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Clinical & Experimental Optometry Jan 2020Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree... (Review)
Review
Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form-deprivation and lens-induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.
Topics: Accommodation, Ocular; Animals; Emmetropia; Eye; Humans; Models, Animal; Myopia; Optics and Photonics; Refraction, Ocular
PubMed: 31742789
DOI: 10.1111/cxo.12991 -
Survey of Ophthalmology 2019Optic disk pit, one of the optic disk cavitary anomalies, is generally congenital and unilateral and occurs equally in males and females. Optic disk pit maculopathy is... (Review)
Review
Optic disk pit, one of the optic disk cavitary anomalies, is generally congenital and unilateral and occurs equally in males and females. Optic disk pit maculopathy is characterized by intraretinal and subretinal fluid at the macula, causing visual deterioration. The origin of the macular fluid and the mechanism of transition to the subretinal space in optic disk pit maculopathy pathophysiology are not yet fully understood. With the evolution of imaging modalities, especially optic coherence tomography, our knowledge of this disorder continues to increase. Although many different treatments have been tried, there is no consensus on the most effective.
Topics: Eye Diseases, Hereditary; Humans; Macula Lutea; Macular Degeneration; Optic Disk; Tomography, Optical Coherence; Visual Acuity
PubMed: 30797884
DOI: 10.1016/j.survophthal.2019.02.006 -
IEEE Transactions on Medical Imaging Mar 2021Retinal fundus images are widely used for the clinical screening and diagnosis of eye diseases. However, fundus images captured by operators with various levels of...
Retinal fundus images are widely used for the clinical screening and diagnosis of eye diseases. However, fundus images captured by operators with various levels of experience have a large variation in quality. Low-quality fundus images increase uncertainty in clinical observation and lead to the risk of misdiagnosis. However, due to the special optical beam of fundus imaging and structure of the retina, natural image enhancement methods cannot be utilized directly to address this. In this article, we first analyze the ophthalmoscope imaging system and simulate a reliable degradation of major inferior-quality factors, including uneven illumination, image blurring, and artifacts. Then, based on the degradation model, a clinically oriented fundus enhancement network (cofe-Net) is proposed to suppress global degradation factors, while simultaneously preserving anatomical retinal structures and pathological characteristics for clinical observation and analysis. Experiments on both synthetic and real images demonstrate that our algorithm effectively corrects low-quality fundus images without losing retinal details. Moreover, we also show that the fundus correction method can benefit medical image analysis applications, e.g., retinal vessel segmentation and optic disc/cup detection.
Topics: Algorithms; Fundus Oculi; Image Enhancement; Retina; Retinal Vessels
PubMed: 33296301
DOI: 10.1109/TMI.2020.3043495 -
Journal Francais D'ophtalmologie Oct 2022Located within the scleral canal, the lamina cribrosa is a sieve-like structure separating the intraocular and retrobulbar portions of the optic nerve. Identified as the... (Review)
Review
Located within the scleral canal, the lamina cribrosa is a sieve-like structure separating the intraocular and retrobulbar portions of the optic nerve. Identified as the main site of axonal damage in glaucomatous optic neuropathy, the study of the lamina cribrosa has been of great interest for many years. Numerous studies have explored the histological and morphological characteristics of the laminar region in healthy subjects as well as glaucoma patients. More recently, the development of adaptive optics systems and new generations of OCT has allowed great progress in the understanding of the pathogenesis of glaucoma and has opened new perspectives for the improvement of diagnostic procedures.
