Evaluation Of Ocular Diameter Parameters Using Swept-Source Optical Coherence Tomography

To investigate the iridocorneal angle-to-angle (ATA), sclera spur-to-sclera spur (STS), and white-to-white (WTW) ocular diameters and their potential influence on anterior chamber intraocular lens (ACIOL) and implantable collamer lens (ICL) sizing in Chinese. 

A retrospective observational cross-sectional study at Shanxi Eye Hospital.

In 60 right eyes (60 subjects), the ATA, STS, and WTW were measured in six axes (0°‒180°, 30°‒210°, 60°‒240°, 90°‒270°, 120°‒300°, 150°‒330°) using SS-OCT. The ACIOL and ICL sizes were calculated based on horizontal and vertical axes anterior segment data. 

ATA and STS were longest on the vertical and shortest on the horizontal axis, while WTW was similar on both axes. These three parameters differed only in the vertical axis (F = 4.910, P = 0.008). ATA and STS were by 0.23 ± 0.08 mm (P = 0.005) and 0.21± 0.08 mm wider (P = 0.010) than WTW, respectively. ICL size was 0.27 ± 0.23 mm smaller when based on horizontal than on vertical axis parameters (P < 0.001), while ACIOL remained similar (P = 0.709). Age correlated negatively and axial length positively with all measured values. ATA, STS, and WTW correlated positively in the same axis (all P < 0.001).

ATA and STS were longer in the vertical than in the horizontal direction, while WTW measurements remained similar. ATA and STS diameters more accurately depict anatomic relationships for phakic IOL sizing than WTW.