Imaging the Bowman's and its importance in refractive surgery

Session Details

Session Title: Imaging Anterior Segment

Session Date/Time: Monday 07/09/2015 | 14:30-16:30

Paper Time: 16:18

Venue: Room 11

First Author: : R.Shroff INDIA

Co Author(s): :    R. Shetty   N. Pahuja   L. Kaweri              

Abstract Details

Purpose:

To elucidate the role of Bowmans membrane in refractive surgery and its impact on visual performance in patients undergoing Small Incision Lenticule Extraction surgery and in patients with keratoconus.

Setting:

Narayana Nethralaya,Bangalore ,India

Methods:

The Bowman's layer was imaged with the Bioptigen Spectral Domain Ophthalmic Imaging System (Bioptigen Inc, Durham, North Carolina) in 100 patients of keratoconus (20 unilateral and 30 form fruste keratoconus). Epi Clear device was used (EBK™, Orca surgicals) for removal of epithelium during crosslinking without traumatising the Bowman's. The Bowman's layer and its microdistortions were analyzed following Small incision lenticule extraction (SMILE) surgery. We also described a novel method of ironing the Bowman's after SMILE and studied its impact on undulations and visual outcome. The optical quality,epithelial profile and biomechanics were also analyzed.

Results:

We studied 78 eyes after SMILE surgery of which 39 were ironed. Undulations were present in 6 ironed eyes (15.3%) and 20 un-ironed eyes (51.2%) which was statistically significant (p = 0.002).The ironed group (22.2±12.25) had significantly better Modulation Transfer Function (p=0.05) than the unironed group (18.63±10.22). Strehl's ratio (0.13±0.06) in ironed group was significantly better (p=0.03) than the unironed group (0.11±0.05).Breaks were found in 10 out of 100 keratoconic eyes, the significance of which was evaluated. Use of Epi Clear device (EBK™, Orca surgicals) for removal of epithelium without traumatising the Bowman's and its potential benefit was noted.

Conclusions:

Eyes that were ironed showed fewer undulations and better optical quality in terms of MTF and SR than unironed eyes on the first postoperative day thereby suggesting that our technique is an effective way to improve immediate visual outcome. Breaks in the Bowman's membrane in keratoconic patients may be responsible for development of haze following crosslinking procedures and needs further evaluation. Imaging of Bowman's membrane using Bioptigen has stressed upon its important role in visual outcome following refractive procedures.

Financial Interest:

NONE