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Hashemi H, Mesbahi S, Jamali A, Ostadimoghaddam H, Yekta A, Khabazkhoob M. The association between ocular biometric components and corneal aberrations. Clin Exp Optom 2024; 107:609-615. [PMID: 37844336 DOI: 10.1080/08164622.2023.2258126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 08/19/2023] [Accepted: 09/08/2023] [Indexed: 10/18/2023] Open
Abstract
CLINICAL RELEVANCE Evaluating factors affecting corneal higher-order aberration component has a very important role in interpreting the characteristics of the formed image on the retina. BACKGROUND To determine the relationship between ocular biometric components and corneal higher-order aberrations in an elderly population. METHODS This report is related to a subsample of the Tehran Geriatric Eye study (TGES), a population-based cross-sectional study that was conducted on individuals aged 60 years and above in Tehran city, Iran using multistage stratified random cluster sampling. All study participants underwent ocular examinations including visual acuity measurement, refraction and slit-lamp biomicroscopy. Anterior segment imaging and corneal aberrometry were performed using Pentacam AXL. RESULTS In the present study, 644 eyes of 415 individuals (56.9% female) with mean age of 66.36 ± 4.70 years were evaluated. According to a multiple generalised estimating equation model, the root mean square of total higher-order aberrations was related to age (β = 0.081, p = 0.002), crystalline lens thickness (β = 0.08, p < 0.001), and corneal diameter (β = -0.04, p = 0.014). The root mean square of total coma aberration was directly related to the female sex (β = 0.02, p = 0.05), and crystalline lens thickness (β = 0.06, p < 0.001). There was a direct relationship between the root mean square of third- and fourth-order higher-order aberrations and crystalline lens thickness (p < 0.001). Spherical aberration was directly related to the male sex (β = -0.02, p = 0.004), axial length (β = 0.05, p < 0.001) and central corneal thickness (β = 0.001, p = 0.025), and was inversely related to anterior chamber depth (β = -0.07, p = 0.031) and crystalline lens thickness (β = -0.25, p < 0.001). CONCLUSION Ocular biometric components are related to corneal aberrations in the elderly. These factors need to be considered in respect of medical and surgical procedures required for the elderly.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Shima Mesbahi
- Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alireza Jamali
- Rehabilitation Research Center, Department of Optometry, Iran University of Medical Sciences, Tehran, Iran
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abbasali Yekta
- Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Khabazkhoob
- Department of Basic Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Shetty N, Shetty R, Ranade R, Narasimhan R, Artal P, Nuijts RMMA, Sinha Roy A. Using adaptive optics to optimize the spherical aberration of eyes implanted with EDOF and enhanced monofocal intraocular lenses. J Cataract Refract Surg 2024; 50:30-36. [PMID: 37732726 DOI: 10.1097/j.jcrs.0000000000001315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 09/08/2023] [Indexed: 09/22/2023]
Abstract
PURPOSE To assess the effect of change in ocular spherical aberration (SA) with adaptive optics on visual acuity (VA) at different defocus after implantation of extended depth-of-focus (EDOF) and enhanced monofocal intraocular lenses (IOLs). SETTINGS Narayana Nethralaya Eye Hospital, Bangalore, India. DESIGN Prospective, longitudinal, observational. METHODS 80 eyes (40 patients) that had cataract surgery were included in the study. 40 eyes were implanted with Eyhance EDOF IOLs and the remaining with Vivity EDOF IOLs. Baseline ocular aberrations were measured with a visual adaptive optics aberrometer, then the optimal SA was determined by increasing it in steps of -0.01 μm up to -0.1 μm until the maximum improvement in near distance VA was observed for a given eye. Then the defocus curve for each eye was measured after modifying the ocular SA by magnitude equal to optimal SA. RESULTS Most of the eyes accepted a negative induced SA of -0.05 μm (Eyhance group: 67.6%; Vivity group, 45.2%). In the Eyhance group (dominant eyes), VA improved at -2 diopters (D) ( P < .02) only and degraded at 0 D, +0.5 D, and +1 D defocus ( P < .05). In the Vivity group, the VA remained unchanged at all defocus ( P > .05). In the Eyhance group (nondominant eyes), VA improved at -3.5 D defocus only and degraded at +1.5 D and +2 D defocus ( P < .05). In the Vivity group, VA improved at -2.5 D defocus ( P < .05) only. CONCLUSIONS A negative induced SA of -0.05 μm in implanted eyes was optimal for a slight improvement in distance-corrected near and intermediate VA without any significant decrease in baseline distance-corrected VA.
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Affiliation(s)
- Naren Shetty
- From the Department of Cataract Surgery, Narayana Nethralaya Eye Hospital, Bangalore, India (N. Shetty, Ranade); Department of Cornea and Refractive Surgery, Narayana Nethralaya Eye Hospital, Bangalore, India (R. Shetty, Ranade); Imaging, Biomechanics and Mathematical Modelling Solutions Lab, Narayana Nethralaya Foundation, Bangalore, India (Narasimhan, Roy); Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Spain (Artal); University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+), Maastricht, the Netherlands (Nuijts)
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Skrzypecki J, Izdebska J, Ordon AJ, Przybek-Skrzypecka J, Szaflik JP. Spherical aberrations and their role in modern ophthalmology. Clin Exp Optom 2023; 106:703-710. [PMID: 36822601 DOI: 10.1080/08164622.2022.2160235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 02/25/2023] Open
Abstract
Spherical aberration is an imperfection of the optical system of the human eye. The role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation is reviewed. Spherical aberration is an imperfection of the optical system of the human eye. In most cases, due to well-developed neuroadaptation, it is insignificant for the perception of the image. Nevertheless, its role in modern ophthalmology is far from straightforward. On the one hand, there are clinical scenarios in which an excess of spherical aberration degrades the retinal image and leads to a high dissatisfaction rate among patients.©Recently, there is a growing interest in the modulation of spherical aberration in the clinical setting. Modern intraocular lenses as well as laser refractive procedures are aimed at interfering with spherical aberrations of the optical system in order to increase range of pseudoaccommodation. Here, we review the role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation.
