Higher-order Aberrations Root Mean Research Articles

Patient-Reported Outcomes and Higher Order Aberrations Following Topography-Guided Femtosecond Laser-Assisted In Situ Keratomileusis.

To examine patient-reported outcomes and higher order aberrations following topography-guided laser-assisted in situ keratomileusis (LASIK). This was a prospective, nonrandomized observational study at a single academic center. Sixty eyes from 30 patients underwent bilateral topography-guided femtosecond LASIK for correction of myopia using the VisuMax 500 femtosecond laser (Zeiss; Oberkochen, Germany) and Allegretto Wave Eye-Q 400 Hz Excimer Laser (Alcon/Wavelight; Erlangen, Germany) with the Contoura topography system (Alcon; Geneva, Switzerland) for topography-modified refraction. The main outcomes of this study were higher order aberrations (HOAs) and results from the Patient-Reported Outcomes with LASIK questionnaire. There was a small, significant increase in HOA root mean square, spherical aberration, and coma at 1, 3, 6, and 12 months following topography-guided LASIK (all P < 0.05), but no change in trefoil. In addition, self-reported worry related to vision (P < 0.001) and ability to perform activities (P < 0.001) significantly improved after surgery. The prevalence of double images, glare, halos, or starbursts decreased from 73% preoperatively to 56%, and no participants reported "very" or "extremely" bothersome visual symptoms after 12 months. Dry eye symptoms per Ocular Surface Disease Index score decreased significantly at 6 (P = 0.01) and 12 (P = 0.002) months after surgery. There was a 100% satisfaction rate with visual outcomes and duration of time to improvement in vision following the procedure. Although there was an increase in HOAs following topography-guided LASIK, there were significant improvements in the presence of double images, glare, halos, and starbursts and vision-related quality-of-life metrics. Overall satisfaction rates in this study were high.

Corneal Higher Order Aberrations and Epithelial Remodeling With Femtosecond Laser-Assisted LASIK Topography-guided and Customized Asphericity Ablation in the Contralateral Eye: A Randomized, Double-Blind, Prospective Study.

To evaluate refractive results, corneal higher order aberrations (HOAs), and epithelial remodeling in the preoperative and postoperative period of regular corneas that had topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) (Contoura WaveLight; Alcon Laboratories, Inc) and compare them with the contralateral eye that underwent ablation customized by asphericity (Custom-Q WaveLight; Alcon Laboratories, Inc) in myopic eyes with or without astigmatism. A prospective, randomized, and double-blind study was conducted. Patients underwent preoperative and postoperative epithelial mapping and corneal tomography to assess the epithelial thickness map, HOAs of the corneal anterior surface, visual acuity, and refractive evaluation. This study enrolled 96 normal eyes of 48 patients. Uncorrected distance visual acuity of 20/20 or better was achieved in 97% of patients and gains in corrected distance visual acuity and effectiveness in correcting refractive astigmatism were similar in both techniques. Seventeen sectors of the corneal epithelium map were assessed by spectral-domain optical coherence tomography and no significant differences were found between techniques preoperatively and postoperatively (P > .05). HOA root mean square, coma Z3±1, trefoil Z3-3, and tissue consumption exhibited statistically significant between-technique differences (P < .05). The Contoura and Custom-Q techniques were similar with respect to refractive and visual outcomes after 3 months, as well as in epithelial remodeling. The Contoura provides lower postoperative HOA root mean square, coma Z3±1, and trefoil Z3-3 values, but the techniques showed no differences in the correction of the corneal astigmatic wavefront component and in the spherical aberration after 3 months. [J Refract Surg. 2023;39(11):751-758.].

Rate of fractional change in corneal tomography parameters in keratoconus using a combination of predictive parameters

BackgroundTo compare the rate of fractional change for multiple corneal tomographic factors in progressive keratoconus (KC).MethodsIn this retrospective case series, 40 eyes (40 patients) with progressive KC (increase in central keratometry of 1.00 D or maximum keratometry of 1.50 D on two visits at least six months apart) were included. Cases with previous history of ocular surgery, poor scans, corneal scars, severe dry eyes, post-excimer ectasia, pellucid marginal degeneration were excluded. Medical records, corneal tomography and anterior corneal wavefront (8 mm) (Scheimpflug tomography, Pentacam, Oculus, Germany) were analyzed. Rate of fractional change (Rx = (x1 − x0)/(|x0|tm)); where, x1 = value at follow-up, x0 = value at initial visit and tm = time in months, was measured.ResultsThe mean age of the patients was 30.0 ± 8.4 years. The mean follow-up duration was 8.9 ± 4.2 months. Coma (0.076 ± 1.4) had the largest rate of fractional change (P = 1.7 × 10−14, Kruskal–Wallis test). The rate of fractional change was higher for aberrometric parameters (anterior corneal higher-order aberrations root mean square and anterior coma) compared to pachymetric and keratometric parameters (P values ranging from 1.4 × 10−4 to 7.4 × 10−10, Mann–Whitney test, effect size ranging from 0.4–0.7). The rate of fractional change was comparable between pachymetric and keratometric factors (P > 0.05 for all comparisons, Mann–Whitney test).ConclusionsAnterior corneal wavefront, especially anterior coma, were noted to have higher rate of fractional change compared to single point keratometric and pachymetric indices in progressive KC. This information can be used for decision-making when monitoring patients with KC.

