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Salvá L, García S, García-Delpech S, Martínez-Espert A, Ferrando V. Optical Performance of a Segmented Extended-Depth-of-Focus Intraocular Lens under the Influence of Different Values of Spherical Aberration Generated by Refractive Surgery. J Clin Med 2023; 12:4758. [PMID: 37510871 PMCID: PMC10381419 DOI: 10.3390/jcm12144758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/14/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens. METHODS The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator. RESULTS Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range. CONCLUSIONS Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients.
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Affiliation(s)
- Luís Salvá
- Oftalmedic Salvà, 07013 Palma de Mallorca, Spain
| | - Scott García
- Oftalmedic Salvà, 07013 Palma de Mallorca, Spain
| | | | - Anabel Martínez-Espert
- Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, 46100 Valencia, Spain
| | - Vicente Ferrando
- Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022 Valencia, Spain
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Xu M, Simmons B, Lerner AL, Yoon G. Controlled elevation of intraocular pressure and its impact on ocular aberrations in healthy eyes. Exp Eye Res 2018; 171:68-75. [PMID: 29501880 DOI: 10.1016/j.exer.2018.02.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/30/2018] [Accepted: 02/28/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Mengchen Xu
- Department of Mechanical Engineering, University of Rochester, Rochester, NY, United States.
| | - Brittany Simmons
- Flaum Eye Institute, Department of Ophthalmology, University of Rochester, Rochester, NY, United States.
| | - Amy L Lerner
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States; Department of Mechanical Engineering, University of Rochester, Rochester, NY, United States.
| | - Geunyoung Yoon
- Flaum Eye Institute, Department of Ophthalmology, University of Rochester, Rochester, NY, United States; Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States.
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Nejima R, Terada Y, Mori Y, Ogata M, Minami K, Miyata K. Clinical utility of femtosecond laser-assisted astigmatic keratotomy after cataract surgery. Jpn J Ophthalmol 2015; 59:209-15. [PMID: 25990805 DOI: 10.1007/s10384-015-0383-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 04/10/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To examine the clinical utility of femtosecond laser-assisted astigmatic keratotomy (FSL-AK) for eyes after cataract surgery. METHODS Eight eyes of 6 patients with an intraocular lens and corneal astigmatism of 2.0 diopters (D) or more underwent FSL-AK. The mean preoperative manifest cylindrical refraction was 2.88 ± 0.64 D and the mean corneal astigmatism was 2.84 ± 0.83 D. Paired symmetrical arcuate incisions were created with the same settings, except for the incision depth. Uncorrected distance visual acuity (UDVA), manifest cylindrical power, and surgically induced astigmatism (SIA) were measured at 1 day, 1 week, and 1 month postoperatively. Fourier analysis of corneal topography and incision depths measured with anterior-segment optical coherence tomography were evaluated 1 month postoperatively. RESULTS In all eyes, the UDVA improved at 1 week and 1 month postoperatively, and the manifest cylinder also decreased postoperatively, while the SIA showed overcorrections in 6 eyes. Fourier analysis showed decreases in spherical and regular astigmatic components and increases in higher-order irregularity. The mean incision depth was measured as 60 µm deeper than the intended depth. CONCLUSION The FSL-AK effectively reduced corneal astigmatism and improved the UDVA, although it was demonstrated that the deeper incisions led to overcorrection.
