Total Spherical Aberration Research Articles

Comparison on visual quality after ICL implantation and femtosecond laser LASIK in correction of high myopia

Objective To compare the visual quality after implantable collamer lens (ICL) implantation and femtosecond laser in situ keratomileusis(FS-LASIK) in correction of high myopia. Methods The data of 182 eyes of 91 cases who underwent refractive surgery were collected and retrospectively analyzed. The patients were divided into two groups: ICL group, 78 eyes of 39 cases, underwent ICL implantation; LASIK group, 104 eyes of 52 cases, underwent FS-LASIK. The postoperative visual quality between the two groups were compared. Results The difference of safety index at 1, 3 and 6 months postoperatively between the two groups were not statistically significant( P=1.000, 0.373, 0.230). The difference in validity index at 3 and 6 months postoperatively between the two groups were statistically significant (P=0.000, 0.000). The difference in diopter at 3 and 6 months postoperatively between the two groups were statistically significant (P=0.042, 0.002). The increasing amplitude of total high order aberration, spherical aberration and coma aberration at 6 months postoperatively in ICL group were lower than those in LASIK group(P=0.000, 0.000, 0.001). Six months after surgery, the difference of contrast sensitivity were not significant between two groups at 1.5 cpd, 3.0 cpd and 6.0 cpd spatial frequencies under light condition(P=0.576, 0.659, 0.840), however, the difference of contrast sensitivity in ICL group were higher than that in LASIK group at 12.0 cpd and 18.0 cpd (P=0.000, 0.000). Under mesopic condition, the contrast sensitivity in ICL group were higher statistically at all spatial frequencies than in LASIK group(P=0.000, 0.000, 0.000, 0.000, 0.000). Conclusion The postoperative long-term uncorrected visual acuity and diopter are more stable in patients with ICL implantation, and the higher order aberration increase less, and the contrast sensitivity is improved in each spatial frequency. The postoperative visual quality is significantly better than FS-LASIK. ICL implantation is a surgical approach of strong predictive, high safety and good stability to treat high myopia. Key words: Lens, intraocular, phakic, posterior chamber; Collamer lens, implantable; Laser in situ keratomileusis, femtosecond; Myopia, high; Visual quality

OPD scan III accuracy: Topographic and aberrometric indices after accelerated corneal cross-linking

PurposeTo determine topographic and aberrometric changes after accelerated cross-linking (ACXL; 18 mW/cm2 for 5 min) as measured with OPD Scan III (Nidek Inc., Tokyo, Japan) and their repeatability in patients with mild and moderate keratoconus (KCN). MethodsIn this prospective study, 25 eyes with mild KCN [Ksteep = 47.24 ± 3.11 diopter (D)] and 20 moderate cases (Ksteep = 52.86 ± 4.39 D) were examined under mesopic conditions (20 lux) twice, 30–45 min apart, at baseline and 6 and 12 months afterwards. Extracted indices were Ksteep, Kflat, ocular and corneal irregularity, ocular and corneal total higher order aberrations (HOAs), coma, trefoil, and spherical aberration (SA). Repeatability index (RI) and intraclass correlation coefficients (ICCs) were determined. ResultsIn mild cases, Ksteep and corneal irregularity had lower RI, but Kflat and ocular irregularity had higher RI (all P > 0.050) at 1 year. The RI for ocular total HOAs, coma, and SA decreased and showed no significant change for trefoil (all P > 0.050). Moderate cases showed non-significant increases in RI for Ksteep, Kflat, ocular and corneal irregularity (all P > 0.050), and all aberrometry indices, and significant increases in RI for ocular coma (P = 0.046) and corneal trefoil (P = 0.037). At 1 year, ICC was >0.75 for all indices except ocular and corneal trefoil (ICC = 0.613 and 0.390) in moderate cases. ConclusionsAt one year after ACXL, OPD Scan III showed acceptable repeatability in mild cases. In moderate cases, topographic indices had acceptable repeatability but poorer compared to the mild group. Overall, ocular HOAs showed better repeatability than corneal ones. These changes should be considered in the interpretation of measurements.

The efficiency of aspheric intraocular lens according to biometric measurements.