Spherical Aberration of Cataractous Eyes and Its Relationship With Age, Ocular Biometry, and Various IOL Platforms.

To determine the median spherical aberration (SA) of the cataractous population, how it relates to biometry, and the theoretical effect of different intraocular lens (IOL) platforms. A retrospective chart review of patients undergoing cataract surgery evaluation with a high quality Pentacam (Oculus Optikgeräte GmbH) were included. Age, gender, Q-value, mean total SA, higher order aberration root mean square wavefront error, and equivalent keratometry were collected from the Holladay report and axial length and anterior chamber depth (ACD) from the IOLMaster 700 (Carl Zeiss Meditec AG). Data from 1,725 eyes of 999 patients were collected. SA had a median of 0.37 µm (95% confidence interval: 0.36 to 0.38. Age (r = .136, P < .001), Q-factor (r = .743, P < .001), and higher order aberration root mean square wavefront error (r = .307, P < .001) were positively correlated with SA. Average equivalent keratometry (r = -.310, P < .001) was negatively correlated with SA. Axial length (r = -0.037, P = .120) and ACD (r = .004, P = .856) had no association with SA. Up to 1,499 (86.9%) theoretically had SA moved closer to zero with IOLs that had negative SA. Up to 102 (5.9%) had SA theoretically worsened. SA is not normally distributed, suggesting that there may be no "average" SA that IOLs should aim to correct. Patients might benefit from tailoring IOL choice to individual SA. Without access to SA data, eyes with steeper average keratometry or younger patients may have less SA, which could influence IOL choice. [J Refract Surg. 2023;39(2):89-94.].

Astigmatism Tolerance and Visual Outcomes After Bilateral Implantation of a Hybrid Continuous Transitional Focus IOL.

To evaluate the astigmatism tolerance and the visual outcomes after implantation of a premium intraocular lens (IOL) with a continuous transitional focus (Precizon Presbyopic; Ophtec BV) in pseudophakic presbyopia correction. This prospective study enrolled 20 patients (40 eyes) after bilateral phacoemulsification and IOL implantation. Corrected and uncorrected visual acuities at 4 m and 80, 67, and 40 cm (CDVA, UDVA, DCI80VA, UI80VA, DCI67VA, UI67VA, DCNVA, and UNVA), astigmatic and spheric defocus curve, mean reading speed (MRS), critical print size (CPS), contrast sensitivity, optical aberrations (modulation transfer function [MTF] cut-off, Strehl ratio, and higher order aberration root mean square [HOA RMS]), objective halometry, and National Eye Institute Refractive Error Quality of Life Instrument 42 [NEI RQL-42] questionnaire were evaluated 3 months after surgery. Astigmatic defocus curves revealed a tolerance up to -1.00 and +0.75 diopters (D) for with-the-rule astigmatism, and up to -1.00 and +1.00 D for against-the-rule astigmatism. Binocular spheric defocus curve showed that the mean visual acuity was greater than 0.15 logMAR from 1.00 to -1.00 D. MRS, CPS, MTF cut-off, Strehl ratio, and HOA RMS were 116.97 ± 21.94 words/min, 0.45 ± 0.06 logRDA, 20.03 ± 4.86 cycles/degree, 0.11 ± 0.07, and 0.28 ± 0.09, respectively. Contrast sensitivity was within the normal range for all tested light conditions. The NEI RQL-42 evidenced high subjective satisfaction for all subscales, especially for far vision, activity limitations, dependence on correction, suboptimal correction, appearance, and satisfaction with correction. The Precizon Presbyopic IOL allows good astigmatism tolerance and both objective and subjective high quality of vision. [J Refract Surg. 2023;39(1):33-39.].

