Standard criterion for fluctuations of the modulation transfer function in the human eye

A. Lorente, A.M. Pons, J. Malo and J.M. Artigas
Ophthalmic and Physiological Optics, Vol. 17 3, pp 267-272 (1997)


It is well known that the modulation transfer function (MTF) characterizes the optical quality of the eye. Recently, some objective techniques have been introduced in order to measure this function in vivo. This techniques can be used to display the temporal fluctuations of the eye+compensation system and to isolate the effect of the compensation element provided that the standard fluctuations for a normal observer were known.

In this work we carry out a study of the MTF of the human eye over a long period of time to quantify the standard fluctuations of the retinal image quality. We have evaluated an MTF-based merit function on normal observers three times a day during a month. The standard deviation of these fluctuations (5%) can be chosen as an appropriate description of the behaviour of the average viewer. We have used this result to study the behaviour of a time-variying compensation element: a disposable contact lens. The study of the eye + disposable contact lens system has been carried out with four types of disposable contact lenses for one month. In spite of their general good behaviour, statistically significant differences from the standard pattern can be observed. This superimposed continuous fluctuation can be due to lens-dependent processes.

Key Words: Human modulation transfer function. Optical quality.

References: 24

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