Abstract
Purpose :
White-to-white distance (WTW) is typically used for sizing an anterior chamber intraocular lens in which the footplates are aimed to rest against the scleral spurs or the angle recesses. The CASIA2 anterior segment optical coherence tomography (AS-OCT) provides direct visualization of the scleral spurs and angle recesses. This device may provide a more accurate method for AC-IOL sizing. The objective of this study is to evaluate the correlation between WTW and the degree of its displacement from scleral spur-to-scleral spur width (STS) and recess-to-recess width (RTR).
Methods :
172 phakic eyes from 172 individuals who had mild cataracts and no history of ocular surgery or laser procedures were enrolled. WTW was measured using LenStar (LenStar LS-900, Haag-Streit AG, Koniz, Switzerland). The STS (distance between scleral spurs at horizontal meridian) and RTR (distance between angle recesses at horizontal median) was assessed in images from CASIA2 (Tomey Corporation, Nagoya, Japan). The displacement length (DL) between WTW and STS as well as WTW and RTR were defined as WTW minus STS and WTW minus RTR, respectively (Figure1). Pearson correlation coefficient and multiple linear regression were performed.
Results :
Means (SD) of WTW, STS, and RTR were 11.80 (0.43), 11.70 (0.43), 11.71 (0.44), respectively. WTW showed significant positive correlation with STS (r=0.811, p<0.001) and RTR (r=0.814, p<0.001). Average DLs of WTW-STS and WTW-RTR were 0.104 and 0.094 mm, respectively. Linear regression with adjustment for age, gender, and axial length showed the DLs were greater with increased WTW (WTW-STS DL: β 0.18, p<0.001 and WTW-RTR DL: β 0.14, p=0.01).
Conclusions :
Greater WTW was significantly associated with higher displacement of WTW from the two distances representing anterior chamber width. Using an AS-OCT device can be more accurate in AC-IOL sizing especially in eyes with bigger corneal diameters.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.