Design of ultra-wide-field scanning laser fundus imaging system with cascaded conicoid mirrors.

We propose and design a multi-stage cascaded scanning laser ophthalmoscope (SLO) for ultra-wide field (UWF), which uses conicoid mirrors, constructed by conjugation of pupil plane. The vergence uniformity and the angular magnification of a cascaded conicoid mirrors (CCM) system are analyzed recursively and optimized preliminarily to achieve high quality imaging with UWF, and the optimal system with the model eye are obtained by simulation and optimization. Two-stage and three-stage cascaded systems are designed with this method, and the formulas of beam vergence and angular magnification are obtained by theoretical derivation. As compared to the two-stage CCM system, the proposed three-stage cascaded UWF SLO has superior performance in imaging quality. Its average RMS radius of spot diagram is calculated to be 26.372 µm, close to the diffractive limit resolution. The image resolution of human retina can be up to 30 µm with 135° FOV in theory. The three-stage cascaded SLO is more suitable for UWF fundus imaging. This study will be helpful for early screening and accurate diagnosis of various diseases in the peripheral retina.

Alignment, calibration, and validation of an adaptive optics scanning laser ophthalmoscope for high-resolution human foveal imaging.

In prior art, advances in adaptive optics scanning laser ophthalmoscope (AOSLO) technology have enabled cones in the human fovea to be resolved in healthy eyes with normal vision and low to moderate refractive errors, providing new insight into human foveal anatomy, visual perception, and retinal degenerative diseases. These high-resolution ophthalmoscopes require careful alignment of each optical subsystem to ensure diffraction-limited imaging performance, which is necessary for resolving the smallest foveal cones. This paper presents a systematic and rigorous methodology for building, aligning, calibrating, and testing an AOSLO designed for imaging the cone mosaic of the central fovea in humans with cellular resolution. This methodology uses a two-stage alignment procedure and thorough system testing to achieve diffraction-limited performance. Results from retinal imaging of healthy human subjects under 30 years of age with refractive errors of less than 3.5 diopters using either 680 nm or 840 nm light show that the system can resolve cones at the very center of the fovea, the region where the cones are smallest and most densely packed.

EVALUATING ULTRA-WIDEFIELD IMAGING UTILITY IN THE DETECTION OF TREATMENT-REQUIRING PERIPHERAL RETINAL TEARS AND HOLES.

PURPOSE: To determine the utility of ultra-widefield (UWF) imaging in detecting pathologic peripheral retinal tears and holes. METHODS: This was a retrospective, observational study. One-hundred ninety-eight eyes of 198 patients diagnosed with acute posterior vitreous detachment were included. Eyes were divided into two groups: 89 eyes with peripheral retinal holes and tears treated with laser retinopexy (treatment group) and 109 control eyes. Patients underwent UWF imaging and indirect ophthalmoscopy with scleral depression. UWF images from both groups were reviewed by two blinded graders and then compared with funduscopic examination and medical records. RESULTS: UWF imaging identified 60 of the 89 eyes (sensitivity of 67.4%) found to have treatment-requiring peripheral retinal lesions and 107 of the 109 control eyes (specificity of 98.2%).The distribution of misses based on octant location did reach statistical significance ( P = 0.004). Lesions anterior to the equator were more likely to be missed (21/41 eyes, 51.2%) compared with those located posterior to the equator (4/20 eyes, 25.0%) and at the equator (4/28, 14.3%), P = 0.002. The combined discordance rate between graders in the entire cohort was 12.1% (24/198 eyes) yielding an interrater agreement of 87.9%. CONCLUSION: UWF imaging showed a moderate sensitivity and high specificity in detecting treatment-requiring retinal tears and holes, with high interrater agreement. Given there is only a moderate sensitivity in identifying treatment-requiring retinal tears and holes, UWF imaging can assist with clinical examination, but a 360-degree scleral depressed examination should remain the gold standard.

Colour tone of retinal arterioles imaged with a colour scanning laser ophthalmoscope can be an indicator of systemic arterial stiffness.

