Purchase this article with an account.
ethan adre, Alex Thanhlong Pham, Keke Liu, Yu-Cherng Chang, Florence Cabot, Siobhan Williams, Giovanni Gregori, Arthur Ho, Marco Ruggeri, Jean-Marie A Parel, Fabrice Manns; Dynamics of Accommodative Changes in the Human Crystalline Lens Thickness Measured with Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2017;58(8):323.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Dynamic changes in lens thickness have been measured using ultrasonography, which requires contact with the eye and provides limited spatial resolution. The purpose is to quantify dynamics of human crystalline lens thickness with accommodation using Optical Coherence Tomography (OCT).
Four eyes from 4 subjects (Age: 26.5 ± 4.2 years) were imaged with a custom-built OCT system that enables dynamic imaging of the anterior segment during accommodation (Ruggeri et al, Biomed Opt Exp 7:1506-1520, 2012). A fixation target provides a step stimulus of accommodation that is triggered at 1.9 s after the start of an OCT image acquisition. 54 images of the eye ranging from the anterior cornea to the retina were acquired at a rate of 8.6 frames per second while the subjects responded to the step stimulus. For each subject, six dynamic OCT acquisitions were performed for step stimulus amplitudes of 1, 2, 3, 4, 5 and 6 D starting from distance vergence. Each OCT image was processed using an automated segmentation algorithm that produces measurements of lens thickness. For each eye and accommodation amplitude, the time-dependence of the lens thickness was fit with an exponential function using a non-linear least square algorithm to obtain the following parameters: peak velocity (mm/s), time constant (s), latency (s), and asymptotic lens thickness change (mm).
The dependence of each parameter on accommodative amplitude was assessed (see figure). The change in lens thickness increased with accommodation amplitude, with an average change of 0.070±0.026 mm/D. Peak velocity and time constant increased with accommodation amplitude from average values of, respectively, 0.01±0.01 mm/s and 0.17±0.10 s at 1 D to 0.16±0.07 mm/s and 0.48±0.11 s at 6 D. There was no significant trend in latency with accommodation amplitude, with average values varying from 0.24±0.07 s at 1 D to 0.31±0.04 s at 6 D. The dynamic parameters are consistent with values obtained using dynamic optical refraction (Kasthurirangan and Glasser, Vis Res, 2006).
Dynamic biometry using OCT enables characterization of the dynamics of lens accommodation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Change in lens thickness (A), peak velocity (B), time constant (C) and latency (D) as a function of accommodation demand (1 to 6 D) for the four subjects.
This PDF is available to Subscribers Only