cSLO Imaging Research Articles

Imaging the Area of Internal Limiting Membrane Peeling after Macular Hole Surgery.

Background: The aim of this study was to compare en-face optical coherence tomography (OCT) imaging and confocal scanning laser ophthalmoscopy (cSLO) imaging at different wavelengths to identify the internal limiting membrane (ILM) peeling area after primary surgery with vitrectomy and ILM peeling for macular hole (MH). Methods: In total, 50 eyes of 50 consecutive patients who underwent primary surgery with vitrectomy and ILM peeling for MH were studied. The true ILM rhexis based on intraoperative color fundus photography was compared to the presumed ILM rhexis identified by a blinded examiner using en-face OCT imaging and cSLO images at various wavelengths. To calculate the fraction of overlap (FoO), the common intersecting area and the total of both areas were measured. Results: The FoO for the measured areas was 0.93 ± 0.03 for en-face OCT, 0.76 ± 0.06 for blue reflectance (BR; 488 nm), 0.71 ± 0.09 for green reflectance (GR; 514 nm), 0.56 ± 0.07 for infrared reflectance (IR; 815 nm) and 0.73 ± 0.06 for multispectral (MS). The FoO in the en-face OCT group was significantly higher than in all other groups, whereas the FoO in the IR group was significantly lower compared to all other groups. No significant differences were observed in FoO among the MS, BR, and GR groups. In en-face OCT, there was no significant change in the ILM peeled area measured intraoperatively and postoperatively (8.37 ± 3.01 vs. 8.24 ± 2.81 mm2; p = 0.8145). Nasal-inferior foveal displacement was observed in 38 eyes (76%). Conclusions: En-face OCT imaging demonstrates reliable postoperative visualization of the ILM peeled area. Although the size of the ILM peeling remains stable after one month, our findings indicate a notable inferior-nasal shift of the overall ILM peeling area towards the optic disc.

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

ObjectiveColour 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...

Retinal Vascular Geometry in Hypertension: cSLO-Based Method.

We aim to introduce a method using confocal scanning laser ophthalmoscopy (cSLO) images for measuring retinal vascular geometry, including vessel branch angle (BA), vessel diameter, vessel tortuosity, and fractal dimension (Df), and to elucidate the relationship between hypertension and these metrics. A total of 119 participants (119 eyes) were enrolled, among which 72 were normotensive and 47 were hypertensive. Infrared cSLO images were extracted from the circular scan around the optics disc using a commercial cSLO + optical coherence tomography instrument. Preprocessed cSLO images were further analyzed using the appropriate tool/macro/plugin of ImageJ. Intraclass correlation coefficients of selected methods used for conducting the cSLO-based geometric analyses were all higher than 0.80. Arterial/arteriolar BA, arteriolar vessel diameter, and total Df in normotensive subjects were 85.80 ± 7.79°, 116.80 ± 12.58μm, and 1.430 ± 0.037, respectively, significantly higher than those of hypertensive subjects (82.13 ± 10.83°, 108.2 ± 11.12μm, and 1.361 ± 0.044, all P < 0.05). The aforementioned metrics remained negatively correlated with hypertension even after adjusting for age alone or age and gender (P < 0.05). However, the difference between arteriolar tortuosity and all studied venous/venular geometric parameters in both subjects was insignificant (all P > 0.05). Proposed cSLO-based methods for assessing various vascular geometric parameters were highly repeatable and reproducible. Arterial/arteriolar BA, arteriolar vessel diameter, and total Df were retinal vascular parameters significantly correlated with hypertension in a negative manner.

Prediction of visual impairment in retinitis pigmentosa using deep learning and multimodal fundus images

BackgroundThe efficiency of clinical trials for retinitis pigmentosa (RP) treatment is limited by the screening burden and lack of reliable surrogate markers for functional end points. Automated methods to determine...

Semi-Automated Live Tracking of Microglial Activation in CX3CR1GFP Mice During Experimental Autoimmune Encephalomyelitis by Confocal Scanning Laser Ophthalmoscopy.

