Evaluation of the Retinal Nerve Fiber Layer and Ganglion Cell Layer After Laser-Assisted in situ Keratomileusis, Femtosecond-Laser in-situ Keratomileusis, and Small Incision Lenticule Extraction Using Optical Coherence Tomography

Yasmine Maher Shaaban,1,2,* Tamer Abdel Fattah Badran1,3,* 1Department of Ophthalmology, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 2Ain Shams Specialized Hospital, Cairo, 11588, Egypt; 3Eye Subspeciality Center (ESC), Cairo, 11402, Egypt*These authors contributed equally to this workCorrespondence: Yasmine Maher Shaaban, Department of Ophthalmology, Faculty of Medicine, Ain Shams University, Cairo, Egypt, Email [email protected]: To compare the effects of applied suction using microkeratome Laser-assisted in situ keratomileusis. (LASIK), femtosecond-laser in-situ keratomileusis (Fs-LASIK), and Small Incision Lenticule Extraction (Fe-SMILE) on the thickness of the Retinal Nerve Fiber Layer (RNFL) and Ganglion Cell Layer (GCL).Patients and Methods: This study included 72 eyes divided into three groups, each with 24 eyes. Each group underwent one of three different procedures. Preoperatively, at one day, one week, and three months postoperatively, Spectral Domain Optical Coherence Tomography (SD-OCT) was used to evaluate the thickness of RNFL and GCL.Results: Preoperatively and at one day, one week, and three months postoperatively, the mean values for RNFL thickness in the LASIK group were 93.2 ± 3.2, 105.9 ± 3.8, 106.2 ± 3.3, and 93.3 ± 3.6 μm, respectively; for the Fs-LASIK group, they were 95.9 ± 3.1, 100.2 ± 3.3, 100.5 ± 3.3, and 96.1 ± 3.1 μm, respectively; and for the Fe-SMILE group, they were 95.6 ± 1.9, 99.8 ± 1.7, 100.2 ± 1.8, and 95.8 ± 1.9 μm, respectively. The mean values for GCL thickness in the LASIK group were 73.9 ± 4.7, 90.2 ± 2.8, 90.8 ± 2.2, and 74.8 ± 4.5 μm, respectively; for the Fs-LASIK group, they were 77.8 ± 4.2, 80.2 ± 3.7, 80.3 ± 3.7, and 77.8 ± 3.5 μm, respectively; and for the Fe-SMILE group, they were 77.0 ± 3.7, 79.8 ± 3.6, 80 ± 3.7, and 77.1 ± 3.6 μm, respectively.Conclusion: All three procedures resulted in a transient increase in RNFL and GCL thicknesses. This increase was rapid, limited, transient, and reversible. It peaked for a week and returned to baseline by the end of this three-month study. At day one and day seven post-operatively, the Lasik group exhibited statistically significantly higher values than the Fs-Lasik and Fe-Smile groups.Keywords: microkeratome, bladeless laser, neurons, axons, imaging