Corneal aberrations after astigmatic keratotomy combined with laser in situ keratomileusis

Abstract

Astigmatic keratotomy increased higher-order corneal aberrations, both coma-like and spherical-like, whereas LASIK performed after AK increased the spherical-like aberration and reduced the coma-like aberration.

Keratectasia after bilateral laser in situ keratomileusis in a patient with previous radial and astigmatic keratotomy

“…15 In previous studies, we showed that LASIK performed in a cornea with radial incisions increases the values of higher-order aberrations, reducing the optical quality of the cornea. 16 These findings agree with those in other studies that report an increase in corneal and optical aberrations after RK and LASIK procedures performed separately. 17,18 We perform bilateral simultaneous LASIK in most patients; however, patients who have had previous incisional corneal surgery should be offered sequential LASIK because of the increased risk for complications such as keratectasia, reduced optical quality, unexpected outcomes including overcorrection and undercorrection, and disturbing side effects (eg, halos, glare, loss of BSCVA).…”

“…We have used a combination of AK followed by LASIK, a procedure we call LASAK, to correct high mixed and myopic astigmatism in a large number of patients; no cases of iatrogenic keratectasia occurred. 16 We also found that in LASAK, RK increased coma-and spherical-like higher-order corneal aberrations, whereas LASIK performed after RK increased spherical-like aberrations but reduced coma-like aberrations, which are more associated with regular and irregular astigmatism. However, in a study of LASIK in eyes with previous RK, we found an increase in comaand spherical-like aberrations after LASIK that was greater for coma-like aberrations than for spherical-like aberrations.…”

“…However, in a study of LASIK in eyes with previous RK, we found an increase in comaand spherical-like aberrations after LASIK that was greater for coma-like aberrations than for spherical-like aberrations. 16 In conclusion, previous corneal incisional surgery can increase the risk for post-LASIK keratectasia. We believe this risk should be included in the informed consent process for patients who have had previous corneal incisional surgery and are scheduled for LASIK.…”

Qualidade visual após retratamento de LASIK personalizado versus convencional

“…Com esta análise, fica claro que, após a cirurgia de retratamento personalizado Zyoptix, os olhos apresentaram um ganho de qualidade visual, principalmente para as freqüên-cias espaciais mais altas, que obtiveram sensibilidades ao contraste comparáveis com as sensibilidades para as freqüên-cias espaciais mais baixas. A melhora da sensibilidade ao contraste, principalmente para freqüências espaciais mais altas, pode ser apoiada pelas constatações de Montes-Micó et al (19) , que enfatizaram que o defocus e as aberrações ópticas primariamente afetam as freqüências espaciais altas.…”

Patterned corneal collagen crosslinking for astigmatism: Computational modeling study

“…Astigmatic keratotomy is a convenient method of astigmatism correction that is inexpensive to implement and easily combined with cataract surgery. However, it is less predictable than photoablative surgery, has a limited range of effect, can induce corneal higher-order aberrations (HOAs) that reduce visual acuity, 1,2 and can destabilize the cornea due to its dependence on deep disruption of collagen lamellar continuity. All the above techniques probably involve some degree of corneal material weakening either as a mechanism for inducing refractive effect or as a byproduct of treatment.…”