Refractive Changes Induced by Spherical Aberration in Laser Correction Procedures: An Adaptive Optics Study

Abstract

An inverse linear correlation exists between the refractive state of the eye and spherical aberration induced within the range of laser vision correction. Small values of spherical aberration do not worsen visual acuity or depth of focus, but positive spherical aberration may induce night myopia. In addition, the changes in spherical refraction when the pupil constricts may worsen near vision when positive spherical aberration is induced or improve it when spherical aberration is negative. [J Refract Surg. 2017;33(7):470-474.].

Effects of varying illumination on ocular aberrations and aberration compensation before and after small incision Lenticule extraction: a prospective cohort study

“…First, night myopic shifts caused by aberrations in the lens are not altered by SMILE, as demonstrated in the present study. Additionally, the exaggeration in postoperative positive spherical aberration may affect spherical refractive error [20,21]. Finally, aberrations such as coma may cause an amplification in astigmatism.…”

“…In addition, there was a correlation between glare and spherical aberrations. Furthermore, Amigó et al [21] discovered that differences in spherical aberration were inversely correlated with differences in subjective refraction, using an adaptive optics system. Thus, the higher occurrence of positive spherical aberration under low illumination may result in a myopic shift in postoperative eyes.…”

Introductory Chapter: Refractive Surgery

“…Currently, modern wavefront aberrometers are incorporating corneal topography systems to calculate the contribution of corneal aberrations (anterior and posterior), and internal aberration (from the crystalline lens) to complete ocular wavefront. Therefore, taking into account the available data, clinicians are able to decide on the type of personalized (customized) ablation profiles [14,15]. In cataract surgery or CLE/RLE candidates, besides standard preoperative assessment, IOL power calculation is crucial data for ensuring an effective surgery result.…”

Refractive surgery beyond 2020

“…The ideal flat wavefront for high fidelity may be optimal for young patients with intact accommodative abilities, whereas adjusted-shape designed to increase the depth of focus may be preferable for some presbyopic patients [17]. The functional needs of the patient will have to be taken into consideration to truly optimize wavefront refractive surgical strategies, and adaptative optic capabilities will certainly have to be accessible to achieve these tasks [18]. A new aberration series has been proposed to better fit the low-and higher-order components of the wavefront.…”

“…Light rays passing through the central zone of the inlay that does not have refractive power will be sharply focused for distance vision, while the refractive peripheral zone focus light rays on the retina for near vision (Table 1) [133,143]. Available scientific evidence with these inlays is far more limited, with monocular reduction of UDVA, loss of contrast sensitivity and a significant frequent loss of CDVA reported [4,[16][17][18].…”