Vector analysis of femtosecond laser-assisted astigmatic keratotomy after deep anterior lamellar keratoplasty and penetrating keratoplasty

Abstract

Femtosecond laser AK has similar safety for correcting suture-out post-DALK and PKP astigmatism; however, it is more effective for DALK. There is a positive correlation between surgically induced astigmatism and magnitude of error.

Comparison of manual and femtosecond astigmatic keratotomy in the treatment of postkeratoplasty astigmatism

“…Although both procedures trended towards undercorrection, FSAK’s correction index of 0.94 was significantly closer to 1.00 when compared to a correction index of 0.74 in manual AK. The correction index and index of success of FSAK in the current study are comparable to previously published vector analyses of FSAK outcomes (anNakhli & Khattak 2019; Elzarga et al 2019). One possible explanation for the low correction index seen in manual AK can be the fact that manual AK incisions were aimed at 75% depth while FSAK incisions were aimed at 90% depth.…”

“…This study compared outcomes of manual AK and FSAK performed in pairwise‐matched eyes with postkeratoplasty astigmatism. Although the efficacy and safety of FSAK in the management of postkeratoplasty astigmatism is well established in the literature (Kumar et al 2010; Fadlallah et al 2015; Trivizki et al 2015; Al Sabaani et al 2016; St. Clair et al 2016; Hashemian et al 2017; anNakhli & Khattak 2019; Elzarga et al 2019), there are little available data comparing it with manual AK techniques (Bahar et al 2008; Hoffart et al 2009; Al‐Qurashi et al 2019). To the best of our knowledge, previously published comparative studies did not find any statistically significant advantage of FSAK over manual AK in any visual or keratometric parameter (Bahar et al 2008; Hoffart et al 2009; Al‐Qurashi et al 2019).…”

“…While multiple single‐arm studies have found FSAK to be effective in reducing postkeratoplasty astigmatism (Kumar et al 2010; Fadlallah et al 2015; Trivizki et al 2015; Al Sabaani et al 2016; St. Clair et al 2016; Hashemian et al 2017; Chang 2018; anNakhli & Khattak 2019; Elzarga et al 2019), only two previous publications directly compared outcomes of FSAK with those of manual AK, and found no statistically significant differences in postoperative visual or refractive outcomes between the groups (Bahar et al 2008; Al‐Qurashi et al 2019). Similar results were found in a prospective comparison of FSAK (10 eyes) and mechanized AK (10 eyes), where a significant difference between the groups was found for manifest astigmatism, but not for any other visual or refractive parameter (Hoffart et al 2009).…”

Repeated Femtosecond Laser-Assisted Astigmatic Keratotomies in Post-Keratoplasty Eyes

“…One of the surgical options is known as arcuate keratotomy (AK). AK involves a series of incisions at approximately 80–90% corneal depth at the steep meridians of the mid-peripheral cornea [ 8 , 9 , 10 , 11 , 12 ]. This procedure can be performed manually or with a femtosecond (FS) laser (i.e., femtosecond laser-assisted astigmatic keratotomy or FLAK) [ 1 ].…”

“…FLAK is known for its effectiveness and safety in decreasing corneal astigmatism after a penetrating keratoplasty (PKP) [ 9 , 18 , 26 , 27 , 28 , 29 , 30 , 31 ]. In many cases, one AK is usually effective in decreasing the amount of astigmatism.…”