Molecular Mechanisms of Retinal Pigment Epithelium Dysfunction in Age-Related Macular Degeneration

The retinal pigment epithelium (RPE), situated upon Bruch’s membrane, plays multiple roles in the ocular system by interacting with photoreceptors and. Therefore, dysfunction of the RPE causes diseases related to vision loss, such as age-related macular degeneration (AMD). Despite AMD being a global cause of blindness, the pathogenesis remains unclear. Understanding the pathogenesis of AMD is the first step for its prevention and treatment. This review summarizes the common pathways of RPE dysfunction and their effect in AMD. Potential treatment strategies for AMD based on targeting the RPE have also been discussed.

PREVALENC OF LOIASIS, AND ITS DISTRIBUTION IN NDOKWE WEST L.G.A, DELTA STATE

Loa Loa is transmitted to humans by deer vectors, the vectors are bloodsucking and diurnal bites, and are found in rainforest areas in western and central Africa. After infection, a human will mate and produce more microfilariae, assuming the presence of mature male and female worms in the host. Although it has no major complications, the high microfilariae load may cause some neurological symptoms and discomfort in the ocular system may make patients uneasy. Loiasis, also known as African eyeworm, is caused by the parasitic worm Loa-Loa. Infection with this microfilaria worm causes an itchy swelling on the body, also known as Calabar bumps which prefers the rainforest-like environment of western and central Africa. Endemicity is particularly high in Cameroon, Congo, Nigeria, Gabon and the Central African Republic. One area of great concern is the fact that the endemicity of Onchocerciasis with Onchocerciasis as a bulk ivermectin therapy can lead to serious adverse effects in patients with high Loa Loa microfilariae densities and loads. This fact requires the development of more specific diagnostic tests for loa-loa so that areas or individuals at higher risk for neurological outcomes can be identified prior to microfilaricidal therapy. Although diethylcarbamazine, the standard treatment method, gives good results, it can cause serious complications when administered in standard doses to patients with high microfilariae load. A few years later, in 1778, Francois Guyost noticed worms in the eyes of West African slaves on a French ship bound for America and successfully removed the worm from a man's eye. Treatment of loiasis includes chemotherapy, in some cases surgical removal of adult worms, followed by systemic therapy.

A Single-Center (Sibiu, Romania), Retrospective Study (March–November 2020) of COVID-19 Clinical and Epidemiological Features in Children

The aim of this study was to describe and analyze epidemiological and clinical features of children screened for COVID-19 at Sibiu Pediatric Clinical Hospital during the first 9 months (March–November) of coronavirus disease pandemic in Romania. A total of 203 pediatric patients with a confirmed diagnosis of COVID-19 were included in the study. The median age of the patients was 121 (IQR 18–181) months and 52.22% had mild clinical type with pneumonia, 35.47% were moderate cases, 3.94% severe cases, 0.99% critically ill cases and 7.39% were asymptomatic. The most common symptoms were fever (n = 130, 64.03%), nasal congestion (n = 138, 67.98%), cough (n = 128, 63.05%) followed by sore throat (n = 64, 31.52%), rhinorrhea (n = 63, 31.03%), fatigue (n = 57, 28.07%), headache (n = 47, 23.15%), diarrhea (n = 39, 19.21%), vomiting (n = 32, 15.76%), myalgia (n = 24, 11.82%), abdominal pain (n = 22, 10.83%). A higher proportion of infants with severe or critical disease was encountered with lymphopenia (n = 9, 90%), neutrophilia (n = 5, 50%), leukocytosis (n = 5, 50%) compared with asymptomatic infants (n = 10, 66.67%, n = 1, 6.67%, n = 3, 20%) or mild (n = 53, 50%, n = 19, 17.92%, n = 15, 14.15%) and moderate (n = 37, 51.39%, n = 9, 12.50%, n = 6, 8.33%) cases (p = 0.095, p = 0.042, p = 0.034). Pediatric patients generally had mild or moderate type of COVID-19, and the critically ill cases were rare. In our study, frequent symptoms were observed in both the systemic and respiratory systems, ear, nose and throat system, and less from gastrointestinal system, central nervous system or ocular system. Additionally, there is an increase in liver and myocardial enzyme levels with an increase in disease severity. Understanding the clinical and laboratory characteristics of pediatric patients is important for diagnosis, management and effective control of the disease.

Mitochondrial Diseases Associated with Retinopathy

Mitochondria are organelles that meet the energy needs of the cell through the electron transport chain and oxidative phosphorylation system. Its functions are regulated by double genomes, nuclear and mitochondrial DNA. Mutations that can occur in both genomes cause mitochondrial diseases, a group of clinically and genetically heterogeneous diseases. The entire ocular system, from the eyelids to the extraocular muscles, to the retina, such as the central nervous system, skeleton, and cardiac muscles, needs high oxidative phosphorylation. Common ophthalmic symptoms of mitochondrial dysfunction include optic atrophy, pigmentary retinopathy, cataracts, sudden vision loss, external ophthalmoplegia. Pigmentary retinopathy is the most common nonspecific retinal pathology and threatens vision. The emergence of the same mutation with different phenotypes in different individuals and tissues affects the clinical appearance of retinal pathologies. Different dystrophies can be observed, ranging from mild retinal pigment epithelial changes to salt pepper retinopathy, from circumferential perifoveal atrophy to reasonable pattern dystrophy. Diagnosis of all mitochondrial diseases requires detailed systemic screening. It is important to recognize and diagnose the ophthalmological signs of mitochondrial disorders as early as possible. Although treatments are mostly symptomatic, antioxidant treatments continue to be developed and gene therapy is promising for new cases.

