title: Refractive and visual outcomes after Keraring intrastromal corneal ring segment implantation for keratoconus assisted by femtosecond laser at 6 months follow-up.
abstract: OBJECTIVE
  We attempted to evaluate the efficacy of femtosecond laser-assisted intrastromal corneal ring segment implantation in patients with keratoconus (KC).
  
  
  METHODS
  A retrospective interventional consecutive clinical study was conducted on patients with KC who were treated with femtosecond laser Keraring implantation. All procedures were performed at Ebsar Eye Center in the period from January 5, 2015, to February 28, 2016.
  
  
  RESULTS
  Thirty eyes of 20 patients were included in this study. The mean age of patients was 27.43±3.57 years. Eleven patients (55%) were female and nine patients (45%) were male. Keraring segments were successfully implanted in all eyes. There were no complications or need for ring repositioning. The follow-up period was 6 months postoperatively. There was a significant improvement in the mean logarithm of the minimum angle of resolution (LogMAR) of uncorrected visual acuity (UCVA) after Keraring segment implantation from 1.5±0.23 preoperatively to 0.54±0.16 at 6 months postoperatively (P=0.001). The preoperative mean LogMAR of best-corrected visual acuity (BCVA) was 0.85±0.17. At 1 month postoperatively, it was 0.35±0.15; at 3 months postoperatively, it was 0.26±0.11, and at 6 months postoperatively, it was 0.14±0.07 (P=0.001). The mean preoperative maximum keratometric value for 3 mm pupil in diopters (K max) significantly decreased from 55.85±5.44 preoperatively (N=30) to 44.05±1.64 D at 6 months postoperatively (P=0.001). There was a statistically significant reduction in the mean preoperative spherical equivalent from -5.43±1.76 D preoperatively to -2.43±0.95 D at 6 months postoperatively. No statistically significant differences were detected between 1 and 3 months of follow-up regarding the visual and refractive outcomes.
  
  
  CONCLUSIONS
  Analysis of the outcomes after Keraring ICRS implantation showed a significant postoperative corneal flattening with a subsequent increase in UCVA and BCVA. Using the femtosecond laser for tunnel creation made the procedure easy and fast with an accurate precise depth of implantation and reduced the risk of operative and postoperative complications.
authors.affiliation: Department of Ophthalmology, Benha University, Banha, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Heikal
authors.affiliation: Department of Ophthalmology, Benha University, Banha, Egypt.
authors.forename: Marwa
authors.initials: M
authors.lastname: Abdelshafy
authors.affiliation: Department of Ophthalmology, Benha University, Banha, Egypt.
authors.forename: Tarek T
authors.initials: TT
authors.lastname: Soliman
authors.affiliation: Department of Ophthalmology, Benha University, Banha, Egypt.
authors.forename: Abdelmonem M
authors.initials: AM
authors.lastname: Hamed
keywords: K astigmatism Keraring; femtosecond laser; spherical error