OBJECTIVE: Colour scanning laser ophthalmoscope (cSLO) offers several advantages, including improved image quality and better visualisation of the retinal structures compared with colour fundus photograph (CFP). This study aimed to identify whether cSLO could be used to predict systemic arterial stiffness. METHODS AND ANALYSIS: We retrospectively analysed the data of 54 patients with 103 eyes. In addition to blood pressure and blood data, all patients had cardio-ankle vascular index (CAVI) measurements, as well as images of the fundus acquired using cSLO and CFP. We determined the retinal artery sclerosis (RAS) index from the colour of the retinal artery in cSLO images, the ratio of arterial to venous diameter (A/V ratio), and Scheie's classification in CFP images. The correlation between each parameter and CAVI was examined using Spearman's rank correlation coefficient, and the correlation between Scheie's classification and CAVI was examined using Steel-Dowass tests. RESULTS: CAVI showed a significant positive correlation with the RAS index (r=0.679, p<0.001) but not with the A/V ratio or Scheie's classification. Multiple regression analysis showed that the RAS index was significantly and independently correlated with CAVI. CONCLUSION: cSLO is a non-invasive imaging modality that has the potential to accurately and instantaneously detect early systemic arterial stiffness.

Deep Density Estimation for Cone Counting and Diagnosis of Genetic Eye Diseases From Adaptive Optics Scanning Light Ophthalmoscope Images.

Purpose: Adaptive optics scanning light ophthalmoscope (AOSLO) imaging offers a microscopic view of the living retina, holding promise for diagnosing and researching eye diseases like retinitis pigmentosa and Stargardt's disease. The technology's clinical impact of AOSLO hinges on early detection through automated analysis tools. Methods: We introduce Cone Density Estimation (CoDE) and CoDE for Diagnosis (CoDED). CoDE is a deep density estimation model for cone counting that estimates a density function whose integral is equal to the number of cones. CoDED is an integration of CoDE with deep image classifiers for diagnosis. We use two AOSLO image datasets to train and evaluate the performance of cone density estimation and classification models for retinitis pigmentosa and Stargardt's disease. Results: Bland-Altman plots show that CoDE outperforms state-of-the-art models for cone density estimation. CoDED reported an F1 score of 0.770 ± 0.04 for disease classification, outperforming traditional convolutional networks. Conclusions: CoDE shows promise in classifying the retinitis pigmentosa and Stargardt's disease cases from a single AOSLO image. Our preliminary results suggest the potential role of analyzing patterns in the retinal cellular mosaic to aid in the diagnosis of genetic eye diseases. Translational Relevance: Our study explores the potential of deep density estimation models to aid in the analysis of AOSLO images. Although the initial results are encouraging, more research is needed to fully realize the potential of such methods in the treatment and study of genetic retinal pathologies.

Vision degrading myodesopsia assessed with optos ultra-widefield scanning laser ophthalmoscope.

BACKGROUND: To investigate the diagnostic sensitivity of Optos imaging for vision degrading myodesopsia (VDM). METHODS: A total of 420 eyes from 345 patients with VDM were collected in this cross-sectional study. All eyes were classified as having posterior vitreous detachment (PVD) or not having PVD. The sensitivity of Optos imaging for the visibility of vitreous floaters was evaluated. The associated factors with the visibility of vitreous floaters on Optos images were analyzed in univariate and multivariate logistic regression analyses. RESULTS: The mean age of all patients was 56.19 ± 13.89 years old, and 66.67% of patients were female. The vitreous floaters were visible on the ultrasound B scan in all eyes, but only in 47.62% of Optos images (55.29% in eyes with PVD and 15% in eyes without PVD). In the multiple binary logistic regression analysis, age (OR = 1.094, 95%CI = 1.063-1.125, P < 0.001), spherical equivalent (OR = 0.869, 95%CI = 0.791-0.955, P = 0.004) and the distance of the floaters from the retina (OR = 1.191, 95%CI = 1.059-1.339, P = 0.003) were significantly correlated with the visibility of vitreous floaters on Optos images. On Optos images, 25.71% of VDM eyes presented additional retinal abnormalities. CONCLUSIONS: Optos imaging has a low sensitivity for vitreous floaters, particularly in eyes without PVD. On Optos imaging, floaters were more visible in older patients, eyes with greater myopia, and floaters that were further from the retina.