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Affiliation(s)
- Ryohei Nejima
- Miyata Eye Hospital, 6-3 Kurahara-cho, Miyakonojo, Miyazaki, 885-0051, Japan,
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Piñero DP, Alcón N. Corneal biomechanics: a review. Clin Exp Optom 2014; 98:107-16. [PMID: 25470213 DOI: 10.1111/cxo.12230] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/12/2014] [Accepted: 08/19/2014] [Indexed: 01/19/2023] Open
Abstract
Biomechanics is often defined as 'mechanics applied to biology'. Due to the variety and complexity of the behaviour of biological structures and materials, biomechanics is better defined as the development, extension and application of mechanics for a better understanding of physiology and physiopathology and consequently for a better diagnosis and treatment of disease and injury. Different methods for the characterisation of corneal biomechanics are reviewed in detail, including those that are currently commercially available (Ocular Response Analyzer and CorVis ST). The clinical applicability of the parameters provided by these devices are discussed, especially in the fields of glaucoma, detection of ectatic disorders and orthokeratology. Likewise, other methods are also reviewed, such as Brillouin microscopy or dynamic optical coherence tomography and others with potential application to clinical practice but not validated for in vivo measurements, such as ultrasonic elastography. Advantages and disadvantages of all these techniques are described. Finally, the concept of biomechanical modelling is revised as well as the requirements for developing biomechanical models, with special emphasis on finite element modelling.
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Affiliation(s)
- David P Piñero
- Department of Ophthalmology (Oftalmar), Medimar International Hospital, Alicante, Spain; Foundation for the Visual Quality, Fundación para la Calidad Visual, Alicante, Spain; Departament of Optics, Pharmacology and Anatomy, University of Alicante, Spain
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Park CH, Kim SY, Kim MS. Laser-assisted in situ keratomileusis for correction of astigmatism and increasing contact lens tolerance after penetrating keratoplasty. KOREAN JOURNAL OF OPHTHALMOLOGY 2014; 28:359-63. [PMID: 25276076 PMCID: PMC4179111 DOI: 10.3341/kjo.2014.28.5.359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 03/05/2014] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine effectiveness of laser-assisted in situ keratomileusis (LASIK) in the treatment of astigmatism following penetrating keratoplasty (PK). Methods We performed a retrospective review of medical records of patients who underwent LASIK following PK and had over 1 year of follow-up data. Results Twenty-six patients (26 pairs of eyes) underwent LASIK following PK. Mean age of the patients at the time of LASIK was 40.7 years (range, 26 to 72 years). Following LASIK, the mean cylinder was reduced by 2.4 diopters and mean reduction of cylinder after LASIK was 65.4% from the preoperative values at the last follow-up visit. Uncorrected visual acuity became 20 / 50 or better in 69.2% of the eyes after LASIK. Best-corrected visual acuity became 20 / 50 or better in 73.1% of the eyes after LASIK. All of them were intolerable to contact lenses before LASIK. After LASIK, 6 pairs (23.1%) did not need to use contact lenses and 18 pairs (69.2%) were tolerable to using contact lenses or spectacles. There were no significant endothelial cell density changes 12 months after LASIK (p = 0.239). Conclusions LASIK is effective in the treatment of astigmatism following PK and increases contact lens and spectacle tolerance.
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Affiliation(s)
- Chang-Hyun Park
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, The Catholic University of Korea College of Medicine, Uijeongbu, Korea. ; Hospital of 18th Fighter Wing, Republic of Korea Air Force, Korea
| | - Su-Young Kim
- Department of Ophthalmology, Uijeongbu St. Mary's Hospital, The Catholic University of Korea College of Medicine, Uijeongbu, Korea
| | - Man-Soo Kim
- Department of Ophthalmology, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea
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Seven I, Sinha Roy A, Dupps WJ. Patterned corneal collagen crosslinking for astigmatism: computational modeling study. J Cataract Refract Surg 2014; 40:943-53. [PMID: 24767795 DOI: 10.1016/j.jcrs.2014.03.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 03/11/2014] [Accepted: 03/13/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To test the hypothesis that spatially selective corneal stromal stiffening can alter corneal astigmatism and assess the effects of treatment orientation, pattern, and material model complexity in computational models using patient-specific geometries. SETTING Cornea and Refractive Surgery Service, Academic Eye Institute, Cleveland, Ohio, USA. DESIGN Computational modeling study. METHODS Three-dimensional corneal geometries from 10 patients with corneal astigmatism were exported from a clinical tomography system (Pentacam). Corneoscleral finite element models of each eye were generated. Four candidate treatment patterns were simulated, and the effects of treatment orientation and magnitude of stiffening on anterior curvature and aberrations were studied. The effect of material model complexity on simulated outcomes was also assessed. RESULTS Pretreatment anterior corneal astigmatism ranged from 1.22 to 3.92 diopters (D) in a series that included regular and irregular astigmatic patterns. All simulated treatment patterns oriented on the flat axis resulted in mean reductions in corneal astigmatism and depended on the pattern geometry. The linear bow-tie pattern produced a greater mean reduction in astigmatism (1.08 D ± 0.13 [SD]; range 0.74 to 1.23 D) than other patterns tested under an assumed 2-times increase in corneal stiffness, and it had a nonlinear relationship to the degree of stiffening. The mean astigmatic effect did not change significantly with a fiber- or depth-dependent model, but it did affect the coupling ratio. CONCLUSIONS In silico simulations based on patient-specific geometries suggest that clinically significant reductions in astigmatism are possible with patterned collagen crosslinking. Effect magnitude was dependent on patient-specific geometry, effective stiffening pattern, and treatment orientation. FINANCIAL DISCLOSURES Proprietary or commercial disclosures are listed after the references.
