-
Romanian Journal of Ophthalmology 2017For many years, amblyopia was regarded as a disorder of the visual system in which an organic cause could not be identified. Optical Coherence Tomography opens new... (Review)
Review
For many years, amblyopia was regarded as a disorder of the visual system in which an organic cause could not be identified. Optical Coherence Tomography opens new horizons in understanding the etiopathology of amblyopia and seems to highlight morphologic anomalies in the retina of the amblyopic eye. The objective of this paper is to analyze the macular thickness, optic nerve changes, and choroidal thickness found in patients diagnosed with amblyopia based on trials reported in the literature. This study analyzes 30 clinical trials regarding amblyopia evaluation with Optical Coherence Tomography. The research articles analyzed were published between 2006 - 2016 and were identified on PubMed database. 19 research studies focused on macular and nerve optic changes, 7 on choroidal changes and 6 on retinal changes after occlusion. The results were discussed according to the type of amblyopia, alteration of macular thickness, optic nerve changes, ganglion cell layer changes, and alteration of choroidal thickness. The results are of great variability, and it seems that macula and choroid involvement is more frequently suggested compared with optic nerve involvement. OCT = Optical Coherence Tomography, RNFL = Retinal Nerve Fiber Layer, GCC = Ganglion Cell Complex, ACD = Anterior Chamber Depth, BCVA = Best Corrected Visual Acuity.
Topics: Amblyopia; Animals; Humans; Macula Lutea; Nerve Fibers; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 29450380
DOI: 10.22336/rjo.2017.18 -
Indian Journal of Ophthalmology Jan 2014Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the... (Review)
Review
Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) meetings. In total, 261 relevant publications and 389 conference abstracts were identified.
Topics: Equipment Design; Humans; Ophthalmoscopes; Optical Devices; Retina; Tomography, Optical Coherence
PubMed: 24492503
DOI: 10.4103/0301-4738.126185 -
Experimental Biology and Medicine... Oct 2021By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and... (Review)
Review
By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and treatment evaluation. A better understanding of the hyper- and hypo-reflective bands in retinal OCT is essential for accurate interpretation of clinical outcomes. In this article, we summarize the interpretations of clinical OCT and adaptive optics (AO) OCT (AO-OCT) of the outer retina in the human eye, and briefly review OCT investigation of the outer retina in animal models. Quantitative analysis of outer retinal OCT bands is compared to established parameters of retinal histology. The literature review and comparative analysis support that both inner/outer segment (IS/OS) junction and IS ellipsoid zone nonexclusively contribute to the second band; and OS, OS tips, and retinal pigment epithelium apical processes contribute to the third band in conventional OCT. In contrast, AO-OCT might predominantly detect the IS/OS junction and OS tip signals at the second and third bands due to its improved sectioning capability and possible AO effect on the sensitivities for recording ballistic and diffusive photons from different regions of the outer retina.
Topics: Animals; Eye Diseases; Fovea Centralis; Humans; Photoreceptor Cells, Vertebrate; Ranidae; Retinal Pigment Epithelium; Tomography, Optical Coherence
PubMed: 34111984
DOI: 10.1177/15353702211022674 -
Optics Letters Feb 2010We developed a photoacoustic ocular imaging device and demonstrated its utility in imaging the deeper layers of the eye including the retina, choroid, and optic nerve....
We developed a photoacoustic ocular imaging device and demonstrated its utility in imaging the deeper layers of the eye including the retina, choroid, and optic nerve. Using safe laser intensity, the photoacoustic system was able to visualize the blood distribution of an enucleated pig's eye and an eye of a living rabbit. Ultrasound images, which were simultaneously acquired, were overlaid on the photoacoustic images to visualize the eye's anatomy. Such a system may be used in the future for early detection and improved management of neovascular ocular diseases, including wet age-related macular degeneration and proliferative diabetic retinopathy.