Topics: Glaucoma; Humans; Intraocular Pressure; Optic Disk; Optic Nerve; Optic Nerve Diseases; Tomography, Optical Coherence
PubMed: 35717219
DOI: 10.1016/j.jfo.2022.03.003 -
[Zhonghua Yan Ke Za Zhi] Chinese... Oct 2022High myopia is an important cause of low vision and blindness in the world, most of which are characterized by the prolongation of the axial length, accompanied by... (Review)
Review
High myopia is an important cause of low vision and blindness in the world, most of which are characterized by the prolongation of the axial length, accompanied by various degenerative changes of fundus posterior pole, especially in the optic disc area and peripapillary structures, such as optic disc tilt, optic cup and rim changes, chorioretinal atrophy, posterior staphyloma and intrachoroidal cavitation, and so on. This article reviews the optic disc morphological features and peripapillary structure changes of high myopia, in order to reveal the pathogenesis of high myopia and provide new ideas for finding more effective prevention and treatment methods.
Topics: Choroid Diseases; Fundus Oculi; Humans; Myopia; Optic Disk; Scleral Diseases; Tomography, Optical Coherence
PubMed: 36220661
DOI: 10.3760/cma.j.cn112142-20220611-00293 -
Physiological Reviews Jul 2024The anterior chamber of the eye (ACE) is distinct in its anatomy, optics, and immunology. This guarantees that the eye perceives visual information in the context of... (Review)
Review
The anterior chamber of the eye (ACE) is distinct in its anatomy, optics, and immunology. This guarantees that the eye perceives visual information in the context of physiology even when encountering adverse incidents like inflammation. In addition, this endows the ACE with the special nursery bed iris enriched in vasculatures and nerves. The ACE constitutes a confined space enclosing an oxygen/nutrient-rich, immune-privileged, and less stressful milieu as well as an optically transparent medium. Therefore, aside from visual perception, the ACE unexpectedly serves as an excellent transplantation site for different body parts and a unique platform for noninvasive, longitudinal, and intravital microimaging of different grafts. On the basis of these merits, the ACE technology has evolved from the prototypical through the conventional to the advanced version. Studies using this technology as a versatile biomedical research platform have led to a diverse range of basic knowledge and in-depth understanding of a variety of cells, tissues, and organs as well as artificial biomaterials, pharmaceuticals, and abiotic substances. Remarkably, the technology turns in vivo dynamic imaging of the morphological characteristics, organotypic features, developmental fates, and specific functions of intracameral grafts into reality under physiological and pathological conditions. Here we review the anatomical, optical, and immunological bases as well as technical details of the ACE technology. Moreover, we discuss major achievements obtained and potential prospective avenues for this technology.
Topics: Humans; Prospective Studies; Anterior Chamber
PubMed: 38206586
DOI: 10.1152/physrev.00024.2023 -
Eye (London, England) Mar 2022To analyse structural characteristics and perifoveal/peripapillary vasculature by OCT in children with peripapillary hyperreflective ovoid mass-like structures (PHOMS)...
BACKGROUND
To analyse structural characteristics and perifoveal/peripapillary vasculature by OCT in children with peripapillary hyperreflective ovoid mass-like structures (PHOMS) and compare the results with those of normal subjects.
METHODS
Forty-five patients (84 eyes) under 18 years old with blurry disc margin were evaluated with spectral domain-OCT and swept course-OCT. Patients were divided into four groups, according to presence of PHOMS and then the size of the existing PHOMS. Eyes with visible optic disc drusen (ODD) were not included. Foveal avascular zone (FAZ) and vessel densities from macula and optic disc area were assessed and potential associations between vessel density and structural parameters, such as peripapillary retinal nerve fibre layer (pRNFL), and macular ganglion cell and inner plexiform layer (mGCIPL) thickness, were analysed.
RESULTS
Among 45 patients (eighty-four eyes), coexisting buried ODD were found only in eyes with PHOMS. The scleral canal diameter was significantly smaller in PHOMS positive eyes compared to control eyes. Vessel density measurements from the papillary, peripapillary and optic nerve head (ONH) regions in the large PHOMS group were significantly lower compared to the control group (papillary; P = 0.014, peripapillary; P = 0.001, ONH; P = 0.046). FAZ area and macular vessel densities showed no difference compared to normal eyes in all three PHOMS groups. pRNFL and mGCIPL thickness did not differ among four groups and correlations were also not significant.
