Corneal irregular astigmatism and curvature changes after small incision lenticule extraction: 3 year follow-up

Session Details

Session Title: Small Lenticule Extraction

Session Date/Time: Sunday 08/10/2017 | 11:00-12:30

Paper Time: 11:57

Venue: Room 3.6

First Author: : H. Sideroudi GREECE

Co Author(s): :    A. Lazaridis    A. Messerschmidt-Roth   G. Labiris   V. Kozobolis   W. Sekundo        

Abstract Details

Purpose:

To evaluate the long-term changes in anterior and posterior corneal irregular astigmatism and curvature after Small Incision Lenticule Extraction (SMILE) in relation to the amount of the extracted tissue.

Setting:

The research took place at the Department of Ophthalmology, Democritus University of Alexandroupolis, Greece and at the Department of Ophthalmology, Philipps University of Marburg, Germany

Methods:

Fifty eyes of 28 patients underwent SMILE for myopia and myopic astigmatism. All procedures were performed using VisuMax® femtosecond-laser. Pentacam HR (Oculus, Germany) was used for preoperative and 3-year postoperative tomography. Corrected distance visual acuity, Fourier parameters (Spherical Component, Regular Astigmatism, Asymmetry and Irregularity) and curvature data of anterior and posterior cornea were evaluated and compared within 2 subgroups according to the magnitude of the refractive correction (low myopia group: (SEQ) ≥-6D, n=23 ; high myopia group: SEQ <-6D; n=27). Associations between the amount of extracted tissue and the changes in anterior and posterior corneal irregular astigmatism were examined.

Results:

A statistically significant increase in curvatures and Fourier derived parameters of anterior corneal surface was detected and the results were significantly correlated with the preoperative SEQ, lenticule thickness and volume. The flattest radius, corneal astigmatism, spherical component, regular astigmatism and irregularity of the posterior cornea decreased significantly only in high myopia. Statistically significant correlation was found between changes in posterior astigmatism and changes in anterior radii (P=0.04) and lenticule thickness. Moreover, changes in posterior corneal irregularity correlated significant with the changes in anterior and posterior radii P= 0.03 and 0.001, respectively), changes in preoperative SEQ (P=0.04) and lenticule thickness (P=0.01).

Conclusions:

Three years after SMILE there was a steepening of the posterior corneal surface in high myopia group which is correlated with the significant flattening of the anterior corneal surface. Total corneal irregularity was positively correlated with the magnitude of the attempted correction.

Financial Disclosure:

NONE