Multimodal high-resolution retinal imaging using a camera-based DMD-integrated adaptive optics flood-illumination ophthalmoscope.

We demonstrate the feasibility of a multimodal adaptive optics flood-illumination ophthalmoscope, able to provide both bright-field and dark-field images (such as phase contrast). The multimodality was made possible by integrating a digital micromirror device (DMD) at the illumination path to project a sequence of complementary high-resolution patterns into the retina. Through a versatile post-processing method that digitally selects backscattered or multiply scattered photons, we were able: (1) to achieve up to four-fold contrast increase of bright-field images when imaging the photoreceptor mosaic and nerve fibers; and (2) to visualize translucent retinal features such as capillaries, red blood cells, vessel walls, ganglion cells, and photoreceptor inner segments through phase contrast.

Fundoscopy in the smartphone age: current ophthalmoscopy methods in neurology.

The observation of the human retina in vivo began in 1851 after the invention of the first ophthalmoscope by the German physicist Hermann von Helmholtz. In the following decades, direct and indirect ophthalmoscopy, with the use of ophthalmoscopes and condensing lenses, respectively, became part of the clinical examination, especially in ophthalmology and neurology. Today, over 170 years later, many ophthalmoscopes and condensing lenses exist on the market. Nevertheless, ophthalmoscopy is still not widely adopted as part of the physical exam of general practitioners, and the teaching of ophthalmoscopy in medical school remains challenging. Studies have shown that students prefer using newer ophthalmoscope models or condensing lenses during training, but most do not feel confident in performing ophthalmoscopy afterwards, regardless of the models used. Also, few students acquire ophthalmoscopes for their future practice, and clinical trials have not clearly demonstrated superiority of newer ophthalmoscope models over the conventional ones in diagnostic accuracy. The technological improvement of smartphone cameras in recent years has made it feasible to photograph the fundus of the eye using ophthalmoscopes or condensing lenses, reducing the need for retinographs and similar equipment. Smartphone assisted indirect fundoscopy is becoming increasingly popular. This approach allows adequate identification of the structures of the fundus, is cost-efficient, easy to implement, and permits easy recording and sharing of the images obtained, which is useful for case discussions and medical teaching. However, controlled clinical trials validating this method in the evaluation of optic nerve pathologies are needed.

A observação da retina humana in vivo começou em 1851, após a invenção do primeiro oftalmoscópio pelo físico alemão Hermann von Helmholtz. Nas décadas seguintes, a oftalmoscopia direta e indireta, com o uso de oftalmoscópios e lentes condensadoras, respectivamente, tornou-se parte do exame clínico, especialmente em oftalmologia e neurologia. Hoje, mais de 170 anos depois, diversos oftalmoscópios e lentes condensadoras estão disponíveis no mercado. No entanto, a oftalmoscopia ainda não é amplamente realizada no exame físico de médicos generalistas e o ensino da oftalmoscopia na faculdade de medicina ainda é desafiador. Estudos mostram que estudantes preferem usar modelos novos de oftalmoscópio ou lentes condensadoras durante seu treinamento, porém a maioria dos estudantes não se sente suficientemente confiante em realizar oftalmoscopia mais tarde, mesmo quando utilizam os modelos mais novos. Além disso, poucos alunos adquirem oftalmoscópios para sua prática futura, e ensaios clínicos não demonstraram uma clara superioridade dos novos modelos de oftalmoscópio em relação ao modelo convencional em acurácia diagnóstica. O aperfeiçoamento tecnológico das câmeras de smartphones nos últimos anos tornou possível fotografar o fundo do olho utilizando oftalmoscópios ou lentes condensadoras, reduzindo a necessidade de retinógrafos e equipamentos similares. A fundoscopia indireta realizada com smartphones vem se tornando cada vez mais popular. Esta abordagem permite a adequada identificação das estruturas do fundo do olho, é custo-efetiva, fácil de implementar e permite o fácil registro e compartilhamento das imagens obtidas, o que é útil para discussão de casos clínicos e para o ensino médico. Entretanto, ensaios clínicos controlados para a validação deste método na avaliação de patologias do nervo óptico são necessários.

