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American Journal of Ophthalmology Oct 2023We used automated image analysis of scanning laser ophthalmoscopy (SLO) to investigate mechanical strains imposed on disc, and retinal and choroidal vessels during...
PURPOSE
We used automated image analysis of scanning laser ophthalmoscopy (SLO) to investigate mechanical strains imposed on disc, and retinal and choroidal vessels during horizontal duction in adults.
DESIGN
Deep learning analysis of optical images.
METHODS
The peripapillary region was imaged by SLO in central gaze, and 35° abduction and adduction, in younger and older healthy adults. Automated image registration was followed by deep learning-based optical flow analysis to track determine local tissue deformations quantified as horizontal, vertical, and shear strain maps relative to central gaze. Choroidal vessel displacements were observed when fundus pigment was light.
RESULTS
Strains in the retina and disc could be quantified in 22 younger (mean ± SEM, 26 ± 5 years) and 19 older (64 ± 10 years) healthy volunteers. Strains were predominantly horizontal and greater for adduction than for abduction. During adduction, maximum horizontal strain was tensile in the nasal hemi-disc, and declined progressively with distance from it. Strain in the temporal hemi-retina during adduction was minimal, except for compressive strain on the disc of older subjects. In abduction, horizontal strains were less and largely confined to the disc, greater in older subjects, and generally tensile. Vertical and shear strains were small. Nasal to the disc, choroidal vessels shifted nasally relative to overlying peripapillary retinal vessels.
CONCLUSIONS
Strain analysis during horizontal duction suggests that the optic nerve displaces the optic canal, choroid, and peripapillary sclera relative to the overlying disc and retina. This peripapillary shearing of the optic nerve relative to the choroid and sclera may be a driver of disc tilting and peripapillary atrophy.
Topics: Adult; Humans; Aged; Optic Disk; Rotation; Retina; Ophthalmoscopy; Lasers; Tomography, Optical Coherence
PubMed: 37343739
DOI: 10.1016/j.ajo.2023.06.008 -
Philosophical Transactions. Series A,... Mar 2020The optical systems mimicking the eye functions are of great importance in various applications including consumer electronics, medical equipment, machine vision systems... (Review)
Review
The optical systems mimicking the eye functions are of great importance in various applications including consumer electronics, medical equipment, machine vision systems and robotics. This optics offers advantages over traditional optical technologies such as the superior adaptation to changing conditions and the comprehensive range of functional characteristics at miniature sizes. This paper presents a review on the recent progress in the development of human eye-inspired optical systems. Liquid-based and elastomer-based tunable optical elements are discussed with the focus on the actuation mechanism, optical performance and the possibility of integration into artificial eye systems. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.
Topics: Biomimetic Materials; Biomimetics; Electronics; Equipment Design; Eye; Humans; Ocular Physiological Phenomena; Optical Devices; Robotics; Vision, Ocular
PubMed: 32008449
DOI: 10.1098/rsta.2019.0442 -
Developmental Dynamics : An Official... Oct 2014The vertebrate eye acquires its basic form during the process of optic cup morphogenesis, during which the optic vesicle emerges from the brain neuroepithelium and,... (Review)
Review
The vertebrate eye acquires its basic form during the process of optic cup morphogenesis, during which the optic vesicle emerges from the brain neuroepithelium and, through a series of cell and tissue movements, transforms itself into the multilayered optic cup, containing neural retina (comprised of retinal progenitors), retinal pigmented epithelium, and the lens, which is derived from the overlying ectoderm. While great strides have been made to understand the developmental signals controlling specification, patterning, and differentiation of the optic cup, only in recent years have the cellular and molecular bases of optic cup morphogenesis begun to be unraveled. One critical component of the morphogenetic process is the extracellular matrix: the complex, glycoprotein-rich layer that surrounds the optic vesicle and lens. Though the extracellular matrix has long been visualized by classical histological techniques and postulated to play various roles in optic cup development, its functional role was uncertain. This is now beginning to change, as live imaging techniques, quantitative image analyses, molecular genetics and in vitro models yield new insights into the process of optic cup morphogenesis and the specific influences of particular extracellular matrix components and their associated signaling pathways.
Topics: Animals; Extracellular Matrix; Eye; Humans; Lens, Crystalline; Morphogenesis; Retina; Retinal Pigment Epithelium; Vertebrates
PubMed: 25044784
DOI: 10.1002/dvdy.24162 -
Proceedings of the National Academy of... Sep 2020High-resolution imaging techniques capable of detecting identifiable endogenous fluorophores in the eye along with genetic testing will dramatically improve diagnostic...
