Abstract: To describe the current aging population in China and globally, especially as it applies to age-related macular degeneration (AMD). To review the current standards of care for treating both wet (exudative) eAMD and dry (atrophic) aAMD. And to introduce a model for experimentation that is based on the Age-Related Eye Disease Study (AREDS) using eye bank tissue. A literature search that outlines current aging populations, standards of clinical treatment as defined by large, multicenter, randomized clinical trials that present level-I data with a low risk for bias. An experimental model system of AMD is presented that enables scientific analysis of AMD pathogenesis by applying grading criteria from the AREDS to human eye bank eyes. Analysis includes proteomic, cellular, and functional genomics. The standard of care for the treatment of eAMD is currently defined by the use of several anti-vascular endothelial growth (anti-VEGF) agents alone or in combination with photodynamic therapy. Monotherapy treatment intervals may be monthly, as needed, or by using a treat-and-extend (TAE) protocol. There are no proven therapies for aAMD. AMD that is phenotypically defined at AREDS level 3, should be managed with the use of anti-oxidant vitamins, lutein/zeaxanthin and zinc (AREDS-2 formulation). By understanding the multiple etiologies in the pathogenesis of AMD (i.e., oxidative stress, inflammation, and genetics), the use of human eye bank tissues graded according to the Minnesota Grading System (MGS) will enable future insights into the pathogenesis of AMD. Initial AMD management is with lifestyle modification such as avoiding smoking, eating a healthy diet and using appropriate vitamin supplements (AREDS-2). For eAMD, anti-VEGF therapies using either pro re nata (PRN) or TAE protocols are recommended, with photodynamic therapy in appropriate cases. New cellular information will direct future, potential therapies and these will originate from experimental models, such as the proposed eye bank model using the MGS, that leverages the prospective AREDS database.
Background: The usage of the light emitting diode (LED) has been increasingly applied in the illumination setting and electronic equipment. However, the effect of LED lights on the retina remains unclear. In this study, we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.
Methods: Thirty-six Sprague-Dawley rats weighing 150–180 g were randomly divided into six groups (n=6 in each group) including a normal control (NC) group, 4 white LED groups at different light intensities (4,000, 6,000, 7,000, and 10,000 lux), and an ultraviolet B (UVB) lighting group (302 nm, 1,000 μw/cm2). After 24 hours of continuous illumination, full-field flash electroretinogram (FERG) and pathological examination were performed in each group.
Results: As revealed by FERG, the impairment of retinal function gradually worsened with the increase of LED light intensity. In contrast, the UVB group had the most severe retinal function impairment. Particularly, the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group. In the NC group, the retina had typical morphologies featured by well-defined structures, clearly visible border between the inner and outer segments, and neatly arranged inner and outer nuclear layer cells. After 24 hours of illumination, the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged, along with a clear border; however, the inner and outer nuclear layers were randomly arranged, and some irregular nuclei and cells were lost. The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group, 7,000 lux group, and 10,000 lux group. The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.
Conclusions: Continuous exposure to white LED light can cause structural and functional damage to rat retinas, and such damage is related to the intensity of illumination. Therefore, the risk of retinal damage should be considered during LED illumination, and proper LED illumination intensity may help to maintain eye health.
Background: To investigate the microstructural features of parapapillary gamma zone and beta zone and their relationship with three-dimensional optic disc shape in non-myopic eyes.
Methods: This cross-sectional study included 62 non-myopic eyes with parapapillary gamma or beta zone and 70 control eyes. On the spectral domain optical coherent tomography (SD-OCT) images, we measured the area of gamma zone and beta zone, the length of border tissue, and related disc parameters. The disc ovality index, disc rotation degrees around three axes, Bruch’s membrane opening (BMO) ovality ratio were calculated based on the SD-OCT images.
