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Vector analysis of astigmatic changes after small incision lenticule extraction (SMILE) and wavefront-guided laser in situ keratomileusis (WFG-LASIK)

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Session Details

Session Title: Presented Poster Session: Keratorefractive Results II

Venue: Poster Village: Pod 2

First Author: : M.Shafik Shaheen EGYPT

Co Author(s): :    M. Khalifa   A. Ghoneim   D. Pinero        

Abstract Details


To evaluate and compare the efficacy of the astigmatic correction analysed by vector analysis after small incision lenticule extraction (SMILE) and wavefront-guided laser in situ keratomileusis (WFG LASIK) in myopic eyes with different levels of astigmatism.


Horus Vision Correction Center (HVCC), Egypt. Ellite Vision Correction Center ( EVCC), Egypt.


Prospective, consecutive, comparative, randomized, and masked clinical trial evaluating 107 myopic eyes (55 patients) with astigmatism up to 4.00D. A total of 52 eyes underwent WFG LASIK surgery (WFG LASIK group) and 55 eyes SMILE surgery (SMILE group). Visual and refractive changes were evaluated during a 6-month follow-up. The astigmatic changes were evaluated using the Alpins method and the following parameters: targeted induced astigmatism (TIA), surgically induced astigmatism (SIA), difference vector (DV), angle of error (AE), correction index (CI), and magnitude of error (ME).


No statistically significant differences were found in 6-month postoperative sphere among WFG LASIK and SMILE groups (p=0.652). Postoperative manifest cylinder and spherical equivalent were significantly lower in the WFG LASIK group (p<0.001). The 6-month postoperative cylinder was ≤ 0.50 D in 79.8% and 100.0% of eyes in the SMILE and WFG LASIK groups, respectively (p<0.001). Concerning the vector analysis, significantly higher DV (p<0.001) and AE (p=0.021), and significantly lower CI (p=0.001) were found in the SMILE group. Mean ME was -0.07±0.20 and -0.20±0.35 in the WFG LASIK and SMILE groups, respectively (p=0.012).


WFG LASIK and SMILE are safe and effective for the correction of myopia combined with different levels of astigmatism, although there is a trend to undercorrection with SMILE. WFG LASIK achieves a higher predictability of the correction of astigmatism.

Financial Disclosure:

research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented

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