Posters

The comparison of corneal parameters taken with Scheimpflug and slit-scanning topography systems in patients with keratoconus: preliminary results

Poster Details

First Author: Z. Ozbek TURKEY

Co Author(s):    Z. Ayhan   B. Derkus   H. Doruk   I. Durak           

Abstract Details

Purpose:

To evaluate and compare the corneal parameters taken with Scheimpflug (Pentacam, Oculus Optikgeräte GmbH) and slit-scanning (Orbscan, Bausch&Lomb) topography systems in keratoconus patients.

Setting:

Department of Ophthalmology Dokuz Eylul University School of Medicine, Izmir, Turkey.

Methods:

Twenty-two eyes of 14 keratoconus patients were analyzed prospectively. All patients underwent Orbscan first and Pentacam next before a complete ophthalmological exam. The evaluated corneal parameters were central and thinnest corneal thickness (CCT and TCT), simulated keratometric (SimK) readings and other topometric parameters such as Kmax, Kmin, Kmean in the central 3mm zone.

Results:

Seven patients were male; seven were female. Mean age was 27.09±10.9 years. Best corrected visual acuity was 0.4±0.2. Mean CCT values measured by Orbscan and Pentacam were 416.2±64.8µm and 444.6±57.03µm (P=0.01). Mean TCT with Orbscan and Pentacam were 367.2±78.6µm and 413.2±75.7µm, respectively (P=0.005). Mean SimK readings of Orbscan and Pentacam were 5.3±3.1D, 4.1±2.6D, respectively (P=0.03) The mean Kmax, Kmin and Kmean values with autorefractokeratometry (Nidek) were 54.2±6.6D, 48.4±6.6D, 50.2±7.05D, respectively. Mean Kmax, Kmin and Kmean with Orbscan were 53.9±8.06D, 49.3±6.8D, 50.1±7.4D, respectively while same parameters with Pentacam were 54.7±9.3D, 50.6±7.8D, 52.6±8.3D (p values: 0.80, 0.16 and 0.005)

Conclusions:

Orbscan and Pentacam topography systems are widely used in the diagnosis and follow-up of the keratoconus. Hovewer, these instruments should not be used interchangeably during follow-up since there may be significantly different values in consecutive measurements with two devices and this may be misleading in our decision for progression.

Financial Disclosure:

NONE