ESCRS - FP12.03 - Comparison Of Small Incision Lenticule Extraction With Stringent Head Positioning Versus Femtosecond Laser-Assisted Laser In Situ Keratomileusis With Iris Registration For <1.50 D Astigmatic Correction Follow-Up One Year

Comparison Of Small Incision Lenticule Extraction With Stringent Head Positioning Versus Femtosecond Laser-Assisted Laser In Situ Keratomileusis With Iris Registration For <1.50 D Astigmatic Correction Follow-Up One Year

Published 2024 - 42nd Congress of the ESCRS

Reference: FP12.03 | Type: Free paper | DOI: 10.82333/6n0g-hv10

Authors: Jihong Zhou* 1 , Fengju Zhang 2 , Wenjuan Wang 3 , Guoli He 3 , Yan Gao 3

1Beijing AierIntech Eye Hospital,Beijing,China;Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Science Key Lab, Capital Medical University,Beijing,China, 2Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Science Key Lab, Capital Medical University,Beijing,China, 3Beijing AierIntech Eye Hospital,Beijing,China

Purpose

To compare low to moderate (＜1.50D) astigmatism correction by vector analysis after small-incision lenticule extraction (SMILE) with stringent head positioning versus femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) with cyclotorsion compensation of iris registration.

Setting

A retrospective cohort study was conducted from August 2013 to December 2020 in Beijing Aier-Intech Eye Hospital. The study included 1,231 patients, with 1,570 eyes in the SMILE group and 503 in the FS-LASIK group. The study evaluated astigmatism in with-the-rule (WTR), oblique (OBL), and against-the-rule (ATR) orientations for both the right and left eyes.

Methods

The study included patients who underwent correcting astigmatism of ＜1.50 diopters (D) in either SMILE with stringent head positioning or FS-LASIK with cyclotorsion compensation of iris registration. The result was analysed using vector analysis based on the Alpins method. Variables are evaluated in all types of astigmatism, including target-induced astigmatism (TIA), surgically induced astigmatism (SIA), difference vector (DV), correction index (CI), angle of error (AE), absolute angle of error (AbsAE), the magnitude of error (ME), flatting index (FI), and index of success (IOS). The mixed linear model was used to compare the vector analysis results for both eyes between the groups.

                                               

Results

Significant differences between SMILE and FS-LASIK were observed among TIA, SIA, ME, and IOS (P=0.010, 0.003, 0.011, and 0.034, respectively). Further comparing the WTR astigmatism, TIA, SIA, DV, AE, ME, and IOS showed significant differences (P= 0.028, 0.028, 0.045, 0.025, 0.028, and 0.012, respectively); FS-LASIK was superior to SMILE in the right eye regarding AE, DV, and IOS (P=0.002, 0.001, and 0.000); however, the opposite in the left eye regarding DV and CI (P=0.001, 0.002). Fewer significant differences were found in OBL and ATR except for TIA and AE(P= 0.015 and 0.000, respectively); in the right eye, FS-LASIK was better than SMILE in terms of AE (P= 0.001), while in the left eye, SMILE was better for AE and DV (P= 0.007, 0.000).

Conclusions

A comparison was made between FS-LASIK and SMILE after 12 months to correct astigmatism (less than 1.50 D), and it was found that both procedures were safe and effective. FS-LASIK showed favourable outcomes for the right eye by compensating for cyclotorsion of iris registration. However, when  SMILE head positioning is stringent was found to be more effective for the left eye, especially for with-the-rule astigmatism.