Confocal scanning laser ophthalmoscopy (cSLO) is a non-invasive technique for real-time imaging of the retina. We developed a step-by-step protocol for the semi-automatic evaluation of myeloid cells in cSLO images from CX3CR1GFP mice, expressing green fluorescent protein (GFP) under control of the endogenous CX3C chemokine receptor 1 locus. We identified cSLO parameters allowing us to distinguish animals with experimental autoimmune encephalomyelitis (EAE) from sham-treated/naïve animals. Especially cell count (CC) and the total microglial area (SuA) turned out to be reliable parameters. Comparing the cSLO results with clinical parameters, we found significant correlations between the clinical EAE score and the SuA and of the inner retinal layer thickness, measured by optical coherence tomography, with the CC as well as the SuA. As a final step, we performed immunohistochemistry to confirm that the GFP-expressing cells visualized by the cSLO are Iba1 positive and validated the step-by-step protocol against manual counting. We present a semi-automatic step-by-step protocol with a balance between fast data evaluation and adequate accuracy, which is optimized by the option to manually adapt the contrast threshold. This protocol may be useful for numerous research questions on the role of microglial polarization in models of inflammatory and degenerating CNS diseases involving the retina.

Unsupervised Approaches for the Segmentation of Dry ARMD Lesions in Eye Fundus cSLO Images.

Age-related macular degeneration (ARMD), a major cause of sight impairment for elderly people, is still not well understood despite intensive research. Measuring the size of the lesions in the fundus is the main biomarker of the severity of the disease and as such is widely used in clinical trials yet only relies on manual segmentation. Artificial intelligence, in particular automatic image analysis based on neural networks, has a major role to play in better understanding the disease, by analyzing the intrinsic optical properties of dry ARMD lesions from patient images. In this paper, we propose a comparison of automatic segmentation methods (classical computer vision method, machine learning method and deep learning method) in an unsupervised context applied on cSLO IR images. Among the methods compared, we propose an adaptation of a fully convolutional network, called W-net, as an efficient method for the segmentation of ARMD lesions. Unlike supervised segmentation methods, our algorithm does not require annotated data which are very difficult to obtain in this application. Our method was tested on a dataset of 328 images and has shown to reach higher quality results than other compared unsupervised methods with a F1 score of 0.87, while having a more stable model, even though in some specific cases, texture/edges-based methods can produce relevant results.

Characterization and allogeneic transplantation of a novel transgenic cone-rich donor mouse line

ObjectivesCone photoreceptor transplantation is a potential treatment for macular diseases. The optimal conditions for cone transplantation are poorly understood, partly because of the scarcity of cones in donor mice. To facilitate allogeneic cone photoreceptor transplantation studies in mice, we aimed to create and characterize a donor mouse model containing a cone-rich retina with a cone-specific enhanced green fluorescent protein (EGFP) reporter. MethodsWe generated OPN1LW-EGFP/NRL−/− mice by crossing NRL−/− and OPN1LW-EGFP mice. We characterized the anatomical phenotype of OPN1LW-EGFP/NRL−/− mice using multimodal confocal scanning laser ophthalmoscopy (cSLO) imaging, immunohistology, and transmission electron microscopy. We evaluated retinal function using electroretinography (ERG), including 465 and 525 nm chromatic stimuli. Retinal sheets and cell suspensions from OPN1LW-EGFP/NRL−/− mice were transplanted subretinally into immunodeficient Rd1 mice. ResultsOPN1LW-EGFP/NRL−/− retinas were enriched with OPN1LW-EGFP+ and S-opsin+ cone photoreceptors in a dorsal-ventral distribution gradient. Cone photoreceptors co-expressing OPNL1W-EGFP and S-opsin significantly increased in OPN1LW-EGFP/NRL−/− compared to OPN1LW-EGFP mice. Temporal dynamics of rosette formation in the OPN1LW-EGFP/NRL−/− were similar as the NRL−/− with peak formation at P15. Rosettes formed preferentially in the ventral retina. The outer retina in P35 OPN1LW-EGFP/NRL−/− was thinner than NRL−/− controls. The OPN1LW-EGFP/NRL−/− ERG response amplitudes to 465 nm stimulation were similar to, but to 535 nm stimulation were lower than, NRL−/− controls. Three months after transplantation, the suspension grafts showed greater macroscopic degradation than sheet grafts. Retinal sheet grafts from OPN1LW-EGFP/NRL−/− mice showed greater S-opsin + cone survival than suspension grafts from the same strain. ConclusionsOPN1LW-EGFP/NRL−/− retinae were enriched with S-opsin+ photoreceptors. Sustained expression of EGFP facilitated the longitudinal tracking of transplanted donor cells. Transplantation of cone-rich retinal grafts harvested prior to peak rosette formation survived and differentiated into cone photoreceptor subtypes. Photoreceptor sheet transplantation may promote greater macroscopic graft integrity and S-opsin+ cone survival than cell suspension transplantation, although the mechanism underlying this observation is unclear at present. This novel cone-rich reporter mouse strain may be useful to study the influence of graft structure on cone survival.

Noninvasive monitoring of suprachoroidal, subretinal, and intravitreal implants using confocal scanning laser ophthalmoscope (cSLO) and optical coherence tomography (OCT)

To address the need for noninvasive monitoring of injectable preformed drug delivery implants in the eye, we developed noninvasive methods to monitor such implants in different locations within the eye. Cylindrical polymeric poly(lactide-co-glycolide) or metal implants were injected into isolated bovine eyes at suprachoroidal, subretinal, and intravitreal locations and imaged noninvasively using the cSLO and OCT modes of a Heidelberg Spectralis HRA + OCT instrument after adjusting for the corneal curvature. Length and diameter of implants were obtained using cSLO images for all three locations, and the volume was calculated. Additionally, implant volume for suprachoroidal and subretinal location was estimated by integrating the cross-sectional bleb area over the implant length in multiple OCT images or using the maximum thickness of the implant based on thickness map along with length in cSLO image.Simultaneous cSLO and OCT imaging identified implants in different regions of the eye. Image-based measurements of implant dimensions mostly correlated well with the values prior to injection using blade micrometer. The accuracy (82–112%) and precision (1–19%) for noninvasive measurement of length was better than the diameter (accuracy 69–130%; precision 3–38%) using cSLO image for both types of implants. The accuracy for the measurement of volume of both types of implants from all three intraocular locations was better with cSLO imaging (42–152%) compared to those obtained using OCT cross-sectional bleb area integration (117–556%) or cSLO and thickness map (32–279%) methods.Suprachoroidal, subretinal, and intravitreal implants can be monitored for length, diameter, and volume using cSLO and OCT imaging. Such measurements may be useful in noninvasively monitoring implant degradation and drug release in the eye.

Age-Related Retinal Changes in Wild-Type C57BL/6J Mice Between 2 and 32 Months.

PurposeThe purpose of this study was to extend our understanding of how aging affects normal retina function and morphology in wild-type C57BL/6J mice, by analyzing electrophysiological recordings and in vivo and post mortem anatomy.MethodsElectroretinograms (ERGs), spectral domain optical coherence tomography (SD-OCT), and confocal scanning laser ophthalmoscope (cSLO) in vivo images were obtained from mice between the ages of 2 and 32 months in four groups: group 1 (<0.5 years), group 2 (1.0–1.5 years), group 3 (1.5–2.0 years), and group 4 (>2.0 years). Afterward, mouse bodies and eyes were weighed. Eyes were stained with hematoxylin and eosin (H&E) and cell nuclei were quantified.ResultsWith aging, mice showed a significant reduction in both a- and b-wave ERG amplitudes in scotopic and photopic conditions. Additionally, total retina and outer nuclear layer (ONL) thickness, as measured by SD-OCT images, were significantly reduced in older groups. The cSLO images showed an increase in auto-fluorescence at the photoreceptor-RPE interface as age increases. H&E cell nuclei quantification showed significant reduction in the ONL in older ages, but no differences in the inner nuclear layer (INL) or ganglion cell layer (GCL).ConclusionsBy using multiple age groups and extending the upper age limit of our animals to approximately 2.65 years (P970), we found that natural aging causes negative effects on retinal function and morphology in a gradual, rather than abrupt, process. Future studies should investigate the exact mechanisms that contribute to these gradual declines in order to discover pathways that could potentially serve as therapeutic targets.

Visualization of Retinal Blood Vessels.

The retina offers a unique opportunity to directly visualize blood vessels in vivo noninvasively. Over the past few decades, several new imaging techniques have been adapted to study the retinal vasculature in the laboratory in animal models and in the clinic in human subjects. High-contrast, finely detailed fundus images can be acquired by confocal scanning laser ophthalmoscopy (cSLO). With fluorescein angiography (FA), the retinal microcirculation can be visualized. High-resolution spectral-domain optical coherence tomography (SD-OCT) is able to acquire cross-section images resolving the microarchitecture of the retina, similar to histology. The techniques and protocols for acquiring cSLO, FA, and SD-OCT imaging of the retinal vasculature and morphology in the rodent are described.