Results: The parapapillary gamma zone composed by externally oblique border tissue was found in inferior, nasal and temporal quadrants of the non-myopic eyes. The presence of gamma zone in non-myopic eyes was correlated with smaller disc ovality index, larger rotation degree around vertical and horizontal axes, and larger BMO ovality ratio (P<0.001). Compared with the non-temporal gamma zone group, eyes with temporal gamma zone had a longer axial length and rotated more around vertical axes (P<0.001). Multivariate analysis showed that the area of gamma zone was correlated with the disc ovality index (P<0.001). The presence and area of beta zone was correlated with age (P<0.01).
Conclusions: In non-myopic eyes, the parapapillary gamma zone composed by external oblique border tissue was significantly associated with the disc ovality and disc rotations around vertical and horizontal axes. From a biomechanical perspective, parapapillary gamma zone may contribute to the optic disc stability in association with the structure of BMO.
Abstract: Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population. The advances in ocular genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRD, with the first approved gene therapy and the commencement of multiple therapy trials. The scope of this review is to familiarize clinicians and scientists with the current landscape of retinal imaging in IRD. Herein we present in a comprehensive and concise manner the imaging findings of: (I) macular dystrophies (MD) [Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), pattern dystrophy (PRPH2), Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)], (II) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4 and RPGR), (III) cone dysfunction syndromes [achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6], blue-cone monochromatism (OPN1LW/OPN1MW array), oligocone trichromacy, bradyopsia (RGS9/R9AP) and Bornholm eye disease (OPN1LW/OPN1MW), (IV) Leber congenital amaurosis (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (V) rod-cone dystrophies [retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)], (VI) rod dysfunction syndromes (congenital stationary night blindness, fundus albipunctatus (RDH5), Oguchi disease (SAG, GRK1), and (VII) chorioretinal dystrophies [choroideremia (CHM), gyrate atrophy (OAT)].
Abstract: Optical coherence tomography angiography (OCTA) is a fast, non-invasive imaging modality that provides detailed information on retinal and choroidal vascular flow and macular structure. OCTA offers an accurate three-dimensional view of the individual retinal vascular plexuses and the choriocapillaris which facilitates the detection of the microvascular abnormalities in a variety of macular diseases. The perfusion indices (vessel density and flow index) are valuable parameters evaluated by OCTA that allow a quantitative interpretation of changes in the retinal vasculature that can reflect the severity of disease. Crystalline retinopathy encompasses a group of conditions whose distinctive feature is the presence of retinal crystals often located in the posterior pole. Select crystalline retinopathies also demonstrate retinal vascular abnormalities as well. Considering that the OCTA is a novel imaging modality and crystalline retinopathies are relatively rare conditions, there are currently few reports of OCTA findings associated with crystalline retinopathy. The advent of OCTA allows visualization of vascular and structural changes in crystalline retinopathies that are unique and cannot be appreciated on other imaging modalities, including fluorescein angiography (FA). This article reviews novel OCTA findings which provide new insights in the pathogenesis of crystalline retinopathies, including Bietti crystalline retinopathy, talc retinopathy, macular telangiectasia type 2, tamoxifen retinopathy, and Sj?gren-Larsson Syndrome maculopathy.
Abstract: Uveitis can cause significant visual morbidity and often affects younger adults of working age. Anterior uveitis, or inflammation limited to the anterior chamber (AC), iris, and/or ciliary body comprises the majority of uveitis cases. Current clinical biomarkers and conventional grading scales for intraocular inflammation are mostly subjective and have only a moderate degree of interobserver reliability, and as such they have significant limitations when used in either clinical practice or research related to uveitis. In recent years, novel imaging techniques and applications have emerged that can supplement exam findings to detect subclinical disease, monitor quantitative biomarkers of disease progression or treatment effect, and provide overall a more nuanced understanding of disease entities. The first part of this review discusses automated algorithms for optical coherence tomography (OCT) image processing and analysis as a means to assess and describe intraocular inflammation with higher resolution than that afforded by conventional AC and vitreous cell ordinal grading scales. The second half of the review focuses on anterior segment OCT and OCT angiography (OCTA) in scleritis and iritis, especially with regards to their ability to directly image and characterize the pathologic structures and vasculature underlying these diseases. Finally, we briefly review experimental animal research with promising but more distant human clinical applications, including in vivo molecular microscopy of inflammatory markers and investigation of gold nanoparticles as a potential contrast agent in OCT imaging. Imaging modalities are discussed in the broader context of trends within the field of uveitis towards greater objectivity and quantifiable outcome measures and biomarkers.
