Outcome of Intrastromal Corneal Ring Segments Implantation in Keratoconus: 5 Years Follow up

Background and objective: Keratoconus (KC) is a progressive non inflammatory bilateral (usually asymmetric) ectatic corneal disease characterized by paraxial stromal thinning, weakening that lead to corneal surface distortion, vision loss primarily from irregular astigmatism and myopia and secondly from corneal scar. The purpose of this study is to evaluate the results of implantation of Intrastromal Corneal Ring ( ICRS) in the cornea, the improvement of visual acuity and long-term mechanical stability results of keratometers values in KC after 5 years follow up of those cases. Methods: In this study ICRS segments were used for the management of KC, the study continued for ten years and each case completed 5 years of follow up, the study started in January 2010 and ended in October 2019, the patients were collected from Erbil Teaching Hospital or from the researcher’s private clinic. One or two ICRS were implanted in the keratoconus corneal area. Statistical analysis included preoperative and postoperative keratometry (K) values, and uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA). Results: Forty-six eyes of 37 patients were involved in this study, topographical corneal changes showed by the decrease in the mean of K1, medians of K2 and the mean of K1 &K2 especially in the first postoperative month and remain stable in most of the cases throughout the 5 years period, this was statistically significant by (P <0.001) value. The medians of UCVA increases in the first 3 years and at some time slightly decreases and remain stable throughout the 5 years of follow up but better than before the operations, and this results is also statistically significant by (P <0.001), the medians of CDVA improved from preoperative to postoperative period during the 5years follow up and remain stable, it was statistically significant (P <0.001), and this is emphasized by the number of the eyes had VA gain. The preoperative Mean of K declined from 52.0(±4) to 48.0(±3.3) in postoperative period and that was statistically significant (P <0.001) Conclusion: In this study there was a significant improvement in the visual acuity and keratometric readings of cases with advanced keratoconus and high astigmatism after implantation of ICRS in which the VA did not improved by glasses or contact lenses, subsequently there was improvement of the topographic state of the cornea and quality of vision for long time and thisdelay the need for corneal grafting surgery. so good selection of patients and implanting the proper ICRS by an expert surgeon will minimize the complication to nearly none. Further studies are needed with larger sample and longer period of follow up with new models of rings, nomograms or tissue implantation allograft.