Survival analysis of myopic regression after small incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis for low to moderate myopia

BackgroundTo report the predictive factors of myopic regression in patients who had undergone small incision lenticular extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileuses (FS-LASIK) after 3–12 months of follow-up.MethodsThis retrospective case series study recruited patients with a subjective sphere of − 1.00 to − 6.00 D myopia. SMILE was performed in 1629 eyes of 1629 patients with a subjective refraction spherical equivalent (SEQ) of − 4.57 ± 1.20 D and 1414 eyes of 1414 patients with a subjective SEQ of − 4.53 ± 1.26 D in FS-LASIK. Refractive outcomes were recorded at 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Predictors affecting myopic regression and other covariates were estimated with a Cox proportional hazard (Cox PH) model for the two surgical methods.ResultsAt 12 months, no significant difference was evident in the efficacy (P = 0.934), predictability (P = 0.733), or stability (P = 0.66) between FS-LASIK and SMILE. The survival rates were 83.7% in the FS-LASIK group and 88.1% in the SMILE group. Multivariate analysis by the Cox PH model revealed a similar probability of postoperative myopic regression with SMILE or FS-LASIK (P = 0.630). Predictors of myopic regression included preoperative higher-order aberration root mean square with 3 mm pupil diameter (pre-HOA-RMS3) (P = 0.004), anterior chamber depth (ACD) (P = 0.015), pre-subjective sphere (P = 0.016), corneal diameter (P = 0.016), optical zone (OZ) (P = 0.02), and predicted depth of ablation (DA) (P = 0.003).ConclusionSMILE and FS-LASIK had a similar risk of myopic regression for low to moderate myopia. Pre-HOA-RMS3, ACD, pre-subjective sphere, corneal diameter, OZ, and predicted DA were predictors of myopic regression.

Objective and Subjective Quality of Vision After SMILE for High Myopia and Astigmatism.

To report subjective and objective quality of vision (QoV) results for high myopic small incision lenticule extraction (SMILE) between -9.00 and -13.00 diopters (D). This was a prospective study recruiting 114 patients undergoing SMILE with attempted spherical equivalent refraction (SEQ) correction from -9.00 to -13.00 D, and cylinder up to 5.00 D. Patients were informed before surgery of the increased risk of QoV symptoms. Patients completed the Rasch validated QoV questionnaire. Objective QoV was assessed by corneal and whole eye aberrations, HD Analyzer Objective Scatter Index (OSI) (Keeler), and contrast sensitivity. Patient satisfaction was assessed on a scale from 0 (very dissatisfied) to 10 (very satisfied). Individual item and total Rasch-scaled scores for the three subscales (frequency, severity, and bothersomeness) of the QoV questionnaire were calculated before and 12 months after surgery. The mean patient satisfaction score was 9.27 ± 1.18 (range: 2 to 10), 8 or higher in 93%, and 7 or higher in 98% of patients. One patient with a satisfaction score of 2 had a simple refractive error re-treatment and then reported a satisfaction score of 10. The total mean ± standard deviation Rasch-scaled QoV score for the frequency, severity, and bothersomeness subscales before surgery was 24 ± 19, 20 ± 16, and 19 ± 18, respectively. Scores increased after surgery to 41 ± 18, 32 ± 16, and 30 ± 21, respectively (P < .001). Corneal aberrations (6 mm, OSI) increased on average by 0.39 µm for spherical aberration, 0.41 µm for coma, and 0.56 µm for higher order aberrations root mean square. OSI increased on average by 0.58. There was a small but statistically significant improvement in contrast sensitivity at 3, 6, 12, and 18 cycles per degree. There were no statistically significant correlations found between subjective scores for starbursts and objective measurements. Satisfaction was high following SMILE for high myopia. As expected, there was an increase in QoV symptoms, mainly glare and starbursts. The acceptance of QoV symptoms for high myopic SMILE was high, indicating that residual refractive error and visual acuity are the major drivers for patient satisfaction with appropriate preoperative informed consent. [J Refract Surg. 2022;38(7):404-413.].

Changes in higher order aberrations after central corneal regularization - a comparative two-year analysis of a semi-automated topography-guided photorefractive keratectomy combined with corneal cross-linking