High-speed measurement of retinal arterial blood flow in the living human eye with adaptive optics ophthalmoscopy.

We present a technique to measure the rapid blood velocity in large retinal vessels with high spatiotemporal resolution. Red blood cell motion traces in the vessels were non-invasively imaged using an adaptive optics near-confocal scanning ophthalmoscope at a frame rate of 200 fps. We developed software to measure blood velocity automatically. We demonstrated the ability to measure the spatiotemporal profiles of the pulsatile blood flow with a maximum velocity of 95-156 mm/s in retinal arterioles with a diameter >100 µm. High-speed and high-resolution imaging increased the dynamic range, enhanced sensitivity, and improved the accuracy when studying retinal hemodynamics.

Accuracy and Time Comparison Between Side-by-Side and Artificial Intelligence Overlayed Images.

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate the accuracy and the time to find a lesion, taken in different platforms, color fundus photographs and infrared scanning laser ophthalmoscope images, using the traditional side-by-side (SBS) colocalization technique to an artificial intelligence (AI)-assisted technique. PATIENTS AND METHODS: Fifty-three pathological lesions were studied in 11 eyes. Images were aligned using SBS and AI overlaid methods. The location of each color fundus lesion on the corresponding infrared scanning laser ophthalmoscope image was analyzed twice, one time for each method, on different days, for two specialists, in random order. The outcomes for each method were measured and recorded by an independent observer. RESULTS: The colocalization AI method was superior to the conventional in accuracy and time (P < .001), with a mean time to colocalize 37% faster. The error rate using AI was 0% compared with 18% in SBS measurements. CONCLUSIONS: AI permitted a more accurate and faster colocalization of pathologic lesions than the conventional method. [Ophthalmic Surg Lasers Imaging Retina 2023;54:108-113.].

Smartphone ophthalmoscope as a tool in teaching direct ophthalmoscopy: a crossover randomized controlled trial.

To evaluate the effectiveness of smartphone ophthalmoscope (SO) in teaching ophthalmoscopy, compared with direct ophthalmoscope (DO). In this cross-over study, 45 final-year medical students attending sessions at a single institution were randomly allocated to two groups (A and B). Both groups attended two training sessions. In the first session, Group A students were taught ophthalmoscopy using DO and Group B students using SO. In the second session, the training sessions were crossed over. A series of eye models with 10 letters placed on the inner surface were designed to assess the students' skill on ophthalmoscopy. Students performed ophthalmoscopy on the eye models, recorded their findings, and completed a questionnaire of feedback on DO and SO. The main outcome measure was the score of ophthalmoscopy, assessed by the student correctly recording each letter (score 1 for each letter). For Group A, the mean score of ophthalmoscopy on the eye model using DO and SO was 3.9±2.4 and 8.2±2.2, respectively. For Group B, the mean score of ophthalmoscopy on the eye model using SO and DO 8.7±1.8 and 5.7±3.5 . Students scored significantly higher in ophthalmoscopy when using SO than DO (P<0.001). They expressed better visualization of the fundus using SO than DO (4.49±0.65 vs 4.13±0.81, P=0.004). Students' performance of ophthalmoscopy was better when SO was used compared with DO. The use of SO as an adjunctive tool is recommended to improve the effectiveness of teaching ophthalmoscopy.

Comparative evaluation of a new frugal binocular indirect ophthalmoscope.

