Centration on the cornea vertex normal during hyperopic refractive photoablation using videokeratoscopy

Area of Science:

• Ophthalmology
• Refractive Surgery
• Laser Vision Correction

Background:

• Hyperopic LASIK aims to correct farsightedness using excimer laser technology.
• Accurate centering of the ablation profile is crucial for optimal refractive outcomes.
• Standard LASIK centering relies on pupil center, which may not align with the visual axis.

Purpose of the Study:

• To assess a novel method for centering excimer laser ablation in hyperopic LASIK.
• To evaluate the efficacy and safety of shifting the ablation center to the corneal vertex normal.
• To utilize a video-based eye tracker system for precise ablation centering.

Main Methods:

• Retrospective review of 52 hyperopic eyes treated with the ESIRIS excimer laser.
• Ablation center was adjusted from pupil center to corneal vertex normal.
• Pupillary offset was measured using Keratron Scout videokeratoscope; outcomes assessed at 3 months postoperatively.

Main Results:

• Preoperatively, vertex normal was consistently oriented nasally relative to the pupil center.
• 94% of eyes (49/52) achieved a refractive outcome within 0.50 diopters of spherical equivalent.
• No significant loss of best spectacle-corrected visual acuity was observed in any eye.

Conclusions:

• Shifting ablation to the corneal vertex normal is an effective strategy for hyperopic LASIK.
• The ESIRIS laser system, combined with videokeratoscopy data, provides predictable efficacy and safety.
• This technique enhances refractive outcomes in hyperopic LASIK by optimizing ablation centering.