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Affiliation(s)
- Janusz Skrzypecki
- Departament of Ophthalmology, Independent Public University Eye Hospital, Warsaw, Poland
- Department of Experimental Physiology and Pathophysiology, Medical University of Warsaw, Warsaw, Poland
| | - Justyna Izdebska
- Departament of Ophthalmology, Independent Public University Eye Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Agata Joanna Ordon
- Departament of Ophthalmology, Independent Public University Eye Hospital, Warsaw, Poland
- Department of Binocular Vision Pathophysiology and Strabismus, Medical University of Lodz, Lodz, Poland
| | - Joana Przybek-Skrzypecka
- Departament of Ophthalmology, Independent Public University Eye Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Pawel Szaflik
- Departament of Ophthalmology, Independent Public University Eye Hospital, Warsaw, Poland
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
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Martínez-Plaza E, López-de la Rosa A, Papadatou E, Habib NE, Del Águila-Carrasco AJ, López-Miguel A, Maldonado MJ, Buckhurst PJ. Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations. Eye (Lond) 2023; 37:1640-1645. [PMID: 36002509 PMCID: PMC10219962 DOI: 10.1038/s41433-022-02211-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/23/2022] [Accepted: 08/10/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND/OBJECTIVES To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt. SUBJECTS/METHODS A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed. RESULTS IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75). CONCLUSIONS Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.
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Affiliation(s)
- Elena Martínez-Plaza
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, Spain
- Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, Spain
| | | | | | - Nabil E Habib
- Royal Eye Infirmary, University Hospitals Plymouth NHS Trust, Plymouth, UK
| | | | - Alberto López-Miguel
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, Spain.
- Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, Spain.
| | - Miguel J Maldonado
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, Spain
- Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, Spain
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Hirabayashi MT, Gharabagi AP, Hesemann NP, Johnson SM, Webel AD, Petroski GF, Davis GR. Spherical Aberration of Cataractous Eyes and Its Relationship With Age, Ocular Biometry, and Various IOL Platforms. J Refract Surg 2023; 39:89-94. [PMID: 36779463 DOI: 10.3928/1081597x-20221207-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
PURPOSE To determine the median spherical aberration (SA) of the cataractous population, how it relates to biometry, and the theoretical effect of different intraocular lens (IOL) platforms. METHODS A retrospective chart review of patients undergoing cataract surgery evaluation with a high quality Pentacam (Oculus Optikgeräte GmbH) were included. Age, gender, Q-value, mean total SA, higher order aberration root mean square wavefront error, and equivalent keratometry were collected from the Holladay report and axial length and anterior chamber depth (ACD) from the IOLMaster 700 (Carl Zeiss Meditec AG). RESULTS Data from 1,725 eyes of 999 patients were collected. SA had a median of 0.37 µm (95% confidence interval: 0.36 to 0.38. Age (r = .136, P < .001), Q-factor (r = .743, P < .001), and higher order aberration root mean square wavefront error (r = .307, P < .001) were positively correlated with SA. Average equivalent keratometry (r = -.310, P < .001) was negatively correlated with SA. Axial length (r = -0.037, P = .120) and ACD (r = .004, P = .856) had no association with SA. Up to 1,499 (86.9%) theoretically had SA moved closer to zero with IOLs that had negative SA. Up to 102 (5.9%) had SA theoretically worsened. CONCLUSIONS SA is not normally distributed, suggesting that there may be no "average" SA that IOLs should aim to correct. Patients might benefit from tailoring IOL choice to individual SA. Without access to SA data, eyes with steeper average keratometry or younger patients may have less SA, which could influence IOL choice. [J Refract Surg. 2023;39(2):89-94.].
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Feng X, Geng M, Meng X, Zou D, Jin Z, Liu G, Zhou C, Ren Q, Lu Y. SGLSA: Sphygmus gated laser speckle angiography for microcirculation hemodynamics imaging. Comput Med Imaging Graph 2023; 103:102164. [PMID: 36563513 DOI: 10.1016/j.compmedimag.2022.102164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/16/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022]
Abstract
Hemodynamics imaging of the retinal microcirculation has been demonstrated to be potential access to evaluating ophthalmic diseases, cardio-cerebrovascular diseases, and metabolic diseases. However, existing structural and functional imaging techniques are insufficient in spatial or temporal resolution. The sphygmus gated laser speckle angiography (SGLSA) is proposed for structural and functional imaging with high spatiotemporal resolution. Compared with classic LSCI algorithms, SGLSA presents a much clearer perfusion image and higher signal-to-noise ratio pulsatility. The SGLSA algorithm also shows better performance on patients than traditional LSCI methods. The high spatiotemporal resolution provided by the SGLSA algorithm greatly enhances the ability of retinal microcirculation analysis, which makes up for the deficiency of the LSCI technology, and attaches great significance to retinal hemodynamic imaging, biomarker research, and clinical diagnosis.
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Affiliation(s)
- Ximeng Feng
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing, China; Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China; Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Mufeng Geng
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing, China; Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China; Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Xiangxi Meng
- Key Laboratory of Carcinogenesis and Translational Research, Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing, China
| | - Da Zou
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Zi Jin
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Gangjun Liu
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Chuanqing Zhou
- College of Medical Instrument, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Qiushi Ren
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing, China; Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China; Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yanye Lu
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China.
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Mota DF, Haddad JS, Rocha KM, George Oral Waring IV, Tanos FW, Ambrosio R. The role of the tear film in dysfunctional lens syndrome: a prospective review. REVISTA BRASILEIRA DE OFTALMOLOGIA 2022. [DOI: 10.37039/1982.8551.20220063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Gupta S, Mahalingam K, Desai A, Kaginalkar A, Bhardwaj M, Singh A, Gupta V. Ocular aberrations in eyes with Primary Congenital Glaucoma. Curr Eye Res 2022; 47:1200-1208. [PMID: 35502999 DOI: 10.1080/02713683.2022.2074045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE To highlight the magnitude of ocular higher order aberrations (HOA) and lower order aberrations (LOA), including component contributions from corneal and internal planes in Primary Congenital Glaucoma (PCG) patients. METHODS Consecutive treated PCG patients co-operative for ocular examination and aberrometry, were enrolled over two years for this cross-sectional, comparative, single centre, unmasked study. Best corrected visual acuity, refraction, IOP, wavefront aberrometry and topography (iTrace) were performed and results were compared with unaffected fellow eyes of unilateral glaucoma patients as well as age and sex matched controls with no ocular anomalies other than treatable refractive error. RESULTS Both eyes of 32 consecutive PCG patients (17 unilateral, 15 bilateral) and 39 controls were enrolled. The median LogMAR corrected distance visual acuity of PCG eyes was 0.68 (IQR: 0.2 - 1.8). Total ocular (Root mean square (RMS) 1.7µm vs 0.3µm, p = 0.014), corneal (RMS 1.1µm vs 0.3µm, p = 0.004) and internal (RMS 1.1µm vs 0.2µm, p = 0.013) aberrations, as well as HOAs and LOAs at each plane were significantly higher in PCG eyes than in controls. Component HOAs from corneal and internal planes were positively correlated with each other (p < 0.001; rs: 0.7). Total aberrations were greater in the affected eyes of PCG compared to the rest. The predominant subtype of HOAs in PCG were coma and trefoil. PCG with corneal opacity/Haab's striae had significantly higher astigmatism than the affected eyes with clear corneae at corneal plane (p = 0.02). The aberrations were not statistically associated with the corneal diameter or refractive error in PCG eyes. CONCLUSIONS Significantly greater aberrations (Total, HOAs and LOAs, at corneal as well as internal plane) were seen among eyes affected with PCG. Though the exact impact of these aberrations on the final visual outcome is difficult to determine, these could play a pertinent role in compromising visual function, thus impacting the management of visual rehabilitation in these patients.
