Tips and tricks for customised ablation

Session Details

Session Title: Presented Poster Session: Keratorefractive Surgery Results II

Venue: Poster Village: Pod 2

First Author: : E.Eskina RUSSIA

Co Author(s): :    V. Parshina                       

Abstract Details

Purpose:

It is known that planning customized ablation requires precise aberrometry, eye tracking and corneal ablation planning. Missing attention can lead to unpredictable refractive outcome and loss of quality of vision. We compared treatment plans from 50 myopic patients with aberration-free and wavefront-guided ablation. It allowed us to present the important rules how to get success with customized ablation and a clinical case, describing a challenging situation solved by customized ablation

Setting:

Laser Surgery Clinic "Sphere", Moscow, Russian Federation

Methods:

40 y.o. moderate myopic patient got a deep corneal opacity and irregularity after the ulceration on right eye (RE). She got a wavefront-guided trans-epithelial keratectomy (TransPRK) with SmartSurfACE technology on RE without any refractive component (only High Order Aberrations were treated). Corneal abberometry was done on the SIRIUS Diagnostic Workstation, Ablation was planned with SCHWIND-CAM software, and ablation preformed on SCHWIND Amaris 500E excimer laser  (all SCHWIND eye-tech-solutions). It was an intensive corneal scar laying between 116  to 178 microns corneal depth.

Results:

Preop data OD and OS: UDVA=0,1 and 0,05, BCVA=0,5 and 1,0, Manifest refraction sph-2,75D cyl-0,75 ax146 and  sph-4,0D cyl-1,0 ax5, CCP 542 and 574µm, at ⌀4mm Spherical aberration -0,17 and 0,09EqD , Coma 0,47 and -0,1EqD, RMS 1,47 and 1,17EqD. Treatment plan OD: CWF refraction free TransPRK ablation with Optical Zone(OZ) 7,5 mm, ablation 125µm, planned RST 417µm+Epithelium. 6 months postoperative OD UDVA=0,95  BCVA=0,95, Refractometry sph-0,87D cyl-1,0 ax176, CCP 423, at ⌀4mm Spherical Aberration 0,11, Coma 0,17, RMS 1,48. While performing only high order aberrations correction we got an additional refractive effect of approximately 2D.

Conclusions:

It is known that there is a difference in central and/or maximum depth of ablation existing (wavefront-guided typically more than aberration-free). We assume that the following differences which significantly are not influencing the refractive effect can be accepted: 11-13μm for 6,25-6,75mm OZ 13-15μm for 6,75-7,25mm OZ 15-17μm for >7,25mm OZ If the differences are larger than these, the surgeon should modify the spherical and cylindrical component until the difference is within range for the selected OZ. Otherwise, the risk that the postoperative refractive outcome differs significantly from the target exits.

Financial Disclosure:

None