scholarly journals Comparison of efficacy and visual quality after CWFG-FS-LASIK, AF-FS-LASIK and SMILE for correcting myopia with asymmetry mid-to-high astigmatism

2020 ◽  
Author(s):  
zhongxiu zhao ◽  
Miaomiao Zhu ◽  
Qian Jian ◽  
Xialu Liu ◽  
Pingting Ma ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Visual Quality ◽  
Modulation Transfer ◽  
Surgical Methods ◽  
Uncorrected Visual Acuity ◽  
Better Than ◽  
High Order Aberrations

Abstract Background: Individualized ablation is not only able to correct corneal low-order aberrations but also to improve corneal high-order aberrations in patients with corneal asymmetry. In this study, we compared the effects of three different surgical methods, namely, corneal wavefront-guided femtosecond laser assisted in-situ keratomileusis (CWFG-FS-LASIK), aberration-free femtosecond laser assisted in-situ keratomileusis (AF-FS-LASIK) and small incision lenticule (SMILE), in patients with mid-to-high astigmatism asymmetric corneas (1-4D).Methods: One hundred-fourteen eyes from 58 patients were enrolled in this retrospective study. We measured and compared the best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), residual astigmatism, total coma, vertical coma (Z3-1), horizontal coma (Z31), modulation transfer function (MTF) and point spread function (PSF) preoperatively and three months postoperatively. Results: The visual acuity of patients in the three groups was increased after surgery, but the improvements in visual acuity and residual astigmatism among them were not significantly different. However, the improvements in 4-mm and 6-mm total coma, Z3-1 and Z31 in patients who underwent CWFG-FS-LASIK were better than those in patients who underwent AF-FS-LASIK and SMILE. Consistent with these results, the improvements in MTF and PSF (3 mm and 5 mm) in the CWFG-FS-LASIK group were better than those in the AF-FS-LASIK and SMILE groups.Conclusions: Among surgeries for treating patients with mid-to-high astigmatism in asymmetric corneas, the selective coma-guided modality was able to decrease the coma of original cornea, improve visual acuity and optimize the visual quality of patients.

scholarly journals Comparison of efficacy and visual quality after CWFG-FS-LASIK, AF-FS-LASIK and SMILE for correcting myopia with asymmetry mid-to-high astigmatism

2020 ◽  
Author(s):  
Zhongxiu Zhao ◽  
Miaomiao Zhu ◽  
Qian Jian ◽  
Xialu Liu ◽  
Pingting Ma ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Visual Quality ◽  
Laser In Situ Keratomileusis ◽  
Modulation Transfer ◽  
Guided Mode ◽  
Surgical Methods ◽  
Uncorrected Visual Acuity

Abstract Background The individualized ablation is not only able to correct corneal low-order aberrations but also improve the corneal high-order aberrations in corneal asymmetry patients. In this study, we compared the effect of patients with mid-to-high astigmatism asymmetric corneas (1-4D) after three different surgical methods: Selective coma guidance femtosecond Laser in-situ keratomileusis (CWFG-FS-LASIK),Aberration-Free femtosecond Laser in-situ keratomileusis (AF-FS-LASIK) and Small incision lenticule (SMILE).Methods One hundred and fourteen eyes from 58 patients were enrolled in the retrospective study. We measured and compared the best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), residual astigmatism, total coma, vertical coma (Z3-1), horizontal coma (Z31), Modulation Transfer Function (MTF) and Point Spread Function (PSF) at preoperation and postoperation after three months.Results Visual acuity of patients in three groups was increased after surgeries, but the improvements of visual acuity and residual astigmatism among them were no significant differences. However, the improvements of 4mm and 6mm total coma, Z3-1 and Z31 in CWFG-FS-LASIK were superior than in AF-FS-LASIK and SMILE. Consistent with this, the improvements of MTF and PSF (3mm and 5mm) in CWFG-FS-LASIK were better than in AF-FS-LASIK and SMILE.Conclusions In surgeries for treating patients with mid-to-high astigmatism in asymmetric corneas, the selective coma-guided mode was able to decrease the coma of original cornea, improve visual acuity and optimize the visual quality of patients.