PurposeTo analyze internal spherical aberration in pseudophakic eyes that underwent aspheric intraocular lens (IOL) implantation, and to investigate the relationships between biometric data and the effectiveness of aspheric IOL implantation.MethodsThis retrospective study included 40 eyes of 40 patients who underwent implantation of an IOL having a negative spherical aberration of -0.20 μm (CT ASPHINA 509M; Carl Zeiss Meditec Inc., Germany). The IOLMaster (version 5.0; Carl Zeiss AG, Germany) was used for preoperative biometric measurements (axial length, anterior chamber depth, central corneal power) and the measurement of postoperative anterior chamber depth. The spherical aberrations were measured preoperatively and 3 months postoperatively using the iTrace (Tracey Technologies, Houston, TX, USA) at a pupil diameter of 5.0 mm. We investigated the relationships between preoperative biometric data and postoperative internal spherical aberration, and compared biometric measurements between 2 subgroups stratified according to internal spherical aberration (spherical aberration ≤ -0.06 μm vs. spherical aberration > -0.06 μm).ResultsThe mean postoperative internal spherical aberration was -0.087 ± 0.063 μm. Preoperative axial length and residual total spherical aberration showed statistically significant correlations with internal spherical aberration (p = 0.041, 0.002). Preoperative axial length, postoperative anterior chamber depth, IOL power, and residual spherical aberration showed significant differences between the 2 subgroups stratified according to internal spherical aberration (p = 0.020, 0.029, 0.048, 0.041 respectively).ConclusionThe corrective effect of an aspheric IOL is influenced by preoperative axial length and postoperative anterior chamber depth. Not only the amount of negative spherical aberration on the IOL surface but also the preoperative axial length should be considered to optimize spherical aberration after aspheric IOL implantation.

Comparison study of the visual quality after different spherical aberration IOL implantation

Objective To compare the visual quality of different total eye spherical aberration after different spherical aberration IOL implantation. Methods Sixty-three eyes of 55 cases underwent phacoemulsification and IOL implantation.All patients were implanted different spherical aberration IOL based on corneal spherical aberration. According to the different postoperative total eye spherical aberration, patients were divided into 3 groups. Group A, postoperative total spherical aberration was(-0.2±0.05)μm, group B was (0±0.03)μm and group C was(+ 0.1±0.03)μm. Three months after surgery, uncorrected visual acuity, best corrected visual acuity, total high order aberration, modulation transfer function(MTF) and satisfaction of the three groups were compared. Results The differences in postoperative uncorrected visual acuity and the best corrected visual acuity between the three groups were not statistically significant(H=4.418, H=0.050; P=0.110, P=0.975). The difference in high order aberration(HOA) was not statistically significant among the three groups(H=2.637, P=0.268). The difference in MTF was statistically significant among the three groups (P=0.000). The difference in satisfaction was statistically significant among the three groups(F=20.845, P=0.000). Conclusion According to the corneal spherical aberration personalized implanted IOL, making total eye spherical aberration to + 0.1 μm, the surgery may obtain better postoperative visual quality and higher satisfaction. Key words: Cataract; Phacoemulsification, IOL implantaion; Spherical aberration; Visual quality

Effect of Iris registration on visual outcome in wavefront-guided LASEK for myopic astigmatism.

This study aimed to investigate the effect of iris registration (IR) on visual outcomes in wavefront-guided LASEK for myopic astigmatism. The retrospective chart review was performed for wavefront-guided LASEK using VISX Star S4 in patients with myopic astigmatism (cylinder≥1.00 diopter[D]). Eyes were divided into IR group (LASEK with IR at the time of surgery) and Non-IR group (LASEK without IR system+failed-IR engagement during LASEK). Visual acuity (VA), astigmatism, higher-order aberration (HOA), and contrast sensitivity were assessed preoperatively and 3months postoperatively. The IR and Non-IR groups were subcategorized depending on the spherical equivalent (lower myopia ≤-5.00D vs. higher myopia >-5.00D) for the comparison of HOA changes. Postoperative uncorrected VAs showed no differences between IR (n=30) and Non-IR (n=46). In astigmatic vector analyses, no differences were noted in the mean magnitude of error and the mean angle of error between two groups. There were no differences in postoperative total HOA, spherical aberration (SA), coma, and trefoil between the groups, either. The total HOA and SA increased in both groups, while coma increased only in Non-IR. In higher myopia, ΔRMS of coma was smaller in IR. Preoperative and postoperative total HOA were linearly correlated in Non-IR, but not for IR. Contrast sensitivity of 12 cycles per degree improved in both groups. IR had similar outcomes to conventional trackers in wavefront-guided LASEK, with less tendency of inducing coma, especially in higher myopia.

