Comparative Proteomic Study of Retinal Ganglion Cells Undergoing Various Types of Cellular Stressors

Retinal ganglion cell (RGC) damage serves as a key indicator of various retinal degenerative diseases, including diabetic retinopathy (DR), glaucoma, retinal arterial and retinal vein occlusions, as well as inflammatory and traumatic optic neuropathies. Despite the growing body of data on the RGC proteomics associated with these conditions, there has been no dedicated study conducted to compare the molecular signaling pathways involved in the mechanism of neuronal cell death. Therefore, we launched the study using two different insults leading to RGC death: glutamate excitotoxicity and optic nerve crush (ONC). C57BL/6 mice were used for the study and underwent NMDA- and ONC-induced damages. Twenty-four hours after ONC and 1 hour after NMDA injection, we collected RGCs using CD90.2 coupled magnetic beads, prepared protein extracts, and employed LC-MS for the global proteomic analysis of RGCs. Statistically significant changes in proteins were analyzed using the Shiny Go program to identify GO biological processes and molecular functions resulting from the treatment. We identified unique and common alterations in protein profiles in RGCs undergoing different types of cellular stressors. Additionally, we observed the absence of certain proteins in treated RGCs compared to the control group. Our study not only identified both unique and shared proteomic changes but also laid the groundwork for the future development of a therapeutic platform for testing gene candidates for DR and glaucoma.

Automatic Method for Optic Disc Segmentation Using Deep Learning on Retinal Fundus Images

OBJECTIVES

The optic disc is part of the retinal fundus image structure, which influences the extraction of glaucoma features. This study proposes a method that automatically segments the optic disc area in retinal fundus images using deep learning based on a convolutional neural network (CNN).

METHODS

This study used private and public datasets containing retinal fundus images. The private dataset consisted of 350 images, while the public dataset was the Retinal Fundus Glaucoma Challenge (REFUGE). The proposed method was based on a CNN with a single-shot multibox detector (MobileNetV2) to form images of the region-of-interest (ROI) using the original image resized into 640 × 640 input data. A pre-processing sequence was then implemented, including augmentation, resizing, and normalization. Furthermore, a U-Net model was applied for optic disc segmentation with 128 × 128 input data.

RESULTS

The proposed method was appropriately applied to the datasets used, as shown by the values of the F1-score, dice score, and intersection over union of 0.9880, 0.9852, and 0.9763 for the private dataset, respectively, and 0.9854, 0.9838 and 0.9712 for the REFUGE dataset.

CONCLUSIONS

The optic disc area produced by the proposed method was similar to that identified by an ophthalmologist. Therefore, this method can be considered for implementing automatic segmentation of the optic disc area.

Alcohol and the Eye

In this article, we present a review of ocular conditions related to alcohol consumption. A search of the literature published from 1952 to March 2020 was performed. The titles and abstracts were screened and the eligible studies were selected. PubMed, ISI Web of Knowledge database, Scopus, Embase, and the Cochrane Library were searched. We categorized the relationship between alcohol intake and ocular conditions by the type of ocular exposure to alcohol. Accordingly, ocular findings following acute alcohol intoxication, optic neuropathy following methanol toxicity, congenital conditions related to maternal alcohol consumption, and ocular disease related to chronic alcoholism are discussed. The main feature of alcohol intoxication in the eye is abnormal eye movement. Acute optic neuropathy secondary to methyl alcohol consumption is a serious ocular disease with permanent vision loss or scotoma. Prenatal exposure to ethanol may end in fetal alcohol spectrum disease, where ocular findings are a constant component. The association between chronic alcohol consumption and increased risks of cataract, age-related macular degeneration, diabetic retinopathy, different types of optic neuropathy, impairment of visual quality, retinal vascular disease, and ocular surface disease has also been reported. Along with detrimental medical and social effects, the role of alcohol consumption in different ocular conditions should be considered, as alcohol-induced visual disturbances may contribute to the heavy burden of alcohol abuse on the healthcare system and overall quality of life.

Multiple sclerosis in ophthalmology: beyond optic neuritis

Disorders of the visual system are one of the main features of multiple sclerosis (MS), and have a great impact on the quality of life of patients. Although optic neuritis is the most frequent manifestation, there are other ophthalmological processes not related to neuritis, a knowledge of which is very useful in the management of patients with MS. These abnormalities are described, grouped into impairments of the afferent pathway, efferent pathway, or upper cerebral areas. Additionally, the main ophthalmological side effects of the drugs currently used in the control of MS are described.

