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Eye (London, England) Feb 2024This short review begins with the theories of Airy, Rayleigh and Abbe on microscope resolution. Next, the principal developments in microscopy in the last half-century... (Review)
Review
This short review begins with the theories of Airy, Rayleigh and Abbe on microscope resolution. Next, the principal developments in microscopy in the last half-century are examined for relevance to ophthalmology: confocal microscopy, photoactivation light microscopy (PALM), stochastic optical reconstruction microscopy (STORM), stimulated emission depletion (STED), structured illumination (SI), 2-photon and multiphoton excitation microscopy with a focused beam. Except for confocal, these are difficult to apply to the eye in vivo, as are the interference methods available in microscopes. However, interferometry in the form of coherence tomography is now a major ophthalmic method which has diverged from microscopy. Multiphoton excitation microscopy with an unfocussed beam is a new, low-damage microscope method so-far not exploited in ophthalmoscopy. The Mesolens, which throws off the historic limitations in microscopy set by the human eye, is described as a possible future aid to ophthalmology of the anterior eye.
PubMed: 38374367
DOI: 10.1038/s41433-024-02970-0 -
Survey of Ophthalmology 2024Multicolor (MC) imaging is an innovative pseudocolor fundus imaging modality based on confocal scanning laser ophthalmoscopy. It effectively scans the retina at... (Review)
Review
Multicolor (MC) imaging is an innovative pseudocolor fundus imaging modality based on confocal scanning laser ophthalmoscopy. It effectively scans the retina at different depths to create a composite image. The green reflectance image depicts the middle retinal while blue reflectance image provides images of the retinal surface. The infrared reflectance image depicts retinal structures at the level of outer retina and choroid. We systematically analyze published case reports, case series, and original articles on MC imaging where it has helped in discovering additional clinical features of retinal diseases not readily apparent on conventional color fundus photography and played a role in monitoring the response to treatment.
Topics: Humans; Ophthalmoscopy; Retinal Diseases; Retina; Fundus Oculi; Fluorescein Angiography
PubMed: 38122907
DOI: 10.1016/j.survophthal.2023.11.011 -
Acta Ophthalmologica Jun 2024Retinopathy of prematurity (ROP) is a vascular disease among preterm infants involving incomplete or abnormal retinal vascularization and is a leading cause of... (Review)
Review
Retinopathy of prematurity (ROP) is a vascular disease among preterm infants involving incomplete or abnormal retinal vascularization and is a leading cause of preventable blindness globally. Measurements of ocular blood flow originating from a variety of imaging modalities, including colour Doppler imaging (CDI), fluorescein angiography (FA) and ocular coherence tomography angiography (OCTA), have been associated with changes in ROP patients. Herein, we discuss and summarize the relevant current literature on vascular imaging and ROP reviewed through December 2022. Differences in vascular imaging parameters between ROP patients and healthy controls are reviewed and summarized. The available data identify significantly increased peak systolic velocity (PSV) in the central retinal artery and ophthalmic artery as measured by CDI, increased vascular tortuosity as measured by FA, smaller foveal avascular zone (FAZ) as measured by FA and OCTA, and increased foveal vessel density (VD) and reduced parafoveal VD as measured by OCTA in ROP patients compared with controls. None of the above findings appear to reliably correlate with visual acuity. The studies currently available, however, are inconclusive and lack robust longitudinal data. Vascular imaging demonstrates the potential to aid in the diagnosis, management and monitoring of ROP, alongside retinal examination via indirect ophthalmoscopy and fundus photography.
Topics: Humans; Retinopathy of Prematurity; Tomography, Optical Coherence; Fluorescein Angiography; Retinal Vessels; Infant, Newborn; Fundus Oculi; Ultrasonography, Doppler, Color; Blood Flow Velocity; Regional Blood Flow
PubMed: 37874229
DOI: 10.1111/aos.15800 -
Molecular and Cellular Pediatrics Sep 2023Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the premature retina with the potential to progress to extraretinal neovascularisation. This review... (Review)
Review
INTRODUCTION
Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the premature retina with the potential to progress to extraretinal neovascularisation. This review serves as an introduction to retinopathy of prematurity (ROP), outlining key parts of ROP pathophysiology, diagnosis and treatment. ROP is traditionally diagnosed by indirect ophthalmoscopy and classified using anatomical zones, stages of disease, and the presence or absence of "plus disease" (dilation and tortuosity of the major retinal arterioles and venules). ROP has a bi-phasic pathophysiology: initial hyperoxia causes reduced retinal vascularisation, followed by pathological vaso-proliferation resulting from subsequent hypoxia and driven by vascular endothelial growth factor (VEGF).