The Effect of the Degree of Astigmatism on Optical Quality in Children.

Purpose To investigate the effect of the degree of astigmatism on optical quality in children. The important objective evaluation parameters we focus on include the RMS of the high-order aberrations, MTF, and PSF. Methods The children, age ranging from 7 to 10 years old, underwent an optometry examination. Fifty-nine children who met the inclusion criteria were divided into three groups: A (1.0 D ≤ astigmatism < 2.0 D), B (2.0 D ≤ astigmatism < 3.0 D), and C (3.0 D ≤ astigmatism < 4.0 D). The OPD-SCAN-III aberrometer was used to measure PSF, MTF, and other optical parameters. Total higher-order aberrations, total coma aberrations, total spherical aberrations, and total trefoil aberrations corresponding to the RMS value, the AR value of MTF, and the SR value of PSF with a 4 mm pupil diameter were assessed. Results RMS-HO, RMS-T.Coma, RMS-T.Tre, and RMS-T.Sph in the three groups were significantly increased with increasing the degree of astigmatism, while there were no significant differences in RMS-T.Sph between the groups. The AR value and the SR value decreased with increasing degree of astigmatism, and there were significant differences in the AR value and the SR value. Conclusion Astigmatism has a significant influence on the higher-order aberrations, MTF, and PSF in the children. The effect of astigmatism value on the optical quality is mainly reflected in the change in these three parameters.

Effect of Spherical Aberration on the Optical Quality after Implantation of Two Different Aspherical Intraocular Lenses.

Purpose To compare the effect of spherical aberration on optical quality in eyes with two different aspherical intraocular lenses. Methods 120 eyes of 60 patients underwent phacoemulsification. In patients' eyes, an aberration-free IOL (Aspira-aA; Human Optics) or an aberration-correcting aspherical IOL (Tecnis ZCB00; Abott Medical Optics) was randomly implanted. After surgery, contrast sensitivity and wavefront measurements as well as tilt and decentration measurements were performed. Results Contrast sensitivity was significantly higher in eyes with Aspira lens under mesopic conditions with 12 cycles per degree (CPD) and under photopic conditions with 18 CPD (p = 0.02). Wavefront measurements showed a higher total spherical aberration with a minimal pupil size of 4 mm in the Aspira group (0.05 ± 0.03) than in the Tecnis group (0.03 ± 0.02) (p = 0.001). Strehl ratio was higher in eyes with Tecnis (0.28 ± 0.17) with a minimal pupil size larger than 5 mm than that with Aspira (0.16 ± 0.14) (p = 0.04). In pupils with a minimum diameter of 4 mm spherical aberration had a significant effect on Strehl ratio, but not in pupils with a diameter less than 4 mm. Conclusions Optical quality was better in eyes with the aberration-correcting Tecnis IOL when pupils were large. In contrast, this could not be shown in eyes with pupils under 4 mm or larger. This trial is registered with Clinicaltrials.gov NCT03224728.

Comparisons of the in-the-bag stabilities of single-piece and three-piece intraocular lenses for age-related cataract patients: a randomized controlled trial

BackgroundTo compare the in-the-bag stability and visual function of single-piece intraocular lenses (IOLs) and three-piece IOLs.MethodsA total of 65 patients with age-related cataracts (80 eyes) were enrolled and randomly assigned to receive in-the-bag implantation of either a single-piece IOL (40 eyes) or a three-piece IOL (40 eyes). Follow-up visits were conducted at 1 week, 1 month and 3 months postoperatively. Visual acuity, refraction and total aberration were examined. IOL position stability (including axial movement, decentration and tilt) was measured using a Scheimpflug imaging system.ResultsAt the 3-month follow-up visit, single-piece IOLs did not exhibit significant axial movement (0.07 ± 0.30 mm, p = 0.13) compared with their axial position at 1 week postoperatively, whereas three-piece IOLs displayed forward axial movement of −0.22 ± 0.23 mm (p < 0.0001). The mean manifest spherical equivalence (SE) of eyes with single-piece IOL was 0.15 ± 0.18D, whereas in eyes with three-piece IOLs, the mean manifest SE was −0.34 ± 0.15D (p < 0.001). There was no statistically significant difference in IOL decentration, tilt, uncorrected visual acuity, best-corrected visual acuity or total spherical aberration between the two groups.ConclusionsThree months after implantation, single-piece IOLs exhibit better axial stability and more stable refractive outcome than three-piece IOLs, but both IOLs perform equally well in terms of decentration, tilt, visual acuity and total aberration.Trial registrationClinicalTrial.gov, NCT02609997, 11/18/2015, retrospectively registered.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-016-0283-4) contains supplementary material, which is available to authorized users.