OBJECTIVES: We compare the optical quality and design characteristic a new low cost solar powered binocular indirect ophthalmoscope (BIO), Holo, to Keeler BIO. METHODS: Twenty-four participants each examined 10 simulation eyes using both the Holo and the Keeler BIO with a 30-diopter condensing lens. Number of Lea symbols printed on the retina of simulation eyes seen and time taken to identify them was recorded. Stereoacuity of 12 participants was tested while using the BIOs. Using 7-point Likert scale, participants gave feedback on design characteristic of both BIOs. RESULTS: There was no statistical difference in number of Lea symbols correctly identified (15.63/20 for Holo vs. 15/20 for Keeler BIO, p = 0.366, paired t test) or time taken to correctly identify each symbol (Holo 0.39 s faster; 95% confidence interval -2.24 to 3.03 s, p = 0.763) using each device. 12 out of 12 participants achieved stereoacuity of 60 arcsec using the Holo while with the Keeler BIO 11 achieved 60 arcsec and one 90 arcsec. There was no statistically significant difference in the scores for clarity of view, quality of illumination, field of view, binocularity, eye strain and robustness between the two devices. The Holo, scored higher for ease of use (6.5 vs. 6, p = 0.00488, Wilcoxon signed-rank test), comfort of wear (6 vs. 5, p = 0.000337) and portability (7 vs. 6, p = 0.000148). CONCLUSION: The Holo has the potential to be a clinically useful yet affordable diagnostic tool suitable for the first time of equipping eye care workers in low resource settings with a BIO at volume.

Perioperative Nursing of Vitrectomy for Ocular Trauma under the Guidance of Ophthalmoscope.

To explore the perioperative nursing methods and clinical effects of vitrectomy under ophthalmoscope in the treatment of severe ocular rupture, this study reviews the clinical effects of vitrectomy in the treatment of severe ocular trauma in China, analyzes the perioperative nursing of vitrectomy for ocular trauma under the guidance of an ophthalmoscope, and analyzes the importance of stage I debridement and suture, the choice of operation time, and the advantages of vitrectomy and perioperative nursing care. The retrospective analysis of these data shows that the clinical effect of peri-vitrectomy for ocular trauma under the guidance of an ophthalmoscope is accurate, and surgical treatment should be carried out as soon as possible according to the patient's condition, which can reduce the complications of suppurative ophthalmitis, eyeball atrophy, and vitreous rebleeding. Perioperative nursing intervention is beneficial to the recovery of visual acuity in patients with severe ocular rupture treated by vitrectomy under the ophthalmoscope, which is worthy of clinical promotion.

The Optos 200Tx Scanning Laser Ophthalmoscope Application in Retinoblastoma Patients' Follow-Up.

Methods: A total of 1134 examinations with Optomap 200Tx were performed for 318 children who were clinically diagnosed with RB in the Ophthalmology Department of Tianjin Medical University Eye Hospital, China, between July 2015 and July 2017, and achieved stable disease lasting for more than 6 months after combined treatment. The children received examinations every 1-12 months (mean 4 months), initially at 31 months to 15 years of age (mean 51 months), and were given a full eye examination under anesthesia (EUA) immediately if recurrent tumor, recurrent vitreous seeding (VS), or recurrent subretinal seeding (SRS) was detected, or in the next follow-up visit if no abnormality was detected, and early treatment was performed when the lesion was confirmed. Results: Recurrence was detected in 4 children in the examination with Optomap 200Tx, including 2 cases of recurrent vitreous seeding (VS) and 2 cases of recurrent subretinal seeding (SRS), which were confirmed by EUA and well controlled after early treatment. Conclusion: The use of Optomap 200Tx in the long-term following up of patients with RB reduces the number of eye examinations under general anesthesia (EUA), increases the time between EUAs, and protects children from exposure to the adverse effects of general anesthetics. Optomap 200Tx can detect recurrent tumor and recurrent seeding, allowing for early treatment which produces better outcomes.

Prospective evaluation of medical student accuracy conducting direct ophthalmoscopy with an unmodified iPhone X.