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Affiliation(s)
- Shikha Gupta
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Karthikeyan Mahalingam
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Arjun Desai
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Ananya Kaginalkar
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Mayank Bhardwaj
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Abhishek Singh
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
| | - Viney Gupta
- Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India 110029
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Benedi-Garcia C, Vinas M, Lago CM, Aissati S, de Castro A, Dorronsoro C, Marcos S. Optical and visual quality of real intraocular lenses physically projected on the patient's eye. BIOMEDICAL OPTICS EXPRESS 2021; 12:6360-6374. [PMID: 34745742 PMCID: PMC8548014 DOI: 10.1364/boe.432578] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 05/06/2023]
Abstract
Visual simulators aim at evaluating vision with ophthalmic corrections prior to prescription or implantation of intraocular lenses (IOLs) in the patient's eye. In the present study, we present the design, implementation, and validation of a new IOL-in-cuvette channel in an Adaptive Optics visual simulator, which provides an alternative channel for pre-operative simulation of vision with IOLs. The IOL is projected on the pupil's plane of the subject by using a Rassow system. A second lens, the Rassow lens, compensates for an IOL of 20 D while other powers can be corrected with a Badal system within a 5 D range. The new channel was evaluated by through-focus (TF) optical quality in an artificial eye on bench, and by TF visual acuity in patients, with various IOL designs (monofocal, diffractive trifocal, and refractive extended depth of focus).
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Affiliation(s)
- Clara Benedi-Garcia
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
| | - Maria Vinas
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
- Currently with Wellman Center for Photomedicine, Massachusetts General Hospital Harvard Medical School, Boston, MA, USA
| | - Carmen M Lago
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
- 2EyesVision, Madrid, Spain
| | - Sara Aissati
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
| | - Alberto de Castro
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
| | - Carlos Dorronsoro
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
- 2EyesVision, Madrid, Spain
| | - Susana Marcos
- Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain
- Center for Visual Sciences, The Institute of Optics, Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
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Haddad JS, Rocha KM, Waring GO, Faria-Correia F, Ambrosio R. Dysfunctional lens syndrome: a prospective review. REVISTA BRASILEIRA DE OFTALMOLOGIA 2021. [DOI: 10.37039/1982.8551.20210037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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12
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Landers J, Goggin M. Ocular preference following implantation of aspheric and spherical intraocular lenses; an intra‐individual comparison. Clin Exp Optom 2021; 93:419-25. [DOI: 10.1111/j.1444-0938.2010.00513.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- John Landers
- The Queen Elizabeth Hospital, Woodville South and the South Australian Institute of Ophthalmology, University of Adelaide, South Australia, Australia.
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Atchison DA. Recent advances in measurement of monochromatic aberrations of human eyes. Clin Exp Optom 2021; 88:5-27. [PMID: 15658922 DOI: 10.1111/j.1444-0938.2005.tb06659.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Revised: 11/18/2004] [Accepted: 11/27/2004] [Indexed: 11/29/2022] Open
Abstract
The field of aberrations of the human eye is moving rapidly, being driven by the desire to monitor and optimise vision following refractive surgery. It is important for ophthalmologists and optometrists to have an understanding of the magnitude of various aberrations and how these are likely to be affected by refractive surgery and other corrections. In this paper, I consider methods used to measure aberrations, the magnitude of aberrations in general populations and how these are affected by various factors (for example, age, refractive error, accommodation and refractive surgery) and how aberrations and their correction affect spatial visual performance.
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Affiliation(s)
- David A Atchison
- School of Optometry, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia
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Abstract
BACKGROUND This study aimed to investigate the short-term effect of cycloplegia on higher-order aberrations (HOAs) in school-age myopic children who received 0.25% atropine for cycloplegic refraction. METHODS We performed a retrospective chart review of 24 myopic children between the ages of 5 and 15 years, who had received one topical drop of 0.25% atropine for three consecutive nights before undergoing cycloplegic refraction. Auto-refraction, visual acuity, and HOAs measured with the iTrace aberrometer were compared before and after atropine use. To account for the effect of cycloplegia, the amount of HOAs under matching scanning sizes was compared. RESULTS There were statistically significant differences in the spherical equivalent, with a hyperopic shift after atropine use (p < 0.001). Corrected visual acuity and spherical aberrations showed no significant change under the respective pupil and scanning sizes before and after atropine use. Under identical scanning sizes, there was a significant change in total spherical aberration (from 0.03 to 0.06 μm, p = 0.044) and internal spherical aberration (from -0.10 to -0.05 μm, p = 0.049) after atropine use. Differences in corneal spherical aberration were insignificant. CONCLUSION The positive shift of spherical aberration induced by the inhibition of accommodation in myopic children may have a possible effect against myopic progression. Future studies can focus on the long-term effect on HOAs and impact on visual quality with lower concentrations of atropine.
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Affiliation(s)
- Yih-Shiuan Kuo
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - May-Yung Yen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- National Yang Ming Chiao Tung University, School of Medicine, Taipei, Taiwan, ROC
- Sue-Tien Ophthalmology Clinic, Yin Sue-Tien Medical foundation, Taipei, Taiwan, ROC
| | - Pei-Yu Lin
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- National Yang Ming Chiao Tung University, School of Medicine, Taipei, Taiwan, ROC
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Patel DD, Lipinski DM. Validating a low-cost laser speckle contrast imaging system as a quantitative tool for assessing retinal vascular function. Sci Rep 2020; 10:7177. [PMID: 32346043 PMCID: PMC7188677 DOI: 10.1038/s41598-020-64204-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/10/2020] [Indexed: 11/18/2022] Open
Abstract
The ability to monitor progression of retinal vascular diseases like diabetic retinopathy in small animal models is often complicated by their failure to develop the end-stage complications which characterize the human phenotypes in disease. Interestingly, as micro-vascular dysfunction typically precedes the onset of retinal vascular and even some neurodegenerative diseases, the ability to visualize and quantify hemodynamic changes (e.g. decreased flow or occlusion) in retinal vessels may serve as a useful diagnostic indicator of disease progression and as a therapeutic outcome measure in response to treatment. Nevertheless, the ability to precisely and accurately quantify retinal hemodynamics remains an unmet challenge in ophthalmic research. Herein we demonstrate the ability to modify a commercial fundus camera into a low-cost laser speckle contrast imaging (LSCI) system for contrast-free and non-invasive quantification of relative changes to retinal hemodynamics over a wide field-of-view in a rodent model.
