scholarly journals Study on the corneal higher-order aberrations and correlation in patients with different degrees of myopia suitable for wavefront-guided FS-LASIK

2019 ◽  
Author(s):  
Cheng-Zhe Wu ◽  
Xun Cui ◽  
Zheng-Ri Li ◽  
Hong Cui ◽  
Hua Jin ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Spherical Aberration ◽  
Anterior Segment ◽  
Higher Order ◽  
Spherical Equivalent ◽  
Higher Order Aberrations ◽  
Wavefront Aberrations ◽  
The Third ◽  
Corneal Refractive Surgery ◽  
Analysis System

Abstract Background: To investigate the characteristics and distribution of anterior and posterior surface wavefront aberrations in patients suitable for corneal refractive surgery. Methods: A total of 121 myopic patients (121 eyes, 14-46 years old) who underwent corneal refractive surgery were randomly selected by the Pentacam anterior segment analysis system with a spherical equivalent (SE) of -1.50 to -12.00 D. The corneal anterior and posterior aberrations (higher-order aberration, HOA; spherical aberration, SA; Coma; Trefoil) and Q and K values were detected, and a correlation analysis of the relevant parameters was carried out. Results: The root-mean-square (RMS) of the third to sixth order aberrations of the ocular and corneal wave surface aberrations at a 6.0-mm pupil showed a decreasing trend in patients suitable for the corneal refractive surgery, and the RMS of the third order aberrations accounted for 62.92% of the total HOAs. The coma ratio (coma ratio: coma/total cornea higher-order aberrations) was increased with the increasing diopters, while the spherical aberration ratio (spherical aberration/ total cornea higher-order aberrations) was not changed. In addition, the spherical aberration was 0.203± 0.082 μm (range: 0.061 to 0.503 μm), and the Q30 was -0.19±0.03 (range: -0.58 to 0.31). There were significant differences in the coma aberrations of preoperative corneal anterior surface (3, 1) between the low, middle and high myopia groups (P=0.013). The spherical equivalent was positively correlated with the corneal coma of the preoperative anterior corneal surfaces (R=-0.241, P=0.009), and the Q value was positively correlated with the total higher-order aberrations (R=0.326, P<0.001). Conclusions: Individual wavefront aberrations on the anterior and posterior surfaces of the cornea are comparatively different, and the Zernike coefficients are related to the degree of myopia. Spherical aberrations are the most overriding aberrations of the cornea.

scholarly journals Study on the corneal higher-order aberrations and correlation in patients with different degrees of myopia suitable for wavefront-guided FS-LASIK

2019 ◽  
Author(s):  
Cheng-Zhe Wu ◽  
Xun Cui ◽  
Zheng-Ri Li ◽  
Hong Cui ◽  
Hua Jin ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Spherical Aberration ◽  
Anterior Segment ◽  
Higher Order ◽  
Spherical Equivalent ◽  
Anterior Surface ◽  
Higher Order Aberrations ◽  
Wavefront Aberrations ◽  
The Third ◽  
Corneal Refractive Surgery

Abstract Background: To investigate the characteristics and distribution of anterior surface wavefront aberrations in patients suitable for corneal refractive surgery. Methods: A total of 121 myopic patients (121 eyes, 18-45 years old) who underwent corneal refractive surgery were randomly selected by the Pentacam anterior segment analysis system with a spherical equivalent (SE) of -0.25 to -10.00 D. The corneal anterior aberrations (total higher-order aberration; spherical aberration; Coma; Trefoil) and Q and K values were detected, and a correlation analysis of the relevant parameters was carried out. Results: The root-mean-square (RMS) of the third to sixth order aberrations of the corneal anterior wavefront aberrations at a 6mm analysis diameter showed a decreasing trend in patients suitable for the corneal refractive surgery, and the RMS of the third order aberrations accounted for 62.92% of the total HOAs. The coma ratio (coma/total cornea higher-order aberrations) was increased with the increasing diopters, while the spherical aberration ratio (spherical aberration/ total cornea higher-order aberrations) was not changed. In addition, the spherical aberration was 0.203±0.082 μm (range: 0.061 to 0.503 μm), and the Q30 was -0.19±0.03 (range: -0.58 to 0.31). There were significant differences in the coma aberrations of preoperative corneal anterior surface (3, 1) between the low, middle and high myopia groups (P=0.013). The spherical equivalent was positively correlated with the corneal coma of the anterior corneal surfaces (R=-0.241, P=0.009), and the Q value was positively correlated with the total higher-order aberrations (R=0.326, P<0.001). Conclusions: Individual wavefront aberrations on the anterior surfaces of the cornea are comparatively different, and the Zernike coefficients are related to the degree of myopia. Spherical aberrations are the most overriding aberrations of the cornea.