ADVANCEMENTS IN MANAGEMENT
This review summarises previous trials to establish optimum oxygen exposure levels in newborns and more recently the development of anti-VEGF agents locally delivered to block pathological neovascularisation, which is technically easier to administer and less destructive than laser treatment.
FUTURE DIRECTIONS
There remains an ongoing concern regarding the potential unwanted systemic effects of intravitreally administered anti-VEGF on the overall development of the premature baby. Ongoing dosing studies may lessen these fears by identifying the minimally effective dose required to block extraretinal neovascularisation.
PubMed: 37712996
DOI: 10.1186/s40348-023-00163-5 -
Veterinary Ophthalmology Sep 2023Assess the refractive states of donkeys and goats.
PURPOSE
Assess the refractive states of donkeys and goats.
METHODS
Forty-two donkeys and 28 goats were enrolled. The mean ± SD ages were 7.68 ± 7.33 years for donkeys and 4.26 ± 2.33 years for goats. Seven donkeys and one goat were <6 months old. Retinoscopy was performed in alert animals, following cycloplegia in goats but not in donkeys. Normality was determined using the Kolmogorov-Smirnov test. The two primary meridians and two eyes were compared using Pearson's correlation and paired Student's t-tests. The association between refractive states and age was examined using one-way ANOVA in donkeys and a paired Student's t-test in goats. One-sample t-tests were conducted to assess if the refractive error distributions were significantly different from "0".
RESULTS
The mean ± SD spherical equivalent (SE) refractive errors of the right and left donkey eyes were -0.80 ± 1.03 D and -0.35 ± 0.95 D, respectively. The majority (86%) of the donkeys had an astigmatic refraction and eight (19%) had anisometropia. The mean SE refractive errors of the right and left goat eyes were -0.15 ± 1.1 D and -0.18 ± 1.2 D, respectively. The majority (54%) of the goat eyes had an astigmatic refraction and five (18%) had anisometropia. The right and left eye SE refractive errors were positively correlated in both species (both p = .9). Age was not correlated with refractive error in both donkeys (p = .09) and goats (p = .6).
CONCLUSIONS
Both goats and donkeys are emmetropic.
Topics: Animals; Retinoscopy; Anisometropia; Equidae; Goats; Refractive Errors; Refraction, Ocular; Prevalence; Goat Diseases
PubMed: 37386869
DOI: 10.1111/vop.13126 -
Journal of Binocular Vision and Ocular... Jul 2023The year 2020 has been greatly anticipated by the entire ophthalmic community. This year's Scobee lecture will be a photographic look at our past with the orthoptists...
The year 2020 has been greatly anticipated by the entire ophthalmic community. This year's Scobee lecture will be a photographic look at our past with the orthoptists and pediatric ophthalmologists we have learned from, taught, and worked with. A sobering snapshot of our present will reveal a world with extreme medical access inequality. This creates a need for an inexpensive screening device for amblyogenic anisometropia. A technique for such a fast and inexpensive screening device will be shown using first retinoscopy; and then compare the effectiveness of the direct Heine streak ophthalmoscope, a common ophthalmic instrument, will be shown to be effective in screening for ≥1 diopter of spherical anisometropia. The challenges of the present hint at an optimistic future for orthoptists, expanding their role as physician extenders to help ease the medical access inequalities in the world. Finally, I introduce the patron saint of the blind and those with vision impairment.
