Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

Abstract

Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results in vivo on 15 cross-sectional images from patients with IOLs. Five eyes with five different types of IOLs, respectively, were enrolled to test the repeatability of the automated measurements during accommodation. Intraocular lens central thickness and anterior and posterior curvature radii measured by long scan depth SD-OCT in vitro and in a model eye matched well with those determined by a micrometer caliper and interferometer. In vivo, there was good correlation of the biometric data determined by automated and manual segmentations (P<0.05, r-value range: 0.635-0.997). There were no significant differences for any variable between the two measurements at each accommodative state (P>0.05). Anterior chamber depth and pupil diameter showed significant changes between the nonaccommodative and 2.5-D accommodative states (P<0.05), whereas the shape of the IOLs did not change significantly (P>0.05). The long scan depth SD-OCT with the automated algorithm was verified to have a great potential in studying accommodative biometric changes of the anterior segment in eyes with IOLs and IOL deflections.