scholarly journals Comparative analysis of the clinical outcomes between wavefront-guided and conventional femtosecond LASIK in myopia and myopia astigmatism

2021 ◽  
Vol 14 (10) ◽  
pp. 1581-1588
Author(s):  
Xiao Gui ◽  
◽  
Sha Li ◽  
Na Zhao ◽  
Hao-Rui Zhang ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Pupil Size ◽  
High Myopia ◽  
Visual Quality ◽  
Comparative Investigation ◽  
Uncorrected Distance Visual Acuity ◽  
Efficacy Index ◽  
Better Than ◽  
High Order Aberrations

AIM: To compare the clinical outcomes of wavefront guided femtosecond LASIK (WFG LASIK) and conventional femtosecond LASIK (NWFG LASIK) in eyes with myopia and myopia astigmatism. METHODS: This was a retrospective, nonrandomized, comparative investigation enrolling 236 eyes of 122 patients (18-50y) with low & moderate and high myopia. The WFG group including 97 eyes (50 patients) undergone WFG LASIK and the NWFG group including 139 eyes (72 patients) undergone conventional LASIK. Mean efficacy index, high order aberrations (HOAs), pupil size and the quality of visual questionnaire were evaluated 6mo postoperatively. RESULTS: There is no difference between WFG group (-0.054±0.049 in logMAR) and NWFG group (-0.040±0.056) in uncorrected distance visual acuity (UDVA) postoperatively. The myopia astigmatism is higher in WFG group than that in NWFG group (P<0.05). However, the mean efficacy index (MEI) in the WFG group (1.09±0.106) is better than that in the NWFG group (1.036±0.124; P<0.001). Increased HOAs were observed in NWFG group (0.30±0.196) than that in WFG group (0.146±0.188; P<0.001). The pupil size is larger in WFG group (5.15±0.76 mm) than that in NWFG group (4.32±0.52 mm). The patients are satisfied with the clinical surgery, yet WFG group showed better visual quality using the questionnaire survey. Meanwhile, high myopia would result in worse MEI, HOAs and visual quality than low & moderate myopia. CONCLUSION: WFG and NWFG FS-LASIK are both effective and safe procedures to correct low & moderate and high myopia, but WFG FS-LASIK gives a better postoperative MEI, aberrometric control and predictable outcome. Meanwhile, WFG FS-LASIK is better than NWFG FS-LASIK in correction of myopia astigmatism. Low & moderate myopia allow better clinical outcomes than high myopia using any surgical method.

scholarly journals Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Hao-Chen Guo ◽  
Wan-Qing Jin ◽  
An-Peng Pan ◽  
Qin-Mei Wang ◽  
Jia Qu ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Diurnal Variation ◽  
High Spatial Frequency ◽  
Visual Quality ◽  
Spherical Equivalent ◽  
Corneal Curvature ◽  
Modulation Transfer ◽  
Wavefront Aberrations ◽  
Uncorrected Visual Acuity ◽  
High Order Aberrations

