Posters

Comparison of total corneal refractive power zones measured by Scheimpflug tomography to simulated keratometry

Poster Details

First Author: T.Kohnen GERMANY

Co Author(s):    B. Tonn   Y. Cubuk   M. Shajari        

Abstract Details

Purpose:

To evaluate differences between total corneal refractive power (TCRP) within specific zones to simulated keratometry (SimK).

Setting:

Goethe University Frankfurt, Germany

Methods:

Over 8000 eyes were measured by Scheimpflug tomography (Pentacam, Oculus Optikgeräte GmbH, Wetzlar) at the Goethe-University Hospital in Frankfurt. 3818 showed no pathological signs like e.g. suspicious measurements in Belin-Ambrosio Display, were marked with “OK” by devices internal checking system and were included in this study. Eyes with SimK<39dpt or >49dpt were excluded. A vector analysis was performed for TCRP at 3, 4 and 5mm and compared to SimK.

Results:

SimK was in average 1.15 ± 0.9 dpt. TCRP was in average 1.13 ± 0.9 dpt at 3mm, 1.10 ± 0.9 dpt at 4mm and 1.09 ± 0.9 dpt at 5mm zone. When comparing SimK to TCRP 71.2% of eyes at 3mm, 83.5% at 4mm and 85.0% at 5mm had a difference of less than 0.25 dpt and 94.2% at 3mm, 99.1% at 4mm and 99.0% at 5mm had a difference of less than 0.5 dpt. Vector analysis showed a difference of 0.18 dpt at 178° between SimK and TCRP3 and 0.16 dpt at 178° for TCRP4.

Conclusions:

Despite the fact that SimK is measured at 15° and topographically rather matches TCRP at the 3mm zone we found better correspondence to TCRP at the 4mm zone. FINANCIAL DISCLOUSRE: NONE