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Evaluation of postoperative central vaulting in eyes implanted with posterior chamber phakic intraocular lens (PIOL): a comparison between preoperative sulcus-to-sulcus (STS) and white-to-white (WTW) based size measurement

Session Details

Session Title: Phakic IOL Implantation I

Session Date/Time: Tuesday 08/10/2013 | 14:00-16:00

Paper Time: 15:24

Venue: Main Lecture Hall (Ground Floor)

First Author: : M.Ghoreishi IRAN

Co Author(s): :    M. Mohammadinia   F. Mohammadi           

Abstract Details

Purpose:

The goal of this study was to compare ciliary sulcus diameter measured by 50 MHz ultrasound biomicroscopy (UBM) and horizontal corneal diameter measured by slit scanning topography; and to evaluate their impact on postoperative vaulting, measured by Sheimpflug imaging.

Setting:

Parsian Clinic, Isfahan, Iran

Methods:

This prospective clinical trial included 60 eyes of 43 patients (12 male, 31 female, mean age 25.78± 4.94 years) with myopia, who were candidates for Implantable Colamer Lens (ICL) implantation. ICL size was determined based on both WTW size obtained with Orbscan (Bausch and Lomb) and STS size measured by UBM (Compact Touch STS, Quantel Medical, France). Patients were divided into two groups based on ICL sizing method used for ICL ordering. In 34 eyes ICL size was ordered based on WTW method (WTW group), and in 26 eyes ICL size was ordered based on STS method (STS group). Postoperative vault height was measured by Sheimpflug imaging (Oculus Pentacam, Germany) 3 months after surgery and the data was compared between two groups.

Results:

Mean preoperative WTW and STS diameters were 11.67± 0.47 mm (ranged 11-12.30 mm) and 11.93± 0.71 mm (ranged 11.1-13.43 mm), respectively. The mean difference was -0.25 ± 0.59 mm (ranged -1.01 to 1.45 mm), that was statistically significant (p= .006). We found poor agreement (R2= .322) between the WTW and STS diameters, although there were statistically significant linear correlations (P=.000). this poor correlation and high degree of variability in the difference between WTW and STS, meaning that if we were to predict sulcus diameter by taking WTW, 56% of the time we will have an error of more than 0.5 mm, which equals one lens size. The mean central vault heights were 360 ± 165.88 (ranged 60-760 um) and 388.46 ± 173.32 (ranged 110-780) in WTW and STS groups, respectively. There was no statistically difference in achieved ICL vault height between WTW-based formula and STS-based formula (p=.532). In STS and WTW groups, 31.8% and 23.5% of the eyes achieved vaults between 400-600um 31.8% and 23.5% respectively. The achieved vault height was less than 90 um in one eye (2.9%) of WTW group, whereas no eye had vault height less than 90 um in STS group.

Conclusions:

In this study, no significant difference were founded in mean vault height between WTW and STS groups, however, comparison of vault values showed the percentage of eyes in ideal range (400-600 um) was higher in STS group. Excessive (>750 um) and inadequate (<90um) vaults were slightly more common in WTW group. ICL sizing based on sulcus diameter method may result in better vault predictability than that of the WTW method.

Financial Interest:

NONE