Efficacy of Intacs Intrastromal Corneal Ring Segments in Patients with Post-LASIK Corneal Ectasia

Purpose: To investigate the efficacy of Intacs implantation in post-LASIK corneal ectasia (PLE) Methods: In this retrospective study, 17 eyes of 12 patients with PLE, that had been implanted Intacs, were evaluated. These parameters were assessed: uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), manifest refractive spherical equivalent (MRSE), refractive cylinder (RC), mean Keratometry (Km), and topographic cylinder (TC). Also preoperatively, thinnest point thickness (TPT) was measured with rotating Scheimpflug camera. The results of single and double-segment Intacs implantation were also reported. Results: Mean UCVA logMAR value improved from 0.93±0.41 to 0.57±0.34 (p=0.007), and BSCVA logMAR from 0.36±0.34 to 0.18±0.18 (p=0.007). MRSE reduced from 4.15±2.71 to 2.48±1.57 diopter (D) (p=0.003), and Km from 44.57±3.93 to 43.00±3.96 D (p=0.003). RC changed from 2.65±1.91 to 2.59±1.12 D (p=0.776), and TC from 2.81±1.71 to 2.44±1.41 D (p=0.365), neither change was statistically significant. BSCVA and UCVA improved in both single and doublesegment groups. Conclusion: Intacs implantation can improve UCVA and BSCVA in cases of PLE, except when TPT is less than 350 microns. Both MRSE and Km reduced after surgery but astigmatism did not change.