Noninvasive Imaging and Measurement of Accommodation Using Dual-Channel SD-OCT

Abstract

SD-OCT, via extended imaging depth through a dual-channel, dual-focus approach, is a feasible and practical modality for noninvasive imaging and measurement of ocular accommodation.

Non-invasive measurements of the dynamic changes in the ciliary muscle, crystalline lens morphology, and anterior chamber during accommodation with a high-resolution OCT

“…The results obtained in the present study are in agreement with those obtained previously [20,22]. One of them used a Scheimpflug camera to measure changes in shape of the crystalline lens during accommodation [20].…”

“…The results obtained in this study show the same tendency as those obtained previously [1,4,[22][23][24], in which the lens thickness increased with vergence. At the same time, it has been reported that the posterior lens surface might move backwards with accommodation, because the increase in lens thickness with accommodation is higher than the decrease in the ACD [20].…”

“…These results reflect that the ALRC is expected to decrease about 11 % per diopter of vergence. From a physiological point of view, the reduction in the ALRC is necessary to increase the refractive power of the crystalline lens [22], and, hence, change the eye focus to near vision.…”

“…According to the results obtained, the anterior and posterior radius of the lens decreased with the accommodation, in which the anterior lens surface becomes more hyperbolic. The other study [22], used a custom build and dual-focus spectral domain OCT to image the anterior segment of the eye from the cornea to the posterior lens surface. Regarding the crystalline lens, these authors obtained that the anterior and posterior radius of curvatures significantly decreased with accommodation.…”

Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

“…Anterior segment biometric changes during accommodation have been measured using A-scan ultrasound (US), 3,17–19 ultrasound biomicroscopy (UBM), 20,21 optical coherence tomography (OCT), 5,22 partial coherence interferometry (PCI), 4,15 Scheimpflug photography, 9 and magnetic resonance imaging (MRI). 7,8,11 A-scan US and PCI provide quantitative information about axial biometry but do not allow visualization of the anterior segment, whereas MRI, UBM, OCT, and Scheimpflug photography capture images of the anterior segment and allow both visualization and quantitative measurement of the anterior segment structures.…”