Abstract: Vogt-Koyanagi-Harada syndrome (VKH) is a bilateral granulomatous panuveitis associated with serous retinal detachments and vitritis, and can be associated with extraocular manifestations of meningismus, poliosis, vitiligo, hearing loss, and headaches. It is mediated by CD4+ T cells that target melanocytes in the eye, ear, meninges, and skin. It classically presents in 4 different phases: prodromal, uveitic, convalescent, and recurrent. There have been considerable advances in our understanding of the disease in recent years, and options for treatment have also expanded beyond systemic corticosteroids though these remain the mainstay of therapy in patients with VKH. This brief review will focus on updates in the diagnosis and treatment of VKH, specifically advances in imaging techniques including the use of optical coherence tomography angiography (OCTA) and enhanced depth imaging (EDI) optical coherence tomography (OCT). OCT parameters that are diagnostically predictive of acute VKH compared to other exudative maculopathies include the presence of subretinal membranous structures, a high retinal detachment, subretinal hyperreflective dots, and RPE folds. Evaluations of choroidal thickness using EDI-OCT demonstrate predominant involvement of the outer choroid in the acute inflammatory phase of VKH, consistent with histopathological analysis. OCTA may emerge as an alternative to fluorescein angiography (FA) and indocyanine angiography (ICGA) but is limited at this time due to its small field of view. While the mainstay of treatment of acute VKH continues to be systemic corticosteroids, biological response modifiers (BRMs) such as adalimumab and infliximab have been shown to be effective in the management of adult and pediatric VKH with one benefit being a faster onset of action compared to conventional immunosuppression. Literature Search: A literature search was done in PubMed using the words “Vogt Koyanagi Harada” “imaging” “diagnosis” “treatment” “therapy “posterior uveitis”.
Abstract: Optical coherence tomography (OCT) is a widely used non-invasive medical imaging technology that has revolutionized clinical care in ophthalmology. New developments, such as OCT angiography (OCTA) are expected to contribute even further to the widespread use of OCT-based imaging devices in the diagnosis and monitoring of patients with ophthalmic diseases. In recent years, many of the disadvantages such as limited field of view and imaging artefacts have been substantially reduced. Similar to the progress achieved in the assessment of retinal disorders, OCT is expected to change the approach to patients seen in the neuro-ophthalmology clinic. In this article, we review the technical features of OCT and OCT-based imaging techniques, highlighting the specific factors that should be taken into account when interpreting OCT in the field of neuro-ophthalmology.
Abstract: Age-related macular degeneration (ARMD), one of the most common causes of blindness, should be considered more due to its exponential increase in the coming 20 years as a result of increasing the age of the population. Whereas more recent studies offered newer scaling systems for ARMD, traditionally it is classified as the early and late stages. The main injury in this disease occurred in retinal pigment epithelium (RPE) and the retina. RPE cells have a crucial role in hemostasis and supporting photoreceptors. In the early stages, damages to RPE are minimal and mainly no treatment is needed because most patients are asymptomatic. However, in the late stages, RPE impairment may lead to the invasion of choroidal vessels into the retina. Although anti-angiogenic agents can inhibit this abnormal growth of blood vessels, they cannot stop it completely, and finally, total loss of retinal cells may occur (geographical atrophy). Since this prevalent disease has not had any cure yet, the concept of substituting the RPE cells should be considered. Repairing the injury to central nervous system cells is almost impossible because the regenerative capacity of these cells is limited. Recently, the use of regenerative substitutes has been suggested to replace damaged tissues. Amniotic membrane (AM) has been raised as a suitable substitute for damaged RPE cells due to all of its unique properties: pluripotency, anti-angiogenic effect, and anti-inflammatory effect. Based on the few studies that have been published so far, it seems that the use of this membrane in the treatment of ARMD can be helpful, but more studies are needed.