Evaluation of corneal higher order aberrations in normal topographic patterns

PurposeThis study reports the characteristics of corneal higher order aberrations (HOAs) in eyes with normal topographic pattern using the Pentacam scheimpflug system. MethodsIn this prospective, observational, comparative study, 165 eyes of 97 patients separated into five groups based on corneal topographic patterns were enrolled. All eyes received a comprehensive ophthalmologic examination including corneal tomographic analysis with the Pentacam system. Keratometry, corneal cylinder, and corneal aberrometric data were recorded and analyzed. Root mean square values (RMS) were calculated for corneal HOAs up to the 6th order, total coma, total trefoil, total spherical aberration, total tetrafoil, and higher order astigmatism. Evaluation of these data to discriminate between the five groups was assessed using the analysis of variance test by Generalized Estimation Equation Linear Model. ResultsCorneal HOAs were found to be significantly higher for Asymmetric Bow Tie and Irregular groups than other groups (p = <0.001). RMS of total coma aberration (Z3−1, Z31, Z5−1, Z51) were significantly greater in the Asymmetric Bow Tie pattern than others, and RMS of total Spherical aberration (Z40, Z60) was significantly higher in the Irregular pattern than other groups (p = <0.001). The results of our study demonstrate that a tendency toward significant higher values of trefoil, tetrafoil, and higher order astigmatism in Irregular pattern (all p < 0.05). Significantly higher amounts of 3rd order RMS in Asymmetric Bow Tie group and 4th to 6th order RMS in Irregular pattern group were other outcomes of our study (p = <0.001). ConclusionsBased on results in this study, there were a good correlation between corneal topographic pattern and corneal HOAs in normal eyes. These results indicate that the corneal HOAs values are largely determined by the topographic patterns. A larger sample size would perhaps have been beneficial to yield in more accurate outcomes.

Comparison of visual quality after the implantation of different types of intraocular lens

Objective To compare the efficacy of different types of intraocular lens (IOL) implantation for age-related cataract. Methods A retrospective case series. Clinical data of 148 eyes of 162 cases of age-related cataract, were collected from April to December in 2014 at our hospital and all subjects were divided into three groups: simple cataract surgery combined with the traditional spherical IOL implantation in 44 eyes, zero spherical aberration AO IOL implantation in 56 eyes and negative spherical aberration ZCB IOL implantation in 48 eyes. The differences in patients age, preoperative uncorrected distance visual acuity and axial length among three groups were not statistically significant (P>0.05). The corneal astigmatism of all patients were less than 0.75 D. Uncorrected distance visual acuity (UCVA), best corrected distance visual acuity (BCVA), uncorrected near visual acuity (UNVA) and best corrected near vision (BCNA) were assessed preoperatively, 1 week, 1 month and 3 months after the surgery. And the ocular spherical aberration of the patients in 3 groups were assessed 3 months after the surgery. The total ocular spherical aberration of all subjects were measured by using the Ray tracing methed with pupil diameters of 4.0 mm. Results After three months, there were not statistically significant differences in UCVA, BCVA, UNVA and BCNA among three groups. After three months there was statistically significant difference among groups in total ocular spherical aberration. According to the data of corneal spherical aberration, the total ocular spherical aberration of patients in each group was divided into 3 grades. It is founded that the total ocular spherical aberration had no statistically significant defferences among groups when the corneal spherical aberration grade was less than 0.15 μm or greater than 0.45 μm. However, there was statistically significant difference when corneal spherical aberration grade was from 0.15 m to 0.45 μm. Conclusion Our earlier observation shows that negative spherical aberration IOL implantation is superior to traditional spherical IOL and aspheric IOL. Key words: Lens, intraocular, various types; Spherical aberration; Visual quality; Comparation

Evaluation of the acute changes in objective accommodation, pupil size and ocular wavefront aberrations after cigarette smoking

