RESUMEN
PURPOSE: Epidemiologic evaluation and investigating the causes of visual impairment in any society is a matter of concern and has a direct effect on the country's health care planning. In this study we describe causes of low vision and blindness in Iranian patients referred to rehabilitation clinics for taking vision aids. METHODS: In this cross-sectional study, visual acuity was classified based on best-corrected visual acuity in the better eye according to the World Health Organization definition (blindness, visual acuity [VA] < 20 / 400; severe visual impairment, VA < 20 / 200-20 / 400; mild to moderate visual impairment, VA < 20 / 60-20 / 200). The causes of blindness and low vision were determined using the 10th version of International Classification of Diseases based on the main cause in both eyes. To describe data, we used mean ± SD and frequency. RESULTS: The study included 432 patients, 65% male, with a mean age of 43.6 ± 25.5 years (range, 3 to 92 years). Mild to moderate visual impairment, severe visual impairment and blindness were present in 122 (28.8%), 196 (46.4%) and 105 (24.8%) of the patients, respectively. The main causes of visual impairment were retinal and choroidal diseases (74.5%), optic nerve and optic tract diseases (9.8%), vitreous and globe disorders (5.3%), congenital cataract (3.1%), and glaucoma (2.6%). The distribution pattern of the causes was similar in all age subgroups. CONCLUSIONS: Diseases of the retina and choroid are the main cause of visual impairment among patients referred to an academic visual rehabilitation clinic in Iran.
Asunto(s)
Ceguera/epidemiología , Enfermedades de la Coroides/epidemiología , Derivación y Consulta/estadística & datos numéricos , Centros de Rehabilitación/estadística & datos numéricos , Enfermedades de la Retina/epidemiología , Baja Visión/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Recursos Audiovisuales , Ceguera/rehabilitación , Niño , Preescolar , Enfermedades de la Coroides/rehabilitación , Femenino , Humanos , Irán/epidemiología , Masculino , Persona de Mediana Edad , Enfermedades del Nervio Óptico/epidemiología , Enfermedades del Nervio Óptico/rehabilitación , Enfermedades de la Retina/rehabilitación , Baja Visión/rehabilitación , Adulto JovenRESUMEN
Mitochondrial diseases in children are often associated with a peripheral neuropathy but the presence of the neuropathy is under-recognized because of the overwhelming involvement of the central nervous system (CNS). These mitochondrial neuropathies are heterogeneous in their clinical, neurophysiological, and histopathological characteristics. In this article, we provide a comprehensive review of childhood mitochondrial neuropathy. Early recognition of neuropathy may help with the identification of the mitochondrial syndrome. While it is not definite that the characteristics of the neuropathy would help in directing genetic testing without the requirement for invasive skin, muscle or liver biopsies, there appears to be some evidence for this hypothesis in Leigh syndrome, in which nuclear SURF1 mutations cause a demyelinating neuropathy and mitochondrial DNA MTATP6 mutations cause an axonal neuropathy. POLG1 mutations, especially when associated with late-onset phenotypes, appear to cause a predominantly sensory neuropathy with prominent ataxia. The identification of the peripheral neuropathy also helps to target genetic testing in the mitochondrial optic neuropathies. Although often subclinical, the peripheral neuropathy may occasionally be symptomatic and cause significant disability. Where it is symptomatic, recognition of the neuropathy will help the early institution of rehabilitative therapy. We therefore suggest that nerve conduction studies should be a part of the early evaluation of children with suspected mitochondrial disease.
Asunto(s)
ADN Polimerasa Dirigida por ADN/genética , Enfermedades Mitocondriales/diagnóstico , Enfermedades del Sistema Nervioso Periférico/diagnóstico , Niño , Análisis Mutacional de ADN , ADN Polimerasa gamma , Diagnóstico Precoz , Pruebas Genéticas , Humanos , Enfermedad de Leigh/diagnóstico , Enfermedad de Leigh/genética , Enfermedad de Leigh/rehabilitación , Proteínas de la Membrana/genética , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/rehabilitación , Proteínas Mitocondriales/genética , ATPasas de Translocación de Protón Mitocondriales/genética , Enfermedades del Nervio Óptico/diagnóstico , Enfermedades del Nervio Óptico/genética , Enfermedades del Nervio Óptico/rehabilitación , Enfermedades del Sistema Nervioso Periférico/genética , Enfermedades del Sistema Nervioso Periférico/rehabilitación , Fenotipo , Prevención SecundariaRESUMEN
This chapter deals with neuro-ophthalmological diseases at different levels of the afferent visual pathways with special regard to visual field defects, their functional impact, and their rehabilitation. The nature of these impairments and their significance for activities of daily living can be quite varied; an exact assessment of the residual function is required to determine specific rehabilitation approaches. Rehabilitation aims to compensate for the visual deficits by means of specific training and visual aids. Visual field defects in the center cause reading disability. Preconditions for reading are a sufficient size of the reading visual field or perceptual span and sufficient resolution of the retinal area used for reading. In central scotoma, as in macular or optic nerve disease, reading ability can be regained by eccentric fixation plus text magnification. In hemianopia, reading depends on the amount of sparing in the center, the side of the defect, and adaptive strategies. Field defects in the periphery cause orientation and mobility problems. In constricted fields, tactile training with a cane is indicated; in hemianopia, explorative saccadic training is effective. With the appropriate technique, rehabilitation can be very successful, and quality of life can be regained in most patients.