Unilateral Blurred Vision as the Sole Presenting Symptom of Chronic Lymphocytic Leukemia

Purpose

To describe a case of infiltrative optic neuropathy caused by chronic lymphocytic leukemia.

Case Report

A 41-year-old white male presented with painless, blurry vision in the left eye. Examination revealed unilateral optic nerve swelling confirmed by optical coherence tomography (OCT). Initial workup revealed mild leukocytosis, eventually diagnosed as chronic lymphocytic leukemia (CLL). No other cause of optic neuropathy was identified despite extensive investigation. The patient developed rapidly progressive retinal ganglion cell nerve fiber layer (NFL) atrophy and relative afferent pupillary defect (RAPD) of the left eye despite steroid treatment but stabilized after four cycles of CLL-targeted chemotherapy. Although infiltrative optic neuropathy is well-known in leukemia, presentation with only subtle vision loss is rare. Vision loss usually presents late in leukemic infiltrative optic neuropathy and therefore must be considered in patients with optic disc swelling and leukocytosis.

Conclusion

When treating CLL, progressive visual decline with coexistent optic neuropathy may warrant chemotherapy.

Transitions of the Understanding and Definition of Primary Glaucoma

Objective:

In previous decades, glaucoma has been primarily attributed to elevated intraocular pressure (IOP), but this has gradually been replaced by the development of optic neuropathy as the central concept of glaucoma in developed countries. However, there still remain strong controversies in the definition of glaucoma in China. In this current review, we are going to discuss these controversies and elaborate on the historical transitions of the definition of glaucoma both in China and developed countries. Furthermore, we will briefly describe the “ocular-cranial pressure gradient” theory and discuss the relationship between glaucoma and degenerative diseases of the central nervous system (CNS) in order to show the complex pathogenesis of glaucoma and the importance for the modification to the definition of glaucoma.

Data Sources:

We performed a comprehensive search in both PubMed and SinoMed using the following keywords: (a) “primary glaucoma” and “guideline,” (b) “ocular-cranial pressure gradient,” and (c) “glaucoma,” “Alzheimer's disease,” and “Parkinson's disease.” The literature search included the related articles with no restrictions on publication date.

Study Selection:

The primary references were Chinese and English articles including (a) original guidelines and expert consensuses of primary glaucoma, (b) reviews focusing on the differences between various versions of these guidelines and consensuses, and (c) papers about ocular-cranial pressure gradient theory and the relationship between glaucoma and CNS degenerative diseases.

Results:

The definitions and classifications of both primary open-angle glaucoma and primary angle-closure glaucoma differ between Chinese glaucoma consensuses and international primary glaucoma guidelines. Chinese definitions and classifications put more emphasis on the IOP, while international guidelines put more emphasis on the presence of optic neuropathy. The ocular-cranial pressure gradient theory and the research on the relationship between glaucoma and CNS degenerative diseases have provided new directions for exploring the pathogenesis of glaucoma.

Conclusions:

As regards the definition and classification of primary glaucoma, we find that there are still some discrepancies between Chinese expert consensuses and international guidelines. Glaucoma is a disease with complex etiologies, while its common characteristic is a specific optic neuropathy. The current definition and understanding of glaucoma is an ongoing and evolving process, reflecting our latest available evidence on its pathogenesis. Chinese ophthalmology community may need to update our guidelines, accommodating these latest developments.

Automated Detection of Retinal Nerve Fiber Layer by Texture-Based Analysis for Glaucoma Evaluation

Objectives

The retinal nerve fiber layer (RNFL) is a site of glaucomatous optic neuropathy whose early changes need to be detected because glaucoma is one of the most common causes of blindness. This paper proposes an automated RNFL detection method based on the texture feature by forming a co-occurrence matrix and a backpropagation neural network as the classifier.

Methods

We propose two texture features, namely, correlation and autocorrelation based on a co-occurrence matrix. Those features are selected by using a correlation feature selection method. Then the backpropagation neural network is applied as the classifier to implement RNFL detection in a retinal fundus image.

Results

We used 40 retinal fundus images as testing data and 160 sub-images (80 showing a normal RNFL and 80 showing RNFL loss) as training data to evaluate the performance of our proposed method. Overall, this work achieved an accuracy of 94.52%.

Conclusions

Our results demonstrated that the proposed method achieved a high accuracy, which indicates good performance.

