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Since the late 1990s, the femtosecond laser technology has gained access to the field of refractive surgery. Initially, its major advantages over mechanical keratomes such as higher precision with less complications were used for the sole creation of the flap. Economic pressures when using two different and costly lasersystems during one operation (the refractive procedure remained the domain of the 193nm-argon-fluoride excimer laser) and the encouraging experiences made regarding flap creation helped to develop the procedure called refractive lenticule extraction (ReLEx®flex) using the femtosecond laser system Visu-Max™ (Carl Zeiss Meditec AG). This new all femtosecond refractive procedure provides the basis for this thesis. After initial tests on a small number of patients and minor adaptations of technical parameters, a feasibility study could be performed on 108 eyes during the years 2006 and 2007.
The main objective of this thesis was to provide long-term data concerning safety, predictability and stability of this new procedure, to look for late onset side effects and to enquire about patients satisfaction with the achieved result.
A total number of 22 patients (41 eyes) volunteered to participate at the follow-up approximately five years after the operation. In order to explore the quality criteria mentioned above, data such as corrected and uncorrected distance visual acuity (CDVA, UDVA) and objective and manifest refraction was documented and analized. In addition, the patients were subjected to a slit-lamp examination and were asked to complete the questionnaire used at previous visits.
In summary one hundred percent of eyes were within ± 1,00 D and seventy-three percent within ± 0,50 D of target refraction. No eye lost two or more lines and only one eye lost one line of CDVA. The mean regression rate over the five year period was 0,07 D. No late onset side effects were reported and for ninety-four percent of eyes the overall satisfaction with the achieved result was ninety percent or higher. All patients, except for one who did not provide an answer to this question, would choose this operation procedure again.
These results indicate that the Refractive Lenticule Extraction is an effective and safe procedure for the treatment of myopia with or without astigmatism and has excellent long-term stability. These findings were published in the Journal of Cataract & Refractive Surgery (Blum et al. 2014).