Abstract
Purpose: :
First measurements of a novel system to correlate directly morphologic changes of the crystalline lens with changes of the total wavefront due to accommodation.
Methods: :
A near-infrared OCT-device (SL-OCT, Heidelberg Engineering, Germany) was coupled with an open view aberrometer (iTrace, Tracey Technologies, USA). Both measuring paths were adjusted collinear to measure at simultaneously the wavefront of the total eye as well as the shape of the crystalline lens at different stages of accommodation. The measured part for curvatures was limited by the achieved pupil diameter. Measurements on 20 eyes of 10 emmetropic, healthy patients (age 19 to 33 years) were performed with an accommodation stimulus of zero, two and four dioptres.
Results: :
With the OCT a decrease in anterior chamber depth of 57µm per dioptre objective accommodationwas measured. Correlation of simultaneously measured change in sphere due to accommodation and change in lens thickness was 82µm per dioptre. Due to simultaneous measurement the change of higher order spherical aberrations and change in lens thickness could be determined to be -0.423µm per mm accommodative change of lens thickness.
Conclusions: :
The first ever made measurements of this novel setup show direct correlation of the lens change to real accommodation ability and not only stimulus. Furthermore the changes in wavefront can be directly correlated to direct morphologic changes of the lens during accommodation for the understanding of the process of accommodation.
Keywords: accommodation • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • aberrations