Ocular Higher-order Wavefront Aberrations Research Articles

Comparison of ocular wavefront aberrations in subluxated lenses before and after lens extraction with intraocular lens implantation

To compare the change in ocular higher-order wavefront aberrations (HOAs), visual acuity, and modulation transfer function (MTF) after lens extraction with intraocular lens (IOL) implantation in patients with subluxated lenses. Iladevi Cataract & IOL Research Centre, Ahmedabad, India. Prospective case series. Eyes with subluxated lenses having lens extraction with IOL implantation were included. Capsular bag fixation with in-the-bag IOL implantation or sutured or sutureless scleral fixation of the IOL was performed. Aberrometry was performed preoperatively and 6months postoperatively. The following were compared: root-mean-square (RMS) value for total ocular HOAs, coma aberration, spherical aberration, MTF, and corrected distance visual acuity (CDVA). Of the 39 eyes with subluxated lenses, 26 eyes had Cionni ring fixation, 9 had sutured scleral fixation, and 4 had intrascleral fixation of the IOL. The mean preoperative and postoperative values, respectively, were as follows: RMS HOAs, 10.5μm±9.5 (SD) and 4.73±4.6μm(P<.001); coma aberration, 2.46±2.4μm and 0.11±0.1μm(P=.03); and spherical aberration, 0.37±0.9μm and 0.02±0.06μm(P=.02). The MTF improved significantly in all eyes (mean 0.05±0.02 preoperatively and 0.32±0.16 postoperatively) (P=.005). The CDVA was statistically significant improved 6months postoperatively. Lens extraction with IOL fixation in eyes with subluxated lenses significantly reduced ocular HOAs and improved the MTF.

Relationship between corneal and ocular higher order wavefront aberrations and age in children

Purpose To evaluate the relationship between corneal and ocular higher order wavefront aberrations (HOAs) and age in young subjects aged 20 years or less.

Ocular Higher-Order Wavefront Aberrations in the Japanese Adult Population: the Yamagata Study (Funagata)

To investigate the relationship between age and ocular higher-order wavefront aberrations (HOAs) in an adult Japanese population, in addition to factors associated with HOA variations. In the Yamagata Study (Funagata) cohort, 227 adult Japanese participants (aged 37-86 years) underwent systemic and ophthalmologic examinations in 2012. Ocular, corneal, and internal HOAs were measured in micrometers. From the Zernike coefficients, we calculated the root mean square of the total HOA, coma, and spherical aberration for a pupil diameter of 4 mm. Linear regression analyses were used to determine whether HOAs were associated with age or other factors. Multiple adjusted linear regression analyses demonstrated that all components of logarithmic HOAs increase with age. Ocular, corneal, and internal HOAs increased by 0.012/y (P < 0.001), 0.007/y (P = 0.010), and 0.014/y (P < 0.001), respectively. Ocular coma also significantly increased with age (0.010/y, P = 0.007), but corneal (P = 0.963) and internal (P = 0.476) coma did not. Age-related spherical aberration increased only in the internal component (0.019/y, P = 0.001). In addition to age, ocular and corneal HOAs were mainly affected by corneal indexes. Aging is associated with increases in ocular HOAs, independent of other possible confounding factors. The association of ocular HOAs with corneal parameters indicates that ocular HOAs are mainly generated by the cornea. Internal HOAs, supposedly generated from cataract progression, may be associated with systemic factors, including serum creatinine levels and blood pressure.

Variations in image optical quality of the eye and the sampling limit of resolution of the cone mosaic with axial length in young adults

To evaluate the variation in higher-order ocular wavefront aberrations and the Nyquist limit of resolution of the cone mosaic (N(c)) in a population of young healthy subjects and the relation to axial length (AL). Fondazione G.B. Bietti IRCCS, Rome, Italy. Case series. An adaptive optics retinal camera prototype (rtx1) was used to image the cone mosaic. Cone density and N(c) were calculated at fixed eccentricity between 260 μm and 600 μm from the foveal center. Ocular higher-order wavefront aberrations were measured using the OPD Scan II device. The coefficient of variation (CoV) was used to analyze the variation in optical and retinal parameters. The correlation of optical and retinal parameters with AL was performed using Pearson analysis. Twelve subjects (age 24 to 38 years; AL 22.61 to 26.63 mm) were evaluated. A high interindividual variation in the higher-order wavefront aberrations was found, ranging from 26% for corneal higher-order aberrations (HOAs) to 41% for intraocular HOAs. The CoV of cone density and N(c) were 16% and 5%, respectively. The decline in cone density and N(c) with AL was statistically significant at all retinal eccentricities (R(2) > 0.44, P<.001). Although there appeared to be random variation in the eye's optical wavefront aberration from subject to subject, the cone-packing density and N(c) were highly correlated with AL. Although the eye's overall image optical quality in the emmetropic group and the myopic group was comparable, the spatial sampling of the cone mosaic decreased with increasing AL. No author has a financial or proprietary interest in any material or method mentioned.