CONCLUSIONS
Children with PHOMS have smaller scleral canal and can entail buried ODD. Vessel densities of optic disc area in large PHOMS eyes are significantly lower than in normal eyes.
Topics: Adolescent; Child; Humans; Macula Lutea; Optic Disk; Optic Disk Drusen; Sclera; Tomography, Optical Coherence
PubMed: 33731891
DOI: 10.1038/s41433-021-01461-w -
Journal of Glaucoma Jun 2020To compare disease severity between preperimetric primary open-angle glaucoma (POAG) patients with and without deep-layer microvasculature dropout. (Comparative Study)
Comparative Study
PURPOSE
To compare disease severity between preperimetric primary open-angle glaucoma (POAG) patients with and without deep-layer microvasculature dropout.
MATERIALS AND METHODS
Ninety-four eyes of 94 preperimetric POAG patients with β-zone parapapillary atrophy (βPPA) were categorized according to the presence of deep-layer microvasculature dropout defined as a complete loss of microvasculature within the choroid or scleral flange on optical coherence tomography angiography. Parameters representing disease severity, that is, visual field (VF) mean deviation (MD), global and sectoral (6-sector) retinal nerve fiber layer (RNFL) thickness, and other factors including age, focal lamina cribrosa (LC) defect, width of βPPA with and without Bruch membrane (BM) (βPPA+BM and βPPA-BM), and optic disc hemorrhage were compared between eyes with and without dropout.
RESULTS
Deep-layer microvasculature dropout was observed in 33 preperimetric POAG eyes (35.1%). Eyes with dropout had significantly thinner RNFL in all areas except the inferonasal sector, worse VF MD, and higher prevalence of focal LC defect, and larger βPPA-BM (P<0.05), whereas the 2 groups did not differ in age, disc hemorrhage, or βPPA+BM width (P>0.05). In the multivariable logistic regression, worse VF MD [odds ratio (OR), 1.485; P=0.045], thinner RNFL (OR, 1.141; P<0.001), and higher prevalence of focal LC defect (OR, 6.673; P<0.001) were significantly associated with dropout.
CONCLUSIONS
Deep-layer microvasculature dropout was observed in a considerable number of preperimetric POAG eyes, and worse disease severity was associated with dropout. Future studies elucidating the pathogenic role of deep-layer microvasculature dropout in the development and progression of glaucoma are warranted.
Topics: Adult; Aged; Choroid; Cohort Studies; Disease Progression; Female; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Microvessels; Middle Aged; Optic Disk; Optic Nerve Diseases; Sclera; Severity of Illness Index; Tomography, Optical Coherence; Visual Fields
PubMed: 32205833
DOI: 10.1097/IJG.0000000000001489 -
Survey of Ophthalmology 2020With the advent of spectral-domain optical coherence tomography, imaging of the posterior segment of the eye can be carried out rapidly at multiple anatomical locations,... (Review)
Review
With the advent of spectral-domain optical coherence tomography, imaging of the posterior segment of the eye can be carried out rapidly at multiple anatomical locations, including the optic nerve head, circumpapillary retinal nerve fiber layer, and macula. There is now ample evidence to support the role of spectral-domain optical coherence tomography imaging of the macula for detection of early glaucoma. Macular spectral-domain optical coherence tomography measurements demonstrate high reproducibility, and evidence on its utility for detection of glaucoma progression is accumulating. We present a comprehensive review of macular spectral-domain optical coherence tomography imaging emerging as an essential diagnostic tool in glaucoma.
Topics: Glaucoma; Humans; Macula Lutea; Reproducibility of Results; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 32199939
DOI: 10.1016/j.survophthal.2020.03.002 -
JAMA Ophthalmology Feb 2021
Topics: Child, Preschool; Eye Abnormalities; Female; Humans; Macula Lutea; Optic Disk; Photography; Predictive Value of Tests; Ultrasonography; Visual Acuity
PubMed: 33595607
DOI: 10.1001/jamaophthalmol.2020.4075