Context: The acute effects of cigarette smoking on pupil size and ocular wavefront aberrations (OWA) have been previously documented. The accommodation status of the eye is well known to be related to ocular aberrations. No previous study has evaluated the impact of cigarette smoking on the accommodation status of the eye. This study presents intriguing findings regarding the changes in objective accommodation of the eye after cigarette smoking.Objective: To evaluate the acute changes in objective accommodation and OWA after cigarette smoking.Materials and methods: A total of 34 otherwise healthy cigarette smoker participants were included in this prospective study. All subjects smoked a single cigarette containing 1 mg nicotine. Measurements of pupil size, OWA and objective accommodation were done before and after smoking. A Wavefront Aberrometer device (Irx3, Imagine Eyes, Orsay, France) was used for the measurements.Results: The mean age of the participants was 36.6 ± 10.3 years (range 21–51 years). Pupil size did not significantly differ before (mean 5.72 ± 1.21 mm) and after smoking (mean 5.68 ± 1.14 mm) (p = 0.62). However, a significant decrease was observed in total spherical aberration (TSA) of the eye after smoking (p = 0.01). There was an increase in objective accommodation after smoking at each accommodative stimulus (range 0–5). This increment was significant at 2 D (p = 0.02) and 3 D (p = 0.03) of stimulus.Discussion and conclusions: The TSA of the eye significantly decreases after smoking. Cigarette smoking also causes a significant increase in objective accommodation at 2 D and 3 D of stimulus.

SMILE and Wavefront-Guided LASIK Out-Compete Other Refractive Surgeries in Ameliorating the Induction of High-Order Aberrations in Anterior Corneal Surface.

Purpose. To compare the change of anterior corneal higher-order aberrations (HOAs) after laser in situ keratomileusis (LASIK), wavefront-guided LASIK with iris registration (WF-LASIK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE). Methods. In a prospective study, 82 eyes underwent LASIK, 119 eyes underwent WF-LASIK, 88 eyes underwent FS-LASIK, and 170 eyes underwent SMILE surgery. HOAs were measured with Pentacam device preoperatively and 6 months after surgery. The aberrations were described as Zernike polynomials, and analysis focused on total HOAs, spherical aberration (SA), horizontal coma, and vertical coma over 6 mm diameter central corneal zone. Results. Six months postoperatively, all procedures result in increase of anterior corneal total HOAs and SA. There were no significant differences in the induced HOAs between LASIK and FS-LASIK, while SMILE induced fewer total HOAs and SA compared with LASIK and FS-LASIK. Similarly, WF-LASIK also induced less total HOAs than LASIK and FS-LASIK, but only fewer SA than FS-LASIK (P < 0.05). No significant difference could be detected in the induced total HOAs and SA between SMILE and WF-LASIK, whereas SMILE induced more horizontal coma and vertical coma compared with WF-LASIK (P < 0.05). Conclusion. FS-LASIK and LASIK induced comparable anterior corneal HOAs. Compared to LASIK and FS-LASIK, both SMILE and WF-LASIK showed advantages in inducing less total HOAs. In addition, SMILE also possesses better ability to reduce the induction of SA in comparison with LASIK and FS-LASIK. However, SMILE induced more horizontal coma and vertical coma compared with WF-LASIK, indicating that the centration of SMILE procedure is probably less precise than WF-LASIK.

Correlation among Myopic Correction, Axial Length and Aberration after Orthokeratology Lens Treatment in Myopic Patients

Purpose: To report the correlation among the amount of myopic correction, axial length elongation, and higher order aberrations after treatment with orthokeratology lenses in myopic patients. Methods: Eighteen patients (36 eyes) treated with orthokeratology lenses for more than 12 months were recruited for this study. Visual acuity, spherical equivalent, axial length, and higher order aberrations were measured at baseline and 1, 6, and 12 months after wearing lenses. Correlations among them were analyzed. Results: Total higher order, spherical, vertical and horizontal coma aberrations were significantly increased from 0.85 ± 1.47, -0.22 ± 0.40, 0.40 ± 0.47, 0.22 ± 0.31 to 1.11 ± 0.72, 0.10 ± 0.38, 0.79 ± 0.63, 0.66 ± 1.29 after 1 month repectively (p 0.05), remaining up to 12 months.Total and corneal spherical aberrations were positively correlated to the amount of myopic correction (p = 0.001 and p = 0.028, repectively) and negatively to the amount of axial length elongation (p = 0.036 and p = 0.079, repectively). Uncorrected visual acuity and spherical equivalent were significantly improved from 0.52 ± 0.08 and -2.41 ± 0.36 to 0.07 ± 0.07 and -0.84 ± 0.32 after 1 month respectively. This improvement was maintained up to 12 months (p = 0.002 and p = 0.001, respectively). Axial length was continuously increased from 24.31 ± 0.53 mm to 24.91 ± 0.60 mm after 12 months, but showed no significant changes (p = 0.721). Conclusions: Although orthokeratology lenses were effective for the correction of myopia, they increased higher order aberrations depending on the amount of myopic correction. Physicians should consider higher order aberrations. Further studies regarding the relationship between axial length elongation and higher order aberrations to retard myopic progression should be conducted. J Korean Ophthalmol Soc 2016;57(7):1050-1055

