Weitwinkelfundusdokumentation bei Retinopathia praematurorum

Background. Fundus documentation in preterm infants has been improved by the advent of a new wide-angle fundus camera (RetCam 120). Patients and methods. In 30 preterm infants we used the RetCam 120 for retinopathy of prematurity (ROP) screening, before and after laser treatment of ROP and after regression of acute phase ROP for documentation of fundus findings. The RetCam 120 is a digital contact wide-angle fundus camera which is based on a 3-chip CCD video camera. Results. The RetCam 120 proved to be feasable for ROP documentation in preterm infants. Fundus documentation enhanced follow-up, teaching and cooperation between ophthalmologists and neonatologists. Conventional ophthalmoscopy is still necessary when using the RetCam 120 in ROP screening. Technical improvements of the camera itself and of the hardware and software is necessary before the RetCam 120 can be used routinely in ROP screening. Conclusion. The wide-angle fundus documentation using the RetCam 120 allows instant visualization and real-time documentation of intraocular findings. The RetCam 120 opens up new possibilities in clinical and scientific work, in teaching and in the new frontiers of ophthalmological telemedicine.     

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.     

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     

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.     

Cobalt blue light unit filter - A smartphone attachment for blue light photography

Purpose:The aim of this study was to carry out blue light photography of fluorescein-stained corneas using a novel smartphone attachment.Methods:A smartphone attachment known as the cobalt blue light unit (C-BLU) was developed. It can filter out all wavelengths of light except the blue light emerging from the flashlight of a smartphone. A pilot study was carried out wherein the images captured with the C-BLU system were compared with slit-lamp photographs of the same patients. This setup was then used to photo document fluorescein-stained corneas in various clinical settings assembled at point-of-care.Results:Many pathologies of the fluorescein-stained cornea were captured using the C-BLU filter. It was used effectively in various settings (remote eye camps, intensive care units (ICU), pediatric group, corneal trauma triaging, etc.). C-BLU was assembled and used by optometrists and ophthalmology residents. The images captured were used for documenting, assisting in the treatment, and also for telecommunication of the patients’ findings.Conclusion:C-BLU is a low-cost pocket-size filter which is easy to use with a modern smartphone without any technical expertise needed to obtain a clear image of fluorescein-stained pathological corneas.     

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.     

Quantitative analysis of retinal vessel diameter reduction after photocoagulation treatment for retinopathy of prematurity

PURPOSE: To evaluate the feasibility of using semiautomated analysis of digital fundus images to quantify effects of photocoagulation on retinal vessel diameter in retinopathy of prematurity (ROP). DESIGN: Case series. METHODS: Fourteen eyes of seven patients with threshold ROP and 12 eyes of six controls were included. Fundus images were captured before and after photocoagulation, or one to three weeks apart in controls, using an NM200D camera (Nidek, Inc, Aichi, Japan). VesselMap software (Imedos, Jena, Germany) measured vessel diameter. The t test analysis was used to assess vessel changes. RESULTS: The authors observed a significant reduction in average largest retinal vein diameter of -18% +/- 16% (+/-1 standard deviation). The average largest artery diameter trended down by -12% +/- 16%. Compared with controls, diameter reduction was significant in veins (P = .014) and arteries (P = .016). CONCLUSIONS: The diameter of retinal vessels decreases after photocoagulation. VesselMap analysis of digital images is feasible and may be helpful in quantifying treatment effects.     

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.     

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.     

Fundus imaging with a mobile phone: A review of techniques

Fundus imaging with a fundus camera is an essential part of ophthalmic practice. A mobile phone with its in-built camera and flash can be used to obtain fundus images of reasonable quality. The mobile phone can be used as an indirect ophthalmoscope when coupled with a condensing lens. It can be used as a direct ophthalmoscope after minimal modification, wherein the fundus can be viewed without an intervening lens in young patients with dilated pupils. Employing the ubiquitous mobile phone to obtain fundus images has the potential for mass screening, enables ophthalmologists without a fundus camera to document and share findings, is a tool for telemedicine and is rather inexpensive.     

Use of offline artificial intelligence in a smartphone-based fundus camera for community screening of diabetic retinopathy

Purpose:The aim of the study was to analyse the reliability of an offline artificial intelligence (AI) algorithm for community screening of diabetic retinopathy.Methods:A total of 1378 patients with diabetes visiting public dispensaries under the administration of the Municipal Corporation of Greater Mumbai between August 2018 and September 2019 were enrolled for the study. Fundus images were captured by non-specialist operators using a smartphone-based camera covering the posterior pole, including the disc and macula, and the nasal and temporal fields. The offline AI algorithm on the smartphone marked the images as referable diabetic retinopathy (RDR) or non-RDR, which were then compared against the grading by two vitreoretinal surgeons to derive upon the sensitivity and specificity of the algorithm.Results:Out of 1378 patients, gradable fundus images were obtained and analysed for 1294 patients. The sensitivity and specificity of diagnosing RDR were 100% (95% CI: 94.72–100.00%) and 89.55% (95% CI: 87.76–91.16%), respectively; the same values for any diabetic retinopathy (DR) were 89.13% (95% CI: 82.71–93.79%) and 94.43% (95% CI: 91.89–94.74%), respectively, with no false-negative results.Conclusion:The robustness of the offline AI algorithm was established in this study making it a reliable tool for community-based DR screening.     

