Rajesh Sinha, Reena Singh Sravanti, Jeewan S Titiyal

Purpose: To study the repeatability in white to white (WTW) measurements with IOL Master, Orbscan, Lenstar and I-trace and compare with sul- cus to sulcus (STS) diameter to assess the correct size of implantable collamer lens (ICL).
Methods: A prospective study was conducted on
71 eyes of 36 patients who were planned for implantation of ICL. Five readings of WTW using Orbscan II, IOL Master, Lens Star, I Trace, Digital Vernier Calipers and STS using ultrasound biomi- croscopy (UBM) were taken. The repeatability of the data was analysed. The ICL vault was recorded postoperatively by anterior segment ocular coher- ence tomography (ASOCT) on day 1, 1 week, 1month, 3 months, 6months, and 1year.
Results: Highest repeatability of WTW was seen with IOL Master with coefficient of repeatability of
0.88. Digital calipers for WTW was found to have the highest correlation with Orbscan followed by lenstar and IOL Master. UBM estimated better ICL size compared to Orbscan in 7% cases. Conclusions: IOL Master, in view of highest repeat- ability, may be used alternatively to Orbscan for WTW with a correction factor for calculation of ICL size. Incorporation of STS in calculating the ICL size along with WTW by digital callipers or orbscan can yield more accurate ICL vault.