Efficacy of Neuro-Optometric visual rehabilitation in Homonymous Hemianopia.

OBJECTIVES: To assess oculomotor dysfunction and the effectiveness of neuro-optometric visual rehabilitation in improving oculomotor parameters in participants with homonymous hemianopia. MATERIALS AND METHODS: Fifty subjects diagnosed with homonymous hemianopia (HH), referred through the neuro-ophthalmology department, were recruited for the study. All the subjects underwent a detailed neuro-optometric evaluation that included testing for sensory, visuo-motor and oculomotor functions. Subjects with homonymous hemianopia were then prescribed with yoked prisms and were randomized to two treatments at one month, namely group 1: yoked prisms (n = 15) and group 2: yoked prisms with in-office visual search training (n = 15). RESULTS: The mean ± SD age of the subjects was 46 ± 12 years. Subjects with HH exhibited a significant delay in the completion time, response and accuracy of tasks on proactive, saccadic and visual search parameters using the SVI compared to age-matched controls (Independent t-test, p < 0.05). A significant improvement in the reading speed and visual search parameters (RM ANOVA, p < 0.001) was seen post neuro-optometric visual rehabilitation with both yoked prisms and SVI. Statistically significant differences were observed in the reaction time of the visual search paradigms between the two rehabilitative modalities yoked (group1), yoked and SVI (group2) (Mann-Whitney U test, p < 0.001), with the group 2 showing better visual search performance outcomes compared to group 1 (yoked). CONCLUSION: Visual search parameters among participants with homonymous hemianopia improved following combined rehabilitation (yoked prisms and visual search trainng).

Prevalence of primary mutations in Leber hereditary optic neuropathy: A five-year report from a tertiary eye care center in India.

PURPOSE: Genetic testing for primary mutations m.3460G>A, m.11778G>A, and m.14484T>C in ND1, ND4, and ND6 genes of mitochondrial DNA is the recommended assay for Leber hereditary optic neuropathy (LHON; OMIM 535000). This report discusses the outcome of molecular genetic screening for these three primary mutations in suspected LHON cases in India. METHODS: Two hundred and seventy-eight unrelated presumed LHON patients who were seen at the neuro-ophthalmology clinic of a tertiary eye care center from 2014-2018 were analyzed. They were genotyped for the three common variants by polymerase chain reaction-based direct sequencing, and their plasmy status was also determined by restriction enzyme digestion. RESULTS: Eighty two of 278 patients were positive for one of the 3 common mutations with m.11778G>A in ND4 gene more frequently distributed (N=72) in homoplasmic state (N=59/82). The mean onset age of visual loss was 21.1years (SD, 9.8 years; range, 5-58 years) in patients harboring the primary mutation. The most common clinical presentation was bilateral sequential painless vision loss with central and cecocentral scotomas in the visual field due to optic disc atrophy. CONCLUSIONS: The study subjects are a sample of a much larger number of suspected LHON cases tested for primary mutations in India. (N= 278) and 29.4% (82/278) of patients harbour one of the 3 common mutations. Screening the entire mitochondrial genome and the other nuclear genes encoding mitochondrial protein, would probably aid in identifying the other less common mtDNA mutations causing LHON in Indian population.

Leber hereditary optic neuropathy-new insights and old challenges.

Leber hereditary optic neuropathy (LHON) is the most common primary mitochondrial DNA (mtDNA) disorder with the majority of patients harboring one of three primary mtDNA point mutations, namely, m.3460G>A (MTND1), m.11778G>A (MTND4), and m.14484T>C (MTND6). LHON is characterized by bilateral subacute loss of vision due to the preferential loss of retinal ganglion cells (RGCs) within the inner retina, resulting in optic nerve degeneration. This review describes the clinical features associated with mtDNA LHON mutations and recent insights gained into the disease mechanisms contributing to RGC loss in this mitochondrial disorder. Although treatment options remain limited, LHON research has now entered an active translational phase with ongoing clinical trials, including gene therapy to correct the underlying pathogenic mtDNA mutation.

Epigenetic regulation of the nuclear genome associated with mitochondrial dysfunction in Leber's hereditary optic neuropathy (LHON).

Leber's hereditary optic neuropathy (LHON) is a mitochondrial hereditary disease in which visual loss affects complex 1 activity of the electron transport chain of mitochondria. It first manifests as painless dulling or blurry in one or even both eyes, and as it develops, sharpness and color perception are lost. In addition to primary mitochondrial DNA (mtDNA) mutations, there are also other environmental and epigenetic factors involved in the pathogenesis of LHON. One of the most common locations for deadly pathogenic mutations in humans is the human complex I accessory NDUFS4 subunit gene. The iron-sulfur clusters of the electron input domain were distorted in the absence of NDUFS4, which reduced complex I function and elevated the production of reactive oxygen species. Therefore, here, we studied the epigenetic alterations of NDUFS4 by focusing on histone activation and repressive markers. We isolated peripheral blood mononuclear cells (PBMCs) from LHON patients and healthy individuals and examined epigenetic modifications in ND4 mutant cells and control cells. Chromatin immunoprecipitation-qRT PCR (ChIP-qRT PCR) assays were performed to investigate the modifications of histones. In comparison to their controls, both LHON patients and ND4 mutant cells exhibited a significant enrichment in activation and repressive markers. This finding indicates that these modifications might mitigate the impact of LHON mutations on complex 1 and aid in elucidating the mechanism underlying the progression of LHON disease.

Changes in visual acuity using low vision devices in patients with Leber hereditary optic neuropathy: A retrospective study.

