The Photopic Negative Response: An Objective Measure of Retinal Ganglion Cell Function in Patients With Leber's Hereditary Optic Neuropathy

Purpose: The photopic negative response (PhNR) is a slow negative component of a flash photopic full-field ERG that has been shown to be specific for retinal ganglion cell (RGC) activity. Direct evaluation of RGC function is desirable in patients with Leber's hereditary optic neuropathy (LHON) in which the loss of central acuity can make it difficult to monitor patients with standard metrics. The purpose of this study was to evaluate the use of PhNR as an objective noninvasive clinical metric in LHON.Methods: Full-field photopic ERG recordings were collected in subjects with the mt.11778G>A/ND4 LHON mutation using a red on blue stimulus. The PhNR was identified using a computer-based automated detection system, and data were manually examined to remove movement artifacts.Results: The PhNR amplitude was compared between controls (n = 13), carriers (n = 17), and affected (n = 6). Mean PhNR amplitude decreased significantly across groups (P < 0.0001). Post hoc Tukey's test revealed a significant decrease in PhNR amplitude between carriers and controls (P < 0.05) and between carriers and affected (P < 0.01).Conclusions: We are able to demonstrate that the PhNR amplitude is significantly decreased in patients affected by LHON compared to carriers in a well-described pedigree. Surprisingly, there was also a decrease in PhNR in carriers, suggesting potential subclinical RGC dysfunction in some carriers. This is important in patients affected with LHON who typically have a dense central scotoma. The PhNR may be a useful objective outcome measure for future clinical trials

Grating acuity deficit, interocular difference and maturation in children with cerebral visual impairment

Determinar o deficit, a diferenca interocular e a maturacao da acuidade visual de resolucao de grades em criancas com defiCiência visual cerebral, correlacionando o deficit com sexo, faixa etaria, etiologia, uso de medicamento anticonvulsivante, inclusao em programa de reabilitacao, resultado da fundoscopia e estado da motilidade extrinseca ocular. Metodos: Este estudo observacional descritivo transversal retrospectivo incluiu 245 criancas com defiCiência visual cerebral referidas para medida da acuidade visual de resolucao de grades pelo potencial visual evocado de varredura. O deficit de acuidade visual de resolucao de grades foi calculado subtraindo-se o resultado de melhor acuidade visual, obtido monocularmente ou binocularmente, da media normal para a idade corrigida do paciente e foi classificado como leve (0,2 &#8804; deficit < 0,4 logMAR), moderado (0,4 &#8804; deficit < 0,9 logMAR) ou grave (deficit &#8805; 0,9 logMAR). A maxima diferenca interocular de acuidade visual considerada aceitavel foi de 0,1 logMAR. A etapa observacional descritiva de coorte retrospectiva incluiu 22 criancas avaliadas em no minimo tres visitas. A maturacao da acuidade visual determinada por regressao linear pela inclinacao da reta ajustada que descreve a acuidade visual (em logMAR) em funcao da idade corrigida (em log de semanas). O nivel de significancia estatistica foi considerado como P&#8804;0,05. Resultados: Do total, 146 criancas eram do sexo masculino (59,59%) e 99 do sexo feminino (40,41%), com idades variando de 1,15 a 166,54 meses (media=31,05 ± 29,20 meses; mediana=19,10 meses). O deficit de acuidade visual de resolucao de grades variou de 0,17 a 1,44 logMAR (media=0,73 ± 0,29 logMAR; mediana=0,72 logMAR), e foi considerado moderado em 53,47% dos casos, grave em 30,20% e leve em 16,33%. O deficit foi significantemente maior no sexo masculino (P=0,023), nas criancas avaliadas a partir do segundo ano de vida (P<0,001), nos usuarios de medicamento anticonvulsivante (P<0,001), na presenca de palidez de papila leve (P=0,0147) e de estrabismo associado a nistagmo (P=0,0366). Nao houve diferenca estatisticamente significante entre o deficit das criancas agrupadas por etiologia e inclusao em programa de reabilitacao. A diferenca interocular de acuidade visual de grades foi calculada em 180 (73,47%) criancas, variando de 0 a 0,66 logMAR (media=0,08 ± 0,10 logMAR ; mediana=0,05 logMAR) e foi significantemente maior para a condicao de estrabismo associado a nistagmo (P=0,0088). Na etapa longitudinal, o deficit final foi significantemente maior quando comparado ao inicial (P=0,0069) e a taxa media de maturacao foi de -0,19 logMAR/log semanas. Conclusoes: O deficit de acuidade visual de resolucao de grades na defiCiência visual cerebral foi moderado ou grave em 83,67% das criancas. A diferenca interocular de acuidade visual foi normal em 79,44% dos casos estudados. A taxa media de maturacao visual foi lentificada, quando comparada aos dados normativosBV UNIFESP: Teses e dissertaçõe