High-resolution imaging techniques capable of detecting identifiable endogenous fluorophores in the eye along with genetic testing will dramatically improve diagnostic capabilities in the ophthalmology clinic and accelerate the development of new treatments for blinding diseases. Two-photon excitation (TPE)-based imaging overcomes the filtering of ultraviolet light by the lens of the human eye and thus can be utilized to discover defects in vitamin A metabolism during the regeneration of the visual pigments required for the detection of light. Combining TPE with fluorescence lifetime imaging (FLIM) and spectral analyses offers the potential of detecting diseases of the retina at earlier stages before irreversible structural damage has occurred. The main barriers to realizing the benefits of TPE for imaging the human retina arise from concerns about the high light exposure typically needed for informative TPE imaging and the requirement to correlate the ensuing data with different states of health and disease. To overcome these hurdles, we improved TPE efficiency by controlling temporal properties of the excitation light and employed phasor analyses to FLIM and spectral data in mouse models of retinal diseases. Modeling of retinal photodamage revealed that plasma-mediated effects do not play a role and that melanin-related thermal effects are mitigated by reducing pulse repetition frequency. By using noninvasive TPE imaging we identified molecular components of individual granules in the retinal pigment epithelium and present their analytical characteristics.
Topics: Animals; Biopsy; Disease Models, Animal; Fluorescent Dyes; Mice; Mice, Inbred C57BL; Optical Imaging; Retina; Retinal Diseases; Retinal Pigment Epithelium
PubMed: 32848058
DOI: 10.1073/pnas.2007527117 -
Annual Review of Vision Science Sep 2020High-resolution retinal imaging is revolutionizing how scientists and clinicians study the retina on the cellular scale. Its exquisite sensitivity enables time-lapse... (Review)
Review
High-resolution retinal imaging is revolutionizing how scientists and clinicians study the retina on the cellular scale. Its exquisite sensitivity enables time-lapse optical biopsies that capture minute changes in the structure and physiological processes of cells in the living eye. This information is increasingly used to detect disease onset and monitor disease progression during early stages, raising the possibility of personalized eye care. Powerful high-resolution imaging tools have been in development for more than two decades; one that has garnered considerable interest in recent years is optical coherence tomography enhanced with adaptive optics. State-of-the-art adaptive optics optical coherence tomography (AO-OCT) makes it possible to visualize even highly transparent cells and measure some of their internal processes at all depths within the retina, permitting reconstruction of a 3D view of the living microscopic retina. In this review, we report current AO-OCT performance and its success in visualizing and quantifying these once-invisible cells in human eyes.
Topics: Humans; Ophthalmoscopy; Retina; Tomography, Optical Coherence
PubMed: 32609578
DOI: 10.1146/annurev-vision-030320-041255 -
Current Eye Research Jan 2015Biomechanics is the study of the relationship between forces and function in living organisms and is thought to play a critical role in a significant number of... (Review)
Review
Biomechanics is the study of the relationship between forces and function in living organisms and is thought to play a critical role in a significant number of ophthalmic disorders. This is not surprising, as the eye is a pressure vessel that requires a delicate balance of forces to maintain its homeostasis. Over the past few decades, basic science research in ophthalmology mostly confirmed that ocular biomechanics could explain in part the mechanisms involved in almost all major ophthalmic disorders such as optic nerve head neuropathies, angle closure, ametropia, presbyopia, cataract, corneal pathologies, retinal detachment and macular degeneration. Translational biomechanics in ophthalmology, however, is still in its infancy. It is believed that its use could make significant advances in diagnosis and treatment. Several translational biomechanics strategies are already emerging, such as corneal stiffening for the treatment of keratoconus, and more are likely to follow. This review aims to cultivate the idea that biomechanics plays a major role in ophthalmology and that the clinical translation, lead by collaborative teams of clinicians and biomedical engineers, will benefit our patients. Specifically, recent advances and future prospects in corneal, iris, trabecular meshwork, crystalline lens, scleral and lamina cribrosa biomechanics are discussed.
Topics: Animals; Anterior Eye Segment; Biomechanical Phenomena; Glaucoma; Humans; Intraocular Pressure; Optic Disk; Translational Research, Biomedical
PubMed: 24832392
DOI: 10.3109/02713683.2014.914543 -
Eye (London, England) Nov 2014Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each... (Review)
Review
Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each of ocular component have been described in detail during the past decades. Due to these abnormalities, the diabetic patient undergoes a degradation of the retinal image by an increase of higher ocular aberrations and ocular scattering coming from mainly tear film, cornea, and crystalline lens. This review aims to provide an overview of current knowledge about the effects of diabetes mellitus in these optical phenomena and its consequence on the visual quality of the diabetic patient.