Topics: Acoustics; Animals; Cell Proliferation; Choroid; Diabetic Retinopathy; Diagnostic Imaging; Equipment Design; Eye; Female; Optic Nerve; Optics and Photonics; Rabbits; Retina; Swine; Temperature
PubMed: 20125691
DOI: 10.1364/OL.35.000270 -
Asia-Pacific Journal of Ophthalmology... 2019The process of emmetropization is the adjustment of the length of the optical axis to the given optical properties of the cornea and lens after the end of the second... (Review)
Review
The process of emmetropization is the adjustment of the length of the optical axis to the given optical properties of the cornea and lens after the end of the second year of life. Up to the end of the second year of life, the eye grows spherically. Axial elongation in the process of emmetropization after the second year of life is associated with a thinning of the retina and a reduced density of retinal pigment epithelium (RPE) cells in the equatorial and retroequatorial region, and a thinning of the choroid and sclera, starting at the equator and being most marked at the posterior pole. In contrast, retinal thickness and RPE density in the macular region and thickness of Bruch membrane (BM) in any region are independent of axial length. It led to the hypothesis that axial elongation occurs by the production of additional BM in the equatorial and retroequatorial region leading to a decreased RPE density and retinal thinning in that region and a more tube-like than spherical enlargement of the globe, without compromise in the density of the macular RPE cells and in macular retinal thickness. The increased disc-fovea distance in axially myopic eyes is caused by the development and enlargement of parapapillary, BM-free, gamma zone, whereas the length of macular BM, and indirectly macular RPE cell density, and macular retinal thickness, remain constant.
Topics: Axial Length, Eye; Bruch Membrane; Disease Progression; Humans; Macula Lutea; Myopia; Optic Disk
PubMed: 31425168
DOI: 10.1097/01.APO.0000578944.25956.8b -
Medical Science Monitor : International... Dec 2023Visualization of the retinal structure is crucial for understanding the pathophysiology of ophthalmic diseases, as well as for monitoring their course and treatment... (Review)
Review
Visualization of the retinal structure is crucial for understanding the pathophysiology of ophthalmic diseases, as well as for monitoring their course and treatment effects. Until recently, evaluation of the retina at the cellular level was only possible using histological methods, because the available retinal imaging technology had insufficient resolution due to aberrations caused by the optics of the eye. Adaptive optics (AO) technology improved the resolution of optical systems to 2 µm by correcting optical wave-front aberrations, thereby revolutionizing methods for studying eye structures in vivo. Within 25 years of its first application in ophthalmology, AO has been integrated into almost all existing retinal imaging devices, such as the fundus camera (FC), scanning laser ophthalmoscopy (SLO), and optical coherence tomography (OCT). Numerous studies have evaluated individual retinal structures, such as photoreceptors, blood vessels, nerve fibers, ganglion cells, lamina cribrosa, and trabeculum. AO technology has been applied in imaging structures in healthy eyes and in various ocular diseases. This article aims to review the roles of AO imaging in the diagnosis, management, and monitoring of age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, hypertensive retinopathy (HR), central serous chorioretinopathy (CSCR), and inherited retinal diseases (IRDs).
Topics: Humans; Retina; Ophthalmoscopy; Tomography, Optical Coherence; Diabetic Retinopathy; Central Serous Chorioretinopathy
PubMed: 38044597
DOI: 10.12659/MSM.941926 -
Ophthalmic Surgery, Lasers & Imaging :... 2009Recent developments in imaging technologies offer great potential for the assessment of retinal ganglion cell disorders, with particular relevance to glaucoma. In... (Review)
Review
Recent developments in imaging technologies offer great potential for the assessment of retinal ganglion cell disorders, with particular relevance to glaucoma. In particular, advances in this field have allowed unprecedented in vivo access to the retinal layers, using many different properties of light to differentiate cellular structures. This article is a summary of currently available and investigational advanced, high-resolution imaging technologies and their potential applications to glaucoma. It represents the topics of discussion at the annual Optic Nerve Rescue and Restoration Think Tank, sponsored by The Glaucoma Foundation, entitled "High Resolution Imaging of the Eye: Advanced Optics, Microtechnology and Nanotechnology" and held in New York, New York, September 28-29, 2007.
