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Vestnik Oftalmologii 2024Pterygium is a common inflammatory-proliferative disease characterized by the invasion of degeneratively altered fibrovascular tissue into the cornea. This literature... (Review)
Review
Pterygium is a common inflammatory-proliferative disease characterized by the invasion of degeneratively altered fibrovascular tissue into the cornea. This literature review analyzes the etiological factors and pathogenetic concepts of its development, describes modern methods of diagnostics and surgical treatment of pterygium, and pays particular attention to the assessment of structural and functional changes in the cornea occurring during the growth of pterygium and after its excision.
Topics: Pterygium; Humans; Ophthalmologic Surgical Procedures; Cornea; Conjunctiva
PubMed: 38739143
DOI: 10.17116/oftalma2024140022136 -
Clinical & Experimental Optometry Jul 2024Clinical imaging provided by optical coherence tomography (OCT) and its variant, OCT-angiography (OCT-A), has revolutionised eyecare practice. The imaging techniques... (Review)
Review
Clinical imaging provided by optical coherence tomography (OCT) and its variant, OCT-angiography (OCT-A), has revolutionised eyecare practice. The imaging techniques allow for the identification and quantification of ocular structures, supporting the diagnosis and prognosis of eye disease. In this review, an overview of the usefulness of OCT-A imaging in the diagnosis and management of a range of ocular conditions is provided when used in isolation or in combination with other imaging modalities and measures of visual function (visual field results). OCT-A imaging has the capacity to identify and quantify ocular vasculature non-invasively, thereby assisting the clinician in the diagnosis or to determine the efficacy of intervention in ocular conditions impacting retinal vasculature. Thus, additional clinically useful information can be obtained in eye diseases involving conditions such as those impacting retinal vessel occlusion, in diabetic retinopathy, inherited retinal dystrophy, age-related macular degeneration, choroidal neovascularisation and optic nerve disorders. Through a clinical case series, various ocular conditions are reviewed, and the impact of OCT-A imaging is discussed. Although OCT-A imaging has great promise and is already used in clinical management, there is a lack of set standards to characterise altered vascular features in disease and consequently for prognostication, primarily due to a lack of large-scale clinical trials and variability in OCT-A algorithms when generating quantitative parameters.
Topics: Humans; Tomography, Optical Coherence; Fluorescein Angiography; Eye Diseases; Retinal Vessels; Fundus Oculi
PubMed: 38452795
DOI: 10.1080/08164622.2024.2323603 -
The British Journal of Ophthalmology Dec 2023To investigate relationships between blood pressure and the thickness of single retinal layers in the macula.
PURPOSE
To investigate relationships between blood pressure and the thickness of single retinal layers in the macula.
METHODS
Participants of the population-based Beijing Eye Study, free of retinal or optic nerve disease, underwent medical and ophthalmological examinations including optical coherence tomographic examination of the macula. Applying a multiple-surface segmentation solution, we automatically segmented the retina into its various layers.
RESULTS
The study included 2237 participants (mean age 61.8±8.4 years, range 50-93 years). Mean thicknesses of the retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer, inner nuclear layer (INL), outer plexiform layer, outer nuclear layer/external limiting membrane, ellipsoid zone, photoreceptor outer segments (POS) and retinal pigment epithelium-Bruch membrane were 31.1±2.3 µm, 39.7±3.5 µm, 38.4±3.3 µm, 34.8±2.0 µm, 28.1±3.0 µm, 79.2±7.3 µm, 22.9±0.6 µm, 19.2±3.3 µm and 20.7±1.4 µm, respectively. In multivariable analysis, higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) were associated with thinner GCL and thicker INL, after adjusting for age, sex and axial length (all p<0.0056). Higher SBP was additionally associated with thinner POS and higher DBP with thinner RNFL. For an elevation of SBP/DBP by 10 mm Hg, the RNFL, GCL, INL and POS changed by 2.0, 3.0, 1.5 and 2.0 µm, respectively.
CONCLUSIONS
Thickness of RNFL, GCL and POS was inversely and INL thickness was positively associated with higher blood pressure, while the thickness of the other retinal layers was not significantly correlated with blood pressure. The findings may be helpful for refinement of the morphometric detection of retinal diseases.
Topics: Humans; Middle Aged; Aged; Aged, 80 and over; Retinal Ganglion Cells; Beijing; Retina; Macula Lutea; Hypertension; Tomography, Optical Coherence
PubMed: 36428008
DOI: 10.1136/bjo-2022-322229 -
Applied Optics Feb 2024Head movement must be stabilized to enable high-quality data collection from optical instrumentation such as eye trackers and ophthalmic imaging devices. Though...