Automatic Glaucoma Detection Method Applying a Statistical Approach to Fundus Images

OBJECTIVES

Glaucoma is an incurable eye disease and the second leading cause of blindness in the world. Until 2020, the number of patients of this disease is estimated to increase. This paper proposes a glaucoma detection method using statistical features and the k-nearest neighbor algorithm as the classifier.

METHODS

We propose three statistical features, namely, the mean, smoothness and 3rd moment, which are extracted from images of the optic nerve head. These three features are obtained through feature extraction followed by feature selection using the correlation feature selection method. To classify those features, we apply the k-nearest neighbor algorithm as a classifier to perform glaucoma detection on fundus images.

RESULTS

To evaluate the performance of the proposed method, 84 fundus images were used as experimental data consisting of 41 glaucoma image and 43 normal images. The performance of our proposed method was measured in terms of accuracy, and the overall result achieved in this work was 95.24%, respectively.

CONCLUSIONS

This research showed that the proposed method using three statistics features achieves good performance for glaucoma detection.

Optical Coherence Tomography Angiography of the Optic Disc; an Overview

Different diseases of the optic disc may be caused by or lead to abnormal vasculature at the optic nerve head. Optical coherence tomography angiography (OCTA) is a novel technology that provides high resolution mapping of the retinal and optic disc vessels. Recent studies have shown the ability of OCTA to visualize vascular abnormalities in different optic neuropathies. In addition, quantified OCTA measurements were found promising for differentiating optic neuropathies from healthy eyes.

Toxoplasmosis Neuroretinitis: A Case Report

Introduction

Neuroretinitis (NR) is considered to be an inflammatory condition which is characterized by optic disc edema and, as a result, formation of a macular star figure. NR is an atypical presentation of toxoplasmosis infection, and such cases are quite rare.

Case Presentation

A 13-year-old girl presented with painless subacute visual loss in her right eye for a week at Khatam-Al-Anbia eye hospital in Mashhad, Iran. Following comprehensive evaluation, a diagnosis of toxoplasmic NR was made. The NR favorably responded to classic anti-toxoplasmosis treatment. A juxtapapillary retinochoroidal scar appeared after disc swelling resolution.

Conclusions

Although toxoplasmosis NR is rare, it should be considered in the differential diagnoses of NR.

Pseudo-Foster Kennedy Syndrome as a Rare Presentation of Vitamin B12 Deficiency

Introduction

Pseudo-Foster Kennedy syndrome is a triad consisting of ipsilateral optic atrophy, contralateral optic disc edema, and ipsilateral anosmia in the absence of an intracranial mass. Vitamin B12 plays an important role in DNA synthesis, and its deficiency causes peripheral neuropathy, myeloneuropathy, and, very rarely, optic neuropathy.

Case Presentation

In this study, we describe a 34-year-old male who presented with progressive loss of visual acuity and field. Fundoscopy showed optic disc edema with telangiectasia in the right eye, while the left eye had optic disc atrophy. We ruled out nearly all possible and common causes of optic neuropathy, and vitamin B12 deficiency was finally diagnosed. After treatment with vitamin B12, the patient improved.

Conclusions

Demyelinating disease, anterior ischemic optic neuropathy, non-arteritic anterior ischemic optic neuropathy, autoimmune disease, and hereditary optic neuropathy could cause optic neuropathy. Normal CBC parameters and the absence of clinical manifestations of vitamin B12 deficiency could not rule out its diagnosis. Careful physical examinations and history-taking with a classical approach led us to the diagnosis of vitamin B12 deficiency and its treatment.

Visual loss in patients with sphenoethmoidal cells

BACKGROUND

A sphenoethmoidal cell is a posterior ethmoid cell that pneumatises superiorly and/or laterally to the sphenoid sinus. Disease within such a cell may cause visual symptoms because of the close relationship of the optic nerve.

CASE REPORTS

This paper reports four cases of chronic rhinosinusitis involving a sphenoethmoidal cell, two with visual loss. The management of such cases is discussed and the current literature is reviewed.

CONCLUSION

Pathology within a sphenoethmoidal cell must be considered in cases of optic neuropathy. The presence of these cells may be relevant even in cases of seemingly uncomplicated rhinosinusitis as they are associated with a higher rate of optic nerve protrusion and dehiscence.

