Comparison of 2 Types of Intrastromal Corneal Rings in Visual Function Improvement and Keratoconus Outcomes
To compare the short term results (3 month) of using Myoring and Keraring assisted by femtosecond laser in management of keratoconus with a view of establishing whether one type of treatment results in significantly better visual outcomes than the other.
This study evaluated 48 eyes of 39 patients aged between 18 and 50 with keratoconus that had implantation of Keraring ICRS (Group A) and Myoring (Group B). The corneal tunnels were created with a femtosecond laser. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, keratometry (K) readings, higher-order aberrations and complications in the 2 groups were compared preoperative, 1 week, 1 month and 3 months postoperatively. To assess patient’s satisfaction, a validated questionnaire was distributed to the patients at the end of this study period.
Group A (Keraring) comprised 31 eyes and Group B (Myoring) 17 eyes. The groups were comparable preoperatively then 1 week, 1 month and 3 months postoperatively. The postoperative increase in UDVA and CDVA was statistically significant in both groups (P<.05). Group A had greater improvement in CDVA than Group B at 1 month (both P<.001). At 3 months, the decrease in the mean maximum K power was statistically significant in Group A (51.27 diopters [D] +/- 4.45 [SD] to 47.86 +/- 3.38 D) and in Group B (51.11 +/- 4.53 D to 47.57 +/- 3.66 D) (P<.05). The mean reduction in maximum K was statistically significantly greater in Group A at 1 week, 1 month and 3 months (P = .018 and P = .024, respectively).
Although both Myoring and Keraring were effective and safe in managing keratoconus, the Keraring ICRS led to more improvement in CDVA and UDVA and a greater reduction in the maximum K value, with comparable postoperative profiles and no major complications.