Automated cone photoreceptor cell identication in confocal adaptive optics scanning laser ophthalmoscope images based on object detection

Cone photoreceptor cell identication is important for the early diagnosis of retinopathy.In this study,an object detection algorithm is used for cone cell identication in confocal adaptive optics scanning laser ophthalmoscope(AOSLO)images.An effectiveness evaluation of identication using the proposed method reveals precision,recall,and F_(1)-score of 95.8%,96.5%,and 96.1%,respectively,considering manual identication as the ground truth.Various object detection and identication results from images with different cone photoreceptor cell distributions further demonstrate the performance of the proposed method.Overall,the proposed method can accurately identify cone photoreceptor cells on confocal adaptive optics scanning laser ophthalmoscope images,being comparable to manual identication.

Automated superpixels-based identification and mosaicking of cone photoreceptor cells for adaptive optics scanning laser ophthalmoscope

An automated superpixels identification/mosaicking method is presented for the analysis of cone photoreceptor cells with the use of adaptive optics scanning laser ophthalmoscope(AO-SLO) images. This is an image oversegmentation method used for the identification and mosaicking of cone photoreceptor cells in AO-SLO images.It includes image denoising, estimation of the cone photoreceptor cell number, superpixels segmentation, merging of superpixels, and final identification and mosaicking processing steps. The effectiveness of the presented method was confirmed based on its comparison with a manual method in terms of precision, recall, and F1-score of 77.3%, 95.2%, and 85.3%, respectively.

Bimorph deformable mirror based adaptive optics scanning laser ophthalmoscope for retina imaging in vivo

A bimorph deformable mirror （DM） with a large stroke of more than 30 μm using 35 actuators is presented and characterized for an adaptive optics （AO） confocal scanning laser ophthalmoscope application. Facilitated with a Shack-Hartmann wavefront sensor, the bimorph DM-based AO operates closed-loop AO corrections for hu- man eyes and reduces wavefront aberrations in most eyes to below 0.1 μm rms. Results from living eyes, including one exhibiting ~5D of myopia and ~2D of astigmatism along with notable high-order aberrations, reveal a prac- tical efficient aberration correction and demonstrate a great benefit for retina imaging, including improving resolution, increasing brightness, and enhancing the contrast of images.

RETINAL SPECTRAL IMAGING AND BLOOD FLOW MEASUREMENT

Measurement of both oxygen saturation and blood flow in the retinal vessels has proved to give important information about the eye health and the onset of eye pathologies such as diabetic retinopathy.In this study,we present the implementation,on a commercially available fundus camera,of a retinal imager and a retina blood flow velocimeter.The retinal imager uses division of aperture to acquire nine wavelength-dependent sub-images of the retina.Careful consideration is taken to improve image transfer by measuring the optical properties of the fundus camera and modeling the optical train in Zemax.This part of the setup is calibrated with optical phantoms of known optical properties that are also used to build a lookup table(LUT)linking phantom optical properties to measured reflectance.The retina blood flow velocimeter relies on tracking clusters of erythrocytes and uses a fast acquisition camera attached to a zoom lens,with a green illumination LED-engine.Calibration is provided using a calibrated quartz capillary tube and human blood at a known flow rate.Optical properties of liquid phantoms are retrieved from measured reflectance using the LUT,and blood flow measurements in the retina are presented.

Central Retinal Microperimetry by Scanning Laser Ophthalmoscopy in Chiasmal Patients with Visual Inattention Temporally at Monocular Visual Acuity Testing

Background: In a previous study, a specific visual behaviour was described in four chiasmal patients. It manifested as inattention/ignorance within the temporal visual space (“visual blocking”) at monocular visual acuity testing. Moreover, in 3 out of the 4, the process of reading a text appeared cognitively impaired. Methods: As a supplement to conventional visual field testing, the present analysis focus was on microperimetry by Scanning Laser Ophthalmocopy (SLO). Our aim was to identify the perceptual retinal counterparts to the temporally located visual field defects as caused by the visual pathway lesion on a chiasmal level, possibly also to indicate the apparently ineffective saccadic movements underlying that only part of the line on the chart could be given. Results and Conclusions: The central retinal areas with lacking recognition by SLO testing were given by black rectangles expressing scotomatous points;they clustered in a zone extending nasally from the fixation area, as expected. The methodology further depicted an orderly fixation in two cases, and only minor deviation in two. Fixation saccades thus were considered by and large within normal and with only exceptional outlier points recorded. All considered, the shortcomings of the perceptual mechanisms underlying the lateralised visual inattention as observed in the four patients have remained without a satisfactory explanation.

Acupuncture Therapy for the Treatment of Optic Nerve Atrophy

Objective: Optical Nerve Atrophy is one of the most common causes of blindness worldwide. The condition is linked to several pathologies, which contribute to the damage of the optic nerve. The presence of a tumor on the optic nerve, improper formation of the optic nerve, glaucoma, hereditary and central nervous system diseases, and anterior ischemic optic neuropathy promote deterioration of the optic nerve. The purpose of this review is to examine the efficacy of acupuncture therapy for ONA. Method: Clinical trials (case control-trials), and randomized control trials (RCTs) were assessed to observe the efficacy of acupuncture as well as the safety of acupuncture, needling manipulation, and acupoints selection. The data collected in this research include scientific research papers from China National Knowledge Infrastructure (CNKI), PUBMED library, National Library of Medicine (NLM), EMBASE, Cochrane Library, Chinese Biomedical Literature Database, and other literature library date present. Ophthalmoscope, OCT, pupils test, ocular alignment, nystagmus, and visual acuity check were the diagnostic tools used for ONA in the included study. ONA treatment has been a challenge to ophthalmologists over the past decades. At present, western approaches have no fixed treatment mechanism for the condition. Early diagnosis, the use of magnifying lenses, and reduction of increased fluid around the spinal cord and brain are the multiple disciplinary approaches used in western medicine for ONA. On the other hand, Acupuncture, a branch of traditional Chinese medicine, which stimulates the body’s natural healing ability to promote physical and emotional well-being, has reported some significant treatment effects for ONA. Result: The overall result shows that Acupuncture greatly improved patients’ visual acuity, visual field, and visual function in the included study. Acupuncture acting alone showed significant superiority over other treatments for optical nerve atrophy. Acupuncture combined with medication could improve a patient’s condition more rapidly than medications alone. Conclusion: Optic nerve atrophy is a threatening condition to the vision, which is a leading cause of blindness worldwide. Acupuncture has improved the condition of patients with ONA more effectively than other treatment mechanisms in the included study. However, more clinical trials need to be carried out to substantiate stronger evidence of acupuncture for ONA.