Influence of induced decentered orthokeratology lens on ocular higher-order wavefront aberrations and contrast sensitivity function

To quantitatively evaluate the effect of overnight orthokeratology lenses intentionally left decentered after 3 months of wear and assess the influence on clinical outcomes such as ocular higher-order wavefront aberrations and contrast sensitivity function. Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan. This prospective study assessed refraction, visual acuity, corneal topography, wavefront aberration, and contrast sensitivity function before and 3 months after overnight orthokeratology treatment. Decentration of the treatment zone from the center of the entrance pupil was determined using computerized videokeratography (TMS-4) and data-analysis software (MatLab). The relationship between decentration and the clinical parameters was analyzed. The mean age of the 23 patients (46 eyes) was 24.2 years+/-3.3 (SD) and the mean spherical equivalent refraction before treatment, -2.38+/-0.98 diopters. The mean magnitude of decentration (0.85+/-0.51 mm) was statistically significantly correlated with the amount of myopic correction (P<.05), increases in coma-like aberration (P<.01), increases in spherical-like aberration (P<.01), and reductions in contrast sensitivity function (P<.0001). Changes in contrast sensitivity function were also statistically significantly correlated with the amount of myopic correction (P<.05), changes in coma-like aberration (P<.01), and changes in spherical-like aberration (P<.01). Stepwise multiple regression analysis showed that the magnitude of decentration was the only explanatory variable related to contrast sensitivity function (P<.0001). Decentered treatment of orthokeratology resulted in decreased contrast sensitivity after treatment, showing that centration of the procedure is crucial to good outcomes.

Correlation of higher-order wavefront aberrations with visual function in pseudophakic eyes

To study the correlation between higher-order wavefront aberrations and visual function in eyes with a spherical monofocal intraocular lens (IOL), and to see if the aberrations differ between eyes that received different types of IOLs. One hundred forty-eight eyes of 148 patients who underwent phacoemulsification and implantation of one of five types of acrylic IOL were enrolled. At 1 month after surgery, ocular aberrations were measured using a Hartmann-Shack aberrometer and corneal aberrations were measured using videokeratography. In addition, the aberration of internal optics was determined by subtracting the corneal aberration from the ocular aberration. These aberrations were correlated with visual acuity and with contrast visual acuity under both photopic and mesopic conditions. Ocular, corneal, and internal optic aberrations (total aberration, coma, and spherical aberration) were all correlated significantly with visual acuity, as well as with photopic and mesopic contrast visual acuity. The associations between internal optic aberrations and visual function tended to be stronger than were those of corneal aberrations. Furthermore, ocular aberrations differed significantly between eyes with the five different IOLs (P< or =0.0078). Specifically, the internal optic spherical aberration was markedly significantly different between eyes (P=0.0142), and the corneal coma showed a marginally significant difference (P=0.0421). Ocular, corneal, and internal optic higher-order wavefront aberrations are correlated significantly with visual function in eyes with a spherical monofocal IOL. The spherical aberration of the internal optics and coma of the cornea vary between eyes with different types of IOL.

Higher-order wavefront aberration and letter-contrast sensitivity in keratoconus

To evaluate the relation between higher-order aberration of the eye and contrast sensitivity function in eyes with keratoconus. In 22 eyes of 14 patients with keratoconus (age 30.5+/-8.4 years, means+/-SD) and 26 eyes of 13 normal controls (age 29.2+/-6.7 years), ocular higher-order wavefront aberration for a 6-mm pupil was measured with the Hartmann-Schack aberrometer (KR-9000 PW, Topcon). The root mean square (RMS) of third- and fourth-order Zernike coefficients was used to represent higher-order aberrations. The letter-contrast sensitivity was examined using the CSV-1000LV contrast chart (Vector Vision). In the keratoconus group, the letter-contrast sensitivity showed significant correlation with third-order (Spearman's correlation coefficient r=-0.736, P<0.001) and fourth-order aberrations (r=-0.464, P<0.05). There was borderline correlation between log MAR BSCVA and third-order (r=0.413, P=0.070) and fourth-order aberrations (r=0.394, P=0.086). In the normal group, the letter-contrast sensitivity had no significant correlation with third-order (r=-0.170, P=0.411) and fourth-order aberrations (r=-0.088, P=0.673), and log MAR best spectacle-corrected visual acuity (BSCVA) showed no correlation with third-order (r=0.063, P=0.762) and fourth-order aberrations (r=-0.282, P=0.165). In eyes with keratoconus, there is significant correlation between contrast sensitivity and ocular higher-order wavefront aberrations.

