Phased Lasik-Surface Ablation Laser Procedure For High Myopes - Utilizing The Flap Stroma.

Residual stromal thickness often becomes the limiting factor for taking up patients for LASIK(laser-assisted in situ keratomileusis) especially in high myopic patient. Surface ablation-transPRK (TransepithelialPRK) on the other end has a high risk of haze with deep ablation depths. 

We thought of this Phased LASIK-Surface ablation laser procedure for high myopes who are unsuitable for LASIK and surface ablation alone. With this we want to utilize the flap stroma in surface ablation.

Patient did not want phakic IOL(intraocular lens) due to financial reason. 

We present a case of a patient with high myopia right eye -11.00/-2.00@13 and left eye -11.00/-1.75@170. The central pachymetry by sirius topgraher was 525 in the right eye and 535 in the left eye. Thus there was not enough residual corneal thickness for LASIK with 110  micron flap and a high risk of haze with surface ablation alone. A phased LASIK with 110 micron flap followed by surface ablation (SmartSurfACE TransPRK, Schwind Amaris 500) six months later was planned. 

We report here a patient with high myopia(right eye -11.0 D/-2.0 D @13 and left eye -11.0 D /-1.75 D @170) wanting laser refractive surgery. On evaluation and topography with sirius topographer the corneal thickess of right eye was 525 microns and left eye was 535 microns. This wasn't enough for us to plan LASIK with  enough residual stromal thickenss and for surface ablation alone the risk was too high for post-operative haze.  Thus, we planned a phased LASIK-Surface ablation(TransPRK) laser procedure with combination of LASIK first for majority of correction -8.0 D both eyes with flap thickness of 110 microns in december 2021. This was followed by surface ablation (SmartSurfACE TransPRK) with Schwind Amaris 500 6 months later in may 2022 for right eye -2.0/-1.75 @10 and left eye 1.5/-1.5 @ 170 . This allowed us to use the STROMA IN FLAP FOR ABLATION during the second phase and integrating the interface in the ablation. Thus achieving a residual stromal thickness of around 300 mircons and chances of haze significantly reduced as the surface ablation was minimal. We have followed up the patient for three and half years showing normal corneal topography with central corneal thickness of 343 in right eye and 350 in left eye. 

Phased LASIK-SURFACE ALBLATION gives best of both and it is really useful in some high myopes where lasik alone or surface ablation alone are risky.
So far, the stroma attached to the flap has never been thought to be utilised. So we thought to use this stroma at a later date to optimise benefit of lasik & SmartSurf TPRK which if done alone was riskier.