The Muranga Teleophthalmology Study: Comparison of Virtual (Teleglaucoma) with in-Person Clinical Assessment to Diagnose Glaucoma

PURPOSE

While the effectiveness of teleophthalmology is generally accepted, its ability to diagnose glaucomatous eye disease remains relatively unknown. This study aimed to compare a web-based teleophthalmology assessment with clinical slit lamp examination to screen for glaucoma among diabetics in a rural African district.

MATERIALS AND METHODS

Three hundred and nine diabetic patients underwent both the clinical slit lamp examination by a comprehensive ophthalmologist and teleglaucoma (TG) assessment by a glaucoma subspecialist. Both assessments were compared for any focal glaucoma damage; for TG, the quality of photographs was assessed, and vertical cup-to-disk ratio (VCDR) was calculated in a semi-automated manner. In patients with VCDR > 0.7, the diagnostic precision of the Frequency Doubling Technology (FDT) C-20 screening program was assessed.

RESULTS

Of 309 TG assessment photos, 74 (24%) were deemed unreadable due to media opacities, patient cooperation, and unsatisfactory photographic technique. While the identification of individual optic nerve factors showed either fair or moderate agreement, the ability to diagnose glaucoma based on the overall assessment showed moderate agreement (Kappa [κ] statistic 0.55% and 95% confidence interval [CI]: 0.48-0.62). The use of FDT to detect glaucoma in the presence of disc damage (VCDR > 0.7) showed substantial agreement (κ statistic of 0.84 and 95% CI 0.79-0.90). A positive TG diagnosis of glaucoma carried a 77.5% positive predictive value, and a negative TG diagnosis carried an 82.2% negative predicative value relative to the clinical slit lamp examination.

CONCLUSION

There was moderate agreement between the ability to diagnose glaucoma using TG relative to clinical slit lamp examination. Poor quality photographs can severely limit the ability of TG assessment to diagnose optic nerve damage and glaucoma. Although further work and validation is needed, the TG approach provides a novel, and promising method to diagnose glaucoma, a major cause of ocular morbidity throughout the world.

Acute papillitis in young female with toxoplasmosis

Papillitis and complicating acute toxoplasma retinochoroiditis, are unusual and atypical features of toxoplasmosis. This report presents a female with unusual acute papillitis. This patient had an active toxoplasmic chorioretinitis lesion that appeared to involve the optic nerve head and a major blood vessel as well as central nervous systems (CNS). Papillitis may be secondary to juxtapapillary retinitis (Jensen choroiditis). Very rarely, the optic nerve head may be the primary site of involvement. This case report illustrates a rare presentation of acute papillitis in a young immunocompetent female.

Leber's Hereditary Optic Neuropathy: The Mitochondrial Connection Revisited

Our current understanding of Leber’s hereditary optic neuropathy (LHON)-mitochondrial connection falls short of comprehensive. Twenty years of intensive investigation have yielded a wealth of information about mitochondria, the mitochondrial genome, the metabolism of the optic nerve and other structures, and the phenotypic variability of classic LHON. However, we still cannot completely explain how primary LHON mutations injure the optic nerve or why the optic nerve is particularly at risk. We cannot explain the incomplete penetrance or the male predominance of LHON, the typical onset in young adult life without warning, or the synchronicity of visual loss. Moreover, primary LHON mutations clearly are not present in every family with the LHON phenotype (including multigenerational maternal inheritance), and they are present in only a minority of individuals who have the LHON optic neuropathy phenotype without a family history. All lines of evidence point to abnormalities of the mitochondria as the direct or indirect cause of LHON. Therefore, the mitochondria-LHON connection needs to be revisited and examined closely. This review will attempt to do that and provide an update on various aspects of LHON.

Posterior Ischemic Optic Neuropathy following Herpes Zoster Ophthalmicus

PURPOSE

To report a case of posterior ischemic optic neuropathy (PION) following herpes zoster ophthalmicus (HZO).

CASE REPORT

A 58-year-old woman with history of recent HZO in her right eye presented with acute painless loss of vision in the same eye to no light perception.Examination revealed a positive relative afferent pupillary defect and a normal appearing optic disc. Inflammatory and infiltrative lesions of the optic nerve were ruled out by laboratory and imaging studies. The patient received systemic acyclovir and prednisolone. Three months later, visual acuity improved to counting fingers, but the optic disc became pale and atrophic leading to a presumptive diagnosis of PION.Considering the positive PCR test for varicella zoster virus and the short time interval between the two presentations, HZO was considered as the most probable cause of the optic neuropathy.

CONCLUSION

Herpes zoster ophthalmicus can be associated with PION.