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Purpose: To compare postoperative evolution of visual acuity, flap thickness, and stromal optical density during the first 3 months after femtosecond (FS) laser in situ keratomileusis surgery for correction of myopia using the iFS 150-kHz FS laser and LenSx FS laser platforms. Methods: This was a prospective case series. Thirty-nine eyes treated with the iFS 150-kHz FS laser versus 38 refraction-matched eyes treated with the LenSx FS laser platform were included. Visual outcomes, flap morphology, and optical density of the stroma (in both flap and residual stromal bed) were compared at 4 visits during a three-month follow-up period. Results: No significant differences were found in uncorrected distance visual acuity in any of the follow-up visits (1 day −0.02 vs. −0.03; 1 week −0.04 vs. −0.03; 1 month −0.04 vs. −0.04; 3 months −0.03 vs. −0.05 logarithm of the minimum angle of resolution). Flaps created with the iFS 150-kHz FS laser were closer to the intended thickness (110 μm) in every postoperative comparison (1 day 108.6 vs. 124.3; 1 week 107.6 vs. 123.6; 1 month 110.4 vs. 126.8; 3 months 116.2 vs. 126.5 μm; P < 0.0001). Dispersion of values, standard deviation, intraflap range, and differences in symmetric points were lower in the iFS 150-kHz FS laser group. Flap stromal optical density was significantly higher in the LenSx FS laser group at day 1 and week 1 (134.5 vs. 158.9 gray scale unit [GSU]; P < 0.0001 and 144.8 vs. 160.1 GSU; P = 0.011, respectively). Residual stromal bed optical density was higher in the LenSx FS laser group at all postoperative visits, and the differences reached significance at 1 week postoperatively (121.9 vs. 135.4 GSU; P = 0.03). Conclusions: Although both devices provided satisfactory visual outcomes, significant differences were detected in flap parameters. Flaps made with the iFS 150-kHz FS laser were thinner, more uniform, transparent, and accurate compared with those obtained with the LenSx FS laser.

FS-LASIK with or without the intraoperative use of MMC is safe and effective to correct hyperopia. However, slightly better refractive outcomes and a lower incidence of re-treatments were observed when intraoperative MMC was used, at least in a 15-month follow-up. [J Refract Surg. 2018;34(1):23-28.].

A 52-year-old man had uneventful bilateral myopic laser in situ keratomileusis (LASIK) with planned monovision. Three months later, the left eye was retreated to improve the near vision. On postoperative day 1, the uncorrected distance visual acuity (UDVA) was 0.95 and the patient reported mild ocular pain. Stage 2 diffuse lamellar keratitis was observed. Despite hourly prednisolone instillation, the UDVA decreased to 0.1 and central flap necrosis syndrome was diagnosed. The flap was lifted and stromal bed irrigation performed. One month later, the UDVA was 0.05 with a hyperopic shift of +3.25 diopters and the flap, which had central haze and several striae, was amputated. Four months later, the UDVA was 0.05 with residual irregular astigmatism. Customized transepithelial photorefractive keratectomy (PRK) was performed; there were no postoperative complications. Three months after PRK, the UDVA was 0.8 with no refractive defect.

Phototherapeutic keratectomy (PTK) was performed to treat preexisting silent epithelial basal membrane dystrophy 1 month after laser in situ keratomileusis in 2 patients (4 eyes). The symptoms resolved dramatically during the follow-up period, with the patients reporting an immediate subjective visual improvement. At the last follow-up visit, 3 months after PTK, the eyes were asymptomatic, the epithelium was regular, no corneal erosions recurred, and the visual acuity was normal with no fluctuations. No eye developed haze greater than grade 1. There was no postoperative hyperopic shift, and no eye lost lines of best spectacle-corrected visual acuity.