Changes in corneal tomography in DMEK patients compared to a healthy control group and the effect on IOL calculation

Session Details

Session Title: Surgical Cornea: Keratoplasty & Corneal Grafts

Session Date/Time: Sunday 23/09/2018 | 14:00-16:00

Paper Time: 14:24

Venue: Room A3, Podium 3

First Author: : L.Zumhagen GERMANY

Co Author(s): :    M. Alnawaiseh   P. Hoffmann                 

Abstract Details

Purpose:

To quantify changes in the refractive power of the anterior and posterior corneal surfaces after Descemet membrane endothelial keratoplasty (DMEK) to optimize the accuracy of intraocular lens (IOL) power calculations based on the corneal biometry acquired by four different devices.

Setting:

Augen- und Laserklinik Castrop-Rauxel, Germany

Methods:

Scheimpflug-based Oculus Pentacam, Placido- and Scheimpflug-based Tomey TMS5, SS-OCT-based Tomey CASIA2 and Zeiss IOL-Master 700 imaging was performed in 42 DMEK patients and 42 age matched healthy control group evaluated for cataract surgery. Corneal radii of anterior and posterior curvature and the device given corneal power were compared.

Results:

Mean radii of anterior curvature acquired by CASIA2, TMS5 and IOL-Master700 in both groups do not differ significantly (mean 7,74-7,79mm). Whereas the radii of posterior curvature measured with CASIA2 (mean: DMEK 6,44mm, control 6,59mm) and TMS2 (mean: DMEK 6,49mm, control 6,65mm) show significant difference between groups but not for Pentacam (mean: DMEK 6,38mm, control 6,46mm). The difference between posterior radii between groups did not cause a significant difference between the refractive power between each device and between the two groups (mean: DMEK 42,49dpt, control 42,62dpt; 1/8 dpt for CASIA2 and TMS5 and 1/4dpt for Pentacam).

Conclusions:

The radii of anterior corneal curvature measured by CASIA2, TMS5, Pentacam, IOL-Master700 seem to be similar between devices and between DMEK and matched healthy control group. The radii of the posterior curvature differ between groups significantly for CASIA2 und TMS5. Due to different refractive indices given by the manufactures the calculated corneal "real" or "total" refractive power between group differ only by less than ¼ of a diopter what is similar to the corneal refractive power as calculated by thick-lens Gaussian optics. Therefore the clinical impact of posterior curvature steepening might be quite small for IOL calculation in DMEK patients.

Financial Disclosure:

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