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. 2020 Nov 13:14:3841-3854.
doi: 10.2147/OPTH.S267091. eCollection 2020.

Analysis and Causation of All Inaccurate Outcomes After WaveLight Contoura LASIK with LYRA Protocol

Manoj Motwani  1
Affiliations

Analysis and Causation of All Inaccurate Outcomes After WaveLight Contoura LASIK with LYRA Protocol

Manoj Motwani. Clin Ophthalmol. .

Abstract

Purpose: This study analyzes every eye that had an outcome greater than 0.25D of sphere or astigmatism from planned goal after treatment with WaveLight Contoura with LYRA Protocol.

Methods: The study included 266 consecutive eyes treated with LASIK Contoura using the LYRA Protocol. All LASIK procedures were performed on the WaveLight EX500 excimer laser. Flaps were created with either the Alcon WaveLight FS200 femtosecond laser or the Moria M2 microkeratome. Eyes that were off by >0.25 diopters (D) sphere or cylinder from the targeted goal within 3 months after surgery were identified and analyzed for cause. Topographical, higher-order aberration, and epithelial maps were created.

Results: Causes for inaccurate outcomes were biomechanical corneal change from LASK flap creation (9.78% of total eyes), pre-operative epithelial compensation of corneal higher-order aberration (4.1% of total eyes), changes to lamellar corneal tension from laser ablation causing a hyperopic shift (1.9% of total eyes), epithelial thickening over the ablation area post-operatively causing a refractive change (1.5% of total eyes), and posterior astigmatism (0.75%).

Conclusion: The causes of the majority of inaccurate outcomes have not been properly defined and must be incorporated into further improving outcomes. Current and planned advances in technology do not address the majority of these causes.

Keywords: LASIK; astigmatism; corneal epithelium; femtosecond laser; higher-order aberration; refractive error; Contoura; topography guided ablation; LYRA protocol.

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Conflict of interest statement

Dr. Motwani has received a grant from Alcon for a previous unrelated study in 2017. Dr. Motwani received non-financial support from Optovue, Inc. (loan of Optovue Avanti, clinical support in understanding analysis of data). Dr. Motwani has a patent pending on a theoretical device that could combine corneal HOA data and epithelial thickness data to achieve a more accurate refractive outcome. The author reports no other potential conflicts of interest for this work.

Figures

Figure 1
Figure 1
(A) Pre-op topography. (B) Pre-op pachymetry showing corneal thickness. (C) Pre-op OCT pachymetry. (D) Pre-op OCT epithelial thickness mapping (ETM). (E) 5 month post-op topography. (F) 5 month post-op OCT pachymetry. (G) 5 month post-op OCT ETM- note the irregular epithelial thickening at the edge of the epithelial ablation.
Figure 2
Figure 2
(A) Pre-op pachymetry showing corneal thickness.(B) Pre-op epithelium map. – 9 mm ETM (Avanti XR).
Figure 3
Figure 3
(A) Pre-op topography (Topolyzer Vario) (B and C) Pre-op OCT pachymetry and epithelial thickness map. 9mm ETM (Avanti XR), (D) 1 month post-op topography, (E and F) 1 month post-op OCT pachymetry and epithelial thickness map. 9mm ETM (G) Post-enhancement 1 year.
Figure 4A
Figure 4A
Continued.
Figure 4
Figure 4
(A) Pre-op topography. (B) Pre-op OCT pachymetry. (C) Pre-op epithelial thickness map. (D) Post-op 1 month topography. (E) Post-op 1 month OCT pachymetry. (F) 1- month post-op epithelial thickness map 9mm ETM (Avanti XR).  The thickened epithelium as opposed to pre-op. (G) Post-enhancement and 1 year post-op. (H, I) OCT Pachymetry map post enhancement and 1 year post-op.
Figure 5
Figure 5
(A) Pre-op topography map (Topolyzer Vario). (B) Pre-op pachymetry showing corneal thickness. (C) Pre-op epithelial thickness map. 9mm ETM (Avanti XR). (D) 3-month post-op topography. (E) 3-month post-op OCT pachymetry (F) 3-month post-op epithelial thickness map (ETM). (G) 4-month post ENH topography. (H) 4-month Post ENH OCT pachymetry. (I) 4-month Post ENH epithelial thickness map (ETM).
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