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Affiliation(s)
- Dwani D Patel
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Daniel M Lipinski
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.
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16
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Pan X, Lie AL, White TW, Donaldson PJ, Vaghefi E. Development of an in vivo magnetic resonance imaging and computer modelling platform to investigate the physiological optics of the crystalline lens. BIOMEDICAL OPTICS EXPRESS 2019; 10:4462-4478. [PMID: 31565502 PMCID: PMC6757483 DOI: 10.1364/boe.10.004462] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/07/2019] [Accepted: 07/12/2019] [Indexed: 05/11/2023]
Abstract
We have developed and validated in vivo magnetic resonance imaging (MRI) protocols to extract parameters (T2 and geometry) of the human lens that, combined with biometric measures of the eye and optical modelling, enable us to investigate the relative contributions made by the gradient of refractive index (GRIN) and the shape of the lens to the refractive properties of each subject tested. Seven young and healthy participants (mean age: 25.6 ± 3.6 years) underwent an ophthalmic examination, and two sessions of MRI scans using a 3 T clinical magnet. Our MRI protocols for studying lens physiological optics and geometrical measurements were repeatable and reliable, using both 1D (95% confidence interval (CI) for mean differences for exponents = [-2.1, 2.6]) and 2D analysis (anterior T2 CI for differences [-6.4, 8.1] ms; posterior T2 CI for differences [-6.4, 8.3] ms). The lens thickness measured from MRI showed good correlation with that measured with clinical 'gold standard' LenStar (mean differences = [-0.18, 0.2] mm). The predicted refractive errors from ZEMAX had reasonable agreements with participants' clinic records (mean differences = [-1.7, 1.2] D). Quantitative measurements of lens geometry and GRIN with our MRI technique showed high inter-day repeatability. Our clinical MRI technique also provides reliable measures of lens geometry that are comparable to optical biometry. Finally, our ZEMAX optical models produced accurate refractive error and lens power estimations.
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Affiliation(s)
- Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Alyssa L. Lie
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Thomas W. White
- Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Paul J. Donaldson
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Center, University of Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Center, University of Auckland, New Zealand
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Schrecker J, Langenbucher A, Seitz B, Eppig T. First results with a new intraocular lens design for the individual correction of spherical aberration. J Cataract Refract Surg 2018; 44:1211-1219. [PMID: 30120004 DOI: 10.1016/j.jcrs.2018.06.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/26/2018] [Accepted: 06/28/2018] [Indexed: 11/19/2022]
Abstract
PURPOSE To assess the feasibility of individual compensation of corneal spherical aberration with a custom intraocular lens (IOL). SETTING Department of Ophthalmology, Rudolf Virchow Klinikum Glauchau, Glauchau, Germany. DESIGN Prospective case series. METHODS Cataract patients were randomized to receive an individual aberration-correcting IOL (Invidua-aA; Group A) or a standard aspheric aberration-free IOL of otherwise identical design (Aspira-aA; Group B). In Group A, the IOL was designed according to preoperative calculation of the corneal spherical aberration Z(4,0). The aim was to achieve an overall postoperative ocular spherical aberration close to zero. Four weeks and 3 months postoperatively, the refraction, visual acuity (far, intermediate, and near distance), photopic and mesopic contrast sensitivities (with and without glare), defocus curve, corneal and ocular spherical aberration, and pupil size were measured. RESULTS Group A, 57 eyes of 42 patients and Group B, 29 eyes of 27 patients. Preoperatively, there was no difference in corneal spherical aberration between groups (P > .05). Three months postoperatively, residual ocular spherical aberration Z(4,0) was significantly lower in Group A (P < .001). Photopic and mesopic contrast sensitivities (with and without glare) were significantly higher in Group A at most spatial frequencies. Monocular defocus curve and distance, intermediate, and near visual acuity outcomes did not differ significantly between groups. CONCLUSIONS Implantation of a custom monofocal aspheric IOL effectively reduced overall ocular spherical aberration. Clinical outcomes indicate that IOLs with an individual spherical aberration correction improve functional vision, especially contrast sensitivity, compared with standard aberration-free IOLs.
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Affiliation(s)
- Jens Schrecker
- Department of Ophthalmology (Schrecker), Rudolf Virchow Klinikum Glauchau, Glauchau, the Institute of Experimental Ophthalmology (Langenbucher, Eppig) and the Department of Ophthalmology (Seitz), Saarland University, Homburg/Saar, Germany.
| | - Achim Langenbucher
- Department of Ophthalmology (Schrecker), Rudolf Virchow Klinikum Glauchau, Glauchau, the Institute of Experimental Ophthalmology (Langenbucher, Eppig) and the Department of Ophthalmology (Seitz), Saarland University, Homburg/Saar, Germany
| | - Berthold Seitz
- Department of Ophthalmology (Schrecker), Rudolf Virchow Klinikum Glauchau, Glauchau, the Institute of Experimental Ophthalmology (Langenbucher, Eppig) and the Department of Ophthalmology (Seitz), Saarland University, Homburg/Saar, Germany
| | - Timo Eppig
- Department of Ophthalmology (Schrecker), Rudolf Virchow Klinikum Glauchau, Glauchau, the Institute of Experimental Ophthalmology (Langenbucher, Eppig) and the Department of Ophthalmology (Seitz), Saarland University, Homburg/Saar, Germany
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18
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Ruggeri M, Williams S, Heilman BM, Yao Y, Chang YC, Mohamed A, Sravani NG, Durkee H, Rowaan C, Gonzalez A, Ho A, Parel JM, Manns F. System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens. BIOMEDICAL OPTICS EXPRESS 2018; 9:3834-3851. [PMID: 30338159 PMCID: PMC6191619 DOI: 10.1364/boe.9.003834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/17/2018] [Accepted: 07/17/2018] [Indexed: 05/22/2023]
Abstract
We present a new in vitro instrument for measuring shape and wavefront aberrations of the primate crystalline lens, both on- and off-axis, while simulating accommodation with a motorized lens stretching system. The instrument merges spectral domain optical coherence tomography (SD-OCT) imaging and ray tracing aberrometry using an approach that senses wavefront aberrations of the lens with the OCT probing beam. Accuracy and repeatability of aberration measurements were quantified. Preliminary experiments on two human and four cynomolgus monkey lenses demonstrate the ability of the system to measure the lens shape, spherical aberration and peripheral defocus, and their changes during simulated accommodation.