Quantifiable In Vivo Imaging Biomarkers of Retinal Regeneration by Photoreceptor Cell Transplantation.

PurposeShort-term improvements in retinal anatomy are known to occur in preclinical models of photoreceptor transplantation. However, correlative changes over the long term are poorly understood. We aimed to develop a quantifiable imaging biomarker grading scheme, using noninvasive multimodal confocal scanning laser ophthalmoscopy (cSLO) imaging, to enable serial evaluation of photoreceptor transplantation over the long term.MethodsPhotoreceptor cell suspensions or sheets from rhodopsin-green fluorescent protein mice were transplanted subretinally, into either NOD.CB17-Prkdcscid/J or C3H/HeJ-Pde6brd1 mice. Multimodal cSLO imaging was performed serially for up to three months after transplantation. Imaging biomarkers were scored, and a grade was defined for each eye by integrating the scores. Image grades were correlated with immunohistochemistry (IHC) data.ResultsMultimodal imaging enabled the extraction of quantitative imaging biomarkers including graft size, GFP intensity, graft length, on-target graft placement, intra-graft lamination, hemorrhage, retinal atrophy, and periretinal proliferation. Migration of transplanted material was observed. Changes in biomarker scores and grades were detected in 14/16 and 7/16 eyes, respectively. A high correlation was found between image grades and IHC parameters.ConclusionsSerial evaluation of multiple imaging biomarkers, when integrated into a per-eye grading scheme, enabled comprehensive tracking of longitudinal changes in photoreceptor cell grafts over time. The application of systematic multimodal in vivo imaging could be useful in increasing the efficiency of preclinical retinal cell transplantation studies in rodents and other animal models.Translational RelevanceBy allowing longitudinal evaluation of the same animal over time, and providing quantifiable biomarkers, non-invasive multimodal imaging improves the efficiency of retinal transplantation studies in animal models. Such assays will facilitate the development of cell therapy for retinal diseases.

EN FACE IMAGING OF OUTER RETINAL PATHOLOGY AFTER RETINAL DETACHMENT.

To explore the potentials of multicolor (MC) confocal scanning laser ophthalmoscopy (cSLO) to detect structural retinal pathology after macula-off rhegmatogenous retinal detachment (RRD) and to describe their appearances. Thirty MC cSLO images of 30 eyes after RRD repair were prospectively studied for the presence of RRD-related pathology. All MC cSLO findings were verified using swept source optical coherence tomography. Positive percent agreements were calculated using swept source optical coherence tomography as reference. Eight RRD-related structural pathologies were identified and characterized: ellipsoid zone (EZ) disruption, foveal EZ rosette, outer retinal fold, retinal detachment line, subretinal fluid blebs, subretinal fluid layer, retinal striae, and intraretinal cysts. Multicolor cSLO positive percent agreements were as follows: EZ disruption: 79%, foveal EZ rosette: 73%, outer retinal fold: 67%, retinal detachment line: 84%, subretinal fluid blebs: 0.70%, subretinal fluid layer: 50%, intraretinal cysts: 60%, and retinal striae: 100%. En face MC cSLO imaging detected and delineated RRD-related structural pathology in high agreement with cross-sectional swept source optical coherence tomography and can supplement optical coherence tomography in the documentation and monitoring of outer retinal remodeling processes after macula-off RRD. Foveal EZ rosette is a new finding of the foveal EZ.

Postretinal Detachment Retinal Displacement: How Best to Detect It?