Semiautomated analysis of retinal vessel diameter in retinopathy of prematurity patients with and without plus disease

PURPOSE: To determine the feasibility of using semiautomated analysis of digital fundus images to quantify the differences in retinal vascular diameter between retinopathy of prematurity (ROP) patients with and without plus disease. DESIGN: Case-control study. METHODS: Thirty eyes of 15 patients with ROP were included in this study. Fourteen eyes of seven patients had plus disease and 16 eyes of eight patients had no evidence of plus disease. Digital fundus images were captured using an NM200D (Nidek, Inc, Aichi, Japan) camera. Vessel diameters were determined using VesselMap software (Imedos, Jena, Germany). The Student t test analysis was used to compare diameters of vessels with and without plus disease. RESULTS: We found that the average venous diameter is significantly larger by 15% in the group with plus disease. CONCLUSIONS: VesselMap analysis of digital images is feasible. This method is able to distinguish between veins with and without plus disease, and may be useful in telemedicine screening strategies.     

Panretinal, high-resolution color photography of the mouse fundus

PURPOSE: To analyze high-resolution color photographs of the mouse fundus. METHODS: A contact fundus camera based on topical endoscopy fundus imaging (TEFI) was built. Fundus photographs of C57 and Balb/c mice obtained by TEFI were qualitatively analyzed. RESULTS: High-resolution digital imaging of the fundus, including the ciliary body, was routinely obtained. The reflectance and contrast of retinal vessels varied significantly with the amount of incident and reflected light and, thus, with the degree of fundus pigmentation. The combination of chromatic and spherical aberration favored blue light imaging, in term of both field and contrast. CONCLUSIONS: TEFI is a small, low-cost system that allows high-resolution color fundus imaging and fluorescein angiography in conscious mice. Panretinal imaging is facilitated by the presence of the large rounded lens. TEFI significantly improves the quality of in vivo photography of retina and ciliary process of mice. Resolution is, however, affected by chromatic aberration, and should be improved by monochromatic imaging.     

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     

A comparison of digital retinal image quality among photographers with different levels of training using a non-mydriatic fundus camera

PURPOSE: To evaluate the quality of digital retinal images taken by three photographers with different levels of photographic training, using a non-mydriatic fundus camera. METHODS: This study compares 45-degree digital retinal images taken with a non-mydriatic fundus camera by three different photographers with different levels of photographic training: (I) A professional ophthalmic photographer with 20 years of experience; (2) a non-professional photographer with 2 days of photographic training and experience with 50 patients; (3) a non-professional photographer with 1 hour of photographic training and experience with 10 patients. The quality of the photographs was evaluated by the consensus of two retina specialists. RESULTS: Sixty-four (64) eyes of 33 subjects were imaged by the three photographers for a total of 192 images. Thirty-four eyes were photographed in the non-dilated state. The trained ophthalmic photographer and the two non-professional photographers did not have statistically significant differences in image quality based on the image evaluations. (Chi-square P-value: 0.57). This finding was consistent for eyes in both the non-dilated and dilated state. CONCLUSIONS: Fundus image quality for images taken with a non-mydriatic camera were not significantly different among three photographers with different levels of training.     

Stereoscopic three-dimensional (3D) slit-lamp photography using a compact 3D digital camera

We describe a novel method of stereoscopic 3D slit-lamp photography using a portable compact 3D digital camera. Thirteen eyes of 13 patients underwent slit-lamp photography using a Fujifilm 3D compact digital camera. We modified a universal smartphone microscope adapter to attach the camera to the slit-lamp. Photography was attempted on Zeiss and on HAAG-Streit slit-lamps. Success was defined as capturing a stereogram that consists of two simultaneous pictures, one from each slit-lamp ocular. Stereoscopic 3D slit-lamp photos could be captured in all 13 eyes in which they were attempted on Zeiss slit-lamps. Captured 3D media included external, eyelid, conjunctival, corneal, anterior chamber, lens, vitreous, and optic disc pathologies. Stereoscopic 3D photography could not be obtained using this Fujifilm 3D digital camera on Haag-Streit slit-lamps because of alignment incompatibility between the oculars of the slit-lamp and the camera. Digital stereoscopic 3D slit-lamp photography is feasible using a compact 3D digital camera and compatible slit-lamp design. Images obtained using this technique may be helpful in clinical education.     