BackgroundThe optical quality in progressive keratoconus deteriorates due to ectasia and distortion of the corneal shape and optics. While corneal cross-linking (CXL) aims at stopping disease progression, “CXL-Plus” combines CXL with excimer laser ablation to improve visual function. Central Corneal Regularization (CCR) represents a therapeutic excimer laser modality specifically designed to smoothen the ectatic corneal shape and to reduce higher order aberrations (HOA). We set out to compare CXL-Plus, consisting of CXL combined with CCR, with CXL by itself for patients with progressive keratoconus.MethodsRetrospective 2-year matched group analysis of patients who either underwent CXL-Plus (n = 28) or CXL as a sole procedure (n = 28) for progressive keratoconus. Main outcome parameters were HOA, visual function and tomographic results 12 and 24 months postoperatively.ResultsAfter 12 months, the total HOA root mean square wavefront error was reduced from 0.79 ± 0.30 to 0.40 ± 0.19 μm (CXL-Plus; p < 0.0001) and changed from 0.71 ± 0.28 to 0.73 ± 0.36 μm (CXL; p = 0.814). Uncorrected distance visual acuity improved from 0.70 ± 0.35 to 0.36 ± 0.29 logMAR (CXL-Plus; p = 0.0002) and from 0.65 ± 0.39 to 0.46 ± 0.37 logMAR (CXL; p = 0.067), translating to gains of three or more lines in 50% (CXL-Plus) and 36% (CXL) of patients. The steepest keratometry value (Kmax) regressed by 5.84 D (CXL-Plus; p < 0.0001) and 0.66 D (CXL; p = 0.752). For none of the investigated parameters a statistically significant change could be shown between 12 and 24 months.ConclusionsCXL-Plus in the form of a CCR reduces HOA and Kmax more effectively than CXL as a sole procedure.

Corneal higher order aberrations after intrastromal corneal ring segment implantation for keratoconus

Background Keratoconus is the most common primary corneal ectatic disease. It is a progressive, noninflammatory, and localized paraxial stromal thinning of the cornea, which often results in bilateral and asymmetrical corneal distortion and anterior corneal protrusion. Patients with corneal protrusion often develop high myopia and irregular astigmatism, resulting in significant impairment of visual acuity.Purpose The aim of this study was to assess changes of higher order aberrations (HOAs) induced by the implantation of intrastromal corneal ring segments (ICRS) in keratoconus.Patients and methods In the current study, a prospective analysis of HOAs, measured by using Pentacam, before and after ICRS implantation was done in a nonrandomized consecutive series of 20 eyes having progressive grade II/III keratoconus (Amsler-Krumeich classification).Results At 1 month postoperatively, a statistically highly significant reduction was found in keratometric readings. The flattest keratometric reading (K1) improved from 46.42±3.08 D preoperatively to 43.25±3.45 D postoperatively, which is highly significant (P<0.01). The steepest keratometric reading (K2) improved from 49.96±3.29 D preoperatively to 46.04±3.15 D postoperatively, which is highly significant (P>0.01). The total HOA root mean square improved from 1.55±0.54 preoperatively to 1.26±0.38 postoperatively, with a statistically significant difference (P<0.05). Primary coma improved from 1.27±0.54 preoperatively to 0.87±0.27 postoperatively, which is highly significant (P>0.01). In addition, astigmatism root mean square changed from 2.42±1.52 preoperatively to 1.98±1.31 postoperatively. Trifoil and quadrifoil showed nonsignificant changes (P>0.05).Conclusion ICRS (Keraring) implantation using femtosecond laser is an effective method for improvement and stabilization of optical, keratometric, and aberrometric measures in keratoconic eyes. Most of the improvement in HOAs was achieved after 1 month and nearly locked up or changed insignificantly till the third month.

Visual Performance and High-Order Aberrations with Different Contact Lens Prototypes with Potential for Myopia Control

ABSTRACT Purpose Contact lenses (CLs) used for myopia control incorporate variable power distribution across the optic zone potentially creating degradation of the high-order aberrations. The present study aims to evaluate the retinal image quality and visual performance in three prototypes of CLs intended to control axial elongation of the eye before they are considered for clinical trials. Methods This is a non-dispensing cross-over, double-blind study where 30 right eyes of myopic subjects worn 3 multifocal test lenses and 1 monofocal control lens in random order. Lens 1 was a radial refractive gradient design (center distance) and Lens 2 and 3 center-near with an additional annular ring for near. Nominal add power was 2.00D, 1.50D, and 2.00D, respectively. Subjects had an age 21.96 ± 2.23 years [18–30] and mean spherical equivalent refraction M = −2.23 ± 1.50D [−0.75 to −5.50] with refractive astigmatism below −0.75D. Higher-order aberrations (HOA), glare formation (halo), high- and low-contrast LogMAR visual acuity (VA), and contrast sensitivity function (CSF) was measured under monocular conditions. Results All individual terms of HOA and total root mean square from 3rd to 8th order increased significantly with the 3 test lenses compared to control. Between test lenses, Lens 1 increased significantly the higher HOA compared with Lens 2 and Lens 3. Halo size was significantly larger with test lenses compared with control, with Lens 1 showing the largest. VA under high-contrast conditions was similar for all lenses. Under low-contrast conditions, Lens 1 and Lens 2 performed significantly worse than control (Bonferroni post hoc correction, p < 0.001). CSF was below normal limits with Lens 1 for 3 and 6 cpd spatial frequency but was not significantly different between test lenses and control. Conclusions Lenses with larger stabilized areas for distance vision interfere less with VA and induce lower values of HOA and image degradation.