PURPOSE: To evaluate fundus examination accuracy of medical students when using an unmodified iPhone X or a direct ophthalmoscope in comparison to a staff ophthalmologist's retinal examination. METHODS: In this prospective comparative analysis, patients underwent dilated fundus examination by novice medical trainees using either an unmodified iPhone X or standard direct ophthalmoscope. The primary outcome was the mean difference and degree of agreement in cup-to-disc ratio between student examination and the staff ophthalmologist's cup-to-disc observation. RESULTS: A total of 18 medical students conducted 230 retinal examinations, 117 with the iPhone X and 113 with the direct ophthalmoscope. A greater proportion of students were unable to report cup-to-disc ratio using the iPhone X (81.2%) vs direct ophthalmoscope (30.1%). Student examination of cup-to-disc ratio led to a systematic bias (95% limits of agreement) of + 0.16 (-0.22 to + 0.54) and + 0.10 (-0.36 to + 0.56) with the iPhone X and direct ophthalmoscope, respectively. iPhone X and direct ophthalmoscope student observation concordance for optic disc colour (88.7 and 82.4%, respectively) and contour (68.3 and 74.2%, respectively) demonstrated low agreement with staff ophthalmologist findings. Student iPhone X observations demonstrated lower agreement with staff findings compared to direct ophthalmoscope observations for spontaneous venous pulsations (Cohen's Kappa = -0.044 vs 0.099). CONCLUSION: Amongst medical trainees, optic disc visualization using an unmodified iPhone X was inferior to the direct ophthalmoscope. When able to visualize the optic nerve head, there was no significant difference in reported cup-to-disc ratio between modalities. However, both modalities demonstrated poor reliability in comparison to staff ophthalmologist findings.

Comparison of patient satisfaction with red-free (green) versus yellow light using binocular indirect ophthalmoscope for retinal examination.

Purpose: Comparison of patient satisfaction with red-free (green) versus yellow light using binocular indirect ophthalmoscope for retinal examination. Methods: This is an observational questionnaire-based study of 100 myopes in the age group of 18-40 years coming for a routine check-up or for refractive surgery workup. The examination was done using an indirect ophthalmoscope and a 20D lens with green or yellow light and was assigned in two groups randomly using the coin toss method, following which, a questionnaire was used to assess the following parameters: a) level of comfort, b) any complaints of discomfort during examination, d) preference of the used light source in future, e) grading of discomfort on a linear scale, and f) patient cooperation and duration of examination. Results: Patients were randomized for observation with IDO using either green light (n = 55) or yellow light (n = 45) filter. In the study, 46 patients (83.6%) were very comfortable and only 9 patients (16.4%) experienced mild discomfort when using red-free (green) light, while only 3 patients (6.7%) were very comfortable and 31 (68.9%) had mild discomfort when using yellow light. The complaints of watering with yellow and green light were noted in 36 patients (80.0%) and 15 patients (27.3%), pain in 13 patients (28.9%) and 3 patients (5.5%), light sensitivity in 29 patients (64.4%) and 4 patients (7.3%), respectively, all being significantly more in yellow light category (P < 0.001). The time of examination was significantly more in yellow light category with 83 ± 10.75 seconds (P < 0.001). Conclusion: Retinal examination using the green filter of indirect ophthalmoscope is more comfortable in examining the patients as compared to routine yellow light with decreased number of complaints, lesser examination time, and better patient cooperation.

MULTICOLOR CONFOCAL SCANNING LASER OPHTHALMOSCOPE IMAGING IN POSTERIOR UVEITIS.

PURPOSE: To study the utility of MultiColor confocal scanning laser ophthalmoscope imaging (MCI) in identifying the morphology of uveitic lesions compared with conventional color fundus photography (CFP) in patients with posterior uveitis. METHODS: In this prospective observational study, subjects with posterior uveitis underwent MCI and CFP. The images obtained by the two modalities were analyzed by two independent reviewers for vitreoretinal surface abnormalities, retinal fluid and hemorrhages, and depth/location of lesions. These findings were compared with the clinical findings and other imaging techniques. RESULTS: Sixty-nine eyes of 43 patients (25 men) with mean age of 33.5 ± 13.9 years were studied. MultiColor imaging had better sensitivity and specificity in detecting vitreoretinal interface abnormalities, such as epiretinal membrane and inner retinal striae, compared with CFP. MultiColor imaging failed to detect retinochoroiditis lesions in 5 of 6 eyes (83%) and choroiditis in 9 46 eyes (20%), which were detected on CFP and clinical examination. Also, MCI showed a high false-positive rate of 34% in detecting intraretinal hemorrhages. CONCLUSION: Retinochoroidal lesions in posterior uveitis may be poorly identified on MCI compared with CFP and clinical examination. One must exercise caution in commenting on disease morphology based on MCI alone.

