Long-Term Study of Biomechanics and Associated Factors of Lenticule Intrastromal Keratoplasty for the Correction of Hyperopia.

Purpose: To investigate long-term corneal biomechanical changes and influencing factors of lenticule intrastromal keratoplasty (LIKE) in the treatment of hyperopia.

Methods: 9 eyes of 9 patients with a mean age of 34.00 ± 9.34 years were included. Full-scale examinations were conducted on all patients preoperatively and during 2 years of follow-ups. Topographical and biomechanical parameters were evaluated with Pentacam and Corvis ST preoperatively and during all follow-up visits.

Results: All surgeries were uneventful without complications. The safety index was 1.27 ± 0.64 and the efficacy index was 0.96 ± 0.62 at the last follow-up. The central corneal thickness (CCT) ( P < 0.05*) and the thinnest corneal thickness (TCT) ( P < 0.05*) significantly increased 2 years postoperatively while the Ambrosio relational thickness horizontal (ARTh) ( P < 0.05*) and the Corvis biomechanical index (CBI) ( P < 0.05*) decreased. The deformation amplitude ratio (DA ratio), the stiffness parameter at the first applanation (SP-A1), the stress-strain index, and the posterior elevation (PE) remained stable 2 years after LIKE. The DA ratio was negatively correlated with the CCT and the TCT (r = -0.54, P = 0.019*; r = -0.59, P = 0.009*) while the SP-A1 was positively correlated with the CCT and the TCT (r = 0.84, P < 0.001*; r = 0.87, P < 0.001*). The ARTh was positively correlated with the TCT (r = 0.47, P = 0.049*), and the CBI was positively correlated with the PE (r = 0.63, P = 0.005*).

Conclusions: LIKE for the correction of hyperopia is safe and effective in the long term. The PE remained stable and the CBI improved 2 years postoperatively.