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Affiliation(s)
- Marco Ruggeri
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Siobhan Williams
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Bianca Maceo Heilman
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Yue Yao
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Yu-Cherng Chang
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Ashik Mohamed
- Ophthalmic Biophysics, L V Prasad Eye Institute, Hyderabad, India
- Brien Holden Vision Institute, Sydney, NSW, Australia
- School of Optometry and Vision Science, University of New South Wales, Sydney NSW, Australia
| | | | - Heather Durkee
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
| | - Cornelis Rowaan
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Alex Gonzalez
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Arthur Ho
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Brien Holden Vision Institute, Sydney, NSW, Australia
- School of Optometry and Vision Science, University of New South Wales, Sydney NSW, Australia
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
- Brien Holden Vision Institute, Sydney, NSW, Australia
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL, USA
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19
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From Presbyopia to Cataracts: A Critical Review on Dysfunctional Lens Syndrome. J Ophthalmol 2018; 2018:4318405. [PMID: 30050689 PMCID: PMC6040261 DOI: 10.1155/2018/4318405] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/05/2018] [Indexed: 01/19/2023] Open
Abstract
Dysfunctional lens syndrome (DLS) is a term coined to describe the natural aging changes in the crystalline lens. Different alterations in the refractive properties and transparency of the lens are produced during the development of presbyopia and cataract, such as changes in internal high order aberrations or an increase in ocular forward scattering, with a potentially significant impact on clinical measures, including visual acuity and contrast sensitivity. Objective technologies have emerged to solve the limits of current methods for the grading of the lens aging, which have been linked to the DLS term. However, there is still not a gold standard or evidence-based clinical guidelines around these new technologies despite multiple research studies have correlated their results with conventional methods such as visual acuity or the lens opacification system (LOCS), with more scientific background around the ocular scattering index (OSI) and Scheimpflug densitometry. In either case, DLS is not a new evidence-based concept that leads to new knowledge about crystalline lens aging but it is a nomenclature change of two existing terms, presbyopia and cataracts. Therefore, this term should be used with caution in the scientific peer-reviewed literature.
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20
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Liu T, Thibos LN. Compensation of corneal oblique astigmatism by internal optics: a theoretical analysis. Ophthalmic Physiol Opt 2017; 37:305-316. [PMID: 28281302 DOI: 10.1111/opo.12364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/06/2017] [Indexed: 11/30/2022]
Abstract
PURPOSE Oblique astigmatism is a prominent optical aberration of peripheral vision caused by oblique incidence of rays striking the refracting surfaces of the cornea and crystalline lens. We inquired whether oblique astigmatism from these two sources should be expected, theoretically, to have the same or opposite signs across the visual field at various states of accommodation. METHODS Oblique astigmatism was computed across the central visual field for a rotationally-symmetric schematic-eye using optical design software. Accommodative state was varied by altering the apical radius of curvature and separation of the biconvex lens's two aspheric surfaces in a manner consistent with published biometry. Oblique astigmatism was evaluated separately for the whole eye, the cornea, and the isolated lens over a wide range of surface curvatures and asphericity values associated with the accommodating lens. We also computed internal oblique astigmatism by subtracting corneal oblique astigmatism from whole-eye oblique astigmatism. RESULTS A visual field map of oblique astigmatism for the cornea in the Navarro model follows the classic, textbook description of radially-oriented axes everywhere in the field. Despite large changes in surface properties during accommodation, intrinsic astigmatism of the isolated human lens for collimated light is also radially oriented and nearly independent of accommodation both in theory and in real eyes. However, the magnitude of ocular oblique astigmatism is smaller than that of the cornea alone, indicating partial compensation by the internal optics. This implies internal oblique astigmatism (which includes wavefront propagation from the posterior surface of the cornea to the anterior surface of the lens and intrinsic lens astigmatism) must have tangentially-oriented axes. This non-classical pattern of tangential axes for internal astigmatism was traced to the influence of corneal power on the angles of incidence of rays striking the internal lens. CONCLUSIONS Partial compensation of corneal astigmatism by internal optics is due mainly to the highly converging nature of wavefronts incident upon the lens resulting from corneal refraction. The degree of compensation is quadratically dependent on eccentricity but is expected to diminish as the eye accommodates. Neutralising the cornea by index-matching defeats internal compensation, revealing classical, radially-oriented oblique astigmatism in the isolated lens.
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Affiliation(s)
- Tao Liu
- School of Optometry, Indiana University, Bloomington, Indiana, USA
| | - Larry N Thibos
- School of Optometry, Indiana University, Bloomington, Indiana, USA
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21
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Delamere NA, Mandal A, Shahidullah M. The Significance of TRPV4 Channels and Hemichannels in the Lens and Ciliary Epithelium. J Ocul Pharmacol Ther 2016; 32:504-508. [PMID: 27513167 DOI: 10.1089/jop.2016.0054] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To function normally, all cells must maintain ion homeostasis, establish a membrane potential, and regulate water content. These actions require active Na-K transport provided by Na,K-ATPase. The lens, however, is made up almost entirely of fiber cells that have little or no Na,K-ATPase activity. Lens ion and water homeostasis rely on Na,K-ATPase activity in a small number of cells at the periphery of epithelium monolayer. Therefore, the function of the epithelium must be integrated with the needs of the fiber mass. This suggests that a remote control mechanism may adjust Na,K-ATPase activity to match increases or decreases of ion leakage, which may occur a considerable distance away. Here, we review evidence that TRPV4 channels in the epithelium become activated when the lens is subjected to osmotic- or damage-induced swelling. This triggers a chain of events in the lens epithelium that opens connexin hemichannels, allowing ATP release that stimulates purinergic receptors, activates Src family tyrosine kinases, and increases Na,K-ATPase activity. Recent studies also revealed functional connexin hemichannels along with TRPV4 channels in nonpigmented ciliary epithelial (NPE) cells that secrete aqueous humor into the eye. Because TRPV4 channels are mechanosensitive, we speculate they might enable the NPE to respond to stimuli such as mechanical distortion associated with volume homeostasis during fluid transfer across the ciliary epithelium or changes in intraocular pressure.
