An ergonomic evaluation of lens accommodation related to visual circumstances

Abstract

This study is intended to make clear the relationships between a number of external conditions (target luminance, size, etc.), dynamic responsiveness of the lens accommodation, and microfluctuation. Further, the effects of ageing and the difference between monocular and binocular observations are examined. These studies established that age factors have a large bearing on the ability of the lens to focus on an object, as well as affecting such abilities as the responsiveness of the lens accommodation, amplitude of lens accommodation response, microfluctuation, and contraction and relaxation time. Of these accommodation functions, such factors as contraction and relaxation time clearly reflect the ease of seeing an object. Clear relationships between the amount of diopter and the ease of seeing an object were also observed. Further, it was established that a binocular observation is more responsive (velocity of contraction) than a monocular one. As to the microfluctuation, on the other hand, clear effects of age on its spectrum distribution were recognized but no definite correlations concerning the ease of seeing an object were observed.

Keywords:

• Eye
• Vision
• Lens accommodation
• VDT
• Ageing.