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Optics Letters Sep 2020Non-confocal adaptive optics scanning laser ophthalmoscopy (AOSLO) has enhanced the study of human retinal photoreceptors by providing complementary information to...
Non-confocal adaptive optics scanning laser ophthalmoscopy (AOSLO) has enhanced the study of human retinal photoreceptors by providing complementary information to standard confocal AOSLO images. Previously we developed the first confocal handheld AOSLO (HAOSLO) capable of in vivo cone photoreceptor imaging in supine and non-cooperative patients. Here, we introduce the first multimodal (M-)HAOSLO for confocal and non-confocal split-detection (SD) imaging to allow for more comprehensive patient data collection. Aside from its unprecedented miniature size and weight, M-HAOSLO is also the first system to perform sensorless wavefront-corrected SD imaging of cone photoreceptors.
Topics: Adult; Equipment Design; Humans; Image Processing, Computer-Assisted; Lasers; Ophthalmoscopes
PubMed: 32870897
DOI: 10.1364/OL.402392 -
Scientific Reports Jun 2020The fovea undergoes significant developmental changes from birth into adolescence. However, there is limited data examining cone photoreceptor density, foveal pit shape,...
The fovea undergoes significant developmental changes from birth into adolescence. However, there is limited data examining cone photoreceptor density, foveal pit shape, and foveal avascular zone (FAZ) size in children. The purpose of this study was to determine whether overall foveal structure differs as a function of age and refractive status in children. Forty-eight healthy children (ages 5.8 to 15.8 years) underwent optical coherence tomography imaging to quantify foveal point thickness and foveal pit diameter, depth, and slope. Adaptive optics scanning laser ophthalmoscope (AOSLO) images of foveal capillaries and cone photoreceptors were acquired in a subset of children to quantify FAZ metrics and cone densities at 0.2, 0.3, and 0.5 mm eccentricities. Results show that foveal pit and FAZ metrics were not related to age, axial length, or refractive status. However, linear cone density was lower in myopic versus non-myopic children at eccentricities of 0.2 mm (mean ± SD = 50,022 ± 5,878 cones/mm vs 58,989 ± 4,822 cones/mm, P < 0.001) and 0.3 mm (43,944 ± 5,547 cones/mm vs 48,622 ± 3,538 cones/mm, P < 0.001). These results suggest FAZ and foveal pit metrics do not systematically differ with age in children, while myopic eyes have decreased linear cone density near the foveal center. Significance Statement: The development of the fovea begins prior to birth and continues through the early teenage years until it reaches adult-like properties. Although the majority of changes during childhood are related to the maturation and migration of cone photoreceptors, in vivo data describing cone packing in children is limited. We assessed overall foveal structure in children as young as 5.8 years old by quantifying cone density and spacing, foveal avascular zone size, and foveal pit morphometry to investigate potential structural differences as a function of age and refractive status. While foveal avascular zone and foveal pit metrics did not significantly differ with age, results indicate that myopic children have lower linear cone densities close to the foveal center compared to non-myopic children.
Topics: Adolescent; Capillaries; Child; Female; Fluorescein Angiography; Fovea Centralis; Humans; Macula Lutea; Male; Myopia; Ophthalmoscopes; Ophthalmoscopy; Retinal Cone Photoreceptor Cells; Retinal Vessels; Tomography, Optical Coherence
PubMed: 32487997
DOI: 10.1038/s41598-020-65645-2 -
Investigative Ophthalmology & Visual... May 2017To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with...
PURPOSE
To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with established biophysical models.
METHODS
Vascular bifurcations in arteries and veins were imaged in 17 NPDR and 26 healthy subjects with the Indiana adaptive optics scanning laser ophthalmoscope (AOSLO). Vessel measurements were grouped according to parent vessel diameters into large (≤50 ∼ <100 μm) and small (≤20 ∼ <50 μm) sizes. Vessel diameters and bifurcation angles were measured manually. Vascular diameters were compared with predictions of Murray's law using curve fitting. For analysis of bifurcation angles, two models from Zamir were compared: one based on the power required for blood pumping, the other based on drag force between blood and vascular wall.
RESULTS
For normal larger vessels, the exponent relating the parent and daughter branching diameters was significantly less than the value of 3 predicted by Murray's law (arteries: 2.59; veins: 1.95). In NPDR, the best-fit exponent was close to 3 for arteries but close to 2 in healthy subjects in veins, (arteries: 3.09; veins: 2.16). For both small arteries and veins, diabetics' exponent differed from healthy subjects (P < 0.01). Bifurcation angles in the healthy subjects (78° ± with a standard error (SE) of 0.9°) were not much different than in NPDR (79° ± SE 1.3°). The model based on minimizing pumping power predicted the measurements better than the one minimizing the vascular drag and lumen surface area.