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Affiliation(s)
| | - Amritlal Mandal
- Department of Physiology, University of Arizona , Tucson, Arizona
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22
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Spherical aberration reduction in nuclear cataracts. Graefes Arch Clin Exp Ophthalmol 2016; 254:1127-33. [PMID: 26984747 DOI: 10.1007/s00417-016-3316-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/30/2016] [Accepted: 02/22/2016] [Indexed: 10/22/2022] Open
Abstract
PURPOSE To measure higher-order aberrations (HOAs) in nuclear cataracts and to investigate spherical aberration changes with nuclear cataract progression. METHODS A total of 102 eyes of older subjects (>50 years) were classified based on the nuclear opalescence (NO) grading of the Lens Opacities Classification System III: Group 1 (< NO2, 35), 2 (NO2, 23), 3 (NO3, 23), and 4 (≥ NO 4:21 eyes). Wave front measurements were performed with a Hartmann-Shack aberrometer. To investigate lenticular spherical aberration, HOAs were examined in 28 eyes before and after phacoemulsification, followed by insertion of an aberration-free intraocular lens. The relationship between lens opacity grade and ocular and lenticular spherical aberrations were investigated. RESULTS Mean spherical aberrations in groups 1, 2, 3, and 4 were 0.25 ± 0.10, 0.16 ± 0.13, 0.12 ± 0.15, and 0.10 ± 0.20 μm, respectively, and showed a significant difference with nuclear opacity grading (p = 0.001). The spherical aberration showed negative associations with nuclear opacity grading (r = -0.408, p < 0.001). The predominant change in HOAs after phacoemulsification was an increase in spherical aberration, and 86 % of lenticular spherical aberrations were presumed to have negative values. The lenticular spherical aberration was negatively correlated with nuclear opacity severity (r = -0.409, p = 0.031). CONCLUSIONS Ocular spherical aberration decreases with the progression of nuclear cataracts due to the negative correlation between lenticular spherical aberration and nuclear opacity severity.
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Maceo Heilman B, Manns F, de Castro A, Durkee H, Arrieta E, Marcos S, Parel JM. Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher. Invest Ophthalmol Vis Sci 2015; 56:1743-50. [PMID: 25670492 DOI: 10.1167/iovs.14-16057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. METHODS Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. RESULTS The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively. CONCLUSIONS Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age.
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Affiliation(s)
- Bianca Maceo Heilman
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
| | - Alberto de Castro
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Heather Durkee
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
| | - Esdras Arrieta
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Susana Marcos
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States Vision Cooperative Research Centre, Brien Holden Vision Institute, University of New South Wales, Sydney, New South Wales, Australia
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Crnej A, Buehl W, Greslechner R, Hirnschall N, Findl O. Effect of an aspheric intraocular lens on the ocular wave-front adjusted for pupil size and capsulorhexis size. Acta Ophthalmol 2014; 92:e353-7. [PMID: 24479668 DOI: 10.1111/aos.12344] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 12/10/2013] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the ocular wave-front of eyes with silicone Intraocular lens (IOLs) with aspheric and spherical optics after cataract surgery, taking into account the patient's pupil size under reading conditions and after pupil dilatation. METHODS In this institutional prospective, randomized, controlled, patient and examiner masked, bilateral trial with intra-individual comparison, 60 eyes of 30 patients with bilateral age-related cataract were included. Each patient received a spherical IOL (CeeOn Edge, 911A, AMO, Santa Ana, CA, USA) in one eye and an aspheric IOL (Tecnis, Z9000, AMO) in the contra-lateral eye. Exclusion criteria were other ocular pathologies, capsular changes or zonular weakness. The main outcome variable was spherical aberration of the ocular wave-front under mesopic pupil conditions measured 2 years after surgery. Additional outcome variables were visual acuity and photopic and mesopic contrast sensitivity. RESULTS There was no significant difference in visual acuity between the two IOL types under physiological pupil conditions and also not after pupil dilation. However, spherical aberrations were significantly lower with the aspheric IOL (SA: spherical 0.38 μm, SD: 0.11 μm; aspheric 0.10 μm, SD: 0.13 μm; p < 0.01), and there was a significant difference in contrast sensitivity at 12 cycles/degree. CONCLUSIONS This is the first randomized and masked trial on visual function and ocular wave-front after implantation with this silicone aspheric IOL, taking the patients' own pupil size into account. The effect on visual function was detectable for mesopic contrast sensitivity, but there was no difference in visual acuity. The SA was found to be significantly lower under physiological pupil conditions as well as when recalculated for the rhexis size and under pharmacological dilatation.
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Affiliation(s)
- Alja Crnej
- Moorfields Eye Hospital NHS Foundation Trust; London UK
| | - Wolf Buehl
- Department of Ophthalmology; Medical University of Vienna; Vienna Austria
| | - Roman Greslechner
- Department of Ophthalmology; Medical University of Vienna; Vienna Austria
| | - Nino Hirnschall
- Moorfields Eye Hospital NHS Foundation Trust; London UK
- Department of Ophthalmology; VIROS - Vienna Institute for Research in Ocular Surgery (VIROS); a Karl Landsteiner Institute; Vienna Austria
| | - Oliver Findl
- Moorfields Eye Hospital NHS Foundation Trust; London UK
- Department of Ophthalmology; VIROS - Vienna Institute for Research in Ocular Surgery (VIROS); a Karl Landsteiner Institute; Vienna Austria
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25
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Al-Sayyari TM, Fawzy SM, Al-Saleh AA. Corneal spherical aberration and its impact on choosing an intraocular lens for cataract surgery. Saudi J Ophthalmol 2014; 28:274-80. [PMID: 25473343 DOI: 10.1016/j.sjopt.2014.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/15/2014] [Accepted: 06/16/2014] [Indexed: 10/25/2022] Open
Abstract
PURPOSE To 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. SETTING AlHokama Eye Specialist Center, Riyadh, Saudi Arabia. PERIOD From the 1st of October 2012 until the 10th of April 2013. METHODS Fifty-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. RESULTS Fifty-three eyes of 45 patients, whose age ranged from 45 to 90 years 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 0.27 μm, 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 0.20 μm. 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). CONCLUSION Customized selection of aspheric IOLs based on the eyes' corneal spherical aberration has no significant importance comparing their results with the non-selected group.
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Affiliation(s)
| | - Samah M Fawzy
- Consultant ophthalmologist, PhD, Ophthalmology Department, Ain Shams University, Cairo, Egypt
| | - Ahmed A Al-Saleh
- Consultant ophthalmologist, PhD, AlHokama Eye Specialist Center, Riyadh, Saudi Arabia
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26
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Sheil CJ, Bahrami M, Goncharov AV. An analytical method for predicting the geometrical and optical properties of the human lens under accommodation. BIOMEDICAL OPTICS EXPRESS 2014; 5:1649-1663. [PMID: 24877022 PMCID: PMC4026897 DOI: 10.1364/boe.5.001649] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/19/2014] [Accepted: 03/18/2014] [Indexed: 05/31/2023]
Abstract
We present an analytical method to describe the accommodative changes in the human crystalline lens. The method is based on the geometry-invariant lens model, in which the gradient-index (GRIN) iso-indicial contours are coupled to the external shape. This feature ensures that any given number of iso-indicial contours does not change with accommodation, which preserves the optical integrity of the GRIN structure. The coupling also enables us to define the GRIN structure if the radii and asphericities of the external lens surfaces are known. As an example, the accommodative changes in lenticular radii and central thickness were taken from the literature, while the asphericities of the external surfaces were derived analytically by adhering to the basic physical conditions of constant lens volume and its axial position. The resulting changes in lens geometry are consistent with experimental data, and the optical properties are in line with expected values for optical power and spherical aberration. The aim of the paper is to provide an anatomically and optically accurate lens model that is valid for 3 mm pupils and can be used as a new tool for better understanding of accommodation.