Topics: Child; Humans; Anisometropia; Orthoptics; Retinoscopy
PubMed: 37057981
DOI: No ID Found -
Telemedicine Journal and E-health : the... Feb 2024The current medical scenario is closely linked to recent progress in telecommunications, photodocumentation, and artificial intelligence (AI). Smartphone eye... (Review)
Review
The current medical scenario is closely linked to recent progress in telecommunications, photodocumentation, and artificial intelligence (AI). Smartphone eye examination may represent a promising tool in the technological spectrum, with special interest for primary health care services. Obtaining fundus imaging with this technique has improved and democratized the teaching of fundoscopy, but in particular, it contributes greatly to screening diseases with high rates of blindness. Eye examination using smartphones essentially represents a cheap and safe method, thus contributing to public policies on population screening. This review aims to provide an update on the use of this resource and its future prospects, especially as a screening and ophthalmic diagnostic tool. In this review, we surveyed major published advances in retinal and anterior segment analysis using AI. We performed an electronic search on the Medical Literature Analysis and Retrieval System Online (MEDLINE), EMBASE, and Cochrane Library for published literature without a deadline. We included studies that compared the diagnostic accuracy of smartphone ophthalmoscopy for detecting prevalent diseases with an accurate or commonly employed reference standard. There are few databases with complete metadata, providing demographic data, and few databases with sufficient images involving current or new therapies. It should be taken into consideration that these are databases containing images captured using different systems and formats, with information often being excluded without essential detailing of the reasons for exclusion, which further distances them from real-life conditions. The safety, portability, low cost, and reproducibility of smartphone eye images are discussed in several studies, with encouraging results. The high level of agreement between conventional and a smartphone method shows a powerful arsenal for screening and early diagnosis of the main causes of blindness, such as cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration. In addition to streamlining the medical workflow and bringing benefits for public health policies, smartphone eye examination can make safe and quality assessment available to the population.
Topics: Humans; Artificial Intelligence; Smartphone; Reproducibility of Results; Diabetic Retinopathy; Telemedicine; Blindness
PubMed: 37585566
DOI: 10.1089/tmj.2023.0041 -
Survey of Ophthalmology 2023Retromode scanning laser ophthalmoscopy imaging captures a pseudo-3-dimensional image of the ocular fundus. Retromode scanning laser ophthalmoscopy imaging was... (Review)
Review
Retromode scanning laser ophthalmoscopy imaging captures a pseudo-3-dimensional image of the ocular fundus. Retromode scanning laser ophthalmoscopy imaging was introduced first in 2008 using the Nidek F-10 scanning laser ophthalmoscope (F-10; Nidek Co., Gamagori, Japan). At that time, no major role was described for this imaging modality. The interest in retromode scanning laser ophthalmoscopy imaging is reemerging with the recent advent of the Mirante that combines scanning laser ophthalmoscopy and optical coherence tomography (Nidek Co., Gamagori, Japan) that can capture retromode images of the fundus. We summarize the findings and clinical implications of retromode imaging using the Nidek F-10 and the Mirante in retinal diseases with the aim of helping researchers direct their future studies.
Topics: Humans; Retinal Diseases; Ophthalmoscopy; Fundus Oculi; Tomography, Optical Coherence
PubMed: 37481077
DOI: 10.1016/j.survophthal.2023.07.004 -
Frontiers in Cellular Neuroscience 2024Microglia play crucial roles in immune responses and contribute to fundamental biological processes within the central nervous system (CNS). In neurodegenerative... (Review)
Review
Microglia play crucial roles in immune responses and contribute to fundamental biological processes within the central nervous system (CNS). In neurodegenerative diseases, microglia undergo functional changes and can have both protective and pathogenic roles. Microglia in the retina, as an extension of the CNS, have also been shown to be affected in many neurological diseases. While our understanding of how microglia contribute to pathological conditions is incomplete, non-invasive imaging of brain and retinal microglia in living subjects could provide valuable insights into their role in the neurodegenerative diseases and open new avenues for diagnostic biomarkers. This mini-review provides an overview of the current brain and retinal imaging tools for studying microglia . We focus on microglia targets, the advantages and limitations of microglia imaging approaches, and applications for evaluating the pathogenesis of neurological conditions, such as Alzheimer's disease and multiple sclerosis.
PubMed: 38348116
DOI: 10.3389/fncel.2024.1355557 -
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