Femtosecond laser-assisted astigmatic keratotomy: a review

Area of Science:

• Ophthalmology
• Corneal Surgery
• Laser Vision Correction

Background:

• Astigmatic keratotomy (AK) is a common method for correcting astigmatism.
• Femtosecond laser-assisted astigmatic keratotomy (FSAK) offers advantages over conventional AK.
• This review focuses on FSAK for native and post-penetrating keratoplasty (PKP) eyes.

Purpose of the Study:

• To review the efficacy and complications of FSAK.
• To compare penetrating and intrastromal FSAK (IFSAK) techniques.
• To evaluate FSAK for astigmatism correction in native and PKP eyes.

Main Methods:

• Review of existing literature on FSAK techniques.
• Evaluation of astigmatic reduction percentages for penetrating and IFSAK.
• Analysis of complications associated with FSAK in different patient groups.

Main Results:

• Both penetrating and IFSAK significantly reduce astigmatism in PKP eyes (35.4%-89.42%) and native eyes (26.8%-58.62%).
• IFSAK provides comparable astigmatic reduction to penetrating FSAK with fewer risks like infection and wound gape.
• Complications in PKP eyes include overcorrection and visual loss; in native eyes, overcorrection and gas breakthrough.

Conclusions:

• FSAK effectively reduces high astigmatism in PKP eyes, though predictability can be low.
• IFSAK is suitable for correcting low astigmatism (<1.5 D) in native eyes during cataract surgery.
• Consideration of posterior cornea and biomechanics, along with nomograms, can enhance FSAK outcomes. Further large-scale studies are needed.