　标准方位眼底摄像技术是ROP远程筛查的有力保障；ROP远程筛查阅片系统对ROP病变检出灵敏度高，可以有效解决目前ROP专业防治人员相对缺乏的困境。     

A simple method for panretinal imaging with the slit lamp

Slit lamp biomicroscopy of the retina with a convex lens is a key procedure in clinical practice. The methods presented enable ophthalmologists to adequately image large and peripheral parts of the fundus using a video-slit lamp and freely available stitching software. A routine examination of the fundus with a slit lamp and a +90 D lens is recorded on a video film. Later, sufficiently sharp still images are identified on the video sequence. These still images are imported into a freely available image-processing program (Hugin, for stitching mosaics together digitally) and corresponding points are marked on adjacent still images with some overlap. Using the digital stitching program Hugin panoramic overviews of the retina can be built which can extend to the equator. This allows to image diseases involving the whole retina or its periphery by performing a structured fundus examination with a video-slit lamp. Similar images with a video-slit lamp based on a fundus examination through a hand-held non-contact lens have not been demonstrated before. The methods presented enable those ophthalmologists without high-end imaging equipment to monitor pathological fundus findings. The suggested procedure might even be interesting for retinological departments if peripheral findings are to be documented which might be difficult with fundus cameras.     

Current status and future possibilities of retinal imaging in diabetic retinopathy care applicable to low- and medium-income countries

Diabetic retinopathy (DR) is a leading cause of blindness among adults and the numbers are projected to rise. There have been dramatic advances in the field of retinal imaging since the first fundus image was captured by Jackman and Webster in 1886. The currently available imaging modalities in the management of DR include fundus photography, fluorescein angiography, autofluorescence imaging, optical coherence tomography, optical coherence tomography angiography, and near-infrared reflectance imaging. These images are obtained using traditional fundus cameras, widefield fundus cameras, handheld fundus cameras, or smartphone-based fundus cameras. Fluorescence lifetime ophthalmoscopy, adaptive optics, multispectral and hyperspectral imaging, and multicolor imaging are the evolving technologies which are being researched for their potential applications in DR. Telemedicine has gained popularity in recent years as remote screening of DR has been made possible. Retinal imaging technologies integrated with artificial intelligence/deep-learning algorithms will likely be the way forward in the screening and grading of DR. We provide an overview of the current and upcoming imaging modalities which are relevant to the management of DR.     

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     

The St. Gallen digital ophthalmological imaging system

BACKGROUND: Digital photography has many advantages over the conventional method. At present commercially available digital ophthalmological imaging systems utilise only a fraction of the advantages of this technique and some of them have fundamental conceptional problems. METHODS: Images of a fundus camera, a slit lamp and a scanning laser ophthalmoscope were digitised using digital and video cameras and/or frame grabber cards. Digital images and movies were recorded via a personal computer. The image recording software was developed using an imaging library and open source software. The recorded images and video sequences were processed with three different commercially available programme packages. The images were archived in a around-the-clock accessible database. RESULT: Our digital imaging system is capable to record normal and high resolution slit lamp images, colour fundus images in normal resolution, Fluorescein angiography images in normal and high resolution, digital simultaneous ICG and Fluorescein videoangiograms (without compression) and high resolution macro images. Different functions, e.g., contrast enhancement are integrated in the image capture software. Most of the parameters of the image acquisition are individually adaptable. The digital image archive supports multiple image and video formats. CONCLUSIONS: Using standard software and hardware components an imaging system can be constructed featuring functions usually not available in commercial ones. Since the system is adaptable, recording of images with a wide variety of parameters, e.g., for measurements for scientific experiments, is possible.     