The comparison of visual outcomes, aberrations, and Bowman\u2019s layer micro-distortions after femtosecond laser small-incision lenticule extraction (SMILE) for the correction of high and moderate myopia and myopic astigmatism

BackgroundThis study compares the clinical outcomes of femtosecond laser small-incision lenticule extraction (SMILE) for the correction of myopia and myopic astigmatism greater than − 10 D, and − 10 D or less respectively.Methods60 eyes/patients were equally selected into group 1 (myopia and myopic astigmatism of − 10 D or less) and group 2 (myopia and myopic astigmatism of over − 10 D), both of which were treated with SMILE. Visual and refractive outcomes, corneal higher-order aberrations, and Bowman’s layer micro-distortions were evaluated preoperatively, 3 months, and 6 months postoperatively.ResultsLogMAR corrected distance visual acuity (CDVA) of group 1 and group 2 was − 0.069 ± 0.047 and − 0.053 ± 0.073 6 months postoperatively (P = 0.48). 100% eyes in group 1 and 97% in group 2 were within 1 D of targeted correction (P = 0.45). Meanwhile, 100% eyes in group 1 and 97% in group 2 had an uncorrected distance visual acuity of 20/25 or better (P = 0.20). Changes in corneal higher-order aberrations root mean square, coma, and trefoil were similar between the two groups but spherical aberration was higher in group 2 (P < 0.01). Micro-distortions were observed in 53% in group 1 and 77% in group 2. More micro-distortions were observed in group 2 (3.40 ± 2.66) than in group 1 (2.07 ± 2.29) (P = 0.041). The total number of micro-distortions was not correlated with postoperative CDVA (P = 0.77).ConclusionsVisual outcomes showed similar results of SMILE for myopic correction of > − 10 D and ≤ − 10 D. Refractive outcomes showed slightly under-correction in higher myopic eyes. Higher myopic treatment tends to induce more spherical aberrations. Micro-distortions had no impact in visual and refractive outcomes.

Stepwise Guided Photorefractive Keratectomy in Treatment of Irregular Astigmatism After Penetrating Keratoplasty and Deep Anterior Lamellar Keratoplasty.

To report the outcome of stepwise ablation using topography-guided photorefractive keratectomy to treat irregular astigmatism after either penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK). This is a retrospective, interventional analysis including patients with irregular astigmatism after either PKP or DALK, who underwent topography-guided photorefractive keratectomy. The entire cohort was analyzed, as well as the PKP and DALK groups separately. Analysis of factors associated with a better outcome was also performed. Thirty-four eyes of 34 patients (20 PKP patients and 14 DALK patients) aged 47.4 ± 15.9 years were included. Twenty-one patients underwent more than 1 ablation. Refractive stability and a minimal period of 5 months were required before repeat ablation. The average follow-up duration was 17.0 ± 6.0 months. Corrected distance visual acuity (CDVA) improved significantly from 0.22 ± 0.14 logarithm of the minimum angle of resolution (logMAR) to 0.14 ± 0.12 logMAR at final follow-up (P = 0.035). Uncorrected distance visual acuity (UDVA) improved significantly from 0.90 ± 0.54 logMAR to 0.57 ± 0.40 logMAR at final follow-up (P = 0.004). CDVA and UDVA improved by ≥1 Snellen lines in 54.2% and 70.8% of the eyes, respectively, and by ≥3 Snellen lines in 16.7% and 54.2% of the eyes, respectively. Statistically significant improvement was seen in optical aberrometry indices (total root mean square, higher-order aberration root mean square, defocus, coma, trefoil, and spherical aberration). The difference between PKP and DALK in either CDVA (P = 0.562) or UDVA (P = 0.384) improvement was nonsignificant. The stepwise topography-guided photorefractive keratectomy approach in cases of irregular astigmatism after PKP or DALK can help improve visual acuity outcomes. Patients should be appropriately counseled that more than 1 treatment will likely be needed.

Effect of iris registration on outcomes of FEMTOLASIK for myopia and myopic astigmatism.

