The effect of lateral tarsal strip surgery on corneal biomechanical parameters measured by Corvis ST

Abstract

Purpose: To evaluate the effect of lateral tarsal strip (LTS) surgery for involutional ectropion on corneal biomechanical properties measured by the Corvis ST device. Methods: This prospective clinical study examined 23 patients (mean age 67.7 years) undergoing LTS for involutional ectropion. Corneal biomechanics were evaluated preoperatively and at 1 month postoperatively using the Corvis ST. Deformation amplitude, applanation length, highest concavity measurements, and corneal biomechanical indices were compared before and after LTS. Results: The second applanation deformation amplitude was significantly reduced after LTS compared to before (0.471 vs 0.428 mm, p = 0.031) indicating improved corneal stiffness. First applanation deflection length also decreased significantly following surgery (2.342 vs 1.967 mm, p = 0.043) suggesting enhanced corneal stability. Highest concavity deformation parameters were unchanged. Corneal biomechanical index, stiffness parameter, and intraocular pressure compensatory effect showed no significant differences pre- versus post-operatively. Conclusions: LTS surgery leads to measurable improvements in select corneal biomechanical parameters, specifically applanation deformation amplitude and deflection length. This preliminary analysis reveals subtle beneficial impacts on corneal stiffness and stability after surgical correction of ectropion. LTS appears to marginally augment corneal biomechanical properties based on Corvis ST assessment.

Keywords

• Lateral tarsal strip
• Ectropion
• Corneal biomechanics
• Corvis ST
• Cornea