Visual Outcomes and Optical Quality After Femtosecond Laser Small Incision Lenticule Extraction: An 18-Month Prospective Study.

To investigate the long-term visual outcomes and optical quality after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction. Fifty-four patients (37 women, 17 men) who underwent SMILE were enrolled in this prospective clinical study. Patient ages ranged from 18 to 40 years, with a mean spherical equivalent of -6.50 ± 1.64 diopters. Data including refractive parameters, retinal image quality, intraocular scattering, and aberrations were collected at 6 and 18 months after surgery. Patient satisfaction was also evaluated. At 18 months after surgery, both the mean safety index and the efficacy index were 1.23 ± 0.23 (range: 0.80 to 1.50); there was no significant difference with indices measured at 6 months (P > .05). No patient lost two or more lines of corrected distance visual acuity. Total higher-order aberrations (HOAs) and coma significantly increased after SMILE (P < .05), whereas total spherical aberrations and trefoil changed only slightly. The mean modulation transfer function cutoff frequency was 36.66 ± 8.54 cycles per degree (cpd) before surgery and 37.81 ± 6.89 cpd at 18 months postoperatively; the mean objective scatter index was 0.62 ± 0.33 before surgery and 0.71 ± 0.38 at 18 months postoperatively. No significant difference was found between the three time points (P > .05). Mean patient satisfaction was 9.31 ± 0.64 (with a maximum score of 10). SMILE showed good safety, efficacy, and stability in correcting moderate to high myopia, and patients were highly satisfied. HOAs increased after SMILE, mainly due to the increase of coma, whereas retinal image quality and intraocular scattering barely changed.

Higher order aberration comparison between two aspherical intraocular lenses: MC6125AS and Akreos advanced optics.

To compare higher order aberrations in two aspherical intraocular lenses (IOLs): Akreos advanced optics (AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface (MC6125AS) with each other. Forty eyes of 39 patients underwent phacoemulsification and Akreos AO and MC6125AS were implanted in their eyes in a random manner. Three months post-operatively, higher order aberrations including spherical aberration, coma aberration, and total aberrations were measured and compared. The total aberration was 0.24±0.17 in eyes with Dr. Schmidt and 0.20±0.01 in eyes with Akreos AO (P=0.361). The mean of coma aberration was 0.17±0.21 and 0.09±0.86 in Dr. Schmidt and Akreos lenses, respectively (P=0.825). Total spherical aberration was almost the same in both groups (Mean: 0.05, P=0.933). Best corrected visual acuity in Akreos AO (0.10±0.68) and Dr. Schmidt (0.09±0.67) did not differ significantly (P=0.700). There is no statistically significant difference in the higher order aberrations between these two aspherical lenses.

Progression of lower and higher-order aberrations: a longitudinal study.