以临床前期糖尿病视网膜病变为例分析医学图像人工智能系统在自发荧光图像识别中的应用

目的：以临床前期糖尿病视网膜病变为例分析医学图像人工智能系统对于自发荧光图像识别的能力，为早期诊断治疗提供技术支持。方法：连续收集2017年8月至2018年5月在温州医科大学附属第三医院眼科门诊就诊患者的眼底自发荧光图像，按是否患有糖尿病标准，纳入正常组102例（200 眼），糖尿病组105例（200眼）。受检者均行裂隙灯显微镜、前置镜、裸眼视力或矫正视力、眼底自发荧光影像等检查。采用基于二维格子复杂性度量的医学图像特征提取和识别系统对糖尿病组及正常组图像进行分析。结果：该系统分析临床前期糖尿病视网膜病变眼底自发荧光图像与正常视网膜自发荧光图像具有可识别差异，提取出具有比较意义的25个特征。针对25个特征进行单个特征及多个特征的10折交叉检验以及5折交叉检验，准确率为82.47%。结论：复杂性分析医学图像人工智能系统可用于识别临床前期糖尿病视网膜病变的眼底自发荧光改变，准确率高。     

Digital fundus imaging: a comparison with photographic techniques

Fluorescein angiographic images from digital and photographic systems were obtained simultaneously from consecutive patients and examined in a side-by-side manner for evaluation of graininess, contrast, focus, and overall image quality. Digital fundus images showed superior contrast and overall image quality compared with photographic images obtained in this manner. These images were rated as somewhat grainier than photographic images. Patients had fewer complications undergoing digital fluorescein angiography versus photographic fluorescein angiography. Digital fundus imaging is a legitimate alternative to photographic imaging and offers the potential advantage of fewer complications compared with photographic techniques.     

Review of the use of digital imaging in retinopathy of prematurity screening

Retinopathy of prematurity (ROP) is a vision-threatening vasoproliferative condition of premature infants worldwide. As survival rates of younger and smaller infants improve, more babies are at risk for the development of ROP and blindness. Meanwhile, fewer ophthalmologists are available for bedside indirect ophthalmoscopy screening examinations. Remote digital imaging is a promising method with which to identify those infants with treatment-requiring or referral-warranted ROP quickly and accurately, and may help circumvent issues regarding the limited availability of ROP screening providers. The Retcam imaging system is the most common system for fundus photography, with which high-quality photographs can be obtained by trained non-physician personnel and evaluated by a remote expert. It has been shown to have high reliability and accuracy in detecting referral-warranted ROP, particularly at later postmenstrual ages. Additionally, the method is generally well received by parents and is highly cost-effective.     

Review of the Use of Digital Imaging in Retinopathy of Prematurity Screening

Retinopathy of prematurity (ROP) is a vision-threatening vasoproliferative condition of premature infants worldwide. As survival rates of younger and smaller infants improve, more babies are at risk for the development of ROP and blindness. Meanwhile, fewer ophthalmologists are available for bedside indirect ophthalmoscopy screening examinations. Remote digital imaging is a promising method with which to identify those infants with treatment-requiring or referral-warranted ROP quickly and accurately, and may help circumvent issues regarding the limited availability of ROP screening providers. The Retcam imaging system is the most common system for fundus photography, with which high-quality photographs can be obtained by trained non-physician personnel and evaluated by a remote expert. It has been shown to have high reliability and accuracy in detecting referral-warranted ROP, particularly at later postmenstrual ages. Additionally, the method is generally well received by parents and is highly cost-effective.     