CONCLUSIONS
The relation between parent and daughter branch diameters changes in diabetes, but the branching angles do not.
Topics: Adult; Arterioles; Diabetic Retinopathy; Female; Healthy Volunteers; Humans; Male; Microscopy, Confocal; Middle Aged; Ophthalmoscopes; Retinal Artery; Retinal Neovascularization; Retinal Vein; Venules
PubMed: 28525557
DOI: 10.1167/iovs.17-21653 -
A neophyte gonioscopist's animative and videographic atlas with focal points for effective practice.Indian Journal of Ophthalmology Feb 2022Though various gonioscopy teaching platforms are available, they predominantly comprise of real time scenarios and videos. For a beginner, we suggest providing...
BACKGROUND
Though various gonioscopy teaching platforms are available, they predominantly comprise of real time scenarios and videos. For a beginner, we suggest providing animations of the real time scenario for cognitive training; and then putting them in real time scenarios for a better concept application and practice.
PURPOSE
This video highlights the basic tips and tricks needed to perform gonioscopy with metaphorical conceptual learning matching the 2D and 3D animations with real time scenarios.
SYNOPSIS
Simple and practical scenarios with technical details on how to perform gonioscopy and various challenges are shown. All the animations and videos are created by us, tailored to a neophyte. The following concepts are covered: normal angle (animation versus real-time), dynamicity of the gonioscopic dates of person, methods of gonioscopy - direct and Indirect, precautions and slit lamp adjustment, bubble trouble, patient examination, iris process versus peripheral anterior synechiae (animation versus real-time), patient examination (angle viewing order) for different lens, how to remove gonioscopy lens from the eye, static versus dynamic gonioscopy, situations where gonioscopy is contraindicated, grading of the angle (with animations), clinical scenarios (pseudoexfoliation, pigment dispersion, angle recession and aniridia), and surgical scenarios (patent ostium and blocked ostium).
HIGHLIGHTS
Multiple animations and real-time videos with focal points for effective practice are the highlights of this video.
VIDEO LINK
https://youtu.be/fFmPmqgdjyM.
Topics: Anterior Chamber; Glaucoma, Angle-Closure; Glaucoma, Open-Angle; Gonioscopy; Humans; Intraocular Pressure; Iris; Iris Diseases; Slit Lamp
PubMed: 35086290
DOI: 10.4103/ijo.IJO_151_22 -
Optics Letters Sep 2004An experimental tracking optical coherence tomography (OCT) system has been clinically tested. The prototype instrument uses a secondary sensing beam and steering... (Clinical Trial)
Clinical Trial
An experimental tracking optical coherence tomography (OCT) system has been clinically tested. The prototype instrument uses a secondary sensing beam and steering mirrors to compensate for eye motion with a closed-loop bandwidth of 1 kHz and tracking accuracy, to within less than the OCT beam diameter. The retinal tracker improved image registration accuracy to <1 transverse pixel (<60 microm). Composite OCT images averaged over multiple scans and visits show a sharp fine structure limited only by transverse pixel size. As the resolution of clinical OCT systems improves, the capability to reproducibly map complex structures in the living eye at high resolution will lead to improved understanding of disease processes and improved sensitivity and specificity of diagnostic procedures.
Topics: Eye Movements; Feedback; Glaucoma; Humans; Image Enhancement; Ophthalmoscopes; Ophthalmoscopy; Pilot Projects; Retina; Tomography, Optical Coherence
PubMed: 15460882
DOI: 10.1364/ol.29.002139 -
Translational Vision Science &... Jul 2023To investigate the agreement between a fundus camera and a scanning laser ophthalmoscope in retinal vessel caliber measurements and to identify whether the presence of...
PURPOSE
To investigate the agreement between a fundus camera and a scanning laser ophthalmoscope in retinal vessel caliber measurements and to identify whether the presence of the central light reflex (CLR) explains potential discrepancies.
