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: Artificial intelligence (AI) methods have become a focus of intense interest within the eye care community. This parallels a wider interest in AI, which has started impacting many facets of society. However, understanding across the community has not kept pace with technical developments. What is AI, and how does it relate to other terms like machine learning or deep learning? How is AI currently used within eye care, and how might it be used in the future? This review paper provides an overview of these concepts for eye care specialists. We explain core concepts in AI, describe how these methods have been applied in ophthalmology, and consider future directions and challenges. We walk through the steps needed to develop an AI system for eye disease, and discuss the challenges in validating and deploying such technology. We argue that among medical fields, ophthalmology may be uniquely positioned to benefit from the thoughtful deployment of AI to improve patient care.
Abstract: Hereditary, metabolic and toxic optic neuropathies cause bilateral, central vision loss and therefore can result in severe impairment in visual function. Accurate, early diagnosis is critical, as nutritional and toxic optic neuropathies may be reversible if identified early, and diagnosis of hereditary optic neuropathies can prevent unnecessary invasive workup, provide prognostic information, and allow for effective genetic counseling. Optical coherence tomography (OCT) is a valuable tool that aids in the diagnosis and prognostication of optic neuropathies as it allows for quantification of changes in the retinal ganglion cells (RGCs) and retinal nerve fiber layer (RNFL) over time. We review the characteristic clinical presentations of hereditary, metabolic and toxic optic neuropathies, with an emphasis on OCT findings.
Abstract: Optical coherence tomography (OCT) provides a non-invasive analysis of the retina in vivo. Lesions which compress the anterior visual pathway can cause anterograde and retrograde neuro-degeneration. Retrograde structural changes to the retina can be detected by OCT. Analyzing patterns of change on OCT can guide diagnostic and treatment decisions for lesions compressing the optic nerve and chiasm to minimize loss of visual function. From our review of current literature, it is clear that thinning of both the retinal nerve fiber and ganglion cell layers (GCLs) can indicate compression. These parameters correlate with visual function loss as detected by perimetry. Furthermore, these measurements have shown to be the most reliable biomarkers to date in predicting visual recovery after treatment of these compressive lesions.
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: Focal intraretinal alterations have been studied to advance our understanding of the pathology of neurodegenerative diseases. The current literature involving focal alterations in the intraretinal layers was reviewed through PubMed using the search terms “focal alteration”, “region of interest”, “optical coherence tomography”, “glaucoma”, “multiple sclerosis”, “Alzheimer’s disease”, “Parkinson disease”, “neurodegenerative diseases” and other related items. It was found that focal alterations of intraretinal layers were different in various neurodegenerative diseases. The typical focal thinning might help differentiate various ocular and cerebral diseases, track disease progression, and evaluate the outcome of clinical trials. Advanced exploration of focal intraretinal alterations will help to further validate their clinical and research utility.
Abstract: Idiopathic intracranial hypertension (IIH) is a condition in which elevated pressure in the cerebrospinal fluid can lead to optic nerve head (ONH) dysfunction and subsequent visual impairment. Physicians are currently limited in their ability to monitor and manage this condition, as clinical symptoms and exam findings are often delayed in response to changes in intracranial pressure. In order to find other biomarkers of disease, researchers are using imaging modalities such as optical coherence tomography (OCT) to observe microscopic changes in the eye in this condition. OCT can create 2-dimensional and 3-dimensional high definition images of the retina of the ONH and has been used to study various conditions such as glaucoma and multiple sclerosis. Numerous studies have used OCT in IIH as well, and they have shown that certain retinal layers and the ONH change in thickness and shape in both the short and long term with intracranial pressure changes. OCT is a promising modality for clinical and scientific evaluation of IIH as it is a noninvasive and practical tool to obtain in depth images. This review will discuss how OCT can be used to assess a patient with IIH, both before and after treatment, along with its limitations and future applications.
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.
