Evaluation of 4 corneal astigmatic marking methods.

Area of Science:

• Ophthalmology
• Surgical Technology
• Corneal Surgery

Background:

• Accurate preoperative corneal marking is essential for effective astigmatism-reducing surgery.
• Toric intraocular lenses require precise alignment to achieve the desired refractive outcome.
• Patient positioning changes (upright to supine) can induce cyclotorsion, impacting surgical accuracy.

Purpose of the Study:

• To compare the accuracy of four different corneal marking devices prior to astigmatism-reducing surgery.
• To evaluate rotational deviation and vertical misalignment associated with each marking method.

Main Methods:

• A randomized, examiner-masked clinical trial involving 60 patients.
• Four corneal marking methods were assessed in the sitting position: slitlamp with insulin needle, pendular marker, bubble marker, and tonometer marker.
• Standardized photographic techniques documented marks, followed by assessment of rotational and vertical deviations.

Main Results:

• The pendular marker demonstrated the least mean rotational deviation (1.8 degrees).
• Significant differences in rotational deviation were found between the pendular marker and both the bubble and tonometer markers.
• The slitlamp-marking device exhibited the least mean vertical misalignment (0.28 mm), with no significant differences between groups for this parameter.

Conclusions:

• All tested corneal marking devices exhibited some deviation from the reference meridian.
• The pendular marker offers the most precise rotational alignment, crucial for toric IOLs.
• Accurate corneal marking is critical to mitigate the impact of cyclotorsion and maximize the efficacy of astigmatism correction.