Posters

Comparison of central corneal thickness measurements with three non-contact pachymeters and a standard ultrasonic pachymeter

Poster Details

First Author: E.Şenel TURKEY

Co Author(s):    M. Durmus              

Abstract Details

Purpose:

To compare central corneal thickness (CCT) measurements obtained by non-contact AL-Scan (AL-S), Sirius Scheimpflug Topography (SST), Non-contact pachytonometer (NCP) and conventional contact ultrasound pachymetry (UP) in healthy corneas.

Setting:

The study was conducted in Ophthalmology Department of Hitit University, Corum, Turkey.

Methods:

In this prospective study, CCT was measured in 144 eyes of 72 healthy subjects. Results were analyzed statistically by interclass correlation (ICC) coefficient to measure the correlation between all pachymeters. Bland-Altman were used to assess agreement among the instruments, and 95% limits of agreement (LoA) for each comparison were calculated.

Results:

The mean CCT by AL-S, CST, UP and NCP were 534.92±42.79 µm (range: 438-631), 545.20±43.08 µm (range: 444-634), 554.20±45.94 µm (range: 449-674), 563.08±43.97 µm (range: 464-665), respectively. The mean differences for CCT measurements were 28.1 µm between NCPachytonometer and AL-Scan optic biometer (ICC:0,970), 17.8 µm between NCP and SSTopography (ICC:0,968), 8.8 mm between NCP and Ultrasound pacymeter (ICC:0,966), 10.2 µm between AL-S and CST (ICC:0,987), 19.2 µm between AL-S and UP (ICC:0,976), and 9 mm between CST and UP (ICC:0,968). The Bland–Altman analysis better shows the clinical relevance of repeatability between the four instruments.

Conclusions:

The correlation is significant between all devices (p<0.01). The best correlation was calculated between AL-S and CST. AL-S and CST consistently measuring lower than ultrasound. NCP measured the highest CCT values. Although CCT values obtained with AL-S, CST, NCP and UP show a good correlation, it should be noted that these devices are not completely interchangeable in clinical practice. FINANCIAL DISCLOUSRE: NONE