Study of wavefront aberrations on the corneal anterior surface and related factors in patients after corneal refractive surgery

2019 ◽  
Author(s):  
Cheng-Zhe Wu ◽  
Xun Cui ◽  
Zheng-Ri Li ◽  
Hong Cui ◽  
Hua Jin ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Spherical Aberration ◽  
Anterior Segment ◽  
Higher Order ◽  
Spherical Equivalent ◽  
Wave Surface ◽  
Related Factors ◽  
Wavefront Aberrations ◽  
Corneal Refractive Surgery ◽  
Analysis System

Abstract Background To investigate the characteristics and distribution of anterior and posterior surface wavefront aberrations in patients suitable for corneal refractive surgery. Methods Sixty myopic patients (120 eyes, 14-46 years old) who underwent corneal refractive surgery were randomly selected by the Pentacam anterior segment analysis system with a spherical equivalent (SE) of -1.50 to -12.00 D. The corneal anterior and posterior aberrations (higher-order aberration, HOA; spherical aberration, SA; Coma; Trefoil) and Q and K values were detected, and a correlation analysis of the relevant parameters was carried out. Results The root mean square (RMS) values from 3 to 6 (RMS 3 to 6) of the whole eye higher-order wave surface aberrations at a 6.0 mm pupil diameter showed a decreasing trend in patients with corneal refractive surgery, and an RMS value of 3 accounted for 62.92% of the total HOAs. The coma ratio increased with increasing diopter, while the spherical aberration ratio was not changed. In addition, the spherical aberration was 0.203 ± 0.082 μm (range: 0.061 to 0.503 μm), and the Q30 was -0.19 ± 0.03 (range: -0.58 to 0.31), which showed a normal distribution. There were significant differences in coma aberrations (3, 1) in the low, middle and high myopia groups (P=0.013). The spherical equivalent was positively correlated with corneal coma (R = -0.241, P = 0.009), and the Q value was positively correlated with total higher-order as well as spherical aberrations (R = 0.326, P <0.001; R = 0.675, P <0.001). Conclusions Individual wavefront aberrations on the anterior and posterior surfaces of the cornea are comparatively different, and the Zernike coefficients are related to the degree of myopia. Spherical aberrations are the most overriding aberrations of the cornea.

scholarly journals Ocular higher-order aberrations features analysis after corneal refractive surgery

2007 ◽  
Vol 120 (4) ◽  
pp. 269-273 ◽  
Author(s):  
Yan WANG ◽  
Kan-xing ZHAO ◽  
Ji-chang HE ◽  
Ying JIN ◽  
Tong ZUO
Keyword(s):  
Refractive Surgery ◽  
Higher Order ◽  
Higher Order Aberrations ◽  
Corneal Refractive Surgery

scholarly journals Misalignment and tilt effect on aspheric intraocular lens designs after a corneal refractive surgery

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243740
Author(s):  
Jesús Pérez-Gracia ◽  
Francisco J. Ávila ◽  
Jorge Ares ◽  
Juan A. Vallés ◽  
Laura Remón
Keyword(s):  
Image Quality ◽  
Refractive Surgery ◽  
Spherical Aberration ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Modulation Transfer ◽  
Wavefront Aberrations ◽  
Corneal Asphericity ◽  
Corneal Refractive Surgery ◽  
Image Position