Purpose. To assess the changes and the diurnal variation of visual quality after orthokeratology in myopic children.Methods.Forty-four eyes of 22 subjects with a mean age of 10.55 ± 1.53 years (8 to 14 years) were enrolled in this prospective study. Their spherical equivalent ranged from −1.25 to −4.25 diopters (D) and astigmatism was less than 1.00 D. Parameters including corneal curvature, ocular objective scatter index (OSI), the modulation transfer function (MTF), root mean square of ocular and corneal wavefront aberrations, and contrast sensitivity function (CSF) were measured before and at two time points during the same day after 1 month of orthokeratology.Results. After orthokeratology, uncorrected visual acuity (UCVA) and spherical equivalent were significantly improved from baseline (P<0.001), and their diurnal variation was not significant (P=0.083,0.568). OSI increased from 0.29 ± 0.15 to 0.65 ± 0.31 (P<0.001). MTF decreased significantly (P<0.01). Corneal curvature and ocular total aberration decreased (P<0.001), while the ocular and corneal higher-order aberration increased significantly (P<0.01). The CSF under photopic condition decreased at 3 cpd (P=0.006) and increased at 18 cpd (P=0.012). The diurnal variation of CSF at 18 cpd under mesopic and high glare conditions and at 12 cpd under photopic condition was significant (P=0.002,0.01,0.017).Conclusions. Orthokeratology can effectively improve UCVA and high spatial frequency CSF by decreasing the low-order aberrations. However, MTF and CSF at low spatial frequency decreased because of the increase of intraocular scattering and high-order aberrations. Meanwhile, CSF at high spatial frequency fluctuates significantly at two times during the same day after 1 month orthokeratology.

scholarly journals Redo surgery using IntraLase femtosecond laser for treating a decentered laser in situ keratomileusis flap

2017 ◽  
Vol 46 (2) ◽  
pp. 901-907
Author(s):  
Yulin Lei ◽  
Jie Hou ◽  
Xiuyun Zheng
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Intraoperative Complications ◽  
Anterior Segment ◽  
Laser In Situ Keratomileusis ◽  
Redo Surgery ◽  
Laser Technique ◽  
Uncorrected Visual Acuity

Objective Decentered flaps are rarely reported after femtosecond laser-assisted in situ keratomileusis flap procedures. We present a patient with a decentered flap after preparation of a corneal flap using the Femto LDV technique. Methods The 22-year-old man required a redo operation because of a decentered corneal flap. It was performed the same day at the patient's insistence and with his consent. The new corneal flap for the redo surgery was prepared using the femtosecond laser technique and IntraLase. Results Uncorrected visual acuity for each eye was 1.2 during the 12-month follow-up. The results of the Femtosecond laser technique showed good predictability and repeatability regarding the preparation of corneal flaps, but it still may cause some intraoperative complications. Conclusion Once redo surgery is needed, the size and depth of the initially prepared flap should be determined using anterior segment optical coherence tomography to pre-set the parameters for preparation of the redo flap.

Effect of defocus combined with rotation on the optical performance of trifocal toric IOLs

2021 ◽  
pp. 112067212110021
Author(s):  
Javier Ruiz-Alcocer ◽  
Irene Martínez-Alberquilla ◽  
Amalia Lorente-Velázquez ◽  
José F Alfonso ◽  
David Madrid-Costa
Keyword(s):  
Visual Quality ◽  
Optical Quality ◽  
Refractive Errors ◽  
Focal Points ◽  
Modulation Transfer ◽  
Optical Analysis ◽  
Toric Intraocular Lens ◽  
Toric Iols ◽  
Reference Situation

Purpose: To objectively analyze the optical quality of the FineVision Toric intraocular lens (IOL) with two cylinder powers when different combinations of rotations and residual refractive errors are induced. Methods: This study assessed the FineVision Toric IOL with two different cylinder powers: 1.5 and 3.0 diopters (D). Three different rotation positions were considered: centered, 5° and 10° rotated. An optical bench (PMTF) was used for optical analysis. The optical quality of the IOLs was calculated by the modulation transfer function (MTF) at five different focal points (0.0, 0.25, 0.50, 0.75, and 1.00 D). Results: The MTF averaged value of the reference situation was 38.58 and 37.74 for 1.5 and 3.0 D of cylinder, respectively. For the 1.5 D cylinder, the combination of 5° of rotation with a defocus of 0.25, 0.50, 0.75, and 1.0 D induced a decrease on the MTF of 12.39, 19.94, 23.43, 24.23 units, respectively. When induced rotation was 10°, the MTF decrease was 17.26, 23.40, 24.33, 24.48 units, respectively. For the 3.0 D cylinder, the combination of 5° with 0.25, 0.50, 0.75, and 1.0 D of defocus, induced a decrease on the MTF of 12.51, 18.97, 22.36, 22.48 units, respectively. When induced rotation was 10°, the MTF decrease was: 18.42, 21.57, 23.08, and 23.61 units, respectively. Conclusion: For both FineVision Toric IOLs there is a certain optical tolerance to rotations up to 5° or residual refractive errors up to 0.25 D. Situations over these limits and their combination would affect the visual quality of patients implanted with these trifocal toric IOLs.