Contributing factors to VEP grating acuity deficit and inter-ocular acuity difference in children with cerebral visual impairment

To investigate contributing factors to visual evoked potential (VEP) grating acuity deficit (GAD) and inter-ocular acuity difference (IAD) measured by sweep-VEPs in children with cerebral visual impairment (CVI).VEP GAD was calculated for the better acuity eye by subtracting acuity thresholds from mean normal VEP grating acuity according to norms from our own laboratory. Deficits were categorized as mild (0.17 a parts per thousand currency sign deficit < 0.40 log units), moderate (0.40 a parts per thousand currency sign deficit < 0.70 log units) or severe (deficit a parts per thousand yen0.70 log units). Maximum acceptable IAD was 0.10 log units.A group of 115 children (66 males-57 %) with ages ranging from 1.2 to 166.5 months (median = 17.7) was examined. VEP GAD ranged from 0.17 to 1.28 log units (mean = 0.68 +/- A 0.27; median = 0.71), and it was mild in 23 (20 %) children, moderate in 32 (28 %) and severe in 60 (52 %). Severe deficit was significantly associated with older age and anti-seizure drug therapy. IAD ranged from 0 to 0.49 log units (mean = 0.06 +/- A 0.08; median = 0.04) and was acceptable in 96 (83 %) children. Children with strabismus and nystagmus had IAD significantly larger compared to children with orthoposition.In a large cohort of children with CVI, variable severity of VEP GAD was found, with more than half of the children with severe deficits. Older children and those under anti-seizure therapy were at higher risk for larger deficits. Strabismus and nystagmus provided larger IADs. These results should be taken into account on the clinical management of children with this leading cause of bilateral visual impairment.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Escola Paulista Med, Dept Oftalmol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Oftalmol, BR-04023062 São Paulo, BrazilWeb of Scienc

Study Design and Methods for a Population-based Study on the Prevalence and Causes of Distance and Near Vision Impairment and Blindness in Parintins City: The Brazilian Amazon Region Eye Survey (BARES)

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPq, Brasilia, Brasil [402120/2012-4]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, FAPESP, Sao Paulo, Brasil [2013/16397-7]Sight First Program - Lions Club International Foundation [1758]Univ Fed Sao Paulo, Oftalmol & Ciencias Visuais, Sao Paulo, BrazilUniv La Frontera, Salud Publ, Temuco, ChileFac Med Ribeirao Preto USP, Oftalmol Otorrinolaringol & Cirurgia Cabeca & Pes, Ribeirao Preto, BrazilUniv Fed Amazonas, Dept Cirurgia, Div Oftalmol, Manaus, Amazonas, BrazilInst Olhos Manaus, Manaus, Amazonas, BrazilUniv Fed Sao Paulo, Oftalmol & Ciencias Visuais, Sao Paulo, BrazilCNPq:402120/2012-4FAPESP: 2013/16397-7Sight First Program: 1758Web of Scienc