Purpose: The reported incidence of postretinal detachment (RD) macular displacement varies markedly (14–72%). This may in part be due to the imaging modalities used. We compared the ability of 2 types of fundus autofluorescence (FAF) imaging modalities to detect this phenomenon. Methods: Prospective study of 70 eyes with macula-involving RDs. 8 weeks postoperatively, patients underwent FAF imaging with 2 machines: a confocal scanning laser ophthalmoscope (cSLO) and a digital fundus camera (FC). Images were graded for the presence of hyperautofluorescent RPE (retinal pigment epithelium) ghost vessels, indicative of retinal displacement, by 2 masked, independent graders. Results: In total, 87.1% of FC images were gradable versus 88.6% of cSLO images. Retinal displacement was detectable in 61.4% of FC images versus 52.8% of cSLO images. Vessel shift often appeared more autofluorescent on FC imaging, but choroidal vessels were more visible. Cohen’s agreement between the imaging modalities was 0.50, rated as moderate agreement. For both imaging modalities, the inter- and intragrader agreement was substantial, representing good test-retest reliability. Conclusions: Detection of post-RD retinal displacement was similar between FC and cSLO FAF imaging, with only moderate agreement between both modalities.

Diagnostic performance of confocal scanning laser ophthalmoscope imaging and compared with color fundus camera in retinal pigment epithelial detachment of polypoidal choroidal vasculopathy

Objective To observe confocal scanning laser ophthalmoscope (cSLO) based retinal imaging and color fundus camera in pigment epithelial detachment (PED) of polypoidal choroidal vasculopathy (PCV). Methods PED of 30 patients (32 eyes) were recruited from June 2016 to June 2017 in the Beijing Tongren Hospital who were detected in high-definition OCT (HD-OCT) and diagnosed as PCV by FFA and ICGA. There were 16 males (17 eyes) and 14 females (15 eyes); aged from 50-83 years, with the mean age of 66.59 years. The photographs of ocular fundus including color fundus camera, cSLO imaging, HD-OCT, FFA and ICGA were analyzed. Multimodal imaging results were regarded as gold standard. Sensitivity and specificity were calculated in serous and hemorrhagic PED diagnosis using color fundus camera and cSLO imaging. The positive number of PED was used to compare between two modes fundus imaging by using χ2 test. Results Twenty serous PED eyes, 3 hemorrhagic PED eyes and 9 serous/hemorrhagic PED eyes were determined using multimodal imaging. The sensitivity and specificity of color fundus camera were 45% and 100% in detecting serous PED and 100% and 91 % in detecting hemorrhagic PED. The sensitivity and specificity of cSLO imaging were 83% and 100% in detecting serous PED and 50% and 86% in detecting hemorrhagic PED. The positive number of serous PED in cSLO imaging was significantly higher than color fundus camera (χ2=7.752, P=0.011). The positive number of hemorrhagic PED in cSLO imaging shows no obvious difference compared with color fundus camera (χ2=1.164, P=0.419). Conclusion The sensitivity and positive number of detecting serous PED with PCV in cSLO fundus imaging were higher than the color fundus camera technology. Key words: Choroid diseases; Retinal pigment epithelial detachment; Confocal scanning laser ophthalmoscope; Color fundus camera

Optical coherence tomography angiography (OCT-A) in an animal model of laser-induced choroidal neovascularization

Aim of the study was to compare optical coherence tomography angiography (OCT-A) and conventional fluorescein angiography (FA) for quantitative analysis of the retinal and choroidal vasculature in the animal model of laser-induced choroidal neovascularization (CNV). Therefore, Dark Agouti rats underwent argon laser photocoagulation to induce CNV at D0. In vivo imaging using combined confocal scanner laser ophthalmoscopy (cSLO)-based FA and OCT-A (Heidelberg Engineering GmbH, Heidelberg, Germany) was performed before and immediately after laser treatment as well as at day 2, 7, 14 and 21. OCT-A en-face images were compared to cSLO images obtained by conventional FA topographic uptake recorded using a series of different pre-defined focus settings. For a quantitative comparison of CNV imaging by OCT-A and FA, CNV area, vessel density, number of vessel junctions, total vessel length and number of vessel end points were analyzed. Subsequent ex vivo analyses of the CNV included immunofluorescence staining of vessels in retinal and RPE/choroidal/scleral flatmount preparations. We found, that OCT-A allowed for high-resolution non-invasive imaging of the superficial, intermediate and deep retinal capillary plexus as well as the choroidal blood vessels in rats. Compared with OCT-A, visualization of CNV progression by invasive FA was less accurate, in particular the deep vascular plexus was visualized in more detail by OCT-A. The area of neovascularization was mainly detected in the deep retinal vascular plexus, outer nuclear layer (ONL), ellipsoid zone (EZ) and the choroid. Within the laser lesions, signs of CNV formation occurred at day 7 with progression in size and number of small vessels until day 21. Due to leakage and staining effects, CNV areas appeared significantly larger in FA compared to OCT-A images (p ≤ 0.0001 for all tested layers). Vessel density, number of vessel junctions, total vessel length and number of vessel end points were significantly higher in intermediate vascular plexus (IVP) and deep vascular plexus (DVP) in OCT-A compared to FA images. Overall, CNV area in flatmounts was similar to OCT-A results and much smaller compared to the area of dye leakage by FA. This study demonstrates that in vivo OCT-A imaging in small animals is feasible and allows for precise analysis of the formation of new blood vessel formation in the animal model of laser-induced CNV. Given its superior axial resolution, sensitivity and non-invasiveness compared to conventional FA imaging, OCT-A opens the door for a more detailed evaluation of CNV development in such a model and, thus, enables the analysis of the response to novel therapeutic interventions in longitudinal in vivo studies.

