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Published on: August 21, 2019
Pachymetric mapping with Fourier-domain optical coherence tomography
Yan Li1, Maolong Tang, Xinbo Zhang
1Center for Ophthalmic Optics and Lasers, Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA.
Journal of Cataract and Refractive Surgery
|May 12, 2010
Summary
Fourier-domain optical coherence tomography (OCT) offers repeatable corneal thickness mapping, with pupil-centered scans outperforming vertex-centered ones. Different pachymetry devices should not be used interchangeably for central corneal thickness assessment.
Area of Science:
- Ophthalmology
- Biomedical Optics
- Medical Imaging
Background:
- Accurate central corneal thickness (CCT) measurement is crucial for diagnosing and managing various ocular conditions.
- Fourier-domain optical coherence tomography (OCT) is a non-contact imaging technique with potential for high-resolution corneal mapping.
- Comparing CCT measurements from OCT with established methods like ultrasound pachymetry and scanning-slit tomography is essential for clinical validation.
Purpose of the Study:
- To assess the repeatability of corneal thickness mapping using Fourier-domain OCT.
- To compare central corneal thickness (CCT) measurements obtained by Fourier-domain OCT with those from ultrasound pachymetry and scanning-slit tomography.
Main Methods:
- Fourier-domain OCT was employed to map corneal thickness in normal eyes, with scans centered either on the corneal vertex or the pupil.
- Repeatability of central and pericentral corneal map sectors was evaluated using pooled standard deviation.
- CCT measurements from OCT were compared against ultrasound pachymetry and scanning-slit tomography.
Main Results:
- Pupil-centered OCT scans demonstrated superior repeatability (SD: 1.3 µm central, 1.8–3.8 µm pericentral) compared to vertex-centered scans (SD: 1.7 µm central, 2.4–5.7 µm pericentral).
- Mean CCT measurements were 536.9 ± 27.0 µm (OCT), 556.6 ± 30.5 µm (ultrasound), and 537.2 ± 32.6 µm (scanning-slit).
- OCT CCT was significantly thinner than ultrasound (P=.007) but not statistically different from scanning-slit tomography (P=.2637), showing good correlation with both (r=0.940 and r=0.934, respectively).
Conclusions:
- Pachymetric mapping with Fourier-domain OCT is highly repeatable, particularly with pupil-centered scans.
- Significant differences in CCT measurements exist between Fourier-domain OCT and ultrasound pachymetry.
- Fourier-domain OCT, ultrasound pachymetry, and scanning-slit tomography should not be used interchangeably for CCT assessment due to measurement variations.
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