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Journal of Optometry Volume 5, Issue 2, April–June 2012, Pages 75-79 open access

Original article

Subjective method of refractometry and depth of focus Método subjetivo de refractometría y profundidad de foco Nikolai M. Sergienko, Anastasia Gromova, Nikolai Sergienko Show more http://doi.org/10.1016/j.optom.2012.02.006

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Open Access funded by Spanish General Council of Optometry Under a Creative Commons license

Abstract Purpose To study the impact of the depth of focus on subjective refraction and distribution of myopic and hyperopic refractions. Methods A total of 450 eyes of 305 subjects in the age range of 23–34 years were recruited for the study. A distribution of refractions was examined using a traditional method of the subjective refractometry on the basis of point-like posterior focus notion. Correction of the results was made on the assumption that the emmetropic eye retains high visual acuity when applying convex lenses with values which are fewer or equal to the depth of focus values. The following values of the depth of focus were used: ±0.55 D, ±0.35 D and ±0.2 D for visual acuity 1.0, 1.5 and 2.0, respectively. Results Application of the traditional method of refractometry produced the following occurrence of refractions: hypermetropia 59.3%, myopia 22% and emmetropia 18.7%. After correction of the initial results of values of the depth of focus the distribution of refractions was as follows: hypermetropia 12.7%, myopia 22% and emmetropia 65.3%. Conclusion The traditional method of subjective refractometry with application of trial lenses was developed on the basis of data of large optical aberrations and significant depth of focus which values should be taken into account during interpretation of results of subjective refractometry. Our data regarding to prevalence of emmetropic refraction falls in line with basic science provisions in respect of the physiology of the eye.

Resumen Objetivo Estudiar el efecto de la profundidad de foco en la refracción subjetiva y la distribución de los estados refractivos miópicos e hipermetrópicos. Métodos Para el estudio se incluyeron 450 ojos de 305 sujetos con un intervalo de edad de 23 a 34 años. Se examinó la distribución de estados refractivos utilizando un método tradicional de refractometría subjetiva sobre la base de la noción de foco posterior en forma de puntos. La corrección de los resultados se realizó asumiendo que el ojo emétrope conserva una alta agudeza visual al aplicar lentes convexas con valores inferiores o equivalentes a los valores de profundidad de foco. Se utilizaron los valores de profundidad de foco siguientes: ±0,55 D, ±0,35 D y ±0,2 D para una agudeza visual de 1,0, 1,5 y 2,0 respectivamente. Resultados La aplicación del método de refractometría tradicional produjo la incidencia de refracciones siguiente: hipermetropía 59,3%, miopía 22% y emetropía 18,7%. Tras la corrección de los primeros resultados de valores de profundidad de foco, la distribución de refracciones fue la siguiente: hipermetropía 12,7%, miopía 22% y emetropía 65,3%. Conclusión El método tradicional de refractometría subjetiva con la aplicación de lentes de prueba se desarrolló basándose en datos de altas aberraciones ópticas y una profundidad de foco significativa, valores que deberían tenerse en cuenta a la hora de interpretar los resultados de refractometría subjetiva. Nuestros datos relativos a la prevalencia de refracción emétrope coinciden con las previsiones científicas básicas respecto a la fisiología del ojo.

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Keywords Refaractometry; Depth of field; Depth of focus; Pseudoaccommodation

Palabras clave Refractometría; Profundidad de campo; Profundidad de foco; pseudoacomodación

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Copyright © 2011 Spanish General Council of Optometry. Published by Elsevier España S.L.

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Subjective method of refractometry and depth of focus - ScienceDirect

Journals Download Books Register Sign in Export Journal of Optometry Volume 5, Issue 2, April–June 2012, Pages 75-79 open access Original ar...

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