Topics: Glaucoma; Humans; Image Enhancement; Magnetic Resonance Imaging; Microtechnology; Optics and Photonics; Retina; Tomography, Optical Coherence
PubMed: 19772272
DOI: 10.3928/15428877-20090901-07 -
Clinical & Experimental Optometry Jan 2021Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality for assessing the vasculature within ocular structures including the retina, macula,... (Review)
Review
Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality for assessing the vasculature within ocular structures including the retina, macula, choroid and optic nerve. OCT-A has a wide range of clinical applications in various optometric conditions which have been independently reported in the literature. This paper aims to present a review of the current literature on the clinical application of OCT-A in optometric practice as well as to analyse and evaluate the quality of the available evidence. This review included 78 articles from a literature search conducted on 26 May 2019 across the following databases: Cochrane Library of Systematic Reviews, Medline, Scopus and Web of Science. Primary ocular pathologies discussed in this review include glaucoma, diabetic retinopathy, age-related macular degeneration, myopia, acquired and congenital macular dystrophies, epiretinal membrane, retinal vein occlusion, retinitis pigmentosa, choroidal melanoma, uveitis, central serous chorioretinopathy, amblyopia and optic neuropathies. Primary outcome variables included vessel density, foveal avascular zone area and diameter, flow velocity and flow index. This review aims to evaluate the evidence available for OCT-A applications in diagnosis and prognosis of ocular conditions in an optometric setting.
Topics: Fluorescein Angiography; Humans; Macula Lutea; Retina; Retinal Vessels; Systematic Reviews as Topic; Tomography, Optical Coherence
PubMed: 32285493
DOI: 10.1111/cxo.13068 -
BMB Reports Feb 2017Glaucoma is characterized by a slow and progressive degeneration of the optic nerve, including retinal ganglion cell (RGC) axons in the optic nerve head (ONH), leading... (Review)
Review
Glaucoma is characterized by a slow and progressive degeneration of the optic nerve, including retinal ganglion cell (RGC) axons in the optic nerve head (ONH), leading to visual impairment. Despite its high prevalence, the biological basis of glaucoma pathogenesis still is not yet fully understood, and the factors contributing to its progression are currently not well characterized. Intraocular pressure (IOP) is the only modifiable risk factor, and reduction of IOP is the standard treatment for glaucoma. However, lowering IOP itself is not always effective for preserving visual function in patients with primary open-angle glaucoma. The second messenger cyclic adenosine 3',5'-monophosphate (cAMP) regulates numerous biological processes in the central nervous system including the retina and the optic nerve. Although recent studies revealed that cAMP generated by adenylyl cyclases (ACs) is important in regulating aqueous humor dynamics in ocular tissues, such as the ciliary body and trabecular meshwork, as well as cell death and growth in the retina and optic nerve, the functional role and significance of cAMP in glaucoma remain to be elucidated. In this review, we will discuss the functional role of cAMP in aqueous humor dynamics and IOP regulation, and review the current medications, which are related to the cAMP signaling pathway, for glaucoma treatment. Also, we will further focus on cAMP signaling in RGC growth and regeneration by soluble AC as well as ONH astrocytes by transmembrane ACs to understand its potential role in the pathogenesis of glaucoma neurodegeneration. [BMB Reports 2017; 50(2): 60-70].
Topics: Animals; Aqueous Humor; Cyclic AMP; Eye; Glaucoma; Humans; Intraocular Pressure; Retinal Ganglion Cells; Signal Transduction
PubMed: 27916026
DOI: 10.5483/bmbrep.2017.50.2.200 -
Annual Review of Vision Science Sep 2019Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing... (Review)
Review
Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing to the invasive nature of physiological approaches. There are exceptions to this generalization, for example, the electroretinogram. This review examines exciting recent advances using in vivo retinal imaging to understand the function of retinal neurons. In some cases, the methods have existed for years and are still being optimized. In others, new methods such as optophysiology are revealing novel patterns of retinal function in animal models that have the potential to change our understanding of the functional capacity of the retina. Together, the advances in retinal imaging mark an important milestone that shifts attention away from anatomy alone and begins to probe the function of healthy and diseased eyes.
Topics: Animals; Humans; Ophthalmoscopy; Optics and Photonics; Retina; Retinal Neurons; Tomography, Optical Coherence; Vision, Ocular
PubMed: 31525142
DOI: 10.1146/annurev-vision-091517-034239