Assessment of Axial Length Measurements in Mouse Eyes

• Type of Material: Article
• Authors: Han na Park, Emory University; Yureeda Qazi, Emory University; Christopher Tan, Emory University; Seema B. Jabbar, Emory University; Yang Cao, Atlanta VA Medical Center; Gregor Schmid, Emory University; Machelle Pardue, Emory University
• Language: English
• Date: 2012-03
• Publisher: Lippincott, Williams & Wilkins
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 American Academy of Optometry
• Final Published Version (URL): http://journals.lww.com/optvissci/Fulltext/2012/03000/Assessment_of_Axial_Length_Measurements_in_Mouse.8.aspx
• Title of Journal or Parent Work: Optometry and Vision Science
• ISSN: 1040-5488
• Volume: 89
• Issue: 3
• Start Page: 296
• End Page: 303
• Grant/Funding Information: NIH R01 EY016435, P30 EY006360 and Veterans Affairs Research Career Scientist Award (to MTP) and Departmental Award from Research to Prevent Blindness.
• Keywords: axial length; spectral domain-optical coherence tomography; low coherence interferometry; myopia; refractive development; ocular biometry; partial coherence interferometry
• Research Categories: Health Sciences, Opthamology

Abstract

Purpose To compare measurements of murine ocular axial lengths (AL) made with 780 nm partial coherence interferometry (PCI) and 1310 nm spectral domain–optical coherence tomography (SD-OCT). Methods AL was measured at postnatal day (P) 58 in C57BL/6J mice. Repeated AL measurements were taken using a custom-made 780 nm PCI and a commercial 1310 nm SD-OCT. Intra- and inter-user variability was assessed along the central optical axis as well as two-degree off-axes angles with the SD-OCT. Data were collected and analyzed using Cronbach’s alpha (α), Bland-Altman coefficient of repeatability (CR), agreement plots, and intra-class correlation coefficients (ICC). Results Axial length measurements agreed well between the two instruments (3.262 ± 0.042 mm for PCI; 3.264 ± 0.047 mm for SD-OCT; n= 20 eyes). The ICC for PCI compared to SD-OCT was 0.92, confirming high agreement between the two instruments. Intra-user ICC for the PCI and SD-OCT were 0.814 and 0.995, respectively. Similarly, inter-user ICC for PCI and SD-OCT were 0.970 and 0.943, respectively. Using SD-OCT, a two-degree misalignment of the eye along the horizontal meridian produced mean differences in AL of −0.002 ± 0.017 mm relative to the centrally aligned images, while similar misalignment along the vertical meridian created 0.005 ± 0.018 mm differences in AL measurements. Conclusions AL measurements from the 780 nm PCI and 1310 nm SD-OCT correlate well. Multiple statistical indices indicate that both instruments have good precision and agreement for measuring murine ocular axial length in vivo. While the vertical meridian had the greater variability in AL in the small mouse eye; two-degree off-axes differences were within the standard deviation of centrally aligned AL.