To compare the visual and refractive outcomes after FEMTOLASIK with and without iris registration. In this randomized, prospective, comparative, contralateral eye study, 118 eyes of 59 patients with myopia and myopic astigmatism underwent LASIK using the Femto LDV femtosecond laser (160µm) and the MEL80 with or without iris registration. For each patient, iris registration FEMTOLASIK was performed on one eye and non-iris registration FEMTOLASIK was performed on the other eye, assigned at random. Patients were evaluated before and 12months. Uncorrected visual acuity, best-corrected visual acuity, manifest refraction, contrast sensitivity, and higher-order aberrations (HOAs) were evaluated. At 12months, the mean UDVA was 0.002±0.07 logMAR (20/19) in iris registration eyes and 0.00±0.06 logMAR (20/24) in non-iris registration eyes (P=0.9). 61% of iris registration eyes and 71.2% of non-iris registration eyes achieved a UDVA of 20/20 or better (P=0.31); 98.3% of eyes with the iris registration FEMTOLASIK and 94.9% with the non-iris registration FEMTOLASIK were within ±0.50D from emmetropia (P=0.71). No statistically significant difference was found in postoperative contrast sensitivity between groups at 3, 6, 12, or 18 cycles/degree (P>0.05). There was significant increase in total HOA root mean square in two groups. The mean error magnitude of surgically induced astigmatism 12months postoperatively was -0.33 in iris registration eyes and -0.24 in the non-iris registration eyes (P=0.36). FEMTOLASIK with and without iris registration provides similar results in myopic and myopic astigmatism patients.

Influence of Overnight Orthokeratology on Corneal Surface Shape and Optical Quality.

Purpose To investigate the changes of corneal surface shape and optical quality during orthokeratology. Methods 49 eyes of 26 patients (10.63 ± 2.02 years old) who underwent overnight orthokeratology for myopia were prospectively examined. The corneal surface shape parameters, including surface regularity index (SRI) and surface asymmetry index (SAI), were attained with an OPD-III SCAN. The higher-order aberrations and higher-order Strehl ratios were calculated under a 3 mm pupil diameter before orthokeratology, 1 month, 3 months, and 6 months after orthokeratology. A P value of less than 0.05 was statistically significant. Results Months after orthokeratology, SRI and SAI were both showing a significant increase in comparison with those before orthokeratology (P < 0.001). After orthokeratology, for a 3 mm pupil, the higher-order Strehl ratio presented a reduction of 0.217 μm (P < 0.001), and the higher-order aberration root mean square (HOA RMS) showed a mean increase of 0.100 μm (P < 0.001). There were significant increases in spherical aberration (P < 0.001) and coma (P = 0.044) after orthokeratology. Trefoil showed a slight reduction at month 6 after orthokeratology, but there was no statistical significance (P = 0.722). Conclusion Overnight orthokeratology for a correction of myopia resulted in a significant improvement in refractive error but increased corneal irregularity and ocular higher-order aberrations, especially in spherical aberration.

Comparison of visual outcomes and higher order aberrations of wavefront-optimized and wavefront-guided myopic laser in-situ keratomileusis

To compare the visual and refractive outcomes of wavefront-optimized (WFO) ablations (wavelight allegretto) and wavefront-guided (WFG) ablations (VISX Custom Vue). Overall, two consecutive groups of eyes were treated for myopia and myopic astigmatism with laser in-situ keratomileusis. One group was treated with WFO ablation and the other group was treated with WFG ablation. Preoperative and 1, 3 and 6 months postoperative refractive evaluation (efficacy, safety, predictability, accuracy, stability, and refractive astigmatism), higher order aberrations (HOAs), and contrast sensitivity were analyzed. The WFO group comprised 20 eyes of 11 patients and the WFG group comprised 34 eyes of 17 patients. Postoperatively, the mean refractive spherical equivalent was −0.21±0.30 D in WFO group and −0.23D±0.57 D in WFG group. The mean values for postoperative uncorrected distance visual acuity were 0.93±0.15 and 0.96±0.16 in WFO and WFG groups, respectively. Safety index was 1.11 in WFO group and 1.17 in WFG group. Six months postoperatively, in WFO group, the induced HOA root mean square (RMS) was 0.25±0.21 μm (P=0.007), induced coma RMS was 0.07±0.23 μm (P=0.84), and induced spherical aberration RMS was 0.03±0.12 μm (P=0.467), whereas induced trefoil RMS was −0.09±0.23 μm (P=0.003). In WFG group, induced HOA RMS was 0.9±0.11 μm (P=0.002), induced coma RMS was 0.01±0.30 μm (P=0.065), and induced spherical aberration RMS was 0.09±0.17 μm (P=0.214), whereas induced trefoil RMS was 0.04±0.15 μm (P=0.005). Contrast sensitivity testing showed a statistically significant improvement in both groups at low spatial frequencies test. Both WFG and WFO showed comparable accuracy, efficacy, and safety with nearly equal induction of all HOA.

Corneal Densitometry and Higher Order Aberrations After Bowman Layer Transplantation: 1-Year Results.

