Abstract
Purpose: :
To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct high-degree astigmatism on eyes with prior penetrating keratoplasty (PK).
Methods: :
Eighteen eyes of 18 patients, 8 men and 10 women, with high levels (> 4.00 diopters [D]) of post-PK astigmatism were studied in a nonrandomized, retrospective, observational case series. Mean age at the time of ICRS implantation was 31 years. Corneal tunnels were created by means of mechanical dissection in all eyes. Minimum time of ICRS implantation was 2 years after PK and at least 6 months after sutures removal. Main outcome measures included UCVA, BCVA, refraction, keratometry and computerized analysis of corneal topography.
Results: :
After a mean follow-up of 12 months, BCVA improved by at least 2 lines in 15 eyes (83.33%), did not change in 2 eyes (11.1%) and worsened in 1 eye (5.55%). UCVA improved in 13 eyes (72.22%) and did not change in 5 eyes (27.77%). Mean preoperative refractive astigmatism decreased from 7.25 to 3.17 D. Mean keratometric astigmatism decreased from 7.75 D preoperatively to 4.0 D after 1 year. The mean spherical component was reduced from -3.75 D preoperatively to -1.25 postoperatively. Stabilization of the effect was observed six months after surgery in most patients. There were no intraoperative complications. Ring segment explantation was performed in 1 eye (5.55%) due to extrusion, after 4 months. There were no signs of corneal endothelial decompensation, graft failures or rejection episode.
Conclusions: :
ICRS implantation is a useful option for the treatment of high-degree astigmatism following PK. It resulted in a significant reduction of refractive cylinder and increase of UCVA and BCVA.
Clinical Trial: :
www.clinicaltrials.gov NCT01018797
Keywords: refractive surgery: other technologies • cornea: clinical science • astigmatism