scholarly journals Changes of corneal high-order aberrations after femtosecond laser-assisted in situ keratomileusis

Medicine ◽  
2018 ◽  
Vol 97 (18) ◽  
pp. e0618 ◽  
Author(s):  
Jing Wang ◽  
Yanlin Ren ◽  
Kun Liang ◽  
Zhengxuan Jiang ◽  
Liming Tao
Keyword(s):  
Femtosecond Laser ◽  
High Order ◽  
High Order Aberrations

scholarly journals Incidence and Outcomes of Anterior Chamber Gas Bubble during Femtosecond Flap Creation for Laser-Assisted In Situ Keratomileusis

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Sloan W. Rush ◽  
Philip Cofoid ◽  
Ryan B. Rush
Keyword(s):  
Femtosecond Laser ◽  
Anterior Chamber ◽  
Bubble Formation ◽  
Visual Outcome ◽  
Gas Bubble ◽  
Gas Formation ◽  
Uncorrected Visual Acuity ◽  
Chamber Gas ◽  
Flap Creation

Purpose. To report the incidence and outcomes of anterior chamber gas bubble formation during femtosecond laser flap creation for laser-assisted in situ keratomileusis (LASIK).Methods. The charts of 2,886 consecutive eyes that underwent femtosecond LASIK from May 2011 through August 2014 were retrospectively reviewed. The incidence, preoperative characteristics, intraoperative details, and postoperative outcomes were analyzed in subjects developing anterior chamber gas bubble formation during the procedure.Results. A total of 4 cases (0.14%) developed anterior chamber gas bubble formation during femtosecond laser flap creation. In all four cases, the excimer laser was unable to successfully track the pupil immediately following the anterior chamber bubble formation, temporarily postponing the completion of the procedure. There was an ethnicity predilection of anterior chamber gas formation toward Asians (p=0.0055). An uncorrected visual acuity of 20/20 was ultimately achieved in all four cases without further complications.Conclusions. Anterior chamber gas bubble formation during femtosecond laser flap creation for LASIK is an uncommon event that typically results in a delay in treatment completion; nevertheless, it does influence final positive visual outcome.

scholarly journals A HIGH VISUAL QUALITY SPRITE GENERATOR USING INTELLIGENT BLENDING WITHOUT SEGMENTATION MASKS

2006 ◽  
Vol 20 (08) ◽  
pp. 1139-1158 ◽  
Author(s):  
I-SHENG KUO ◽  
LING-HWEI CHEN
Keyword(s):  
Moving Objects ◽  
Automatic Segmentation ◽  
Visual Quality ◽  
Experimental Result ◽  
Feature Point Extraction ◽  
Comparison Results ◽  
Segmentation Methods ◽  
Wu Method ◽  
Better Than

The sprite generator introduced in MPEG-4 blends frames by averaging, which will make places, that are always occupied by moving objects, look blurred. Thus, providing segmented masks for moving objects is suggested. Several researchers have employed automatic segmentation methods to produce moving object masks. Based on these masks, they used a reliability-based blending strategy to generate sprites. Since perfect segmentation is impossible, some ghost-like shadows will appear in the generated sprite. To treat this problem, in this paper, an intelligent blending strategy without needing segmentation masks is proposed. It is based on the fact that for each point in the generated sprite, the corresponding pixels in most frames belong to background and only few belong to moving objects. A counting schema is provided to make only background points participate in average blending. The experimental result shows that the visual quality of the generated sprite using the proposed blending strategy is close to that using manually segmented masks and is better than that generated by Lu-Gao-Wu method. No ghostlike shadows are produced. Furthermore, a uniform feature point extraction method is proposed to increase the precision of global motion estimation, the effectiveness of this part is presented by showing the comparison results with other existing method.

