Open Access Systematic Review Article

Ethambutol Effect on Retinal and Optic Nerve Structural Changes in Toxic Optic Neuropathy Case: A Literature Review

Itzar Chaidir Islam, Batari Todja Umar, Rahmawati Minhajat, Agussalim Bukhari, Dwi Kesuma Sari, Cahyono Kaelan

Ophthalmology Research: An International Journal, Page 26-36
DOI: 10.9734/or/2022/v16i330237

Introduction: Ethambutol (EMB) is one of the first-line antituberculosis drugs that reported to cause toxic effects on the eye structure. This study aims to elucidate the histological mechanism of retinal and optic nerve damage in toxic optic neuropathy cases.

Reference Sources: The literature search was conducted in the PUBMED and MEDLINE databases using the latest publication of the 2012-2022 series.

Studies Selection: The observational and randomized controlled trial studies analyzing the effect of ethambutol on retinal nerve fiber layer, retinal ganglion layer, inner cell plexiform layer thickness, optic nerve tissue, best-corrected visual acuity (BCVA), color perception, visual evoked response, and patients' visual field were included.

Data Extraction Method: Articles that met the inclusion criteria underwent a specific evaluation, whereby the main focus was the ethambutol on retinal and optic nerve tissue.

Results: The results showed that ethambutol affects the thinning of the Retinal Nerve Fiber Layer (RNFL), decreasing the amount of Ganglion Cells and changing the optic nerve's histological function by damaging the mitochondria and axonal fiber.

Conclusion: It was concluded that ethambutol has adverse effects on retinal and optic nerve tissue due to several mechanisms and significantly affects the patient's visual outcome.

Open Access Case study

Central Retinal Vein Occlusion Secondary to Paroxysmal Nocturnal Hemoglobinuria

Thiago Sande Miguel, Ermes Rodrigues Machado Filho, Bruna Sande Miguel, Daniel Almeida da Costa, Maurício Bastos Pereira

Ophthalmology Research: An International Journal, Page 1-7
DOI: 10.9734/or/2022/v16i330234

Aims: To describe a Central Retinal Vein Occlusion Secondary to Paroxysmal Nocturnal Hemoglobinuria.

Presentation of Case: A 25 years old, male, student, in regular follow-up in the Hematology sector due to Paroxysmal Nocturnal Hemoglobinuria in regular use of Eculizumab. He reports a month ago that he suddenly noticed, upon waking up in the morning, blurring and decreased visual acuity in her left eye.

Discussion: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder characterized by hemolysis, thrombosis, and bone marrow failure caused by defective expression of glycosylphosphatidylinositol-anchored (GPI-anchored) complement inhibitors. Most commonly, PNH is caused by the loss of PIGA function, which is necessary for GPI biosynthesis.

Conclusions: Patients with hemolytic anemia, unexplained thrombosis, especially in uncommon sites, cytopenias and bone marrow failure syndromes, dysphagia, and unexplained abdominal pain should be screened for PNH. PNH patients can benefit greatly from the treatments available, with a reduction in the risk of serious sequelae and a considerable improvement in their quality of life. So that the patient continues to be followed up in the ophthalmology department, with decreased visual acuity ipsilateral to the lesion, with a relative afferent pupillary defect on that side.

Open Access Original Research Article

Oculo-visual Assessment of Children and Adolescents with Special Needs in Selected Schools within IMO State, Nigeria

Chioma Lilian Owunna, Chigozie John Ekenze, Ifeoma Kate Okorie, Augustine Ugochukwu Akujobi, Jacqueline E. Obioma-Elemba, Oyinyechi Lilian Umunnakwe, Mamzhi Seljul Crown Ramyil, Timothy Olugbenga Ogundeko

Ophthalmology Research: An International Journal, Page 8-19
DOI: 10.9734/or/2022/v16i330235

Aim: This was a cross-sectional study conducted to assess the oculo-visual status of children with special needs in three selected special schools in Imo State, Nigeria.

Children with special needs are at a higher risk of visual impairment as compared to normal population. Interestingly, majority of the ocular disorders are treatable.

