Change in Vector Corneal Cyclinder Correction for Femtosecond Nonpenetrating Intrastromal Astigmatic Keratotomy During Femtosecond Laser–Assisted Cataract Surgery
To describe the stability of femtosecond laser non-penetrating intrastromal astigmatic keratotomy between 1 and 6 months after femtosecond laser-assisted cataract surgery.
Sevety-eight eyes with corneal astigmatism and a mean pre-op keratometric cylinder of 1.2 dioptres(range 0.46 to 2.63)underwent femtosecond laser-assisted cataract surgery with concurrent paired non-penetrating intrastromal astigmatic keratotomy (FSAK) at 8.0 mm optical zone. All cases were performed using the Catalys system, and utilising a nomogram previously described. Refraction, and 3 methods of keratometry and topography were taken pre and at 1 and 6 months post-op. A control group of 51 eyes were analyzed to determine the surgically induced astigmatism.
Prior to surgery the mean keratometric cylinder was 1.20dc in the group undergoing femtosecond astigmatic treatment and at 1 month post-treatment was 0.80dc and at 6 months was 0.78dc. The vector change between pre-op to 1 month was 0.72dc. The vector change between pre-op and at 6 months was also 0.72dc. The mean vector change between 1 month post op and 6 months post op was 0.41dc. There was no significant change in astigmatic cylinder effect between one and six months post op, demonstrating stability.
Femtosecond laser non-penetrating intrastromal astigmatic cylinders reduces mean astigmatism with a 75% of intended vector at 1 month and at 6 months. The astigmatic cylinder effect remains stable at 6 months postop.