Laser bridge astigmatic keratotomy (AK): novel incision architecture for optimizing vision in femtosecond laser AK; comparison of novel vs traditional incision architecture for 30 and 45 degree incisions using patient-specific computational modeling

Session Details

Session Title: Challenge of Astigmatism Correction

Session Date/Time: Sunday 14/09/2014 | 17:00-18:30

Paper Time: 17:06

Venue: Capital Hall A

First Author: : A.Nevyas-Wallace USA

Co Author(s): :    C. Roberts   H. Studer           

Abstract Details

Purpose:

To compare novel astigmatic keratotomy (AK) “Laser Bridge” incision architectures to standard AK for 30 and 45 degree femtosecond (FS) laser incisions using patient-specific computational modeling and to assess astigmatic effect and induction of higher order aberrations (HOA)

Setting:

Private group practice

Methods:

Finite element modeling was used to perform simulations of FS laser arcuate corneal relaxing incisions on patient-specific corneal models. The previously clinically validated model accounted for corneal stroma being denser anteriorly than posteriorly. Simulations of AK incisions of uniform depth and thickness were compared with those of AK incisions of novel “Laser Bridge” AK architecture. Astigmatic effect and induced higher order aberrations were assessed for incisions 30 and 45 degrees in length made at the 8mm optical zone.

Results:

Astigmatic effect of the 30 degree novel incisions was 15% greater than that of incisions whose depth and thickness were uniform. Compared with incisions of uniform depth and thickness, the 30 degree incisions of novel “Laser Bridge” incision architecture diminished induced spherical aberration by 20%; diminished induced coma by 82%; diminished induced trefoil by 81%; and diminished induced tetrafoil by 20%. The 45 degree incisions of novel “Laser Bridge” incision architecture diminished induced spherical aberration by 30%; diminished induced coma by 69%; diminished induced trefoil by 52%; and diminished induced tetrafoil by 90%.

Conclusions:

words Our novel incision architecture for FS AK – “Laser Bridge” incisions – produced optimal simulation results with substantially less induction of coma, spherical aberration, trefoil, and tetrafoil. For many versions, correction of astigmatism was nonetheless greater than that achieved by an incision of uniform depth and thickness. The ability to control incision architecture, in combination with patient-specific numerical prediction of surgical outcome, may be a key contribution of the FS laser to potential improvement of not only unaided but also best spectacle corrected visual acuity.

Financial Interest:

One or more of the authors... gains financially from product or procedure presented, One or more of the authors... is employed by a forNONEprofit company with an interest in the subject of the presentation