Head movement must be stabilized to enable high-quality data collection from optical instrumentation such as eye trackers and ophthalmic imaging devices. Though critically important for imaging, head stabilization is often an afterthought in the design of advanced ophthalmic imaging systems, and experimental devices often adapt used and/or discarded equipment from clinical devices for this purpose. Alternatively, those seeking the most stable solution possible, including many users of adaptive optics ophthalmoscopy systems, utilize bite bars. Bite bars can provide excellent stability but are time consuming to fabricate, decreasing imaging efficiency, and uncomfortable for many patients, especially the elderly and/or those with prosthodontics such as dentures who may refuse participation in a study that requires one. No commercial vendors specifically offer head mount solutions for experimental ophthalmic imaging devices, resulting in nearly every custom device having a different solution for this commonly encountered problem. Parallelizing the head stabilization apparatus across different custom devices may improve standardization of experimental imaging systems for clinical trials and other multicenter investigations. Here we introduce a head mount design for ophthalmic imaging that is modular, adjustable, and customizable to the constraints of different experimental imaging configurations. The three points of head contact in our solution provide excellent stabilization across a range of head sizes and shapes from small children to adults, and the ease of adjustment afforded by our design minimizes the time to get participants stabilized and comfortable.
Topics: Adult; Aged; Child; Humans; Data Collection; Diagnostic Imaging; Eye; Face; Ophthalmoscopy
PubMed: 38437390
DOI: 10.1364/AO.513801 -
Experimental Eye Research Jun 2024Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and... (Review)
Review
Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.
Topics: Aqueous Humor; Humans; Lymphatic System; Sclera; Trabecular Meshwork; Lymphatic Vessels; Veins; Uvea; Animals; Intraocular Pressure; Lymph; Ciliary Body
PubMed: 38642600
DOI: 10.1016/j.exer.2024.109904 -
Canadian Journal of Ophthalmology.... Jun 2024
Topics: Humans; Fovea Centralis; Tomography, Optical Coherence; Diagnosis, Differential; Fluorescein Angiography; Eye Abnormalities; Male; Visual Acuity; Retinal Diseases; Female; Fundus Oculi
PubMed: 38280728
DOI: 10.1016/j.jcjo.2024.01.001 -
International Journal of Molecular... Jan 2024Two-photon excitation microscopy (TPM) and multiphoton fluorescence microscopy (MPM) are advanced forms of intravital high-resolution functional microscopy techniques... (Review)
Review
Two-photon excitation microscopy (TPM) and multiphoton fluorescence microscopy (MPM) are advanced forms of intravital high-resolution functional microscopy techniques that allow for the imaging of dynamic molecular processes and resolve features of the biological tissues of interest. Due to the cornea's optical properties and the uniquely accessible position of the globe, it is possible to image cells and tissues longitudinally to investigate ocular surface physiology and disease. MPM can also be used for the in vitro investigation of biological processes and drug kinetics in ocular tissues. In corneal immunology, performed via the use of TPM, cells thought to be intraepithelial dendritic cells are found to resemble tissue-resident memory T cells, and reporter mice with labeled plasmacytoid dendritic cells are imaged to understand the protective antiviral defenses of the eye. In mice with limbal progenitor cells labeled by reporters, the kinetics and localization of corneal epithelial replenishment are evaluated to advance stem cell biology. In studies of the conjunctiva and sclera, the use of such imaging together with second harmonic generation allows for the delineation of matrix wound healing, especially following glaucoma surgery. In conclusion, these imaging models play a pivotal role in the progress of ocular surface science and translational research.
Topics: Animals; Mice; Cornea; Sclera; Microscopy, Fluorescence; Microscopy, Fluorescence, Multiphoton; Conjunctiva
PubMed: 38338948
DOI: 10.3390/ijms25031670 -
Journal of Glaucoma Aug 2023In Japanese open angle glaucoma (OAG) eyes correlation of 30-degree visual field mean deviation (MD) and visual field index (VFI) with circumpapillary vessel density is...
PRCIS
In Japanese open angle glaucoma (OAG) eyes correlation of 30-degree visual field mean deviation (MD) and visual field index (VFI) with circumpapillary vessel density is systematically stronger than that with circumpapillary retinal nerve fiber layer thickness (RNFLT), and is preserved in myopia and high myopia.
PURPOSE
The purpose of this study was to investigate the influence of refractive error on the relationship between circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and circumpapillary vessel density (cpVD), respectively, and global visual field parameters in Japanese open angle glaucoma (OAG) eyes.
MATERIAL AND METHODS
One eye of 81 Japanese OAG patients (spherical equivalent refractive error: +3.0 to -9.0 D) underwent 360-degree cpRNFLT and cpVD measurements with Cirrus HD 5000-AngioPlex optical coherence tomography and 30-2 Humphrey visual field testing for mean deviation (MD) and visual field index (VFI) within 1 month. Correlations were determined for the whole population and each refractive error subgroups, separately: emmetropia/hyperopia (n=24), mild (n=18), moderate (n=20), and high myopia (n=19).
RESULTS
For the total population, significant strong to very strong correlations were found between MD, VFI, and both cpRNFLT and cpVD, respectively, with consistently higher r -values for cpVD (highest r -values: 0.532 for cpRNFLT, P <0.001; 0.722 for cpVD, P <0.001). Of the refractive subgroups, statistically significant correlations between cpRNFLT and the visual field parameters were maintained only in the hyperopia/emmetropia and moderate myopia groups. In contrast, statistically significant, strong to very strong correlations between cpVD and both MD and VFI, always exceeding the corresponding r -values found for cpRNFLT were found in all refractive subgroups, with r -values ranging between 0.548 ( P =0.005) and 0.841 ( P <0.001).
CONCLUSIONS
Our results suggest that in Japanese OAG eyes the relationship of MD and VFI with cpVD is strong. It is systematically stronger than that with cpRNFLT and preserved in each conventional refractive error category including high myopia.
Topics: Humans; Glaucoma, Open-Angle; Optic Disk; Hyperopia; Intraocular Pressure; Retinal Vessels; Retinal Ganglion Cells; Refractive Errors; Tomography, Optical Coherence; Myopia
PubMed: 37314189
DOI: 10.1097/IJG.0000000000002251 -
Nature Communications Aug 2023In vertebrate vision, early retinal circuits divide incoming visual information into functionally opposite elementary signals: On and Off, transient and sustained,...
In vertebrate vision, early retinal circuits divide incoming visual information into functionally opposite elementary signals: On and Off, transient and sustained, chromatic and achromatic. Together these signals can yield an efficient representation of the scene for transmission to the brain via the optic nerve. However, this long-standing interpretation of retinal function is based on mammals, and it is unclear whether this functional arrangement is common to all vertebrates. Here we show that male poultry chicks use a fundamentally different strategy to communicate information from the eye to the brain. Rather than using functionally opposite pairs of retinal output channels, chicks encode the polarity, timing, and spectral composition of visual stimuli in a highly correlated manner: fast achromatic information is encoded by Off-circuits, and slow chromatic information overwhelmingly by On-circuits. Moreover, most retinal output channels combine On- and Off-circuits to simultaneously encode, or multiplex, both achromatic and chromatic information. Our results from birds conform to evidence from fish, amphibians, and reptiles which retain the full ancestral complement of four spectral types of cone photoreceptors.
Topics: Male; Animals; Retina; Chickens; Retinal Cone Photoreceptor Cells; Brain; Excipients; Mammals
PubMed: 37652912
DOI: 10.1038/s41467-023-41032-z -
Journal of Neurology Aug 2023The multi-order visual system represents an excellent testing site regarding the process of trans-synaptic degeneration. The presence and extent of global versus...
BACKGROUND
The multi-order visual system represents an excellent testing site regarding the process of trans-synaptic degeneration. The presence and extent of global versus trans-synaptic neurodegeneration in people with multiple sclerosis (pwMS) is not clear.
OBJECTIVE
To explore cross-sectional and longitudinal relationships between retinal, thalamic and cortical changes in pwMS with and without MS-related optic neuritis (pwMSON and pwoMSON) using MRI and optical coherence tomography (OCT).
METHODS
162 pwMS and 47 healthy controls (HCs) underwent OCT and brain MRI at baseline and 5.5-years follow-up. Peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell inner plexiform layer (mGCIPL) thicknesses were determined. Global volume measures of brain parenchymal volume (BPV)/percent brain volume change (PBVC), thalamic volume and T2-lesion volume (LV) were derived using standard analysis protocols. Regional cortical thickness was determined using FreeSurfer. Cross-sectional and longitudinal relationship between the retinal measures, thalamic volume and cortical thickness were assessed using age, BPV/PBVC and T2-LV adjusted correlations and regressions.
RESULTS
After age, BPV and T2-LV adjustment, the thalamic volume explained additional variance in the thickness of pericalcarine (R increase of 0.066, standardized β = 0.299, p = 0.039) and lateral occipital (R2 increase of 0.024, standardized β = 0.299, p = 0.039) gyrii in pwMSON. In pwoMSON, the thalamic volume was a significant predictor only of control (frontal) regions of pars opercularis. There was no relationship between thalamic atrophy and cortical thinning over the follow-up in both pwMS with and without MSON. While numerically lower in the pwMSON group, the inter-eye difference was not able to predict the presence of MSON.
CONCLUSIONS
MSON can induce a measurable amount of trans-synaptic pathology on second-order cortical regions.
Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Cross-Sectional Studies; Longitudinal Studies; Magnetic Resonance Imaging; Multiple Sclerosis; Optic Neuritis; Retina; Retinal Ganglion Cells; Tomography, Optical Coherence; Cerebral Cortical Thinning; Retrograde Degeneration
PubMed: 37067590
DOI: 10.1007/s00415-023-11709-y