Purchase this article with an account.
Benjamin Xu, Rafaella Cleto Penteado, Robert N Weinreb; Diurnal Variation in Optical Coherence Tomography Measurements of Anterior Segment Structures. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2081.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Anterior segment optical coherence tomography (AS-OCT) has rapidly increased in popularity as a means of studying the anatomy and biomechanics of the anterior segment. While physiologic factors such as pupil size are known to affect AS-OCT measurements, it is not known if measurement values vary with the time of day. This study examines the diurnal variation of anterior segment structures in young healthy eyes by comparing AS-OCT measurements values obtained in the morning and late afternoon.
Eight subjects ranging from age 28 to 40 with no history of eye conditions or intraocular surgery were selected for this study (6 male, 2 female; mean age 31.2 ± 4.5 years). Anterior segment imaging was performed with a CASIA2 AS-OCT device (Tomey Corporation, Nagoya, Japan) in a fixed lighting environment between the hours of 8 to 9 AM and 4 to 5 PM. Four evenly spaced AS-OCT images per eye were analyzed. Nine parameters including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), iris area (IA), anterior chamber depth (ACD), lens vault (LV), anterior chamber width (ACW), and anterior chamber area (ACA) were measured using the built-in CASIA2 image analysis program.
Pupil diameter was similar between the AM and PM groups (5.10 ± 0.70 mm in AM, 5.18 ± 0.66 mm in PM, p = 0.77). There was no significant difference between AM and PM cumulative measurement values for any of angle parameters (p-value range from 0.22 to 0.93). Additionally, there was no significant difference between AM and PM measurement values obtained from each of the eight sections through the angle (p-value range from 0.25 to 0.99. There were varying amounts of agreement between measurement values for the different parameters (ICC values from 0.63 for TIA500 to 0.99 for ACD), but all qualified as good or excellent.
Minimal diurnal variation of AS-OCT measurement values were detected in young healthy adults.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only