Characterization of Artifacts Associated With Multicolor Confocal Scanning Laser Ophthalmoscopy.

To characterize the appearance of three types of artifacts observed on multicolor confocal scanning laser ophthalmoscopy (cSLO). Retrospective review of 159 eyes of 96 consecutive patients from the Duke Eye Center who underwent multicolor cSLO with spectral-domain optical coherence tomography (SD-OCT). Infrared (IR), green, blue, and multicolor reflectance images were evaluated for artifacts with corresponding SD-OCT scans available for reference. Multicolor cSLO artifacts were detected in 23.3% (37 of 159) of eyes and comprised three main patterns: spot, wisp, and net. Only three instances of these artifacts were detected on IR reflectance versus 34, 37, and 35 instances on green, blue, and multicolor reflectance, respectively. Artifacts were observed in 0% of eyes with clear lenses, 27.7% of eyes with cataracts, and in 20.8% of eyes with posterior chamber intraocular lenses. Awareness of spot, wisp, and net artifacts when interpreting multicolor cSLO images may facilitate the identification of true retinal pathology. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:810-815.].

Imaging performance and quantitative analysis of confocal scanning laser ophthalmoscope for cystoid macular edema

Background Cystoid macular edema (CME) is caused by many fundus diseases.The noninvasive clinical diagnosis methods for CME are conventional color fundus photography up to now.However, these images can not display the CME range well.Confocal scanning laser ophthalmoscope (cSLO) based retinal imaging can provide clear picture with high contrast.However, whether cSLO imaging is feasible in the quantitative assessment of CME remains unclear. Objective This study was to image the boundary of CME and assess the quantification of CME image from cSLO imaging technology. Methods A series case-observational study was designed.This study protocal was approved by Ethic Committee of Beijing Tongren Hospital.cSLO based retinal imaging technology was carried out on consecutive 24 eyes of 24 patients with clinically diagnosed and OCT confirmed CME in Beijing Tongren Eye Center from August to December 2015 under the informed consent of each individual.The radial scan range was 45°× 45° and the line scan level was 49 at macula area.The pseudocolar image, green light reflective image (532 nm) and infrared reflective image (785 nm) were collected.The imaging was analyzed by EasyScan software (version 1.2.2). Fundus color photography and SD-OCT were carried out in each patient.The images were graded by specialists according to the SD-OCT cross sectional results. Results The primary causes of CME included epiretinal membrane (10 eyes), branch retinal vein occlusion (BRVO)(6 eyes), central retinal vein occlusion (CRVO)(4 eyes), diabetic retinopathy (DR)(3 eyes) and CRVO with BRVO (1 eye). A CME image was exhibited on the fundus color photogram with the obscure boundary; while the clear range of CME was displayed by the cSLO imaging.The mean score of CME from pseudocolar image, green light reflective image and infrared reflective image was 3.21±0.78, 2.67±0.96 and 2.54±0.83, respectively, which was significantly higher than 1.33±0.82 from the fundus color photography (all at P<0.01). Conclusions In CME patients, the imaging quality from cSLO-based retinal imaging technology is better than that from traditional fundus color photography.Combined with SD-OCT sectional scan analysis, cSLO-based retinal imaging technology may offer a method to observe and record more fundus details for CME diagnosis. Key words: Image processing, computer-assisted; Diagnostic techniques, ophthalmological; Lasers; Retinal imaging; Ophthalmoscopy; Cystoid macular edema/diagnosis; Tomography, optical coherence; Confocal scanning laser ophthalmoscope/methods