Purpose To numerically evaluate and compare the tolerance to misalignment and tilt of aspheric intraocular lenses (IOLs) designed for three eyes: with standard cornea and with simulated corneas after myopic and hyperopic laser ablation surgery. Methods Three aspheric IOLs of +20.00 diopter (D) with different spherical aberration (SA) (Z40) values have been designed using a theoretical model eye. Drastic changes on the theoretical eye anterior corneal asphericity have been performed to simulate myopic and hyperopic refractive surgeries. The effect of IOL misalignment and tilt on the image quality has been evaluated using a commercial optical software design for the three eye models. Image quality was assessed from the modulation transfer function (MTF), root mean square (RMS) values of defocus, astigmatism, coma and spherical aberration (Z40), and retinal images obtained from a visual simulator using an aleatory optotype of 0.00 LogMar visual acuity (VA). Results IOL misalignment and tilt reduced MTF values in general, and increased wavefront aberrations errors. Aberration-free IOLs maintained best the MTF values when misalignments were applied, together with good on-axis optical quality. IOLs with negative SA (Z40) correction decreased the MTF value under 0.43 for misalignments values higher than 0.50 mm with the three corneas. The effect of misalignment on RMS astigmatism and coma was correlated with the IOL SA (Z40) and with the three corneas. Conclusions This theoretical study shows that the largest degradation in image quality arises for the IOL with the highest amount of spherical aberration (Z40). Moreover, it has been found that the aspherical design has a more influential role in misalignment tolerance than in tilt tolerance.

scholarly journals Comparison of Higher-Order Aberration Values between Different Aberrometry Technologies in Preoperative Laser Refractive Surgery Patients

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Md Muziman Syah ◽  
Khairidzan Mohd Kamal ◽  
Najwa Munirah Mohd Yusof ◽  
Aminul Hakim Sofian Sauri ◽  
Noor Atikah Mad ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Spherical Aberration ◽  
Higher Order ◽  
Higher Order Aberrations ◽  
Corneal Aberrations ◽  
Laser Technologies ◽  
Wavefront Measurement ◽  
Significant Difference ◽  
Profiler Plus ◽  
Higher Order Aberration

Introduction: Purpose of this study was to evaluate the inter-device agreement of ocular and corneal higher-order aberration measurements using various aberrometers. Materials and method: Ocular and corneal higher-order aberrations were measured from 57 eyes. For ocular aberration, the measurements were obtained from WASCA Analyzer (Carl Zeiss Meditec, Jena, Germany), i-Profiler Plus (Carl Zeiss Meditec, Jena, Germany) and OPD-Scan III (NIDEK Co. Ltd., Tokyo, Japan). Whereas for corneal aberration, an additional measurement was obtained from Atlas Corneal Topographer 9000 (Carl Zeiss Meditec, Jena, Germany). All the measurements were displayed by the Zernike algorithm. Root mean squares of total, 3rd and 4th order of higher-order aberrations were compared between any three devices using repeated measured analysis of variance. The Bland-Altman analysis and Pearson's correlation were employed to assess agreement and strength of relationship between measurements. Results: For ocular aberrations, there were no significant difference (P > 0.05) in all comparisons except for total higher-order aberration, oblique and horizontal trefoil. Whereas for corneal aberrations, vertical coma, spherical aberration and with-therule/against-the-rule secondary astigmatism between devices were found to be significantly different (P < 0.05). The most agreeable device pairs for ocular and corneal aberrations were demonstrated by i-Profiler Plus - OPD Scan III (95% limit of agreement: -0.340 to 0.730) and Atlas Corneal Topographer 9000 - i-Profiler Plus (limit of agreement: 0.196 to 0.520) respectively. The r-values are stronger than 0.70. Conclusion: There were differences in the value of higher-order aberrations between different aberrometry technologies. Clinical impact due to the differences in wavefront measurement between skiascopy, Placido-based and laser technologies need to be investigated further.

scholarly journals Comparison of correcting myopia and astigmatism with SMILE or FS-LASIK and postoperative higher-order aberrations

2021 ◽  
Vol 14 (4) ◽  
pp. 523-528
Author(s):  
Peng-Fei Zhao ◽  
◽  
Yue Wang ◽  
Cai-Yun Fu ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Spherical Aberration ◽  
Higher Order ◽  
High Order ◽  
Controlled Study ◽  
Spherical Equivalent ◽  
Higher Order Aberrations ◽  
Post Surgery ◽  
Significant Difference ◽  
High Order Aberration