Drusen detection in retro‐mode imaging by a scanning laser ophthalmoscope

Purpose: The Nidek F‐10 is a scanning laser ophthalmoscope that is capable of a novel fundus imaging technique, so‐called ‘retro‐mode’ imaging. The standard method of imaging drusen in age‐related macular degeneration (AMD) is by fundus photography. The aim of the study was to assess drusen quantification using retro‐mode imaging. Methods: Stereoscopic fundus photographs and retro‐mode images were captured in 31 eyes of 20 patients with varying stages of AMD. Two experienced masked retinal graders independently assessed images for the number and size of drusen, using purpose‐designed software. Drusen were further assessed in a subset of eight patients using optical coherence tomography (OCT) imaging. Results: Drusen observed by fundus photography (mean 33.5) were significantly fewer in number than subretinal deposits seen in retro‐mode (mean 81.6; p < 0.001). The predominant deposit diameter was on average 5 μm smaller in retro‐mode imaging than in fundus photography (p = 0.004). Agreement between graders for both types of imaging was substantial for number of deposits (weighted κ = 0.69) and moderate for size of deposits (weighted κ = 0.42). Retro‐mode deposits corresponded to drusen on OCT imaging in all eight patients. Conclusion: The subretinal deposits detected by retro‐mode imaging were consistent with the appearance of drusen on OCT imaging; however, a larger longitudinal study would be required to confirm this finding. Retro‐mode imaging detected significantly more deposits than conventional colour fundus photography. Retro‐mode imaging provides a rapid non‐invasive technique, useful in monitoring subtle changes and progression of AMD, which may be useful in monitoring the response of drusen to future therapeutic interventions.     

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.     

眼底疾病影像学检查的合理应用及联合应用

近年来,眼底的影像学诊断技术发展很快,为深入认识和准确诊断眼底病提供了最新的方法.常用的光学影像学方法有彩色相、无赤光相、自发荧光相、荧光素眼底血管造影(FFA)、吲哚青绿血管造影(ICGA)和频域光学相干断层扫描(S-OCT)等.充分掌握眼底影像学的基本知识,合理选择影像学方法,有针对性地进行检查,仔细分析和评价检查结果,对视网膜脉络膜疾病的诊断、鉴别诊断、治疗方案的制定和随访都具有重要的临床意义.     

Fundus Autofluorescence in Optic Disc Drusen: Comparison of Confocal Scanning Laser Ophthalmoscope and Standard Fundus Camera

We have evaluated fundus autofluorescence (FAF) imaging in optic disc drusen (ODD). After a detailed ophthalmological examination, 28 eyes of 16 patients were evaluated by FAF imaging using a confocal scanning laser ophthalmoscope and a standard fundus camera. ODD displayed bright nodular autofluorescence. Increased FAF was observed using both the scanning laser ophthalmoscope and the fundus camera. However, high quality images with precise localization of hyaline material at the optic nerve head were only possible using FAF imaging with the confocal scanning laser ophthalmoscope. FAF images obtained using the fundus camera revealed only brightness at the optic nerve head without any detail except when maximum flash intensity was used. We conclude that FAF imaging may be used as a non-invasive, safe and rapid ancillary test for the confirmation of the diagnosis of drusen of the optic disc.     

Fundus autofluorescence imaging in patients with Stargardt dystrophy and fundus flavimaculatus

PURPOSE: To identify patterns of fundus autofluorescence (AF) in patients with Stargardt dystrophy and fundus flavimaculatus. MATERIAL AND METHODS: 20 patients in age 7 to 47 years with Stargardt dystrophy and fundus flavimaculatus, were examined. Ophthalmic evaluation included nonstandarized Snellen visual acuity, complete ophthalmic examination, fluorescein angiography and color fundus photographs. The autofluorescence images were obtained using a confocal scanning laser ophthalmoscope HRA2. RESULTS: In 15 patients lack or decreased AF signal in a foveal region with punctate diffuse spots with increased and decreased AF signal extending far from the macular region were observed. In 4 patients apart from lack of the AF signal in the central area punctate spots were restricted to the macular region. In 1 patient AF image was copletely normal. CONCLUSIONS: Autofluorescence imaging allows for evaluation of the area with changes on the RPE level typical for this disease and is helpful, noninvasive examination for diagnostic process in such patients. A wide variation in clinical phenotype can occur in patients with Stargardt disease and fundus flavimaculatus. Obtained different phenotypes in autofluorescence imaging may correlate with different clinical types of this disease, described in the literature.     

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.