Abstract
Purpose :
Optical coherence tomography (OCT) of anterior segment provides three-dimensional visualization of the anterior structure including the crystalline lens or, in the case of post-cataract surgery, the intraocular lens (IOL). Cross-sectional images of the crystalline lens potentially can be used for cataract monitoring while OCT of the IOL implant can be used as an evaluation tool during or after the surgery.
Methods :
An anterior segment (AS) add-on lens was designed to be used in combination with the PLEX® Elite 9000 (ZEISS, Dublin, CA) swept-source OCT system with 1060 nm central wavelength. The add-on lens has a telecentric geometry with a built-in fixation target. PLEX Elite prototype software was modified and equipped with AS tracking and AS specific scan patterns:
- AS 6x6 mm Angio at 200kHz with 6 mm depth
Two healthy subjects (ages 32 and 67) and an IOL implanted eye (age 60) were scanned with central fixation to visualize the lens.
Results :
The results show the capability of visualizing the crystalline lens in healthy subjects of different ages (Figure 1 a-d). With 6 mm depth, anterior chamber from cornea to the middle part of lens can be captured. Alternatively, by moving the delay arm (B-scan position), both surfaces (Figure 1, green arrows) of the lens can be seen in the cross-sectional image. However, the mirror image of the cornea (orange arrows) also appears as an artifact (Figure 1 b, d, f). Opacification of the crystalline lens with age is significantly visible in the cross-sectional images of the healthy subjects. We also imaged an eye with intraocular lens implant at both depths. Both surfaces of the clear IOL are visible in the B-scans (Figure 1 e & f).
Conclusions :
We successfully scanned healthy crystalline and implanted IOL in different age groups with anterior segment optical coherence tomography using PLEX Elite and AS add-on lens attachment. Results show the potential of the method in monitoring of cataract progression and evaluation of cataract surgery outcome. The current study has a limitation of 6 mm depth; however, the conjugate mirror can be removed in post processing or axial depth can be increased at a lower A-scan rate.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.