AIM: To compare the effect of myopia and astigmatism correction and postoperative change in higher-order aberration as results of receiving small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). METHODS: A prospective and non-randomized controlled study was conducted. The subjects are divided into two groups according to different operations received: 229 eyes of 116 patients in the SMILE group and 168 eyes of 86 patients in the FS-LASIK group. All subjects were followed up for 3mo by monitoring their uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent, higher-order aberrations, and the preoperative and postoperative complications. RESULTS: At 1wk, 1, and 3mo post-surgery, 224 eyes (97.8%), 227 eyes (99.1%) and 229 eyes (100%) had UCVA≥20/20 in the SMILE group, while 165 eyes (98.2%), 167 eyes (99.4%) and 167 eyes (99.4%) had UCVA≥20/20 in the FS-LASIK group, respectively (χ2=0.146, 2.135, and 1.124; all P&#x0026;#x003E;0.05). BCVA reduction was not observed in both groups at 1 and 3mo of post-surgery (χ2=0.734 and 1.898, P&#x0026;#x003E;0.05). There was no statistically significant difference in the spherical equivalent between the two groups at 1 and 3mo post-surgery, though the percentage of the spherical equivalent within ±0.50 D at 3mo post-surgery was 98% in the SMILE group, which was higher than that of the FS-LASIK group (92%, χ2=1.872, P&#x0026;#x003E;0.05). The root mean square (RMS) values of total high-order aberration, coma, and spherical aberration of the two groups increased significantly in the early postoperative period and decreased after 3mo, but the values were still higher than the preoperative levels (P&#x0026;#x003C;0.05); there was no significant difference between the two groups in the RMS values of total higher-order aberrations and specific higher-order aberrations (P&#x0026;#x003E;0.05). The incidence of complications in the SMILE group was lower than that in the FS-LASIK group (χ2=14.52, P&#x0026;#x003C;0.05). CONCLUSION: SMILE and FS-LASIK can effectively treat myopia, significantly improve visual acuity, and increase the total high-order aberration, spherical aberration, and coma. The incidence of complications after SMILE is relatively low.

scholarly journals Impact of Treatment Decentration on Higher-Order Aberrations after SMILE

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Yu ◽  
Wenwen Zhang ◽  
Xinliang Cheng ◽  
Jianru Cai ◽  
Hui Chen
Keyword(s):  
Visual Acuity ◽  
Spherical Aberration ◽  
Higher Order ◽  
Safety Index ◽  
Higher Order Aberrations ◽  
Wavefront Aberrations ◽  
Corrected Distance Visual Acuity ◽  
Lenticule Extraction ◽  
Efficacy Index ◽  
The Mean

Purpose. To evaluate decentration following femtosecond laser small incision lenticule extraction (SMILE) and sub-Bowman keratomileusis (SBK) and its impact on higher-order aberrations (HOAs). Methods. Prospective, nonrandom, and comparison study. There were 96 eyes of 52 patients who received SMILE and 96 eyes of 49 patients who received SBK in this study. Decentration was calculated 6 months after surgery with Pentacam. HOAs and visual acuity after the surgery were examined for patients in both groups before and 6 months after surgery. Results. The mean decentration displacement in SMILE group was significantly less than SBK group (P=0.020). 89 eyes were decentered within 0.50 mm after SMILE and SBK. The association between vertical decentration and the induced spherical aberration was insignificant in SMILE group (P=0.035). There was an association between decentration and safety index, efficacy index, vertical coma, spherical aberration, and HOAs in root mean square (RMS, μm) after SBK (all P<0.05). No difference was found in uncorrected and corrected distance visual acuity, safety index, efficacy index, and wavefront aberrations between the two subgroups at any delimited value after SMILE (all P>0.05). Decentration exceeding 0.37 mm affected vertical coma and RMSh of SBK eyes (P=0.002, 0.005). Conclusion. SMILE surgery achieved more accurate centration than SBK surgery. Vertical decentration is associated with the induced spherical aberration in SMILE.

scholarly journals Matched comparison of corneal higher order aberrations induced by SMILE to femtosecond assisted LASIK and to PRK in correcting moderate and high myopia: 3.00mm vs. 6.00mm