BackgroundThe aim of the present study was to investigate the effect of near-work on lower and higher-order aberrations, and its progression over a 9-month period during the school year.MethodsData from 24 young-adult myopic eyes, and 24 non-myopic eyes were used in this investigation. The lower-order aberrations, coma, spherical aberration (SA), and total root mean square (RMS) of higher order aberrations (total HOA) were measured using an open-field iTrace aberrometer, at both the initial baseline evaluation, and then at the follow-up visits over a 9-month period. Pupil size of 4 mm was used for the aberration measurements.ResultsThe group mean (SD) of the subjects (mean age: 23.6 +/- 3.4 years) at the initial and follow-up visit was 0.47D (0.47D) and 0.31D (0.41D), in the non-myopes and -3.58D (2.08D) and -3.86D (2.14D) in the myopes, respectively. Significant increases in myopic refraction were observed. The group mean (SD) total HOA at the initial and final visit was 0.12 (0.08) and 0.11 (0.06) microns, in the non-myopes, and 0.15 (0.08) and 0.15 (0.08) microns, in the myopes, respectively. The group mean RMS of the coma at the initial and final visit was 0.06 (0.04) and 0.07 (0.05), in the non-myopes, and 0.08 (0.06) and 0.09 (0.06) microns, in the myopes, respectively. The group mean SA of the subjects at the initial and last visit was 0.04 (0.04) and 0.03 (0.03), in the non-myopes, and 0.04 (0.04) and 0.04 (0.04) microns, in the myopes, respectively.ConclusionsThere was a significant difference in myopic refraction, over the 9-month assessment period. However, no significant difference in total HOA, SA, and coma between the initial and follow-up visits in both the myopes and the non-myopes was observed.

Acute effect of cigarette smoking on pupil size and ocular aberrations: a pre- and postsmoking study.

Aim. To evaluate the acute effects of cigarette smoking on photopic and mesopic pupil sizes and wavefront aberrations. Methods. Cigarette smoker volunteers were recruited in the study. Photopic and mesopic pupil sizes and total ocular aberrations were measured before smoking and immediately after smoking. All volunteers were asked to smoke a single cigarette containing 1.0 mg nicotine. Pupil sizes and total ocular aberrations were assessed by optical path difference scanning system (OPD-Scan II ARK-10000, NIDEK). Only the right eyes were considered for statistical analysis. The changes of pupil size and total ocular aberrations after smoking were tested for significance by Wilcoxon signed ranks test. Results. Mean photopic pupil size decreased from 3.52 ± 0.73 mm to 3.29 ± 0.58 mm (P = 0.001) after smoking. Mean mesopic pupil size was also decreased from 6.42 ± 0.75 mm to 6.14 ± 0.75 mm after smoking (P = 0.001). There was a decrease in all the measured components of aberrations (total wavefront aberration, higher-order aberration, total coma, total trefoil, total tetrafoil, total spherical aberration and total higher-order aberration) after smoking; however the differences were insignificant for all (P > 0.05). Conclusion. Our results indicate that pupil constricts after smoking. On the other hand, smoking does not alter ocular aberrations.

Clinical study of customized aspherical intraocular lens implants.

To compare if there is an improvement in visual functions with age-related cataracts between patients receiving a aspherical intraocular lens (IOL) based on corneal wavefront aberration and patients randomly assigned lenses. A total of 124 eyes of 124 patients with age-related cataracts were placed in experimental group and a group receiving randomly assigned (RA) lenses. The experimental group was undergone Pentacam corneal spherical aberration measurement before surgery; the targeted range for residual total spherical aberration after surgery was set to 0-0.3 µm. Patients with a corneal spherical aberration <0.3 µm were implanted with a zero-spherical aberration advanced optics (AO) aspherical IOL and patients with an aberration ≥0.3 µm received a Tecnis Z9003 aspherical lens in experimental group. RA patients were randomly implanted with an AO lens or a Tecnis Z9003 lens. Three months after surgery total spherical aberration, photopic/mesopic contrast sensitivities, photopic/mesopic with glare contrast sensitivities, and logMAR vision were measured. Statistical analysis on logMAR vision showed no significant difference between two groups (P=0.413). The post-surgical total spherical aberration was 0.126±0.097 µm and 0.152±0.151 µm in the experimental and RA groups, respectively (P=0.12). The mesopic contrast sensitivities at spatial frequencies of 6, 12 and 18 c/d in the experimental group were significantly higher than of the RA group (P=0.00; P=0.04; P=0.02). The mesopic with glare contrast sensitivity in the experimental group at a spatial frequency of 18 c/d was also significantly higher vs the RA group (P=0.01). Pre-surgical corneal spherical aberration measurement in cataract patients followed by customized selection of aspherical IOL implants improved mesopic contrast sensitivities at high spatial frequencies, and thus is a superior strategy compared to the random selection of aspherical IOL implants.

Total spherical aberration of the cornea in patients with cataract.