Topics: Cornea; Diabetes Mellitus; Humans; Lens, Crystalline; Refractive Errors; Retina; Vitreous Body
PubMed: 25125072
DOI: 10.1038/eye.2014.176 -
Journal of Biomedical Optics Jul 2016The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24...
The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median=24 years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between −2.00 and −5.00 diopters (D) (median=−3.41 D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C40) and secondary (C60) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C40 (r=−0.49, p<0.05) and a very strong correlation with C60 (r=0.78, p<0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye’s positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye.
Topics: Adolescent; Adult; Algorithms; Contact Lenses; Cornea; Corneal Topography; Humans; Myopia; Orthokeratologic Procedures; Pupil; Refraction, Ocular; Treatment Outcome; Young Adult
PubMed: 27435895
DOI: 10.1117/1.JBO.21.7.075011 -
Eye (London, England) Apr 2023Metastasis to the eye can involve the choroid (90%), ciliary body (2%), iris (8%), and retina, optic disc, vitreous, and/or lens capsule (<1-4%). The mean number of... (Review)
Review
Metastasis to the eye can involve the choroid (90%), ciliary body (2%), iris (8%), and retina, optic disc, vitreous, and/or lens capsule (<1-4%). The mean number of uveal metastasis per eye (1.7), mean tumour base (11.6 mm) and thickness (3.2 mm), tumour colour (86% yellow), and presence of subretinal fluid (72%), are all clinical features suggestive of the diagnosis. Imaging with ultrasonography demonstrates an echodense mass (80%) and optical coherence tomography shows a "lumpy bumpy" choroidal surface (64%), both important diagnostic features. Uveal metastases typically emanate from primary cancer of the breast (37%), lung (27%), kidney (4%), gastrointestinal tract (4%), cutaneous melanoma (2%), lung carcinoid (2%), prostate (2%), thyroid (1%), pancreas (1%), and other sites (3%). Occasionally, fine needle aspiration biopsy is employed if the primary site is not known. In 16% of cases, the primary site remains unknown. Rarely, metastases affect the retina, vitreous, and lens capsule, most often originating from cutaneous melanoma and in patients previously treated with checkpoint inhibitor therapy. Kaplan-Meier analysis in a series of 1111 patients with uveal metastasis revealed 32% survival at 3 years and 24% at 5 years. Patients with uveal metastasis from carcinoid tumour showed most favourable survival at 5-years (92%), whereas pancreatic and kidney cancer demonstrated least favourable survival (0%). The 5-year survival was better for females (versus (vs.) males) (31% vs. 21%) and older adults (vs. children) (40% vs. 0%). In this review, we examine several large-cohort publications on the topic of ocular metastasis.
Topics: Male; Female; Child; Humans; Aged; Melanoma; Ciliary Body; Skin Neoplasms; Uveal Neoplasms; Optic Disk; Iris; Choroid; Retina; Melanoma, Cutaneous Malignant
PubMed: 35306540
DOI: 10.1038/s41433-022-02015-4 -
Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents.Scientific Reports Jan 2022Evaluation of interocular asymmetry of optical coherence tomography (OCT) parameters is important for the glaucoma and optic neuropathies. This study was performed to...
Evaluation of interocular asymmetry of optical coherence tomography (OCT) parameters is important for the glaucoma and optic neuropathies. This study was performed to evaluate the interocular asymmetry of OCT parameters in healthy children and adolescents. The circumpapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) parameters, and macular ganglion cell-inner plexiform layer (GCIPL) thickness were measured in 620 eyes of 310 healthy children and adolescents using Cirrus HD-OCT. The interocular asymmetry (right eye-left eye) in the OCT parameters was analyzed. The mean ± standard deviation age was 10.3 ± 3.7 years (range 5-17). The right eyes showed thinner superior quadrant RNFL, thicker nasal and temporal quadrant RNFL, lesser rim and disc areas, and thinner average, superior, and superonasal GCIPL than the left eyes (P < 0.05). The 2.5th and 97.5th percentile interocular difference tolerance limits were - 9.0 μm and 11.0 μm for average RNFL thickness, - 0.21 and 0.18 for average cup-to-disc ratio, and - 4.0 μm and 4.0 μm for average GCIPL thickness, respectively. Interocular differences were found in RNFL thickness, ONH parameters, and GCIPL thickness in healthy children and adolescents. These findings should be considered when comparing OCT parameters between the right and left eyes.
Topics: Adolescent; Child; Child, Preschool; Female; Glaucoma; Healthy Volunteers; Humans; Male; Nerve Fibers; Optic Disk; Optic Nerve Diseases; Retina; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 35027614
DOI: 10.1038/s41598-021-04563-3