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Affiliation(s)
- Conor J. Sheil
- Applied Optics Group, School of Physics, National University of Ireland, Galway, University Road, Galway,
Ireland
| | - Mehdi Bahrami
- Faculty of Science, Engineering and Computing, Kingston University London, Penrhyn Road, Kingston upon Thames, KT1 2EE,
UK
| | - Alexander V. Goncharov
- Applied Optics Group, School of Physics, National University of Ireland, Galway, University Road, Galway,
Ireland
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Optical quality comparison between spherical and aspheric toric intraocular lenses. Eur J Ophthalmol 2014; 24:699-706. [PMID: 24519505 DOI: 10.5301/ejo.5000440] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To measure and compare the optical quality of spherical and aspheric toric intraocular lenses (IOLs). METHODS Wavefront aberrations of AcrySof Toric and IQ Toric IOLs (Alcon Laboratories) for different powers were measured at 3- and 5-mm pupils by Nimo TR0805 instrument. The Zernike coefficients of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. The point spread functions (PSFs) of each IOL evaluated were calculated from the wavefront aberrations. The PSF images also were calculated from the IOL wavefront aberrations, adding the cornea's aberrations to simulate the optical quality after their implantation. RESULTS Spherical toric IOLs showed positive and aspheric toric IOLs negative spherical aberrations. Statistically significant differences were found in spherical aberration root mean square (RMS) values between spherical and aspheric IOLs for both pupil sizes (p<0.05). Aspheric toric IOLs showed higher spherical aberration RMS values. We found differences in PSF images between both IOL designs at 5-mm pupil. The PSFs corresponding to the aspheric toric IOLs showed more spread out than the PSFs corresponding to the spherical toric IOLs. However, when corneal aberrations were added, aspheric toric IOLs showed better optical quality than spherical toric IOLs. CONCLUSIONS At 3-mm pupil, the optical quality between the IOL designs was similar, but at 5-mm pupil the optical quality was higher for spherical IOLs than aspheric IOLs. However, when theoretical corneal aberrations were added, aspheric toric IOLs showed better optical quality than spherical toric IOLs, due to the compensation between aspheric toric IOL negative spherical aberration and corneal positive spherical aberration.
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Semeraro F, Romano MR, Duse S, Costagliola C. Quality of vision in patients implanted with aspherical and spherical intraocular lens: Intraindividual comparison. Indian J Ophthalmol 2013; 62:461-3. [PMID: 24008781 PMCID: PMC4064223 DOI: 10.4103/0301-4738.116489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aims: To compare the quality of vision in pseudophakic patients implanted with aspherical and spherical intraocular lenses (IOLs). Materials and Methods: Randomized prospective longitudinal intrapatient comparison between aspherical and spherical IOLs performed on 22 patients who underwent bilateral cataract surgery. Best corrected visual acuity, subjective contrast sensitivity, Strehl ratio and spherical aberrations (SA), and higher order wavefront aberrations for a 3.5 mm and a 6.0 mm pupil were measured after 3 months of cataract surgery. Results: SA (Z4,0) decreased significantly in eyes with aspherical IOL implant (P =0.004). Modulation transfer function (MTF) and point spread function (PSF) resulted no significant difference between the two groups (P =0.87; P = 0.32). Conclusion: Although the SA is significantly lower in eyes implanted with aspherical IOL, the quality of vision determined with MTF and PSF does not significantly differ for subjective and objective parameters that were analyzed.
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Affiliation(s)
| | - Mario R Romano
- Istituto di Clinica e Ricerca Humanitas, Rozzano, Milano; Department of Health Sciences, University of Molise, Campobasso, Italy
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Kingston AC, Cox IG. Population spherical aberration: associations with ametropia, age, corneal curvature, and image quality. Clin Ophthalmol 2013; 7:933-8. [PMID: 23723685 PMCID: PMC3666881 DOI: 10.2147/opth.s44056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The aim of this analysis was to determine the total ocular wavefront aberration values of a large phakic population of physiologically normal, ametropic eyes, gathered under the same clinical protocol using the same diagnostic wavefront sensor. MATERIALS AND METHODS Studies were conducted at multiple sites in Asia, North America, Europe, and Australia. A Bausch + Lomb Zywave II Wavefront Aberrometer (Rochester, NY, USA) was used to measure the lower and higher order aberrations of each eye. Data analysis was conducted using linear regression analysis to determine the relationship between total spherical aberration, ametropia, age, corneal curvature, and image quality. RESULTS Linear regression analysis showed no correlation (r = 0.0207, P = 0.4874) between degree of ametropia and the amount of spherical aberration. There was also no correlation when the population was stratified into myopic and hyperopic refractive groups (r m = 0.0529, P m = 0.0804 and r h = 0.1572, P h = 0.2754). There was a statistically significant and weak positive correlation (r = 0.1962, P < 0.001) between age and the amount of spherical aberration measured in the eye; spherical aberration became more positive with increasing age. Also, there was a statistically significant and moderately positive correlation (r = 0.3611, P < 0.001) with steepness of corneal curvature; spherical aberration became more positive with increasing power of the anterior corneal surface. Assessment of image quality using optical design software (Zemax™, Bellevue, WA < USA) showed that there was an overall benefit in correcting the average spherical aberration of this population. CONCLUSION Analysis of this dataset provides insights into the inherent spherical aberration of a typical phakic, pre-presbyopic, population and provides the ability to determine what drives the spherical aberration of the eye, as well as what potential benefit a person could gain by compensating for that average spherical aberration.
