Posters

Changes in human anterior and posterior corneal curvature and surgically induced astigmatism after laser astigmatic keratotomy and clear corneal incisions using Scheimpflug tomography in femtosecond-assisted lens surgery

Poster Details

First Author: M.Böhm GERMANY

Co Author(s):    F. Loeffler   C. Titke   M. Herzog   K. Petermann   O. Klaproth   T. Kohnen     

Abstract Details

Purpose:

To quantitatively analyze the changes in human anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA) and surgically induced astigmatism (SIA) after clear corneal incisions (CCI) and laser astigmatic keratotomy (LK) based on total corneal refractive power (TCRP) using Scheimpflug imaging in femtosecond-assisted lens surgery.

Setting:

Department of Ophthalmology, Goethe University Frankfurt, Germany

Methods:

In this prospective cohort study 55 patients (91 eyes) undergoing femtolaser-assisted lens surgery were enrolled (November 2013 - July 2014). Preoperative and 1- and 3-month postoperatively corneal astigmatism was measured with Pentacam. Depending on preoperative astigmatism eyes were subdivided into 3 groups receiving temporal CCI (group 1: TCRP ≤ 0.50 D), CCI on steep meridian (group 2: TCRP ≤ 0.51 – 0.75 D) or LK (group 3: TCRP ˃ 0.75 D) based on Wang’s et al. nomogram. Vector analyses using Holladay-Cravy-Koch formula and Alpins method was performed. Data was analyzed and P ˃.05 was considered as statistically significant (Wilcoxon-Test).

Results:

In group 1 preoperative ACA (0.38 ± 0.16 D) was significantly higher 3 month (0.46 ± 0.23 D) postoperatively, whereas preoperative PCA (0.24 ± 0.12 D) did not change significantly postoperatively (0.28 ± 0.13). Preoperative ACA (0.59 ± 0.28 D) and PCA (0.25 ± 0.09 D) in group 2 showed no significant difference postoperatively (ACA: 0.45 ± 0.24, PCA: 0.25 ± 0.11). Preoperative ACA (0.97 ± 0.32 D) in group 3 was significantly lower 3 month (0.66 ± 0.34 D) postoperatively, preoperative PCA (0.26 ± 0.11 D) did not change.

Conclusions:

CCI on the temporal axis showed a slight significant increase of ACA, but not of PCA. CCI on the steep axis showed no significant reduction in ACA and no change in PCA. LK reduces ACA significantly, whereas PCA not significantly. SIA of ACA after 3 month was 0.25 D in group 1, 0.36 D in group 2 and 0.74 D in group 3, whereas the SIA of PCA was 0.16, 0.16 and 0.12 D, respectively. The SIA is higher for ACA compared to PCA. To conclude the results suggest that ACA is more affected by CCI and LK than PCA.

Financial Disclosure:

One or more of the authors receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, One or more of the authors travel has been funded, fully or partially, by a competing company, One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, One or more of the authors receives consulting fees, retainer, or contract payments from a competing company