Simulated cup/disc ratio: a tool for ophthalmologists

Abstract

PURPOSE: To evaluate and compare the observers' ability to measure simulations of cup/disc ratios (CDR) as concentric and non-concentric circles. METHODS: In a prospective, random, and masked setting, 43 images representing the CDR spectrum from 0.2 to 0.9 for vertical and horizontal CDR measurements were developed and presented on a computer screen to 171 participants. RESULTS: There were satisfactory agreements according to the kappa coefficient (0.755 and 0.730 for horizontal and vertical cup disc ratios, respectively) and Lin's concordance correlation (R=0.88 and R=0.86 for horizontal and vertical measurements, respectively). However, very poor agreement was found for intermediate CDR values. The worst agreement occurred when the CDR was between 0.4 and 0.6 for both the horizontal and vertical values. The kappa coefficient was 0.37 and 0.39 for 0.4 CDR (horizontal and vertical, respectively), 0.39 and 0.38 for 0.5 CDR (horizontal and vertical, respectively) and 0.45 and 0.41 for 0.6 CDR (horizontal and vertical, respectively). CONCLUSION: Despite a good general agreement between the gold standard and the participants' responses, the absolute agreement for intermediate CDR values was very poor for both horizontal and vertical values.

OBJETIVO: Avaliar e comparar a habilidade de observadores em medir a razão escavação/disco (CDR) por meio de figuras esquemáticas. MÉTODOS: Em um estudo prospectivo, randomizado e mascarado, 43 imagens representado CDR horizontais e verticais entre 0,2 e 0,9 foram desenvolvidas e apresentadas em uma tela de computador para 171 participantes. RESULTADOS: Para todos os intervalos de CDR a concordância foi satisfatória para análise kappa (0,755 e 0,730 para CDR horizontais e verticais, respectivamente) e para concordância de Lin (R=0,88 e R=0,86 para medidas horizontais e verticais respectivamente). No entanto, a concordância foi fraca para valores intermediários de CDR. A pior concordância ocorreu para CDR horizontais e verticais entre 0,4 e 0,6. CONCLUSÃO: Apesar da boa concordância geral entre as respostas corretas e as respostas dadas pelos participantes, a concordância absoluta para valores intermediários de CDR mostrou-se muito fraca tanto para figuras horizontais como verticais.