METHODS
For this cross-sectional study, we obtained fundus camera and scanning laser ophthalmoscope images from 85 eyes of 85 healthy individuals (aged 50-65 years) with different blood pressure status. We measured the central retinal artery equivalent (CRAE) and central retinal artery vein equivalent (CRVE) with the Knudtson-Parr-Hubbard algorithm and assessed the CLR using a semiautomatic grading method. We used Bland-Altman plots, 95% limits of agreement, and the two-way mixed effects intraclass correlation coefficient for consistency [ICC(3,1)] to describe interdevice agreement. We used multivariable regression to identify factors associated with differences in between-device measurements.
RESULTS
The between-device difference in CRAE (9.5 µm; 95% confidence interval, 8.0-11.1 µm) was larger than the between-device difference in CRVE (2.9 µm; 95% confidence interval, 1.3-4.5 µm), with the fundus camera yielding higher measurements (both P < 0.001). The 95% fundus camera-scanning laser ophthalmoscope limits of agreement were -4.8 to 23.9 µm for CRAE and -12.0 to 17.8 µm for CRVE. The corresponding ICCs(3,1) were 0.89 (95% confidence interval, 0.83-0.92) and 0.91 (95% confidence interval, 0.86-0.94). The between-device CRAE difference was positively associated with the presence of a CLR (P = 0.002).
CONCLUSIONS
Fundus cameras and scanning laser ophthalmoscopes yield correlated but not interchangeable caliber measurements. The CLR induces bias in arteriolar caliber in fundus camera images, compared with scanning laser ophthalmoscope images.
TRANSLATIONAL RELEVANCE
Refined measurements could yield better estimates of the association between retinal vessel caliber and ophthalmic or systemic disease.
Topics: Humans; Cross-Sectional Studies; Retinal Vessels; Retinal Vein; Retinal Artery; Reflex
PubMed: 37450282
DOI: 10.1167/tvst.12.7.16 -
Experimental Eye Research Mar 2014Simultaneous non-invasive visualization of blood vessels and nerves in patients can be obtained in the eye. The retinal vasculature is a target of many retinopathies....
Simultaneous non-invasive visualization of blood vessels and nerves in patients can be obtained in the eye. The retinal vasculature is a target of many retinopathies. Inflammation, readily manifest by leukocyte adhesion to the endothelial lining, is a key pathophysiological mechanism of many retinopathies, making it a valuable and ubiquitous target for disease research. Leukocyte fluorography has been extensively used in the past twenty years; however, fluorescent markers, visualization techniques, and recording methods have differed between studies. The lack of detailed protocol papers regarding leukocyte fluorography, coupled with lack of uniformity between studies, has led to a paucity of standards for leukocyte transit (velocity, adherence, extravasation) in the retina. Here, we give a detailed description of a convenient method using acridine orange (AO) and a commercially available scanning laser ophthalmoscope (SLO, HRA-OCT Spectralis) to view leukocyte behavior in the mouse retina. Normal mice are compared to mice with acute and chronic inflammation. This method can be readily adopted in many research labs.
Topics: Acridine Orange; Animals; Blood Flow Velocity; Cell Movement; Diabetes Mellitus, Type 1; Fluorescein Angiography; Fluorescent Dyes; Leukocytes; Male; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Microscopy, Confocal; Ophthalmoscopes; Regional Blood Flow; Retinal Artery; Retinal Vasculitis; Retinal Vein; Tomography, Optical Coherence; Vascular Endothelial Growth Factor A; Video Recording
PubMed: 24333760
DOI: 10.1016/j.exer.2013.12.002 -
Acta Ophthalmologica Sep 2017To report the results and complications of scleral buckling for the treatment of rhegmatogenous retinal detachment (RRD) using 25-gauge chandelier endoillumination.
PURPOSE
To report the results and complications of scleral buckling for the treatment of rhegmatogenous retinal detachment (RRD) using 25-gauge chandelier endoillumination.
METHODS
A total of 61 patients (61 eyes) with RRD were treated with scleral buckling. For the sclera buckling procedure, a 25-gauge chandelier was inserted through the pars plana for intra-ocular illumination, and retinal tears were identified and treated with episcleral cryotherapy under surgical microscope. On postoperative days 1, 3 and 7, the intra-ocular pressure was measured by a non-contact tonometer. On postoperative months 1 and 3, ultrasound biomicroscopy was used to examine the pars plana incision.
RESULTS
In the surgical procedure, there was no lenticular or retinal damage due to the chandelier insertion. There was no conjunctival bleb formation at pars plana incision and no incidence of endophthalmitis after surgery. The mean intra-ocular pressure was 15.74 ± 2.98, 15.83 ± 2.76 and 16.14 ± 2.52 mmHg on postoperative days 1, 3 and 7, respectively. The one-time retinal reattachment rate was 93.4%. No visible vitreous incarceration was found in the incision of the pars plana.