Validation of a portable,non-mydriatic fundus camera compared to gold standard dilated fundus examination using slit lamp biomicroscopy for assessing the optic disc for glaucoma

PurposeTo evaluate the sensitivity and specificity of a portable non-mydriatic fundus camera to assess the optic disc for glaucoma.MethodsWe conducted a single-site, cross-sectional, observational, instrument validation study. Non-mydriatic fundus photographs centred at the optic disc were obtained from 276 eyes of 68 glaucoma and 70 normal patients, using a portable fundus camera (Smartscope, Optomed, Oulu, Finland). A senior Glaucoma consultant, masked to the patient’s study participation, performed a gold standard dilated fundus examination to make the diagnosis of glaucoma. Following this, a mydriatic photograph was taken by a standard table-top fundus camera. All the images were digitalized and de-identified by an independent investigator and presented to two remote graders, masked to the patients, their diagnoses, and photographic modality. Based on individual disc characteristics, a diagnosis of screening positive or negative for glaucoma was made. In the end, the independent investigator re-identified the images. Sensitivity and specificity to detect glaucoma with the undilated Smartscope camera was calculated compared to dilated fundus examination.ResultsGrading remote images taken with the portable non-mydriatic fundus camera showed a sensitivity of 96.3% (95% confidence interval (CI): 91.6–98.8%) and 94.8% (95% CI: 89.7–97.9%) and a specificity of 98.5% (95% CI: 94.9–99.8%) and 97.8% (95% CI: 93.9–99.6%) for the two graders respectively as compared to gold standard dilated fundus examination.ConclusionThe non-mydriatic Smartscope fundus images have high sensitivity and specificity for diagnosing glaucoma remotely and thus may be an effective tool for use in community outreach programs.Subject terms: Optic nerve diseases, Diagnosis     

智能手机照相功能在裂隙灯显微摄影中的应用

目的探讨智能手机附带的照相功能在裂隙灯显微镜显微摄影中应用的价值。方法利用易获取的材料自制转接环,将智能手机的照相机与裂隙灯显微镜目镜接驳,在自制辅助照明光和弥散光配合下,进行裂隙灯显微镜眼前段摄影,对采集的图片进行数据库管理、利用互联网进行交流。结果自制接口能够精确接驳于裂隙灯显微镜的光学系统,能使智能手机附带的照相机顺利成像。所获得的照片清晰度、色彩还原度、对比度均较好。能够较为清晰地显示组织细节、病变特点。结论500～800万像素的智能手机采集的裂隙灯显微镜照片,在影像质量上可满足临床需求,能够丰富客观临床资料,有助于方便快捷地进行同行交流,直观地进行医患交流,在眼外伤方面,可为法医和医保鉴定提供图像资料。自制转接环成本低廉、易于普及。     

Our experience with smartphone and spherical lens for the eye fundus examination during humanitarian project in Africa

To present the experience of eye fundus photo documentation by using the plus 20 diopters spherical Volk lens and a smartphone with 4.2 Mpix camera and LED flash within the screening project of eye disorders in countries where the standard ophthalmology equipment is not available. Totally 241 patients underwent ophthalmology screening examination. The documentation of the eye fundus included patients with Burkitt lymphoma, Kala Azar, malnutrition with unknown etiology, tuberculosis, HIV positive patients, Usher syndrome and hypertension. This technique as an alternative way of screening will become a standard within examination of patients with eye disorders in outfield regions of developing countries.     

Telemedicina en retinopatía del prematuro: Atravesando fronteras en la salud visual pediátrica. Estudio TELEROP

General objectiveTo evaluate the accuracy and validity of images with smartphone compared to the RetCam® system for the diagnosis of retinopathy of prematurity (ROP).MethodologyObservational, longitudinal and masked study carried out at the Dr. Elías Santana hospital. Infants with birth weight ≤ 1500 g, gestational age ≤ 30 weeks and/or patients exposed to risk factors or complications linked to ROP were included. These subjects were screened using images with smartphone or RetCam®, both compared to conventional fundoscopy. The ICROP classification was used for staging. The main results analyzed were sensitivity, specificity, positive predictive values and kappa index.Results915 images (n = 121) were obtained, distributed in smartphone group (50.4%) and RetCam® group (49.6%) between August 2020 and March 2021. Subjects with ROP had lower gestational age (30.2 sem ± 2.8), birth weight (1361 g ± 398), and greater exposure to oxygen therapy (12.8 days ± 11.3). The RetCam® group presented sensitivity = 80%, specificity = 78%, positive predictive value = 90% and kappa index = 0.70. The smartphone group presented sensitivity = 88%, specificity = 90%, positive predictive value = 93.75% and kappa index = 0.81.ConclusionsBoth diagnostic methods were accurate to identify ROP. The smartphone group obtained superior results with excellent resolution, representing a cost-effective method to create a global impact on reducing preventable blindness in the pediatric population.