Methodology: The study was conducted on children ages 5-25years (mean 12.0 ± 3.2 years) and detailed ocular examination on 296 children using standard examination techniques was recorded. Results: Results revealed that oculo-visual disorders were seen in 196 (66.2%) children. Oculo-visual disorders were found in 75.5% of children with hearing impairment, 83.3% in children with cerebral palsy, 75% in children with autism, 85.7% in children with Down syndrome, 38.6% in children with speech disability, and 64% in children who are deaf and dumb. The most common ocular disorders seen in these children were refractive errors (30.5%), strabismus (12.7%), amblyopia (8.9%) and cataract (7.7%). Children requiring further evaluation were referred to base hospitals in Imo State, Nigeria.

Conclusion: Oculo-visual problem is highly prevalent among children with special needs in Imo State, most commonly, the problems were refractive errors, strabismus, amblyopia, cataract and cornea disorders. The prevalence was predominant among the female teenagers (15-19years). Government and stakeholders in the health care and humanitarian sectors should place more priority on the ocular-health status of children with special needs.

Open Access Original Research Article

Evaluation of Visual Acuity among Commercial Motorcyclists (Okada Riders) in the Main Campus of Abia State University Uturu Abia State Nigeria

C. D. Ubani, A. K. Amah, Cosmas Chidozie Ofoegbu, Chijioke, I. Ugboaja

Ophthalmology Research: An International Journal, Page 20-25
DOI: 10.9734/or/2022/v16i330236

The visual ability of road users is fundamental to traffic safety. Despite the high burden of traffic crashes and associated mortality in low-income countries such as Nigeria, evidence for an association between vision function and traffic safety outcomes is scarce. Therefore, the aim of this work was to evaluate the visual acuity of commercial motorcyclists operating within the main campus of Abia State University, Uturu. Two hundred operators who had been on the job for at least one year constituted the test population, while staff and students of Abia State University, Uturu, who were sex and aged-matched and who are not commercial motor cyclists constituted the control group. Data were obtained with the aid of a structured questionnaire and clinical examinations were carried out by standard procedures. Results showed that Snellen’s fraction which is a indicator of visual acuity for the left eye of control and test groups  was recorded as 0.98+- 0.30 and 0.88+- 0.35 respectively and for the right eyes 0.99+- 0.10 and 0.87+- 0.50 respectively. Only 38% of test group had normal visual acuity of 6/6 compared to 73% of control. Visual acuity correlated negatively with age for the left (r = - 0.712) and right (r = - 0.740) eyes as well as with length of service for left (r = -0.623 and right (r = - 0.632) eyes of motorcyclist operators. In conclusion, visual acuity was inversely proportional to age and length of service.   

Open Access Original Research Article

Efficacy Analysis of Corneal Photo-vitrification (CPV) for Improved Vision of Age-related Macular Degeneration (AMD) Eyes

Jui-Teng Lin, Michael Berry

Ophthalmology Research: An International Journal, Page 37-48
DOI: 10.9734/or/2022/v16i330238

Purpose: To analyze the safety and efficacy of corneal photovitrification (CPV) for improved visions of age-related macular degeneration (AMD) eyes.

Study Design: Using CPV for improved visions of AMD eyes.

Place and Duration of Study: New Taipei City, Taiwan, and Austin, TX, USA; between April, 2022 and June, 2022.

Methodology: The CPV efficacy is calculated based on the rate equation given by dM/dt=-k(t) M(t), where M(t) is the PCV-treated corneal stroma; and k(t) is the rate coefficient given by an Arrhenius formula, k(t) = A0 exp[−Ea/(RT(t,z)], where t and z are the laser irradiation time and depth of the cornea stroma; Ea  is the activation energy and R is the gas constant. The temperature spatial and temporal profiles are given by the numerical solutions of a heat diffusion equation with a volume heating source. Various effective depths including the tissue damage depth, temperature penetration depth and conversion depth, governed by the tissue absorption coefficient, light intensity and dose (or irradiation time), and the related threshold values, are introduced in replacing the conventional penetration depth based on a Beer's law.

Results: The suggested protocol for CPV treatments include: a diode laser at about 2 µm wavelength (with absorption coefficient about 100 cm-1). The laser dose is about 25 J/cm2/spot and irradiation time of 150 ms.

Conclusion: The efficacy of CPV may be predicted/calculated by our modeling based on rate equation and the corneal stroma temperature rise due to laser heating. The preferred retinal locus (PRL) movement observed post-CPV is caused mainly by neuroadaptation.