Biomechanics in DALK: Big bubble vs manual lamellar dissection

Area of Science:

• Ophthalmology
• Biomaterials Science
• Surgical Innovation

Background:

• Deep anterior lamellar keratoplasty (DALK) is a surgical technique for corneal diseases.
• Big bubble formation is a critical step in DALK, aiming to separate Descemet's membrane.
• Failed big bubble formation necessitates manual lamellar dissection, raising questions about its impact on corneal biomechanics.

Purpose of the Study:

• To compare the biomechanical properties of corneal tissue after DALK surgery.
• To evaluate differences between successful big bubble formation and manual lamellar dissection.
• To assess the influence of donor-trephine punch size disparity on corneal biomechanics.

Main Methods:

• A retrospective comparative study of 60 keratoconus patients who underwent DALK.
• Patients were grouped based on successful (big bubble +) or failed (big bubble -) big bubble formation.
• Corneal hysteresis and corneal resistance factor were measured using the Ocular Response Analyzer 12 months post-surgery.

Main Results:

• No statistically significant difference in corneal hysteresis or corneal resistance factor between big bubble (+) and big bubble (-) groups.
• Corneal hysteresis and resistance factor were positively associated with central corneal thickness.
• No relationship was found between punch sizes and corneal hysteresis or resistance factor.

Conclusions:

• Corneal biomechanical properties (hysteresis and resistance factor) are comparable after DALK, regardless of big bubble formation success.
• Manual lamellar dissection is not disadvantageous concerning the biomechanical integrity of the cornea.
• Central corneal thickness is a significant factor influencing corneal biomechanical measurements post-DALK.