Comparison of the screening efficiency of epiretinal membrane using confocal scanning laser ophthalmoscope imaging and color fundus camera in elderly people

Objective To determine the positive results of confocal scanning laser ophthalmoscope (cSLO) based retinal imaging and traditional color fundus camera in screening epiretinal membrane (ERM) in elderly people. Methods A total of 184 retired staffs from certain company (363 eyes) were included in this study, 153 were men (304 eyes) and 31 were women (59 eyes). The mean age was 74.35 years (range 47 - 92 years). All subjects were underwent fundus imaging using cSLO technology and traditional color fundus camera and Cirrus high definition optical coherence tomography (HD-OCT). The imaging quality of two technologies were analyzed and compared according to the evaluation standards. The positive accordance rate was used to compare between two modes fundus imaging (cSLO technology and traditional color fundus camera) and HD-OCT. Results In 363 eyes, the positive number of screening ERM using HD-OCT was 122 eyes (33.6%); the positive number of traditional color fundus camera was 33 eyes (9.1%); the positive number of cSLO imaging was 76 eyes (20.9%). The HD-OCT positive accordance rate of screening ERM using traditional color fundus camera and cSLO technology were 27.0% vs. 62.3%. The HD-OCT positive accordance rate of screening ERM using cSLO technology was significant higher than traditional color fundus camera (χ2=30.81, P<0.001). Conclusion The HD-OCT positive accordance rate of screening ERM in elderly people was higher using cSLO technology than using traditional color fundus camera. Key words: Retinal diseases/diagnosis; Macula lutea; Tomography, optical coherence

An Automated Approach for Localizing Retinal Blood Vessels inConfocal Scanning Laser Ophthalmoscopy Fundus Images.

In this work, we present a rules-based method for localizing retinal blood vessels in confocal scanning laser ophthalmoscopy (cSLO) images and evaluate its feasibility. A total of 31 healthy participants (17 female; mean age: 64.0 ± 8.2 years) were studied using manual and automatic segmentation. High-resolution peripapillary scan acquisition cSLO images were acquired. The automated segmentation method consisted of image pre-processing for gray-level homogenization and blood vessel enhancement (morphological opening operation, Gaussian filter, morphological Top-Hat transformation), binary thresholding (entropy-based thresholding operation), and removal of falsely detected isolated vessel pixels. The proposed algorithm was first tested on the publically available dataset DRIVE, which contains color fundus photographs, and compared to performance results from the literature. Good results were obtained. Monochromatic cSLO images segmented using the proposed method were compared to those manually segmented by two independent observers. For the algorithm, a sensitivity of 0.7542, specificity of 0.8607, and accuracy of 0.8508 were obtained. For the two independent observers, a sensitivity of 0.6579, specificity of 0.9699, and accuracy of 0.9401 were obtained. The results demonstrate that it is possible to localize vessels in monochromatic cSLO images of the retina using a rules-based approach. The performance results are inferior to those obtained using fundus photography, which could be due to the nature of the technology.

Comparison of confocal scanning laser ophthalmoscope and color fundus camera to assess retinal and choroidal disease using

Objective To cpmpare the assessment of retinal and choroidal disease using confocal scanning laser ophthalmoscope (cSLO) imaging and color fundus camera. Methods Sixty-seven patients (90 eyes) with fundus diseases were included in this study. There were 35 males (51 eyes) and 32 female (39 eyes), mean age was 51.32 years. All subjects underwent fundus imaging using cSLO technology and traditional color fundus camera, positive numbers of every retinal pathological change were calculated and compared. Spectral domain-optical coherence tomography (SD-OCT) was also done to compare the accordance rate between two modes of fundus imaging (cSLO technology and traditional color fundus camera) and SD-OCT in choroidal changes. Results The positive numbers of retinal microaneurysm (χ2=4.157, P 0.05). The SD-OCT accordance rate of choroidal pathological changes using cSLO technology was higher than traditional color fundus camera (χ2=9.143, P=0.007). Conclusion In retinal and choroidal diseases, the imaging quality of cSLO fundus imaging technology is better than the traditional color fundus camera technology. Key words: Retinal diseases/diagnosis; Choroid diseases/diagnosis; Tomography, optical coherence