Selective modulation of ocular aberrations with Bowman's-assisted in situ keratomileusis (BASIK): a prospective study on myopic patients

Session Details

Session Title: SMILE vs PRK, Ocular Surface Disease

Session Date/Time: Monday 24/09/2018 | 08:00-10:30

Paper Time: 08:56

Venue: Room A3, Podium 3

First Author: : N.Pahuja INDIA

Co Author(s): :    R. Shetty   R. Vaishnav   P. Khamar   R. Chandapura   A. Sinha Roy        

Abstract Details

Purpose:

To assess changes in visual acuity, contrast sensitivity and ocular aberrations between laser assisted in situ keratomileusis (LASIK) and Bowman's assisted in situ keratomileusis (BASIK)

Setting:

Prospective, interventional, single blinded, contralateral eye study at Narayana Nethralaya Eye Hospital, India

Methods:

Forty one patients underwent conventional wavefront optimized LASIK in one eye and BASIK in the other eye. LASIK and BASIK used anterior keratometry from Pentacam (OCULUS Optikgerate Gmbh, Germany) and keratometry from Bowman's surface (RTVue Optical coherence tomography, Optovue, USA). Uncorrected and corrected distance visual acuity was assessed at before and after surgery. Further, contrast sensitivity and ocular aberrations (central 4.5 mm with 6th order zernike) were assessed preoperative, 1 month and up to 6 months after surgery (Voptica Inc, Spain). All variables were reported as median.

Results:

Sphere (-4.25D vs. -4.5D, p=0.87) and cylinder (-0.75D vs. -0.75D,p=0.99) were similar between LASIK and BASIK. Similarly from OCT, anterior flat (41.9D vs. 42.1D,p=0.86) and steep (43.8D vs. 43.7D,p=0.53) keratometry were similar. Bowman flat (41.5D vs. 41.6D, p=0.92) and steep (43.6D vs. 43.6D,p=0.27) keratometry were also similar. Preoperative (p~0.7) and change in contrast sensitivity (p=0.75) were similar. Vertical coma increased (p<0.05) in magnitude after LASIK (0.072 μm) and BASIK (0.065 μm). Spherical aberration (SA) increased [p<0.0001] after BASIK (pre: -0.01, 1 month: 0.036 and up to 6 month: 0.043 μm). In LASIK, the increase was insignificant (p=0.11).

Conclusions:

Postoperatively, BASIK gave comparable visual acuity and contrast to LASIK. However, change in SA was significant only in BASIK eyes. Patient specific difference in keratometry between anterior and Bowman's surface could be a specific modulator of ocular SA. This is the first study to describe a novel application of Bowman's surface topography for refractive treatments.

Financial Disclosure:

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