KERATO Biomechanics Study 2: A Comparative Evaluation Before and After Corneal Cross-Linking Using Brillouin...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Biomechanics

Background:

• Keratoconus is a progressive corneal ectasia leading to vision impairment.
• Epithelium-off corneal cross-linking (CXL) is a standard treatment to halt keratoconus progression.
• Accurate assessment of biomechanical changes post-CXL is crucial for treatment efficacy.

Purpose of the Study:

• To evaluate biomechanical changes after epithelium-off corneal cross-linking (CXL) in progressive keratoconus.
• To compare the efficacy of Brillouin microscopy (BOSS) and ultra-high-speed Scheimpflug camera (Corvis ST) in detecting these changes.

Main Methods:

• A retrospective, multicenter study included 23 eyes from 24 patients with progressive keratoconus.
• Biomechanical properties were assessed pre- and 1-month post-CXL using BOSS and Corvis ST.
• Brillouin measurements included Brillouin frequency shift (BFS) in different corneal sectors. Corvis ST assessed dynamic corneal response (DCR) parameters like inverse concave radius (1/R) and stress-strain index (SSI).

Main Results:

• Brillouin microscopy showed significant corneal stiffening post-CXL, with increased mean and maximum BFS in inferior and equatorial regions (P < .001).
• A strong correlation was found between preoperative BFS and postoperative changes (R² = 0.597, P < .001).
• Corvis ST confirmed stiffening via decreased 1/R values (P = .002), but SSI showed no significant change.

Conclusions:

• Both Brillouin microscopy and Corvis ST effectively detect corneal stiffening after CXL.
• Brillouin microscopy provides localized biomechanical insights, complementing Corvis ST.
• These findings support Brillouin microscopy's potential for guiding customized CXL treatments.