One-year follow-up of changes in refraction and aberrations induced by corneal incision

Abstract

PurposeTo evaluate the surgically induced changes in refraction (sphere and astigmatism) and higher order aberrations by corneal incision for one year.SettingUniversity Hospital “Virgen de la Arrixaca”, Murcia, Spain.DesignRetrospective interventional case series.MethodsCorneal power, astigmatism and higher order aberrations (HOA) were calculated from corneal topography measured in 27 eyes prior to surgery and at 2 weeks, 1, 2, 3 and 6 months and 1 year following cataract surgery with 3.2-mm corneal incision. At every stage, optical changes were calculated as the difference between pre- and post-surgery data (in each follow-up) using the formulas of obliquely crossed cylinders for the refraction and Zernikes coefficients for HOA.ResultsAt 2 weeks after surgery the mean corneal values of induced sphere, cylinder and the root mean square (RMS) of HOA were +0.54±0.27 D, -0.77±0.32 D and 0.15 microns respectively. These parameters decreased significantly (p-values between 0 and 0.01) at 3 months to +0.33±0.27 D sphere, -0.50±0.24 D cylinder and 0.10±0.05 microns HOA and were stable at the next follow-ups. Induced spherical equivalent was around zero at all visits. The changes in HOA were mainly due to trefoil aberration.ConclusionsLinear corneal incisions do not change the spherical power but can induce significant values of astigmatism and trefoil aberration in the cornea. However, these changes revert fully or partially to preoperative values by the third month after surgery and remain stable with time.

Astigmatic correction of simultaneous femtosecond laser-assisted cataract surgery (FLACS) with intrastromal arcuate keratotomy (ISAK) versus Toric intraocular Lens Impantation with conventional phacoemulsification

“…In the toric IOL group, the mean reduction of corneal astigmatism was 0.20 D from topography and 0.32 D from the automated keratometer at the 1-month follow-up, which dropped to 0.07 D from topography and 0.13 D from the automated keratometer at the 6-month follow-up. These changes can be attributed to the effect of surgically induced astigmatism, and our results are consistent with results of previous studies [ 31 , 32 ]. Obviously, compared to baseline preoperative levels, the amount of reduction was not significant in the toric IOL group, while significant reduction of corneal astigmatism was noted in the AK group.…”

Influence of Overhanging Bleb on Corneal Higher-Order Aberrations after Trabeculectomy

“…Because OHB is one of the late complications, in our study, all cases were analyzed 3 months or more after TLE. Like cataract surgery, as for small-incision cataract surgery, changes in corneal aberrations may occur early after surgery; however, these changes gradually returned to preoperative values by 2 or 3 months after surgery [ 29 , 30 , 31 ]. In our study, all cataract surgeries were performed with small incisions using a phacoemulsification platform, and all cataract surgery cases were measured 3 months or more after cataract surgery.…”

Two Different Corneal Incision Designs for Correcting Corneal Astigmatism During Cataract Surgery With Multifocal Intraocular Lens Implantation

“…[19][20][21] In this study, the ocular HOAs decreased signi cantly after surgery, which indicated an increase of visual quality with mulitifocal IOL implantation. It has been shown that corneal incisions can increase the values of the root mean square (RMS) of corneal HOAs [22][23][24][25] ; thus, we assessed the changes in corneal aberrations after surgery. The wavefront parameters of total HOAs, trefoil, coma, spherical aberrations, and secondary astigmatism were compared, since these aberrations constitute the major components of HOAs.…”