Cornea Asphericity Changes In Keratoconus Corneas After Implantation Of Single Intracorneal Corneal Ring Segment Vs Implantation Of Double Intracorneal Segments In The Cornea For Treatment Of Keratoconus

To compare the effect of implantation of intracorneal rings on corneal sphericity between one segment ring and double segment ring implantation in keratoconus eyes.

Retrospective study done on 30 eyes of keratoconus patients between 2019and 2021. Intracorneal rings were implanted in the cornea for treatment of keratoconus The two study groups one had one segment ring implanted (group A)and the other had 2 segment rings implanted (group B0. One or two segments were implanted according to Kera ring nomogram. Corneal sphericity measured by Q value from Pentacam was studied preoperative and 6month postoperative, keratometric values, visual acuity and refraction of the patients were also studied preoperatively and 6month postoperative.

The changes in refraction were statistically significant before and after surgery in both groups regarding UCVA and refraction. Comparing both groups regarding sphere and cylinder refraction,we found that there was significant difference in sphere refraction pre and postoperatively (p<0.001& 0.009 respectively) and in cylinder refraction preoperatively (p =0.024). The changes in Q anterior were significant in both groups. Moreover, the changes in K1, K2, Kmax and astigmatism values before and after ring implantation were significant in both groups. Comparing the results of K1, K2, Kmax and Q anterior significant difference was observed between the two groups after surgery while there was significant difference in K1and K2 before surgery.

Intracorneal ring segments implantation for treatment of keratoconus either one or two rings change the anterior corneal asphericity approximating the Q anterior value to the ideal Q value(0.49)and improve the UCVA and the BCVA of patients besides decrease the refractive sphere and cylinder values. Implantation of two rings have higher effect than implantation of one ring on approximating the Q anterior value to ideal.