Purpose: This study was conducted to estimate the visual acuity improvement in patients with Leber hereditary optic neuropathy (LHON) with the help of low vision devices (LVDs) and to analyze the types of distant and near LVDs prescribed to the patients with LHON. Methods: A retrospective case review of 74 subjects with LHON who were referred to a low vision care clinic at a tertiary eye center from 2016 to 2019 were recruited. The reason for referral was assessed from the patients' electronic medical records (EMR). Demographic data of the patients, visual acuity status, type of LVD prescribed, and visual acuity improvement with LVD were documented. Results: Out of 74 patients, 91.9% (n = 68) were male, and the median age of patients was 21 (16) years. A 4× monocular telescope was prescribed for 2.7% of patients (n = 2) and SEETV binocular telescope for 1.4% (n = 1) was advised for distance. The most commonly prescribed near LVD was the 6× cutaway stand magnifier for 22 patients (29.7%). Four patients (5.4%) were prescribed with Notex, the most commonly prescribed non-optical LVD. Niki CCTV (12.2%, n=9) was the most commonly prescribed assistive device. The subjects were divided into three groups based on age: group I consisted of those <18 years of age, group II 18-40 years, and group III >40 years for the interpretation of visual improvement. There was a statistically significant improvement (group I: P < 0.001, group II: P < 0.0001, group III: P < 0.003) in near vision with help of LVDs in all three groups. Conclusion: The use of LVDs and rehabilitation can help patients with LHON to lead a better life and will be more beneficial.

Reading eye movements in traumatic brain injury.

PURPOSE: The aim of this study was to measure the reading eye movements in subjects with traumatic brain injury (TBI) using ReadAlyzer. ReadAlyzer is an objective eye movement recording device that tracks the eye movements while reading. METHODS: Reading eye movements were measured using ReadAlyzer in 30 subjects with TBI (mild, moderate and severe) who had binocular vision and reading related symptoms and 60 asymptomatic controls. RESULTS: There was a significant decrease in reading eye movement parameters in subjects with TBI compared to controls. Reading eye movement parameters are represented in median and interquartile range (IQR). Subjects with TBI presented with an increased number of fixations/100 words (median 137, IQR 106-159) and regressions/100 words (24, 12-36), and reduced reading rate (154, 128-173) words per minute. They also had a lesser grade level equivalent (4.0, 3.0-7.0) and reduced comprehension (70, 60-80) percentage compared to controls (Mann-Whitney U test, p<0.05). Reading eye movement parameters were also significantly affected in mild and moderate-severe TBI subjects compared to controls (Kruskal-Wallis test, p<0.05). CONCLUSION: Reading eye movement performance using ReadAlyzer was found to be decreased in traumatic brain injury. Reading assessment may serve as a clinical measure to understand the oculomotor system following TBI.

Bilateral optic neuropathy with central diabetes insipidus in a child.

Central nervous system germ cell tumors are rare and they occur in the first two decades of life.[1] Optic nerve germinomas can sometimes mimic optic nerve inflammation.[2] In this case report, we discuss an 11-year-old girl who presented with features of presumed bilateral optic neuritis and developed polyuria and polydipsia, subsequently she was diagnosed to have infiltrative etiology. Her clinical and radiological presentations were initially consistent with inflammatory optic neuropathy. Poor visual recovery to steroid therapy and progressive visual loss warranted the need for optic nerve biopsy which revealed germinoma.

Idiopathic intracranial hypertension associated with anaemia, secondary to antiretroviral drug in a human immunodeficiency virus positive patient.

Papilledema in a patient with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome is an alarming finding. Any condition giving rise to raised intracranial tension (ICT) can cause papilledema, and in these patients, it could be secondary to opportunistic infections like meningitis to neoplasm. We report a case of a 28-year old female with HIV on antiretroviral therapy, who presented to us, with papilledema. Her fundus examination revealed superficial hemorrhages and Roth's spots along with papilledema. Patient was diagnosed with idiopathic intracranial hypertension (IIH), and all other possible systemic associations were ruled out. Her blood tests showed severe anemia. The papilledema and retinal changes resolved with treatment of anemia. This is a rare presentation of IIH in HIV positive patient due to anemia, secondary to zidovudine adverse effect.

Spheniodal mucocele causing bilateral optic neuropathy and ophthalmoplegia.

Sphenoid sinus mucocele comprises only 2% of all paranasal sinus mucoceles. In literature, there is a case report on sphenoidal mucocele causing bilateral optic neuropathy, with unilateral partial recovery and cranial nerve palsy, but we did not come across any literature with bilateral optic neuropathy and ophthalmoplegia together caused by spheno-ethmoidal mucocele. We present such a rare case of spheno-ethmoidal mucocele causing bilateral optic neuropathy and unilateral sixth nerve palsy who had postsurgery, unilateral good vision recovery, and complete resolution of sixth nerve palsy.

Isolated cortical blindness without simultaneous neurological involvement in progressive multifocal leukoencephalopathy in a patient with human immune deficiency virus infection.

BACKGROUND: This is a case report of cortical blindness in a HIV-positive patient with progressive multifocal leukoencephalopathy (PML) without any other associated neurological dysfunction. FINDINGS: Young HIV-positive patient presented to us with sudden profound visual loss. On examination and further investigation, we have diagnosed cortical blindness without any other focal neurological deficit due to PML. CONCLUSION: Our case highlights the fact that PML needs to be suspected in patients with HIV, presenting with cortical blindness even without any other focal neurological defect.