Multispectral retinal video-ophthalmoscope with fiber optic illumination.

Multispectral imaging is used in various applications including astronomy, industry and agriculture. In retinal imaging, the single-shot multispectral image stack is typically acquired and analyzed. This multispectral analysis can provide information on various structural or metabolic properties. This paper describes the multispectral improvement of a video-ophthalmoscope, which can acquire retinal video sequences of the optic nerve head and peripapillary area using various spectral light illumination. The description of the multispectral video imaging is provided and several applications are described. These applications include multispectral retinal photoplethysmography, visualization of spontaneous vein pulsation and multispectral RGB image generation.

Cross-Camera External Validation for Artificial Intelligence Software in Diagnosis of Diabetic Retinopathy.

Aims: To investigate the applicability of deep learning image assessment software VeriSee DR to different color fundus cameras for the screening of diabetic retinopathy (DR). Methods: Color fundus images of diabetes patients taken with three different nonmydriatic fundus cameras, including 477 Topcon TRC-NW400, 459 Topcon TRC-NW8 series, and 471 Kowa nonmyd 8 series that were judged as "gradable" by one ophthalmologist were enrolled for validation. VeriSee DR was then used for the diagnosis of referable DR according to the International Clinical Diabetic Retinopathy Disease Severity Scale. Gradability, sensitivity, and specificity were calculated for each camera model. Results: All images (100%) from the three camera models were gradable for VeriSee DR. The sensitivity for diagnosing referable DR in the TRC-NW400, TRC-NW8, and non-myd 8 series was 89.3%, 94.6%, and 95.7%, respectively, while the specificity was 94.2%, 90.4%, and 89.3%, respectively. Neither the sensitivity nor the specificity differed significantly between these camera models and the original camera model used for VeriSee DR development (p = 0.40, p = 0.065, respectively). Conclusions: VeriSee DR was applicable to a variety of color fundus cameras with 100% agreement with ophthalmologists in terms of gradability and good sensitivity and specificity for the diagnosis of referable DR.

In Vivo Capillary Structure and Blood Cell Flux in the Normal and Diabetic Mouse Eye.

Purpose: To characterize the early structural and functional changes in the retinal microvasculature in response to hyperglycemia in the Ins2Akita mouse. Methods: A custom phase-contrast adaptive optics scanning light ophthalmoscope was used to image retinal capillaries of 9 Ins2Akita positive (hyperglycemic) and 9 Ins2Akita negative (euglycemic) mice from postnatal weeks 5 to 18. A 15 kHz point scan was used to image capillaries and measure red blood cell flux at biweekly intervals; measurements were performed manually. Retinal thickness and fundus photos were captured monthly using a commercial scanning laser ophthalmoscope/optical coherence tomography. Retinal thickness was calculated using a custom algorithm. Blood glucose and weight were tracked throughout the duration of the study. Results: Elevated blood glucose (>250 mg/dL) was observed at 4 to 5 weeks of age in Ins2Akita mice and remained elevated throughout the study, whereas euglycemic littermates maintained normal glucose levels. There was no significant difference in red blood cell flux, capillary anatomy, lumen diameter, or occurrence of stalled capillaries between hyperglycemic and euglycemic mice between postnatal weeks 5 and 18. Hyperglycemic mice had a thinner retina than euglycemic littermates (p < 0.001), but retinal thickness did not change with duration of hyperglycemia despite glucose levels that were more than twice times normal. Conclusions: In early stages of hyperglycemia, retinal microvasculature structure (lumen diameter, capillary anatomy) and function (red blood cell flux, capillary perfusion) were not impaired despite 3 months of chronically elevated blood glucose. These findings suggest that hyperglycemia alone for 3 months does not alter capillary structure or function in profoundly hyperglycemic mice.