Wavefront Analysis in Asian-Brazilians

To compare the distribution of ocular higher order wavefront aberrations (third to sixth order) in the Brazilian population of Asian and non-Asian refractive surgery patients. Preoperative refractive and wavefront data were reviewed for 648 eyes in 324 patients who underwent custom ablation at the Excimer Laser Santa Cruz refractive surgery center in São Paulo, Brazil, from March 2002 to July 2005. Patients were divided into two groups: Asian patients and non-Asian patients, based on family history. Statistical analysis was performed to assess the differences between the groups with respect to manifest refractive spherical equivalent, astigmatism, pachymetry, OPD-root-square-mean (RMS) for a 6.0-mm pupil, total wavefront aberrations, third- to sixth-order higher order aberrations, and individual aberrations. The mean spherical equivalent refraction in the Asian group of -4.38 diopters (D) was significantly higher than the spherical equivalent refraction of -3.46 D in the non-Asian group (t= -4.32; P=.00001). Comparison of the differences between groups with respect to higher order aberrations, coma, trefoil, quadrafoil, spherical aberration, higher order astigmatism, and pachymetry was not statistically significant. Asian patients have a higher prevalence of myopia than non-Asian patients. No differences were noted in higher order aberrations between Asian and non-Asian patients.

Contrast Sensitivity Function and Ocular Higher-Order Wavefront Aberrations in Normal Human Eyes

To investigate the relation between contrast sensitivity function and ocular higher-order wavefront aberrations in normal human eyes. Prospective observational case series. Three hundred seven eyes of 161 normal subjects, ranging in age from 15 to 60 years (30.9+/-8.0 [mean +/- standard deviation]). Ocular higher-order aberrations were measured for a 4-mm pupil using the Hartmann-Shack wavefront analyzer. The root-mean-square of the third- and fourth-order Zernike coefficients was used to represent comalike and spherical-like aberrations, respectively. We measured contrast sensitivity, low-contrast visual acuity (VA), and letter contrast sensitivity. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. Pupil diameter in a photopic condition was recorded using a digital camera. Multiple linear regression analysis revealed that comalike aberration (P = 0.002) was significantly associated with AULCSF, but spherical-like aberration (P = 0.200), age (P = 0.185), and photopic pupil diameter (P=0.252) were not. Comalike aberration showed a significant correlation with low-contrast VA (P<0.001), but spherical-like aberration (P = 0.293), age (P = 0.266), and pupil diameter (P = 0.756) did not. Comalike aberration was found to be significantly associated with letter contrast sensitivity (P<0.001), but spherical-like aberration (P=0.082), age (P = 0.370), and pupil diameter (P = 0.160) were not. In normal human eyes, comalike aberration of the eye significantly influences contrast sensitivity function.

Influence of Pupil Diameter on the Relation between Ocular Higher-Order Aberration and Contrast Sensitivity after Laser In Situ Keratomileusis