To investigate the distribution of corneal spherical aberration in patients with cataract using the Pentacam HR. Consecutive cataract patients were examined using the Pentacam HR high-resolution rotating Scheimpflug camera (Oculus, Wetzlar, Germany). In one eye of each patient, the root-mean-square (RMS) of anterior, posterior, and total corneal spherical aberration Z4(0) was calculated by ray-tracing on an area of 6 mm diameter. The Pearson correlation coefficient (r) was used to assess correlations between Z4(0) RMS values and age/total corneal refractive power. The χ2 test was used to compare the proportion of eyes qualifying for spherically neutral or negatively aspheric (-0.17 and -0.27 μm) intraocular lenses (IOLs) by targeted level of residual spherical aberration. Fifty-seven men and 92 women were included (mean [±SD] age, 71.73 [±9.12] years). The RMS mean (±SD) values of Z4(0) were +0.353 (±0.132) μm, -0.121 (±0.034) μm, and +0.328 (±0.132) μm, respectively, for the anterior, posterior, and total cornea. The anterior, posterior, and total Z4(0) were on average significantly higher (p < 0.001) in women than in men. In both sexes, statistically significant (p < 0.05) age-related changes were found for the anterior and total Z4(0) but not for the posterior Z4(0) (p > 0.05). The total Z4(0) and total corneal refractive power were significantly correlated in men (p = 0.01) but not in women (p = 0.14). For postoperative targets of 0 ± 0.05/+0.10 ± 0.05 μm residual Z4(0), the proportion of eyes that would have qualified for implantation of negatively aspheric IOLs with -0.17 and with -0.27 μm was similar (61.1 and 56.3%, respectively; p = 0.09); significantly fewer eyes (6.7%) would have qualified for implantation of neutrally aspheric IOLs (p > 0.05). Total corneal Z4(0) measured by Pentacam HR might be higher than that reported in previous studies. In most patients, the implantation of commercially available negatively aspheric IOLs would partially compensate for the positive total corneal Z4(0).

Corneal spherical aberration and its impact on choosing an intraocular lens for cataract surgery

PurposeTo analyze the post operative results of targeting zero spherical aberration by selecting the best-fit aspheric intraocular lens (IOL), based on preoperative corneal spherical aberration of patients with phacoemulsification surgery. SettingAlHokama Eye Specialist Center, Riyadh, Saudi Arabia. PeriodFrom the 1st of October 2012 until the 10th of April 2013. MethodsFifty-three eyes, were subjected to phacoemulsification cataract surgery and divided into two groups, 34 eyes were implanted with aspheric IOLs based on their corneal spherical aberration targeting post operative zero total spherical aberration, whereas 19 eyes were implanted with neutral aspheric IOLs regardless of their corneal spherical aberrations (CSAs). As a pre and post routine examination, patients underwent: slit lamp testing, intraocular pressure (IOP) measuring, fundus examination, best spectacle corrected visual acuity (BSCVA), manifest refraction, pupillometry, axial length, contrast sensitivity, and corneal aberration measurement using Pentacam HR (OCULUS, Germany) at the 6-mm optical zone. Post operatively, visual function questionnaire (VF-14) was asked to all patients. ResultsFifty-three eyes of 45 patients, whose age ranged from 45 to 90years old, were available for analysis, the selected group was implanted with: Tecnis ZA9003 or ZCB00 (Abbott Medical Optics) IOLs in 17 eyes with corneal spherical aberration of more than 0.27μm, AcrySof IQ SN60WF (Alcon Laboratories Inc.) IOLs were implanted in 4 eyes with CSA=(0.2–0.27)μm, and Rayner 970C, 920H or 620H IOLs with spherical aberration (SA)=0 in 13 eyes with CSA less than 0.20μm. The other group of 19 eyes was implanted with aspheric IOLs that have zero spherical aberration (Rayner 970C or 920H) regardless of their CSA. Root mean square (RMS) of total corneal aberration positively correlates to the pupil diameter (P=0.0031, r=0.3989). A low negative correlation was found between the corneal spherical aberration of the fourth ordered (Z40) and the axial length (r=−0.2009, P=0.1492). There was no significant difference between the selected and non-selected group in contrast sensitivity, best spectacle corrected visual acuity, and visual satisfaction (P=0.5316, P=0.3919, P=0.7667). ConclusionCustomized selection of aspheric IOLs based on the eyes’ corneal spherical aberration has no significant importance comparing their results with the non-selected group.