To evaluate corneal densitometry and higher order aberrations (HOAs) up to 1 year after Bowman layer (BL) transplantation. This was a retrospective study carried out at a tertiary referral center. Fifteen eyes of 14 patients who underwent BL transplantation for advanced keratoconus and had at least 1 year of follow-up were examined before BL transplantation and postoperatively at 1 day, 1 week, and 1, 3, 6, and 12 months. Corrected distance visual acuity (CDVA) with spectacles and contact lenses, anterior and posterior HOAs, and corneal densitometry were analyzed. One year after surgery, average logarithm of the minimum angle of resolution of spectacle-CDVA changed from 1.35 (±0.46) preoperatively to 0.96 (±0.32, P < 0.001), whereas average logarithm of the minimum angle of resolution of CDVA with contact lens remained stable after surgery (P = 0.126). Anterior and posterior HOA root mean square decreased from 3.08 ± 0.59 to 2.67 ± 0.71 μm and 7.32 ± 2.20 to 6.30 ± 2.18 μm, respectively (P < 0.05). Spherical aberration ((Equation is included in full-text article.)) improved on both anterior and posterior corneal surfaces (P < 0.001). After 1 year, corneal backscattering values showed an increase as compared with preoperative values mostly involving the central and posterior layers of the cornea, with a peak 1 month after surgery (P < 0.005 in zones 2-6 and 6-10 mm). No correlation between HOAs or corneal backscatter and CDVA was found. Corneal HOAs, especially spherical aberration, decreased for both anterior and posterior corneal surfaces after BL transplantation, whereas corneal backscattering increased, mostly in the central and posterior layers, where the graft has been placed. Changes in HOAs and corneal backscattering did not correlate with CDVA.

Induced Higher-order aberrations after Laser In Situ Keratomileusis (LASIK) Performed with Wavefront-Guided IntraLase Femtosecond Laser in moderate to high Astigmatism.

BackgroundWavefront-guided Laser-assisted in situ keratomileusis (LASIK) is a widespread and effective surgical treatment for myopia and astigmatic correction but whether it induces higher-order aberrations remains controversial. The study was designed to evaluate the changes in higher-order aberrations after wavefront-guided ablation with IntraLase femtosecond laser in moderate to high astigmatism.MethodsTwenty-three eyes of 15 patients with moderate to high astigmatism (mean cylinder, −3.22 ± 0.59 dioptres) aged between 19 and 35 years (mean age, 25.6 ± 4.9 years) were included in this prospective study. Subjects with cylinder ≥ 1.5 and ≤2.75 D were classified as moderate astigmatism while high astigmatism was ≥3.00 D. All patients underwent a femtosecond laser–enabled (150-kHz IntraLase iFS; Abbott Medical Optics Inc) wavefront-guided ablation. Uncorrected (UDVA), corrected (CDVA) distance visual acuity in logMAR, keratometry, central corneal thickness (CCT) and higher-order aberrations (HOAs) over a 6 mm pupil, were assessed before and 6 months, postoperatively. The relationship between postoperative change in HOA and preoperative mean spherical equivalent refraction, mean astigmatism, and postoperative CCT were tested.ResultsAt the last follow-up, the mean UDVA was increased (P < 0.0001) but CDVA remained unchanged (P = 0.48) and no eyes lost ≥2 lines of CDVA. Mean spherical equivalent refraction was reduced (P < 0.0001) and was within ±0.50 D range in 61 % of eyes. The average corneal curvature was flatter by 4 D and CCT was reduced by 83 μm (P < 0.0001, for all), postoperatively. Coma aberrations remained unchanged (P = 0.07) while the change in trefoil (P = 0.047) postoperatively, was not clinically significant. The 4th order HOAs (spherical aberration and secondary astigmatism) and the HOA root mean square (RMS) increased from −0.18 ± 0.07 μm, 0.04 ± 0.03 μm and 0.47 ± 0.11 μm, preoperatively, to 0.33 ± 0.19 μm (P = 0.004), 0.21 ± 0.09 μm (P < 0.0001) and 0.77 ± 0.27 μm (P < 0.0001), six months postoperatively. The change in spherical aberration after the procedure increased with an increase in the degree of preoperative myopia.ConclusionsWavefront-guided IntraLASIK offers a safe and effective option for vision and visual function improvement in astigmatism. Although, reduction of HOA is possible in a few eyes, spherical-like aberrations are increased in majority of the treated eyes.

Changes in Corneal Power After Descemet Stripping Automated Endothelial Keratoplasty.

