Flap dimensions created with the Hansatome microkeratome: correlation with Orbscan-derived anterior segment data

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Laser in situ keratomileusis (LASIK) is a common refractive surgery procedure.
• The Hansatome microkeratome is frequently used for creating corneal flaps during LASIK.
• Understanding flap dimensions and their correlation with ocular biometrics is crucial for surgical outcomes.

Purpose of the Study:

• To evaluate the flap dimensions generated by the Hansatome microkeratome.
• To investigate the relationship between these flap dimensions and anterior segment biometric data obtained from Orbscan II measurements.

Main Methods:

• The study included 44 myopic eyes from 22 patients undergoing LASIK with the Hansatome microkeratome.
• Intraoperative video recordings were analyzed to determine flap and hinge sizes.
• Orbscan II measurements provided data on corneal thickness, curvature, white-to-white diameter, and anterior chamber depth.
• Correlation analyses were performed between flap dimensions and biometric data.

Main Results:

• The mean corneal flap diameter was approximately 9.6 mm, with no significant difference between eyes.
• The mean hinge size was around 5.0 mm, also showing no significant inter-eye difference.
• A significant positive correlation was found between flap size and preoperative corneal thickness (r=0.487, P<.001).
• No significant correlations were observed between flap size and corneal curvature, white-to-white diameter, or anterior chamber depth.

Conclusions:

• The Hansatome microkeratome consistently produces corneal flaps close to the intended diameter.
• Preoperative corneal thickness is a key determinant of the resulting flap size in LASIK procedures.
• Hinge size did not correlate with the measured anterior segment biometric parameters.