CONCLUSION
There was no complication found due to the chandelier insertion in early postoperative period. Chandelier endoillumination is a feasible method for retinal visualization under surgical microscope during scleral buckling.
Topics: Adolescent; Adult; Aged; Child; Equipment Design; Female; Follow-Up Studies; Humans; Light; Male; Microscopy, Acoustic; Middle Aged; Ophthalmoscopes; Retina; Retinal Detachment; Retrospective Studies; Scleral Buckling; Surgery, Computer-Assisted; Time Factors; Treatment Outcome; Visual Acuity; Young Adult
PubMed: 27966834
DOI: 10.1111/aos.13326 -
Sensors (Basel, Switzerland) May 2020This paper proposes a teleophthalmology support system in which we use algorithms of object detection and semantic segmentation, such as faster region-based CNN (FR-CNN)...
This paper proposes a teleophthalmology support system in which we use algorithms of object detection and semantic segmentation, such as faster region-based CNN (FR-CNN) and SegNet, based on several CNN architectures such as: Vgg16, MobileNet, AlexNet, etc. These are used to segment and analyze the principal anatomical elements, such as optic disc (OD), region of interest (ROI) composed by the macular region, real retinal region, and vessels. Unlike the conventional retinal image quality assessment system, the proposed system provides some possible reasons about the low-quality image to support the operator of an ophthalmoscope and patient to acquire and transmit a better-quality image to central eye hospital for its diagnosis. The proposed system consists of four steps: OD detection, OD quality analysis, obstruction detection of the region of interest (ROI), and vessel segmentation. For the OD detection, artefacts and vessel segmentation, the FR-CNN and SegNet are used, while for the OD quality analysis, we use transfer learning. The proposed system provides accuracies of 0.93 for the OD detection, 0.86 for OD image quality, 1.0 for artefact detection, and 0.98 for vessel segmentation. As the global performance metric, the kappa-based agreement score between ophthalmologist and the proposed system is calculated, which is higher than the score between ophthalmologist and general practitioner.
Topics: Algorithms; Humans; Ophthalmology; Optic Disk; Retina; Telemedicine
PubMed: 32429400
DOI: 10.3390/s20102838 -
Turkish Journal of Medical Sciences Jun 2020To investigate the effect of intravitreal golimumab on rabbit retina histopathology.
BACKGROUND/AIM
To investigate the effect of intravitreal golimumab on rabbit retina histopathology.
MATERIALS AND METHODS
Sixteen albino New Zealand rabbits were divided into three groups. The right eye of each rabbit in groups I, II, and III received a single intravitreal injection of 5 mg/0.05 mL (6 eyes), 10 mg/0.1 mL (6 eyes), or 20 mg/0.2 mL (4 eyes) golimumab, while left eyes served as controls with the same volume of a balanced salt solution injection. All animals were examined using slit-lamp biomicroscopy and indirect ophthalmoscopy before and after intravitreal injection and at days 1 and 7. Animals were euthanized on day 7 and the eyes were enucleated for immunohistochemistry evaluation and electron microscopic examination of the retinas.
RESULTS
For groups I, II, and III, the number of cells in the outer nuclear layer and the inner nuclear layer was decreased compared to those in the control groups. In group I, the percentage of caspase-3 staining of the outer nuclear layer was significantly higher than that in the control. For groups II and III, TUNEL and caspase-3 staining percentages in the outer and inner nuclear layers were found to be significantly higher than those for the control groups. In the ganglion cell layer, for groups I, II, and III, neither TUNEL nor caspase-3 staining percentages showed any significant difference between two groups. No significant dose-dependent relationship was found for increasing doses of golimumab in all layers. Myelin figures and karyorrhexis in the photoreceptor cells were prominent in electron microscopy of the golimumab-injected eyes.
CONCLUSION
Golimumab caused apoptosis in both photoreceptors and bipolar cells of the rabbit retina. Potential retinal toxicity of intravitreal golimumab should be considered if an intravitreal administration is planned.
Topics: Animals; Antibodies, Monoclonal; Apoptosis; Disease Models, Animal; Intravitreal Injections; Ophthalmoscopy; Rabbits; Slit Lamp; Toxic Optic Neuropathy
PubMed: 32151118
DOI: 10.3906/sag-1911-11