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 Visual acuity and image quality in 5 diffractive intraocular lenses

2017 ◽  
Vol 28 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Genís Cardona ◽  
Fidel Vega ◽  
Miguel A. Gil ◽  
Consuelo Varón ◽  
José A. Buil ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Image Quality ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Modulation Transfer ◽  
Multifocal Intraocular Lenses ◽  
Corrected Distance Visual Acuity ◽  
Good For

Purpose: To compare objective image quality at distant, intermediate, and near foci with the corresponding visual acuity (VA) in patients symmetrically implanted with 5 different diffractive multifocal intraocular lenses (IOLs) (ReSTOR SV25T0, Tecnis ZKB00, Tecnis ZLB00, AT LISA 809, and AT LISA Tri 839MP) and a monofocal lens (Tecnis ZA9003) 3 months after cataract intervention. Methods: Objective image quality, measured as the area under the modulation transfer function curve (AMTF), was tested in vitro in an eye model. In addition, corrected distance visual acuity and distance-corrected intermediate and near visual acuities (DCIVA and DCNVA) were assessed in a group of 79 patients, randomly implanted with one of the lenses. Results: Image quality and VA at the distant focus was good for all lens designs, but was similarly compromised at the intermediate focus, where the best DCIVA corresponded to the low add ZKB00. At the near focus, the monofocal lens and the distance dominant SV25T0 had the worst AMTF values, with the ZLB00 presenting the best DCNVA. The relationship between AMTF and VA was found not to be linear, with VA being similarly good for AMTF values over a certain threshold. Conclusions: Visual acuity of pseudophakic patients reflected the optical quality of the specific IOL design within a certain range of measurements, beyond which maximum VA is limited by other ocular, optical, and neuropsychophysical factors.

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 Optical Bench Analysis of 2 Depth of Focus Intraocular Lenses

2021 ◽  
pp. 77-85
Author(s):  
Andreas F. Borkenstein ◽  
Eva-Maria Borkenstein ◽  
Holger Luedtke ◽  
Ruediger Schmid
Keyword(s):  
Spherical Aberration ◽  
Optical Design ◽  
Individual Case ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Optical Bench ◽  
Modulation Transfer ◽  
Depth Of Focus ◽  
The Individual ◽  
The Right

<b><i>Background:</i></b> The aim of the study was to analyze the objective optical properties of 2 enhanced depth of focus (EDoF) intraocular lenses (IOLs) using optical bench analysis. <b><i>Methods:</i></b> This experimental study investigates 2 new EDoF IOLs, the Alcon AcrySof IQ Vivity and the Bausch &amp; Lomb LuxSmart Crystal, on the optical bench, using OptiSpheric IOL PRO2 (Trioptics, Germany) in order to assess the optical quality according to ISO 11979 with ISO-2 Cornea. IOLs (power 22.0 D) were evaluated regarding modulation transfer function (MTF) at 50 lp/mm and Strehl ratio (SR) using a 3.0-mm and a 4.5-mm aperture. In addition, wavefront measurements were obtained using WaveMaster® IOL 2 device (Trioptics, Germany), and USAF targets were analyzed. <b><i>Results:</i></b> Centered: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.250/0.257 and with 4.5 mm aperture 0.202/0.243. The SR (mean) with 3.0 mm aperture was 0.261/0.355 and with 4.5 mm aperture 0.176/0.206. Decentered by 1 mm: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.266/0.247 and with 4.5 mm aperture 0.126/0.215. The SR (mean) with 3.0 mm aperture was 0.272/0.234 and with 4.5 mm aperture 0.133/0.183. Tilted by 5 degree: the MTF (mean) at 50 lp/mm (AcrySof IQ Vivity/LuxSmart Crystal) with 3.0 mm aperture was 0.221/0.360 and with 4.5 mm aperture 0.214/0.229. The SR (mean) with 3.0 mm aperture was 0.232/0.428 and with 4.5 mm aperture 0.225/0.229. The simulated visual function using USAF test targets showed corresponding qualitative results. Wavefront measurements proved a complex optical design. Higher order aberrations in the central part of the optics were modulated up to the 10th order to enhance the range of functional vision to near distance, leaving the peripheral parts of the optics aberration free or as aberration correcting. <b><i>Conclusion:</i></b> The diversity of EDOF IOLs, their optics, and their respective impact on the vision quality must be understood in order to select the appropriate IOL in each individual case. This analysis of new, innovative IOL optics based on increased negative spherical aberration may help the ophthalmic surgeon to select the IOL which meets the individual requirements of the patient for best postoperative outcomes. It seems that there is no perfect IOL that is equally suitable for all patients, but the right choice is an individual, customized approach dealing with patients’ expectations.

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.

Equation for Corneal Asphericity After Corneal Refractive Surgery

2003 ◽  
Vol 19 (1) ◽  
pp. 65-69
Author(s):  
José R Jiménez ◽  
Rosario G Anera ◽  
Luis Jiménez del Barco
Keyword(s):  
Refractive Surgery ◽  
Corneal Asphericity ◽  
Corneal Refractive Surgery

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

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Michael Lasta ◽  
Kata Miháltz ◽  
Illés Kovács ◽  
Pia Veronika Vécsei-Marlovits
Keyword(s):  
Contrast Sensitivity ◽  
Pupil Size ◽  
Spherical Aberration ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Strehl Ratio ◽  
Minimum Diameter ◽  
Link Type ◽  
Medical Optics ◽  
Aspherical Iol

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.

scholarly journals Phakic Intraocular Lenses in Keratoconus

2015 ◽  
Vol 4 (3) ◽  
pp. 103-106
Author(s):  
Jorge L Alio ◽  
Pablo Sanz-Díez
Keyword(s):  
Refractive Surgery ◽  
Optical Quality ◽  
Intraocular Lenses ◽  
Tissue Ablation ◽  
Corneal Tissue ◽  
Effective Operation ◽  
Phakic Intraocular Lenses ◽  
Myopic Astigmatism ◽  
Corneal Thinning

ABSTRACT Purpose To discuss and summarize the indications, contraindications and results in refractive surgery for keratoconus. Summary Keratoconus is an ectatic corneal disease characterized by a progressive corneal thinning and irregular astigmatism that negatively impact in the visual function and the optical quality of the patients. The refractive surgery in keratoconus has been discussed by several authors. The two primary lines of action are phakic lens implantation and corneal tissue ablation using photorefractive keratectomy. The use of phakic intraocular lenses (IOLs) to correct myopia and compound myopic astigmatism associated with keratoconus is gaining popularity. Recent findings The use of phakic IOLs to correct myopia and compound myopic astigmatism associated with keratoconus is gaining popularity. According to a recent study by our group the safety of this procedure in visual terms is high (post-CDVA/ pre-CDVA = 1.19 ± 0.29). It is also an effective operation (post-UDVA/pre-CDVA = 0.90 ± 0.26). How to cite this article Alio JL, Sanz-Díez P. Phakic Intraocular Lenses in Keratoconus. Int J Kerat Ect Cor Dis 2015;4(3):103-106.

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