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Elliptical versus conventional circular flaps in LASIK surgery

Poster Details

First Author: A.Gupta INDIA

Co Author(s):    S. Gupta   J. Kumar   R. Gupta        

Abstract Details


This prospective, interventional clinical study intended to compare the visual performance, changes in corneal asphericity, corneal biomechanics and corneal aberrations using customized elliptical flaps versus circular flaps in eyes undergoing iLASIK.


This study was carried out on the patients undergoing iLASIK at the Advanced Eye Centre, Post-Graduate Institute of Medical Education and Research, Chandigarh. Ethical clearance was obtained from the institutional review board.


A prospective, interventional study was conducted on 145 patients (290 eyes). These patients were divided into- Group I (elliptical flap Lasik) and group II (circular flap Lasik). Elliptical flaps were created using 2% over-sizing of the horizontal diameter of the Lasik flap. Rest of the surgical parameters and the procedure remained the same in all the eyes. Post-operatively, the functional performance in the form of improvement in the un-corrected visual acuity, best-corrected visual acuity were assessed and compared between the two groups. The other parameters studied were changes in the corneal biomechanics, corneal asphericity, and corneal aberrations.


The mean age of the patients was 24.10 ± 3.73 years. 43.4% of the patients were males. The percentage of the patients achieving the un-corrected visual acuity of 6/6 and above was comparable in the two groups (97.9% versus 97.2%). Also, the change in the mean refractive spherical equivalent was significant, but comparable between the two groups (p=0.858). Although, the corneal biomechanics changed significantly in the two groups, but the amount of change was less in the elliptical group (CH: p=0.02 versus 0.002, CRF: p= 0.08 versus 0.000). The change in the amount of corneal asphericity was also less in the elliptical group. The surgically induced higher order aberrations were also less in the elliptical flap patients, especially coma and tetrafoil. Intra-operative and the pos-operative complications were comparable in the two groups.


Customization of the LASIK flaps appears to minimize the changes in the corneal biomechanics, corneal asphericity and induces lesser post-operative higher-order aberrations. The visual performance, however, remains the same even after customization of the flap for the Lasik surgery. This can serve as an alternative approach to the present surgical parameters in the Lasik surgery with better visual performance for the patients. FINANCIAL INTEREST: NONE

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