AB105.Database of retinal images in visually impaired individuals:drusen and age-related macular degeneration(AMD)

Background:With a large portion of older adults living longer,the number of individuals diagnosed with low vision is increasing.The use of optical coherence tomography/scanning laser ophthalmoscope(OCT/SLO)to diagnose retinal disease has become common place in the last 10 years,yet currently there are no OCT/SLO databases for pathological vision.Our aim is to develop a clinical database of individuals who have drusen(i.e.,lipid deposits found under the retina),or have been diagnosed with age-related macular degeneration(AMD),with information as to how the structure of the diseased retina changes over time,as well as measures of visual and cognitive functional performance.Methods:Fundus photographs and retinal scans will be taken using the same model of optos OCT/SLO located in three test sites(MAB-Mackay Rehabilitation Centre,School of Optometry Clinic at the University of Montreal,and the Lighthouse Institute,New York,USA).For each individual entry in the database,demographic and diagnosis information will be available.All OCT/SLO images will be graded according to the Age-related Eye Disease Study standard,in addition to number and size of drusen,severity of geographic atrophy,severity of pigment mottling and presence of choroidal neovascularization.Retinal topography and Raster scans from the OCT/SLO will provide a cross-sectional look at affected retinas.Fixation stability will be recorded using the SLO function,and present four different tasks that are designed to reproduce typical tasks of daily vision,with each task lasting for 10 seconds.The tasks are cross fixation,face recognition,visual search,and reading.These tasks in addition to the retinal scans will be used to determine the eccentricity of a preferred retinal locus from the anatomical fovea,and can be used as an outcome measure for clinical interventions in visually impaired patients.Results:The database will be available to professors training eye-care practitioners and rehabilitation specialists as a teaching tool.Students will be able to familiarize themselves with the retina and a variety of AMD-related pathologies before they start working with patients.The database will also be accessible by researchers interested in studying AMD from basic science to epidemiology,to investigate how drusen and AMD impact visual and cognitive functional performance.Conclusions:The common infrastructure is easily accessible to all VHRN members on request.The database will also be accessible online in 2018(see http://cvl.concordia.ca for more information).

Characterization of the retinal vasculature in fundus photos using the PanOptic iExaminer system

Background:The goal was to characterize retinal vasculature by quantitative analysis of arteriole-to-venule(AM)ratio and vessel density in fundus photos taken with the PanOptic iExaminer System.Methods:The PanOptic ophthalmoscope equipped with a smartphone was used to acquire fundus photos centered on the optic nerve head.Two fundus photos of a total of 19 eyes from 10 subjects were imaged.Retinal vessels were analyzed to obtain the AN ratio.In addition,the vessel tree was extracted using deep learning U-NET,and vessel density was processed by the percentage of pixels within vessels over the entire image.Results:All images were successfully processed for the AN ratio and vessel density.There was no significant difference of averaged AN ratio between the first(0.77±0.09)and second(0.77±0.10)measurements(P=0.53).There was no significant difference of averaged vessel density(%)between the first(6.11±1.39)and second(6.12±1.40)measurements(P=0.85).Conclusions:Quantitative analysis of the retinal vasculature was feasible in fundus photos taken using the PanOptic ophthalmoscope.The device appears to provide sufficient image quality for analyzing AN ratio and vessel density with the benefit of portability,easy data transferring,and low cost of the device,which could be used for pre-clinical screening of systemic,cerebral and ocular diseases.

Characterization of the retinal vasculature in fundus photos using the PanOptic iExaminer system

Background:The goal was to characterize retinal vasculature by quantitative analysis of arteriole-to-venule(A/V)ratio and vessel density in fundus photos taken with the PanOptic iExaminer System.Methods:The PanOptic ophthalmoscope equipped with a smartphone was used to acquire fundus photos centered on the optic nerve head.Two fundus photos of a total of 19 eyes from 10 subjects were imaged.Retinal vessels were analyzed to obtain the A/V ratio.In addition,the vessel tree was extracted using deep learning U-NET,and vessel density was processed by the percentage of pixels within vessels over the entire image.Results:All images were successfully processed for the A/V ratio and vessel density.There was no significant difference of averaged A/V ratio between the first(0.77±0.09)and second(0.77±0.10)measurements(P=0.53).There was no significant difference of averaged vessel density(%)between the first(6.11±1.39)and second(6.12±1.40)measurements(P=0.85).Conclusions:Quantitative analysis of the retinal vasculature was feasible in fundus photos taken using the PanOptic ophthalmoscope.The device appears to provide sufficient image quality for analyzing A/V ratio and vessel density with the benefit of portability,easy data transferring,and low cost of the device,which could be used for pre-clinical screening of systemic,cerebral and ocular diseases.