High-order Aberrations in Keratoconus

2016 ◽  
Vol 5 (3) ◽  
pp. 128-131 ◽  
Author(s):  
Hagar Hefner-Shahar ◽  
Nir Erdinest
Keyword(s):  
Refractive Surgery ◽  
Early Stage ◽  
Visual Quality ◽  
High Order ◽  
Wavefront Analysis ◽  
Technological Advances ◽  
High Order Aberrations

ABSTRACT With all the technological advances today and the increasing number of people undergoing refractive surgery, the importance of detecting keratoconus (KC) prior to surgery has become evident. Although by using a topographer we can detect early stage KC, however, by using wavefront analysis technology, we are able to detect KC at an even earlier stage. Every eye possesses a number of aberrations. However, in a KC patient's eye, there are approximately five to six times the numbers of high-order aberrations (HOAs) than in a healthy eye. Using this technology to detect and assess the HOAs, it was found that in a KC cornea, it is possible to detect at a very early stage a much higher value of vertical coma aberrations compared with a normal eye. By using this technology, it is possible to study and understand the characteristics of the quality of the image on the retina, thereby understanding its impact on the patient's visual quality. How to cite this article Hefner-Shahar H, Erdinest N. Highorder Aberrations in Keratoconus. Int J Kerat Ect Cor Dis 2016;5(3):128-131.

The Effect of Astigmatism Axis on Visual Acuity

2016 ◽  
Vol 27 (3) ◽  
pp. 308-311 ◽  
Author(s):  
Michael Mimouni ◽  
Achia Nemet ◽  
Russell Pokroy ◽  
Tzahi Sela ◽  
Gur Munzer ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Refractive Surgery ◽  
Laser In Situ Keratomileusis ◽  
Stepwise Multiple Regression ◽  
Spherical Equivalent ◽  
Tel Aviv ◽  
Uncorrected Distance Visual Acuity ◽  
Laser Refractive Surgery ◽  
Better Than

Purpose To evaluate the effect of astigmatism axis on uncorrected distance visual acuity (UDVA) in emmetropic eyes that underwent laser refractive surgery. Methods This retrospective study included patients who underwent laser in situ keratomileusis or photorefractive keratectomy between January 2000 and December 2015 at the Care-Vision Laser Centers, Tel Aviv, Israel. Eyes with a 3-month postoperative spherical equivalent between -0.5 D and 0.5 D were included in this study. Eyes with ocular comorbidities and planned ametropia were excluded. Study eyes were divided into 3 groups according to the steep astigmatic axis: with the rule (WTR) (60-120), oblique (31-59 or 121-149), and against the rule (ATR) (0-30 or 150-180). The UDVA of these 3 groups was compared. The oblique group was divided into oblique ATR and oblique WTR, which were compared with each other. Results A total of 17,416 consecutive eyes of 8,708 patients were studied. The WTR eyes (n = 10,651) had significantly better UDVA (logMAR 0.01 ± 0.08) than the oblique (n = 3,141, logMAR 0.02 ± 0.09) and ATR eyes (n = 3,624, logMAR 0.02 ± 0.10) (p<0.001). The oblique WTR group had significantly better UDVA than the oblique ATR group (p<0.001). The UDVA of the oblique and ATR groups was similar. Stepwise multiple regression analysis showed that the group accounted for 15% of the UDVA variance (p = 0.04). Conclusions The astigmatic axis has a small but significant effect on UDVA in emmetropic eyes; WTR was better than oblique and ATR astigmatism. Therefore, when correcting astigmatism, it may be preferable to err towards WTR astigmatism.

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