Biomechanical changes in keratoconus after customized stromal augmentation

Area of Science:

• Ophthalmology
• Biomechanical Engineering
• Corneal Surgery

Background:

• Advanced keratoconus (KCN) involves progressive thinning and weakening of the cornea.
• Current treatments aim to halt progression and improve visual acuity.
• Small-incision lenticule extraction (SMILE) lenticules offer a potential option for stromal augmentation in KCN.

Purpose of the Study:

• To evaluate the biomechanical effects of stromal augmentation using SMILE lenticules in advanced KCN patients.
• To assess changes in corneal parameters measured by Corvis ST after lenticule implantation.

Main Methods:

• A clinical trial included 22 advanced KCN patients who received implanted lenticules (>100 μ).
• Corvis ST was used to measure biomechanical parameters at 3, 6, and 24 months post-implantation.
• Analysis included applanation events, concavity changes, and Vinciguerra screening parameters, with regression analyses for correlating factors.

Main Results:

• Significant improvements in corneal stiffness (e.g., increased HC time, SP-A1) and central corneal thickness were observed.
• Corneal deformation parameters (e.g., HC deformation amplitude, CBI) showed significant decreases.
• Mean spherical equivalent and keratometry values improved post-procedure.

Conclusions:

• Stromal augmentation with SMILE lenticules induces significant and measurable changes in corneal biomechanics in advanced KCN.
• These findings suggest potential for SMILE lenticules in managing advanced keratoconus by enhancing corneal structural integrity.