Accuracy of Javal??s Rule in the Determination of Spectacle Astigmatism

The aging effect on corneal curvature and the validity of Javal’s rule in Hong Kong Chinese

“…The amount of corneal astigmatism in our sample was less than 2.50DC and therefore a linear relationship should be expected. Elliott et al (15) suggested no matter the original Javal's rule or Grosvenor's simplified rule is used, the accuracy in determining the spectacle astigmatism is of limited value compared to retinoscopy and autorefraction.…”

New method of quantifying corneal topographic astigmatism that corresponds with manifest refractive cylinder

“…Although the net polar value of the ORA can be described on average by Javal's rule, 12 there is variability in the ORA and its net polar value between eyes. 13 The variability in the ORA magnitude arises from 2 independent sources; that is, variability in ORA between eyes together with measurement variability (both systematic and random) of the corneal astigmatism and refractive cylinder. For a given set of eyes, the intereye variability cannot be influenced, which means that any variability in the ORA magnitude for this sample must be due to changes in the corneal parameters because the individual refractive cylinder is common to all 4.…”

Concordancia entre los valores de astigmatismo obtenidos con la ley de Javal y la refracción subjetiva.

“…Estudios previos han evaluado la relación de la ley de Javal con el astigmatismo refractivo; Elliot y colaboradores (16), en 1994, compararon el astigmatismo obtenido de las medidas queratométricas y el resultante de la refracción del subjetivo, el cual se determinó por el grado de astigmatismo medido en los anteojos de los pacientes. Ellos determinaron que la simplificación de Grosvenor a la ley de Javal era más acertada en la predicción del astigmatismo resultante; sin embargo, solo el 66 % de los valores mostró diferencias de 0,50 D, en comparación entre los dos datos (17).…”