LONG TERM OUTCOMES OF BOWMAN’S MEMBRANE RELAXATION FOR ENHANCEMENT OF FEMTOSECOND INTRASTROMAL LENTICULE IMPLANTATION (FILI) PERFORMED FOR THE MANAGEMENT OF HIGH HYPEROPIA

To evaluate, retrospectively, the feasibility and report long-term outcomes with Bowman’s membrane relaxation (BMR),  for enhancing  the residual refractive error following Femtosecond intrastromal lenticule implantation (FILI). 

BMR was performed using a Hessburg-Barron trephine to create a circular incision into the Bowman’s Membrane and anterior corneal fibres up to the depth of around 120-130 µm. Post enhancement clinical outcomes were analysed at a mean period of 36 months (range 14-57 months).

our eyes of 3 patients ( mean age 29 years), underwent enhancement with BMR for a significant residual refractive error of + 2.25 D SE following FILI for high hyperopia (mean SE +7.00 D). Post BMR,  the residual refraction reduced to +0.31 D, resulting in improvement in UDVA from 0.55 to 0.33 LogMAR. The mean front keratometry (Pentacam HR) increased from 46.2 D to 49.3 D, and the mean back keratometry increased from -5.9 to -6.3D following BMR, the latter returning to the baseline (pre-FILI) value of -6.3 D.  An increase in Q-value with a corresponding increase in higher order aberrations(HOA) was observed. Corneal biomechanics (Corvis-ST) indicated reduction of stiffness and other parameters post-enhancement. No intra or post-operative complications were noted. 

Bowman's Membrane Relaxation (BMR) may be a  safe, simple and effective technique for enhancement of residual hyperopia following tissue addition techniques such as FILI. There could be an evidence that BMR may reverse the posterior curvature changes negating the steepening effect of the anterior cornea following tissue  addition, potentially aiding in the enhancement.