Refractive Corneal Lenticule Extraction by CLEAR: Analysis of our own Data 700 Patients

Purpose : analysis of the results of using CLEAR technique on a significant sample of patients with myopia of various degrees. Patients and methods . A total of 700 patients were included. There were 518 female (74%) and 182 male (26%) aged 18 to 50 (28.4 ± 7.6) years. Patients underwent CLEAR surgery (corneal lenticule removal for advanced refractive correction) in both eyes on the FEMTO LDV Z8 multifunctional femtosecond laser system. The average follow-up period for the patients was 6 months. Results . A statistically significant increase of UCDVA from 0.21 ± 0.14 before surgery to 0.95 ± 0.07 in the maximum follow-up period was shown (p < 0.05). Significant positive dynamics of the spherical component of refraction was noted (p < 0.05), with mean values of 0.14 ± 0.34 at the 6-month follow-up period, which corresponded to the target emmetropia. When analyzing the dynamics of the cylindrical component of refraction, its decrease from –0.82 ± 0.39 in the preoperative period to -0.40 ± 0.40 in the maximum followup period was shown (p > 0.05). Keratometry parameters K1 and K2 also showed a tendency to decrease after 1 day of observation with a subsequent increase in the observation period of 6 months. The greatest decrease in corneal thickness was noted on the next day after surgery (from 551.9 ± 34.3 to 439.4 ± 41.8 μm). Further, the increase of this index up to 455.7 ± 34.4 μm in the maximum observation period was noted. Among the complications we noted the loss of vacuum in two cases (0.28 %) at the initial stage of mastering the technique, incisional tear in 6 cases (0.85 %), opaque bubble layer in 7 cases (1 %), single subconjunctival hemorrhages. Conclusion . Our own experience of corneal lenticule removal for advanced refractive correction in 700 patients showed that the technique was easy to master, comfortable for surgeon and the patient, safe and effective in the correction of myopia and myopic astigmatism, and there were no significant decrease in corneal thickness during the follow-up period of 6 months.