Comparison of the keratometric index before and after small incision lenticule extraction

Session Details

Session Title: Presented Poster Session: Keratorefractive Surgery Results I

Venue: Poster Village: Pod 2

First Author: : V.de Rojas SPAIN

Co Author(s): :    A. Tobio                       

Abstract Details

Purpose:

To compare the keratometric index (KI) before and after Small Incision Lenticule Extraction (SMILE).

Setting:

Victoria de Rojas Instituto Oftalmológico (A Coruña) Spain.

Methods:

Retrospective case series including 50 eyes (50 patients) that underwent SMILE procedures. Pre and postoperative corneal images obtained by a rotating Scheimpflug camera (Sirius) were reviewed and the following data were recorded: Anterior and posterior corneal curvature radii (3-mm zone) and pachymetry. Preoperative and postoperative anterior-to-posterior corneal curvature and KI (Gullstrand equation for thick lenses) were calculated. Medical records were reviewed and the following data were searched: age, sex, preoperative and postoperative spherical equivalent.

Results:

Mean postoperative anterior corneal radii significantly increased and mean postoperative corneal radii significantly decreased after SMILE (p<0,0001). Mean anterior-to-posterior corneal curvature significantly increased (1,19±0,02 to 1,32±0,05 mm; p<0,0001) and mean KI significantly decreased after SMILE (1.3292±0.0009 to 1.3239±0.0019 p<0,0001). Linear regression analysis showed a significant directly correlation between the refractive change and: the flattening of anterior radii (r=0,9272; r2=0,8598), the increase of the mean anterior-to-posterior corneal curvature (r=0,8872; r2=0,7872). An inversely correlation was found between refractive change and the reduction of the KI (r=0,8907; r2=0,7934). Posterior corneal radii decrease showed a weak relationship with the refractive change (r=0,4714; r2=0,2222).

Conclusions:

SMILE induces a change in the anterior-to-posterior corneal curvature and thus, a change in the standard KI. This change must be taken into account when performing IOL calculations in patients who had undergone a SMILE procedure.

Financial Disclosure:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented