Avaliação da integridade da via visual e medida objetiva da acuidade visual de resolução de grades pelos potenciais visuais evocados de varredura na baixa de visão inexplicada

• Ano de defesa: 2021
• Autor(a) principal: Soares, Tarciana De Souza [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Adults; Visual Evoked Potentials; Visual Acuity; Simulation Of Illness; Exacerbation Of Symptoms; Visual Pathways; Adultos; Potenciais Evocados Visuais; Acuidade Visual; Simulação De Doença; Exacerbação De Sintomas; Vias Visuais
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=11168721; https://repositorio.unifesp.br/handle/11600/68319

Objective: To investigate the diagnostic contribution of objectively measured grating visual acuity (GVA) by sweep visual evoked potentials (SVEP) along with visual pathway integrity assessed by pattern-reversal visual evoked potentials (PRVEP) in cases suspected of unexplained visual loss (UVL). Methods: This was a retrospective case-control study that included adult patients under suspicion of UVL and controls submitted to electrophysiological evaluation. Optotype visual acuity (OVA) was measured by an ETDRS 4-meter chart and grating visual acuity (GVA) by SVEP. UVL patients were assigned into three distinctive categories, according to the presence of ocular disease and motivation, as follows: exaggerators, malingerers and psychogenic. Two groups of healthy controls (one for PRVEP and other for SVEP) were tested. Receiver operating characteristic (ROC) curve was constructed both to determine the best cutoff to identify UVL cases and to compute its sensitivity/specificity. Results: A total of 76 patients [39 (51.3%) females] with UVL were analyzed. UVL group comprised 60 (79.0%) exaggerators, 11 (14.4%) malingerers and 5 (6.6%) with psychogenic visual loss. Controls were 49 subjects evaluated for PRVEP [28 (57.1%) females] and 28 subjects for SVEP [18 (64.3%) females]. Diferences between optotype and grating acuities≥ 1.0 logMAR were found in 39 (51,3%) UVL patients. The mean difference between OVA and GVA was 1.02±0.64 (median=0.84; 95% CI: 0.91 to 1.14) in UVL patients (n=118 eyes). The area under ROC (AUC) for GVA to diagnose UVL was 0.997 with a cutoff of 0.09 logMAR showing specificity of 100.0 % and sensitivity of 96.1 % to the eye with higher discrepancy between the two measured acuities. In Dunn's multiple comparison test exaggerators had significantly worse GVA, PRVEP latency and amplitude when compared to malingering, psychogenic and controls. Conclusion: Grating acuity objectively measured by sweep visually evoked potentials contributed to the diagnosis of unexplained visual loss in adults, with clinical validity showing high sensitivity and specificity. The assessment of the visual pathway integrity by pattern-reversal visual evoked potentials complemented grating acuity measurement. Both electrophysiological tests should be considered as useful tools in the diagnosis of unexplained visual loss.