Abstract
Purpose:
To investigate the anterior segment dimension changes of the eye with an intraocular lens (IOL) during accommodation, which were imaged by a spectral domain optical coherence tomography (SD-OCT).
Methods:
A specifically adapted and designed SD-OCT with a long scan depth of approximately 12 mm was applied to image from the anterior surface of cornea to the posterior surface of the IOL by one snap. A model eye with known parameters was used for verification. Custom software, in the form of an automated algorithm, was developed to correct the optical distortion and to obtain the anterior segment dimensions, including central corneal thickness (CCT), anterior chamber depth (ACD) and width (ACW), pupil diameter (PD) and IOL central thickness (IOLCT). We enrolled 14 patients with monofocal IOL and 5 patients with accommodative IOL (AIOL). One eye of each patient was chosen to be imaged at both minimal and maximal accommodations. The repeatability measurements were performed on 14 eyes with monofocal IOLs at minimal accommodation. The coefficient of repeatability (CORs) and the intra-class correlation coefficient (ICC) was calculated to evaluate the repeatability.
Results:
The SD-OCT measured anterior segment dimensions for a model eye with a fluorosilicone acrylates cornea and a polymethyl methacrylate IOL matched well with its known parameters. Repeated measurements of each parameter did not differ significantly (P > 0.05). The SD of the differences between two measurements for CCT, ACD, ACW, PD and IOLCT were 6 μm, 14 μm, 201 μm, 220 μm, and 30 μm, respectively. The CORs and ICC for all the variables were excellent (0.35%-6.15% and 1.000-0.953, respectively). Among the patients with monofocal IOLs, we found that the PD decreased in all eyes and 13 of the tested eyes demonstrated an increase in ACD with increasing accommodative demand. However, in 1 of the tested eyes, the ACD decreased during accommodation. Among the 5 eyes with AIOL, all the PDs and ACDs were found decreased during accommodation. However, the CCT, ACW and IOLCT were not found changed during accommodation.
Conclusions:
The long scan depth SD-OCT combined with the automated algorithm was confirmed to have good accuracy and repeatability for the anterior segment dimensional measurements in eyes with IOL. It will be a potential tool in the morphological studies of the eye with IOL during the accommodation process.
Keywords: 567 intraocular lens •
404 accommodation •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)