AIM: To compare the anterior and posterior corneal astigmatism and total refractive astigmatism before and after MyoRing implantation in keratoconus(KCN)patients.

METHODS: In this historical cohort study, the preoperative and postoperative total refractive, anterior and posterior corneal astigmatism of KCN patients implanted with a 360-degree full-ring implant(MyoRing)were compared before and after four consecutive follow-up sessions at 3, 6, 9, and 12 mo after surgery.

RESULTS: The study encompassed 79 KCN patients(85 eyes), comprising 43 males and 36 females. The mean age of the patients was 29±7.41 years, ranging from 17 to 48 years. Throughout the follow-up sessions, a gradual decrease was observed in the trend of changes for total refractive astigmatism, anterior corneal astigmatism, and posterior corneal astigmatism. Postoperatively, total refractive astigmatism measurements exhibited a significant decrease of 2.09 D at 12 mo after MyoRing implantation(4.27±3.15 vs 2.18±1.63 D, P<0.001). Additionally, post-operative measurements revealed an enhancement of approximately 3.20 D and 0.59 D for anterior and posterior corneal astigmatism, respectively \〖6.40±1.90 vs 3.20±1.75 D for anterior corneal astigmatism(P<0.001)and 1.30±0.55 vs 0.71±0.35 D for posterior corneal astigmatism(P<0.001)\〗.

CONCLUSION: MyoRing implantation demonstrates significant improvements in astigmatism parameters, encompassing total refractive astigmatism as well as anterior and posterior corneal astigmatism.