To examine the optical effects of Descemet stripping automated endothelial keratoplasty (DSAEK) by evaluating changes in anterior and posterior corneal curvatures and aberrations. Eighty-three eyes treated using DSAEK combined with cataract surgery (the DSAEK group) and 41 control eyes of healthy patients (the control group) were included. Patients were examined before and 1 year after surgery with autokeratometry and Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany). The preoperative posterior corneal curvature was estimated from the anterior corneal curvature. The mean intended postoperative refraction in the DSAEK group was -0.75 ± 0.62 diopters (D), which was statistically different from the achieved refraction of +0.50 ± 0.93 D at the 1-year follow-up (P < .001). The average biometry prediction error was a hyperopic shift of +1.27 ± 0.80 D. Anterior corneal power was significantly higher before than after DSAEK with a difference of -0.63 ± 0.68 D (P = .03) correlating significantly with the hyperopic change (r(2) = 0.23, P < .01). The posterior corneal power after DSAEK showed a significant steepening of -0.69 ± 0.38 D (P < .01) from the estimated preoperative power and a difference of -0.64 ± 0.38 D (P < .01) from the posterior corneal power in the control group. The change correlated significantly with the hyperopic change (r(2) = 0.10, P < .01). The combined changes in anterior and posterior keratometry increased the correlation coefficient to r(2) = 0.34 (P < .01). Significant differences were observed for total higher-order aberrations root mean square and coma root mean square after DSAEK compared to controls. No significant changes were observed in spherical aberration. The hyperopic shift in the DSAEK group can be explained by changes in anterior and posterior corneal surfaces. Spherical aberration was not changed by DSAEK, suggesting that aspherical intraocular lenses may be implanted on the same indications as in normal cataract surgery.

Comparison of corneal power, astigmatism, and wavefront aberration measurements obtained by a point-source color light-emitting diode–based topographer, a Placido-disk topographer, and a combined Placido and dual Scheimpflug device

To evaluate and compare the performance of a point-source color light-emitting diode (LED)-based topographer (color-LED) in measuring anterior corneal power and aberrations with that of a Placido-disk topographer and a combined Placido and dual Scheimpflug device. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas USA. Retrospective observational case series. Normal eyes and post-refractive-surgery eyes were consecutively measured using color-LED, Placido, and dual-Scheimpflug devices. The main outcome measures were anterior corneal power, astigmatism, and higher-order aberrations (HOAs) (6.0 mm pupil), which were compared using the t test. There were no statistically significant differences in corneal power measurements in normal and post-refractive surgery eyes and in astigmatism magnitude in post-refractive surgery eyes between the color-LED device and Placido or dual Scheimpflug devices (all P > .05). In normal eyes, there were no statistically significant differences in 3rd-order coma and 4th-order spherical aberration between the color-LED and Placido devices and in HOA root mean square, 3rd-order coma, 3rd-order trefoil, 4th-order spherical aberration, and 4th-order secondary astigmatism between the color-LED and dual Scheimpflug devices (all P > .05). In post-refractive surgery eyes, the color-LED device agreed with the Placido and dual-Scheimpflug devices regarding 3rd-order coma and 4th-order spherical aberration (all P > .05). In normal and post-refractive surgery eyes, all 3 devices were comparable with respect to corneal power. The agreement in corneal aberrations varied. Drs. Wang, Koch, and Weikert are consultants to Ziemer Ophthalmic Systems AG. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics Corp.

Clinical results with a supplementary toric intraocular lens for the correction of astigmatism in pseudophakic patients.

To evaluate the visual outcomes of pseudophakic patients who underwent supplementary toric intraocular lens (IOL) implantation to correct astigmatic refractive errors. Pseudophakic patients referred for the implantation of a supplementary toric IOL (Sulcoflex Toric 653T) were evaluated. Uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), spherical equivalent (SE) refraction, rotational stability, higher order aberrations (HOA), and photopic glare and no-glare contrast sensitivity (CSV-1000, VectorVision) were evaluated. A total of 10 eyes of 10 patients were included. The mean age was 56.42 ± 5.9 years (range 45-65 years). Mean follow-up was 6.99 ± 5.1 months (6-18 months). Postoperatively, UDVA improved to 0.10 ± 0.12 (0.3 to -0.1) (p = 0.004) and CDVA to 0.07 ± 0.12 (0.3 to -0.1) (p = 0.021). Mean SE was -0.30 ± 0.56 D (-1.00 to +0.75) (p = 0.001). Mean toric IOL axis rotation at 6-month follow-up was 3.0° ± 2.45° (0-6). Ocular aberrometry values decreased after surgery (for average HOA root mean square, p = 0.008). Photopic contrast sensitivity (for all spatial frequencies) showed a trend for improvement after surgery; however, this was not borne out from the analysis (p&gt;0.05). The implantation of the Sulcoflex Toric IOL to correct astigmatism in pseudophakic patients provided excellent visual outcomes, predictability of refractive results, rotational stability, and optical performance. The implantation of this IOL is a safe and effective technique to correct pseudophakic cylindrical refractive errors and reduce spectacle dependence in these patients.