Nitric Oxide Interaction with the Eye

Nitric oxide (NO) is acknowledged as a vital intercellular messenger in multiple systems in the body. Medicine has focused on its functions and therapeutic applications for decades, especially in cardiovascular and nervous systems, and its role in immunological responses. This review was composed to demonstrate the prevalence of NO in components of the ocular system, including corneal cells and multiple cells in the retina. It discussed NO’s assistance during the immune, inflammation and wound-healing processes. NO is identified as a vascular endothelial relaxant that can alter the choroidal blood flow and prompt or suppress vascular changes in age-related macular degeneration and diabetes, as well as the blood supply to the optic nerve, possibly influencing the progression of glaucoma. It will provide a deeper understanding of the role of NO in ocular homeostasis, the delicate balance between overproduction or underproduction and the effect on the processes from aqueous outflow and subsequent intraocular pressure to axial elongation and the development of myopia. This review also recognized the research and investigation of therapies being developed to target the NO complex and treat various ocular diseases.

Systemically administered central nervous system drugs induced ocular side effects: a review

Several systemic drugs have reported ocular and visual side effects that affect patient management. It is imperative to be familiar with the associated side effects which can be mild or transient and may seriously threaten vision. This article deals briefly with the mechanisms and reasons that account for the impact that systemically administered central nervous system (CNS) drugs can exert on the visual or ocular system. The eye care practitioner can be instrumental in detecting and reporting ocular side effects, advising patients and collaborating with other members of the patient’s healthcare team. One of the difficulties include becoming familiar with the countless systemic medications prescribed to patients. Another is being able to correlate a particular side effect with a suspected drug. Several of the ocular adverse effects such as glaucoma, cataract, blurred vision, color vision, optic neuritis, maculopathy, dry eye, etc., are vision threatening and often patients fail to recognize or describe the symptoms appropriately. Therefore, physicians and paramedical members like staff nurses, clinical pharmacists and other members must make adequate observations while recommending these drugs to patients.

Determination of Optic Axes by Corneal Topography among Italian, Brazilian, and Chinese Populations

This study aims to describe a new universal method to identify the relative three-dimensional directions of visual, pupillary, and optical axes of the eye and the angles between them using topography elevation data. The method was validated in a large clinical cohort, and ethnical differences were recorded. Topography elevation data were collected from 1992 normal eyes of 966 healthy participants in Italy, Brazil, and China. The three main axes were defined as follows: optical axis (OA) was defined as the optimal path of light that passes through the ocular system without refraction. The pupillary axis (PA) line was defined using X and Y coordinates of the pupil centre with the chamber depth, in addition to the centre of a sphere fitted to the central 3 mm diameter of the cornea. The visual axis (VA) was taken by its best approximation, the coaxially sighted corneal light reflex. The alpha angle was measured between the VA and OA, and the kappa angle between the VA and PA. The average values of kappa and alpha angles were 3.41 ± 2.84 and 6.04 ± 2.43 in the Italian population, 2.6 ± 1.53 and 5.87 ± 2.3 in the Brazilian population, and 2.09 ± 1.22 and 3.85 ± 1.48 in the Chinese population.

Synergic Effect of Novel WS2 Carriers Holding Spherical Cobalt Ferrite @cubic Fe3O4 (WS2/s-CoFe2O4@c-Fe3O4) Nanocomposites in Magnetic Resonance Imaging and Photothermal Therapy for Ocular Treatments and Investigation of Corneal Endothelial Cell Migration

The design of novel materials to use simultaneously in an ocular system for driven therapeutics and wound healing is still challenging. Here, we produced nanocomposites of tungsten disulfide carriers with spherical cobalt ferrite nanoparticles (NPs) as core inside a cubic iron oxide NPs shell (WS2/s-CoFe2O4@c-Fe3O4). Transmission electron microscopy (TEM) confirmed that 10 nm s-CoFe2O4@c-Fe3O4 NPs were attached on the WS2 sheet surfaces. The cytotoxicity of the WS2 sheets and nanocomposites were evaluated on bovine cornea endothelial cells (BCECs) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for a duration of three days. The MTT assay results showed low toxicity of the WS2 sheets on BCECs by 67% cell viability at 100 μg/mL in 24 h, while the nanocomposites show 50% cell viability in the same conditions. The magnetic resonance imaging (MRI) of nanocomposites revealed the excellent T2-weighted imaging with an r2 contrast of 108 mM−1 S−1. The in vitro photothermal therapy based on WS2 sheets and WS2/s-CoFe2O4 @c-Fe3O4 nanocomposites using 808 nm laser showed that the maximum thermal energy dispatched in medium at different applied power densities (1200 mw, 1800, 2200, 2600 mW) was for 0.1 mg/mL of the sample solution. The migration assay of BCECs showed that the wound healing was approximately 20% slower for the cell exposed by nanocomposites compared with the control (no exposed BCECs). We believe that WS2/s-CoFe2O4@c-Fe3O4 nanocomposites have a synergic effect as photothermal therapy agents for eye diseases and could be a target in an ocular system using MRI.