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Affiliation(s)
- Ibrahim Seven
- From Cole Eye Institute (Seven, Sinha Roy, Dupps), Ocular Biomechanics and Imaging Laboratory, and the Department of Biomedical Engineering (Seven, Dupps), Lerner Research Institute, Cleveland Clinic, and the Department of Chemical and Biomedical Engineering (Seven), Cleveland State University, Cleveland, Ohio, USA; Narayana Netralaya (Sinha Roy), Bangalore, India
| | - Abhijit Sinha Roy
- From Cole Eye Institute (Seven, Sinha Roy, Dupps), Ocular Biomechanics and Imaging Laboratory, and the Department of Biomedical Engineering (Seven, Dupps), Lerner Research Institute, Cleveland Clinic, and the Department of Chemical and Biomedical Engineering (Seven), Cleveland State University, Cleveland, Ohio, USA; Narayana Netralaya (Sinha Roy), Bangalore, India
| | - William J Dupps
- From Cole Eye Institute (Seven, Sinha Roy, Dupps), Ocular Biomechanics and Imaging Laboratory, and the Department of Biomedical Engineering (Seven, Dupps), Lerner Research Institute, Cleveland Clinic, and the Department of Chemical and Biomedical Engineering (Seven), Cleveland State University, Cleveland, Ohio, USA; Narayana Netralaya (Sinha Roy), Bangalore, India.
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Uyar OM, Kaya V, Demircan A. Laser in situ keratomileusis after deep anterior lamellar keratoplasty. J Cataract Refract Surg 2013; 39:482. [PMID: 23506937 DOI: 10.1016/j.jcrs.2013.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Indexed: 11/16/2022]
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Bühren J, Yoon G, MacRae S, Huxlin K. Contribution of optical zone decentration and pupil dilation on the change of optical quality after myopic photorefractive keratectomy in a cat model. J Refract Surg 2010; 26:183-90. [PMID: 20229950 DOI: 10.3928/1081597x-20100224-04] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 03/11/2009] [Indexed: 11/20/2022]
Abstract
PURPOSE To simulate the simultaneous contribution of optical zone decentration and pupil dilation on retinal image quality using wavefront error data from a myopic photorefractive keratectomy (PRK) cat model. METHODS Wavefront error differences were obtained from five cat eyes 19+/-7 weeks (range: 12 to 24 weeks) after spherical myopic PRK for -6.00 diopters (D) (three eyes) and -10.00 D (two eyes). A computer model was used to simulate decentration of a 6-mm sub-aperture relative to the measured wavefront error difference. Changes in image quality (visual Strehl ratio based on the optical transfer function [VSOTF]) were computed for simulated decentrations from 0 to 1500 mum over pupil diameters of 3.5 to 6.0 mm in 0.5-mm steps. For each eye, a bivariate regression model was applied to calculate the simultaneous contribution of pupil dilation and decentration on the pre- to postoperative change of the log VSOTF. RESULTS Pupil diameter and decentration explained up to 95% of the variance of VSOTF change (adjusted R(2)=0.95). Pupil diameter had a higher impact on VSOTF (median beta=-0.88, P<.001) than decentration (median beta=-0.45, P<.001). If decentration-induced lower order aberrations were corrected, the impact of decentration further decreased (beta=-0.26) compared to the influence of pupil dilation (beta=-0.95). CONCLUSIONS Both pupil dilation and decentration of the optical zone affected the change of retinal image quality (VSOTF) after myopic PRK with decentration exerting a lower impact on VSOTF change. Thus, under physiological conditions pupil dilation is likely to have more effect on VSOTF change after PRK than optical zone decentration.