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohammad Miraftab ◽  
Hassan Hashemi ◽  
Mohammadreza Aghamirsalim ◽  
Shiva Fayyaz ◽  
Soheila Asgari
Keyword(s):  
Visual Acuity ◽  
High Myopia ◽  
Spherical Aberration ◽  
Corneal Thickness ◽  
Higher Order ◽  
Laser In Situ Keratomileusis ◽  
Higher Order Aberrations ◽  
Surgical Methods ◽  
Matched Comparison ◽  
Surgical Group

Abstract Background The refractive surgeries induce corneal higher order aberrations (C-HOAs). In this study, change of C-HOAs after small-incision lenticule extraction (SMILE) compared to femtosecond assisted laser in situ keratomileusis (femto-LASIK), and to photorefractive keratectomy with mitomycin-C (PRK) under photopic and mesopic conditions. Methods In this prospective study, age, gender, and apical corneal thickness (ACT) matched cases with moderate myopia [spherical equivalent (SE) 3.00 to 6.00D) to high myopia (SE > 6.00D)] were enrolled. In addition to visual acuity and refraction, total C-HOA, coma, spherical aberration (SA), and trefoil in the 3- and 6-mm zones were measured before and 3 and 6 months after surgery. Results Overall, 372 moderate myopia cases (124 eyes of 124 individuals in each surgical group) and 171 high myopia cases (57 eyes of 57 individuals in each surgical group) were enrolled. At baseline, the differences in age, gender, ACT, uncorrected and corrected visual acuity, and SE were not statistically significant between subgroups of surgical methods within each myopia group (all P > 0.05). At 12 months, in the moderate myopia group, there was less increase in 6-mm zone total C-HOA, coma, and SA with SMILE compared to the other groups (all P < 0.05). In the high myopia group, there was greater increase in photopic total C-HOA and trefoil and less increase in mesopic SA with SMILE (all P < 0.05). Conclusions In correction of moderate myopia, SMILE has better results in mesopic condition. In high myopia correction, femto-LASIK and PRK have better results in photopic and SMILE in mesopic condition.

Changes in Higher Order Aberrations after Wavefront-Guided Prk for Correction of Low to Moderate Myopia and Myopic Astigmatism: Two-Year Follow-Up

2007 ◽  
Vol 17 (4) ◽  
pp. 507-514 ◽  
Author(s):  
D. Wygledowska-Promienska ◽  
I. Zawojska
Keyword(s):  
Visual Acuity ◽  
Excimer Laser ◽  
Spherical Aberration ◽  
Higher Order ◽  
Control Group ◽  
Higher Order Aberrations ◽  
Order Root ◽  
Group 2 ◽  
Myopic Astigmatism ◽  
Group 1

Purpose To assess efficacy, safety, and changes in higher order aberrations after wavefront-guided photorefractive keratectomy (PRK) in comparison with conventional PRK for low to moderate myopia with myopic astigmatism using a WASCA Workstation with the MEL 70 G-Scan excimer laser. Methods A total of 126 myopic or myopic-astigmatic eyes of 112 patients were included in this retrospective study. Patients were divided into two groups: Group 1, the study group; and Group 2, the control group. Group 1 consisted of 78 eyes treated with wavefront-guided PRK. Group 2 consisted of 48 eyes treated with spherocylindrical conventional PRK. Results Two years postoperatively, in Group 1, 5% of eyes achieved an uncorrected visual acuity (UCVA) of 0.05; 69% achieved a UCVA of 0.00; 18% of eyes experienced enhanced visual acuity of −0.18 and 8% of −0.30. In Group 2, 8% of eyes achieved a UCVA of 0.1; 25% achieved a UCVA of 0.05; and 67% achieved a UCVA of 0.00 according to logMAR calculation method. Total higher-order root-mean square increased by a factor 1.18 for Group 1 and 1.6 for Group 2. There was a significant increase of coma by a factor 1.74 in Group 2 and spherical aberration by a factor 2.09 in Group 1 and 3.56 in Group 2. Conclusions The data support the safety and effectiveness of the wavefront-guided PRK using a WASCA Workstation for correction of low to moderate refractive errors. This method reduced the number of higher order aberrations induced by excimer laser surgery and improved uncorrected and spectacle-corrected visual acuity when compared to conventional PRK.

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