Huvitz HRK-8000A, Руководство по обслуживанию

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62 Auto Ref/Keratometer HRK-8000A ------------------------------------------------------------------------------------------------
6. Technical Materials
(1) Fogging Method
It is recommended that the refractive power of eye is measured when it is in the hyperopia-state.
There happens some measurement error called mechanic myopia due to the accommodation of
eye when it is measured by locating the internal eye-fixing target to the position corresponding
to the eyesight of examinee.
Foggy method is the method that the size of the target is modified to be greater than the
eyesight of the examinee by +1D ~ +2D in order to reduce the error caused by this
accommodation. There is also another method called accommodation paralysis method.
Mechanic myopia occurs more easily in the case of the youth. Additionally, the accommodation
of eye is one of the functions of the eye. It controls the thickness of crystalline lens according to
the movement of the ciliary body and changes the refractive power of crystalline lens.