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Affiliation(s)
- Jens Bühren
- University of Rochester Eye Institute, University of Rochester Medical Center, Rochester, NY, USA.
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Bühren J, Nagy L, Yoon G, MacRae S, Kohnen T, Huxlin KR. The effect of the asphericity of myopic laser ablation profiles on the induction of wavefront aberrations. Invest Ophthalmol Vis Sci 2010; 51:2805-12. [PMID: 20042646 DOI: 10.1167/iovs.09-4604] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare the effects of laser profile asphericity on the induction of wavefront aberrations, susceptibility to decentration, and depth of focus in a polymethylmethacrylate (PMMA) model. METHODS Four PMMA lenses received an excimer laser ablation of -6 D with a 6-mm optical zone and different amounts of primary spherical aberration (Z(4)(0)): 0, -0.346, -1.038, and -2.076 microm. The curvature of each lens was measured by using surface profilometry, and wavefront changes were computed from curvature differences. Changes in optical quality were compared by treatment simulation of 13 real myopic eyes. The influence of pupil diameter, ablation decentration, and defocus on retinal image quality was measured by using the optical transfer function-based visual Strehl ratio (VSOTF). RESULTS Aspheric ablation profiles induced significantly less primary but higher secondary spherical aberration (Z(6)(0)) than did the standard profile; however, Z(4)(0) compensation was incomplete. Simulated treatments with aspheric profiles resulted in significantly better retinal image quality and higher decentration tolerance than did the standard profile. Optical depth of focus was not affected with a 3-mm pupil, whereas with a 6-mm pupil, there was a small but statistically significant decrease in depth of focus. CONCLUSIONS Aspheric laser profiles showed theoretical optical benefits over standard ablation profiles for the treatment of myopia, including terms of decentration tolerance. However, there remained profound induction and thus, undercorrection of Z(4)(0), due to loss of laser ablation efficiency in the lens periphery.
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Affiliation(s)
- Jens Bühren
- University of Rochester Eye Institute, Rochester, New York, USA
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Abstract
PURPOSE OF REVIEW Many patients who have undergone corneal transplantation are unable to achieve satisfactory visual acuity with spectacle and contact lens correction alone. For these patients, refractive surgery becomes a viable option to reduce the post-keratoplasty ametropia. With the many recent advances in refractive surgery for naturally occurring refractive error, new possibilities arise for application to this complicated set of patients. This review discusses key recent developments in refractive surgery after corneal transplantation. RECENT FINDINGS The biomechanical effects of incisional keratotomy on post-keratoplasty corneas continue to be studied, and these techniques remain a common and simple method of reducing astigmatism. Photorefractive keratectomy, previously problematic for regression and haze formation, is gaining new prominence as early experience with the adjunctive use of mitomycin C has demonstrated good results. Long-term studies with laser in-situ keratomileusis (LASIK) have continued to show good safety and efficacy. Modern developments in cataract surgery appear to have lower incidences of graft rejection and failure. Developments in lens implantation technology continue to offer expanding options for intraocular refractive surgery. SUMMARY Although visual rehabilitation after corneal transplantation remains a formidable challenge, developments in refractive surgery for naturally occurring ametropias directly translate into an improved ability to help these most challenging refractive cases. Continued research will bring about improved efficacy while maintaining a high level of safety.
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