Posterior corneal surface changes after hyperopic laser in situ keratomileusis

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Hyperopic laser in situ keratomileusis (H-LASIK) is a refractive surgical procedure.
• Understanding changes in corneal topography after H-LASIK is crucial for patient outcomes.
• The posterior corneal surface's response to H-LASIK requires detailed investigation.

Purpose of the Study:

• To evaluate posterior corneal surface topographic changes after hyperopic laser in situ keratomileusis (H-LASIK).
• To assess these changes using Orbscan I slit-scanning corneal topography.
• To correlate topographic changes with attempted refractive correction.

Main Methods:

• Prospective study of 25 eyes from 15 patients undergoing H-LASIK.
• Posterior corneal topography measured preoperatively and 1 year postoperatively using Orbscan I.
• Analysis of topographic changes at nasal, temporal, superior, and inferior points within a 5.0 mm diameter zone.

Main Results:

• A mean backward shift of the posterior cornea was observed, ranging from -2.3 to -4.5 micrometers.
• No significant differences in posterior corneal surface changes were found between examined points.
• The magnitude of attempted correction significantly correlated with the observed posterior corneal topographic changes.

Conclusions:

• Orbscan measurements indicate a backward displacement of the posterior cornea after H-LASIK.
• These observed changes may represent artifactual shifts related to Orbscan's magnification ratio.
• The findings highlight the importance of considering potential measurement artifacts in posterior corneal topography post-H-LASIK.