To investigate the influence of pupil diameter on the relation between induced changes in ocular higher-order wavefront aberrations and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. In 215 eyes of 117 patients (age, 33.2 +/- 8.3 years) undergoing LASIK for myopia of -1.25 to -13.5 D (-5.28 +/- 2.55 D), ocular wavefront aberrations and contrast sensitivity function were determined before and 1 month after surgery. Preoperative photopic pupil diameter was measured with a digital camera. Ocular higher-order aberrations were measured for a 4-mm pupil with a Hartmann-Shack wavefront analyzer. The root-mean-square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like aberration, respectively. From the contrast-sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. One hundred five eyes had a photopic pupil diameter of 4 mm or larger, and the remaining 110 had a photopic pupil diameter smaller than 4 mm. There were no statistically significant differences in the background clinical data between these two groups. In the eyes with a photopic pupil diameter of 4 mm or larger, the changes in third-order comalike aberrations did not correlate with the changes in AULCSF (Pearson correlation coefficient, r = -0.037, P = 0.723) and 10% low-contrast visual acuity (r = 0.125, P = 0.224), but fourth-order spherical-like aberrations correlated significantly with the changes in AULCSF (r = -0.229, P = 0.024) and 10% low-contrast visual acuity (r = 0.221, P = 0.038). In the eyes with photopic pupil size smaller than 4 mm, there were significant correlations between the changes in comalike aberrations and the changes in AULCSF (r = -0.487, P < 0.001) and 10% low-contrast visual acuity (r = 0.310, P = 0.003), but spherical-like aberrations showed no correlation with the changes in AULCSF (r = -0.078, P = 0.485) and 10% low-contrast visual acuity (r = 0.208, P = 0.158). In eyes with larger photopic pupil diameter, increases in spherical-like aberration dominantly affect contrast sensitivity, whereas in eyes with smaller pupil size, changes in coma-like aberration exert greater influence on visual performance.

Influence of wavefront aberration and corneal subepithelial haze on low-contrast visual acuity after photorefractive keratectomy

To assess low-contrast visual acuity (LCVA) after photorefractive keratectomy in relation to ocular higher-order wavefront aberration and corneal subepithelial haze. Prospective, cross-sectional analysis. Photorefractive keratectomy was performed in 51 eyes of 27 subjects with myopic refractive error of -2.0 to -10.5 diopters. Ocular higher-order wavefront aberrations for a 4-mm pupil were measured using Topcon Hartmann-Shack wavefront aberrometer, and the extent of corneal subepithelial haze was quantified with Nidek TSPC-3 hazemeter before and 1 month after photorefractive keratectomy. Low-contrast visual acuity was recorded with Vector Vision CSV-1000LanC10% chart. Total higher-order, third-order (coma-like), and fourth-order (spherical-like) aberrations of the eye were determined. The influence of wavefront aberration and corneal subepithelial haze on LCVA was analyzed. Total higher-order, third-order, and fourth-order aberrations significantly increased by surgery (P < .001, Wilcoxon signed rank test). Photorefractive keratectomy induced a significant increase in corneal haze (P < .01), but no case presented severe corneal haze (grade 3 or greater by Fantes grading). By surgery, LCVA was reduced significantly (P < .001). The logarithm of the minimal angle of resolution LCVA showed a significant correlation with total higher-order aberration (Spearman rank correlation coefficient, r(s) = 0.642, P < .0001). Both third-order (r(s) = 0.618, P < .0001) and fourth-order aberrations (r(s) = 0.552, P < .0001) also significantly correlated with logarithm of the minimal angle of resolution LCVA. There was no correlation between the degree of corneal haze and logarithm of the minimal angle of resolution LCVA (r(s) = 0.094, P = .523). In eyes with mild to moderate corneal haze after photorefractive keratectomy, deterioration of LCVA is mainly attributable to increases in wavefront aberration, and not to corneal haze.

Age-related changes in corneal and ocular higher-order wavefront aberrations

PurposeTo investigate age-related changes in ocular and corneal higher-order wavefront aberrations and elucidate relative contributions of the cornea and the lens in the age-related changes. DesignObservational case series. MethodsCorneal and ocular higher-order wavefront aberrations in the central 6 mm diameter were measured with videokeratography and the Hartmann-Shack wavefront aberrometer in 75 normal eyes of 75 patients with a mean age of 43.5 ± 11.7 years (range, 18–69 years). Higher-order wavefront aberrations were calculated with Zernike polynomials up to sixth order. From the Zernike coefficients, we calculated root mean square (RMS) of coma and spherical aberration. To examine age-related changes of the polarity of spherical aberration, the changes of the Zernike coefficient Z40 was also investigated. ResultsBoth corneal (r = .307, P = .007) and ocular (r = .334, P = .0033) coma RMS showed positive correlations with age. There was a positive correlation between corneal and ocular coma RMS (r = .468, P < .0001). The RMS of corneal spherical aberration did not change with aging (r = .153, P = .1895), whereas the RMS of ocular spherical aberration had a positive correlation with aging (r = .308, P = .0068). ConclusionsThese results suggest that the ocular coma increases with age, mainly because of the increase in the corneal coma, and the ocular spherical aberration increases with age, mainly because of the increase in the spherical aberration in the internal optics.