Repeatability and agreement in optical biometry of a new swept-source optical coherence tomography–based biometer versus partial coherence interferometry and optical low-coherence reflectometry

Purpose. To report choroidal thickness and volume in healthy eyes using swept source optical coherence tomography (SS-OCT).Methods. A prospective observational study of 122 patients examined with swept source OCT (DRI-OCT, Topcon, Japan). In each eye, we performed 256 horizontal scans, 12 mm in length and centered on the fovea. We calculated choroidal thickness manually with a built-in caliper and automatically using DRI-OCT mapping software. Choroidal volume was also automatically calculated. We measured axial length with optical low-coherence reflectometry (Lenstar LS 900, Haag-Streit, Switzerland).Results. The choroid has focally increased thickness under the fovea. Choroid was thinnest in the outer nasal quadrant. In stepwise regression analysis, age was estimated as the most significant factor correlating with decreased choroidal thicknessF=23.146, P<0.001followed by axial lengthF=4.902, P=0.03. Refractive error was not statistically significantF=1.16, P=0.28.Conclusions. SS-OCT is the first commercially available system that can automatically create choroidal thickness and volume maps. Choroidal thickness is increased at the fovea and is thinnest nasally. Age and axial length are critical for the estimation of choroidal thickness and volume. Choroidal measurements derived from SS-OCT images have potential value for objectively documenting disease-related choroidal thickness abnormalities and monitoring progressive changes over time.

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Comparison of Two Novel Swept-Source Optical Coherence Tomography Devices to A Partial Coherence Interferometry-Based Biometer

10.21203/rs.3.rs-132028/v1 ◽

2020 ◽

Author(s):

Tommy Chan ◽

Marco Yu ◽

Vivian Chiu ◽

Gilda Lai ◽

Christopher Leung ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber Depth ◽

Cross Sectional Study ◽

Systematic Difference ◽

Partial Coherence ◽

Optical Coherence ◽

Cross Sectional ◽

Swept Source ◽

Partial Coherence Interferometry ◽

Significant Disagreement

Abstract Purpose To evaluate the repeatability and agreement of cornea and biometry measurements obtained with two swept-source optical coherence tomography (SSOCT) and a partial coherence interferometry-based device.METHODS This is a cross-sectional study. Forty-eight eyes of 48 patients had three consecutive measurements for ANTERION (Heidelberg Engineering, Germany), CASIAII (Tomey, Japan) and IOLMaster500 (Carl Zeiss Meditec, USA) on the same visit. Mean keratometry (Km), central cornea thickness (CCT), anterior chamber depth (ACD) and axial length (AL) were recorded. Corneal astigmatic measurements were converted into vector components – J0 and J45. Intra-device repeatability and agreements of measurements amongst the devices were evaluated using repeatability coefficients (RCs) and Bland-Altman plots, respectively. RESULTS All devices demonstrated comparable repeatability for Km (p≥0.138). ANTERION had the lowest RC for J0 amongst the devices (p≤0.039). Systematic difference was found for the Km and J0 obtained with IOLMaster500 compared to either SSOCTs (p≤0.010). The ACD and AL measured by IOLMaster500 showed a higher RC compared with either SSOCTs (p<0.002). Systematic difference was found in CCT and ACD between the two SSOCTs (p<0.001), and in AL between ANTERION and IOLMaster500 (p<0.001), with a mean difference of 1.6 µm, 0.022mm and 0.021 mm, respectively. CONCLUSIONS Both SSOCTs demonstrated smaller test-retest variability for measuring ACD and AL compared with IOLMaster500. There were significant disagreement in keratometry and AL measurements between the SSOCTs and PCI-based device; their measurements should not be considered as interchangeable but the disagreement could be refined by readjustment of intraocular lens constant in clinical practice.

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