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Affiliation(s)
- Amanda C Kingston
- Bausch + Lomb, Rochester, NY, USA ; Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
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Kröger RH. Optical plasticity in fish lenses. Prog Retin Eye Res 2013; 34:78-88. [DOI: 10.1016/j.preteyeres.2012.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 12/09/2012] [Accepted: 12/11/2012] [Indexed: 01/05/2023]
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Park CY, Oh JH, Chuck RS. Predicting ocular residual astigmatism using corneal and refractive parameters: a myopic eye study. Curr Eye Res 2013; 38:851-61. [PMID: 23621376 DOI: 10.3109/02713683.2013.790976] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate the nature of ocular residual astigmatism (ORA) in myopic patients and to identify indicators to predict a patient's ORA from corneal and ocular refractive data. METHODS In total, 356 myopic eyes from 178 patients (M:F = 41:137) were examined using a Scheimpflug keratometer (Pentacam) and a wavefront analyzer (WaveScan). Vertex distance-adjusted total ocular astigmatism and corneal astigmatism [anterior corneal power (ACP) and true net power (TNP)] were used to calculate ORA, respectively. A power vector system (J0 and J45) was adopted for the astigmatism analysis. RESULTS The mean age of the study eyes was 27.6 ± 5.0 years, and mean refractive spherical equivalent, sphere and cylinder was -4.94 ± 1.90 diopter, -4.42 ± 1.87 diopter, and -1.05 ± 0.82, respectively. Corneal astigmatism measured by TNP was more representative of total ocular astigmatism than ACP (p < 0.001). Both the J0 and J45 components of ORA showed significant negative correlation with corneal astigmatism measured by ACP and TNP (p < 0.001). ORA (J0 and J45) was negatively correlated with total ocular spherical equivalent and positively correlated with total ocular astigmatism. CONCLUSIONS We verified the general compensatory effect of corneal astigmatism by internal optics in myopic patients. TNP was closer to refractive astigmatism than ACP was. Total ocular spherical equivalent and total ocular astigmatism showed significant correlation with ORA. Therefore these can be possible indicators to predict ORA.
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Affiliation(s)
- Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Koyang, Kyunggido, South Korea
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Birkenfeld J, de Castro A, Ortiz S, Pascual D, Marcos S. Contribution of the gradient refractive index and shape to the crystalline lens spherical aberration and astigmatism. Vision Res 2013; 86:27-34. [PMID: 23597582 DOI: 10.1016/j.visres.2013.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 11/18/2022]
Abstract
The optical properties of the crystalline lens are determined by its shape and refractive index distribution. However, to date, those properties have not been measured together in the same lens, and therefore their relative contributions to optical aberrations are not fully understood. The shape, the optical path difference, and the focal length of ten porcine lenses (age around 6 months) were measured in vitro using Optical Coherence Tomography and laser ray tracing. The 3D Gradient Refractive Index distribution (GRIN) was reconstructed by means of an optimization method based on genetic algorithms. The optimization method searched for the parameters of a 4-variable GRIN model that best fits the distorted posterior surface of the lens in 18 different meridians. Spherical aberration and astigmatism of the lenses were estimated using computational ray tracing, with the reconstructed GRIN lens and an equivalent homogeneous refractive index. For all lenses the posterior radius of curvature was systematically steeper than the anterior one, and the conic constant of both the anterior and posterior positive surfaces was positive. In average, the measured focal length increased with increasing pupil diameter, consistent with a crystalline lens negative spherical aberration. The refractive index of nucleus and surface was reconstructed to an average value of 1.427 and 1.364, respectively, for 633 nm. The results of the GRIN reconstruction showed a wide distribution of the index in all lens samples. The GRIN shifted spherical aberration towards negative values when compared to a homogeneous index. A negative spherical aberration with GRIN was found in 8 of the 10 lenses. The presence of GRIN also produced a decrease in the total amount of lens astigmatism in most lenses, while the axis of astigmatism was only little influenced by the presence of GRIN. To our knowledge, this study is the first systematic experimental study of the relative contribution of geometry and GRIN to the aberrations in a mammal lens.
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Affiliation(s)
- Judith Birkenfeld
- Instituto de Óptica "Daza de Valdés", Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid, Spain.
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Ruiz-Alcocer J, Madrid-Costa D, García-Lázaro S, Albarrán-Diego C, Ferrer-Blasco T. Visual simulation through an aspheric aberration-correcting intraocular lens in subjects with different corneal profiles using adaptive optics. Clin Exp Optom 2013; 96:379-84. [PMID: 23298381 DOI: 10.1111/cxo.12003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 07/30/2012] [Accepted: 08/27/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The aim of this study was to analyse the visual quality of the AcrySof IQ SN60WF(®) intraocular lens (IOL) when combined with different corneal profiles. METHODS Ten eyes of 10 participants with no prior history of refractive or cataract surgery were evaluated. An adaptive optics visual simulator was used to simulate the wavefront aberration pattern of an aspheric aberration-correcting IOL (AcrySof IQ SN60WF(®)). Normal corneas (group A), low and high myopic corneal ablations (groups B and C, respectively) and low and high hyperopic corneal ablations (groups D and E, respectively) were also simulated. Monocular distance visual acuities at 100, 50 and 10 per cent of contrast were measured. RESULTS At 100, 50 and 10 per cent contrast, no differences were found between groups A and B (p > 0.06 for all contrasts). Group A obtained better values than groups C, D and E for all contrasts (p = 0.031, p = 0.038, p = 0.032 at 100, 50 and 10 per cent of contrast, respectively). At the same time, group B obtained better values than groups C, D and E (p = 0.041, p = 0.042, p = 0.036 at 100, 50 and 10 per cent of contrast, respectively). Within the five groups, the worst results were always obtained for group E (p = 0.017, p = 0.021 and p = 0.025 at 100, 50 and 10 per cent of contrast, respectively). CONCLUSIONS The results suggest that the aspheric aberration-correcting IOL studied provides comparable results, when it is combined with normal corneas and with corneas with simulated low myopic ablations. When negative amounts of residual spherical aberration after cataract surgery are expected to be achieved, IOLs with more positive spherical aberration should be considered.
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Affiliation(s)
- Javier Ruiz-Alcocer
- Optics and Optometry Department, Universidad Europea de Madrid, Madrid, Spain.
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Vaghefi E, Malcolm DTK, Jacobs MD, Donaldson PJ. Development of a 3D finite element model of lens microcirculation. Biomed Eng Online 2012; 11:69. [PMID: 22992294 PMCID: PMC3494564 DOI: 10.1186/1475-925x-11-69] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 08/10/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens. METHODS Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it. RESULTS Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens. CONCLUSION Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency.
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Affiliation(s)
- Ehsan Vaghefi
- Department of Optometry and Vision Sciences, University of Auckland, Building 502, Level 4, 85 Park Road, Grafton, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Duane TK Malcolm
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Marc D Jacobs
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Optometry and Vision Sciences, University of Auckland, Building 502, Level 4, 85 Park Road, Grafton, Auckland, New Zealand
- School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Tilt and decentration of an intraocular lens implanted in the ciliary sulcus after capsular bag defect during cataract surgery. Graefes Arch Clin Exp Ophthalmol 2012; 251:89-93. [DOI: 10.1007/s00417-012-2141-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 07/05/2012] [Accepted: 08/11/2012] [Indexed: 11/26/2022] Open
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Dai GM. Theoretical analysis for spherical aberration induction with low-order correction in refractive surgery. APPLIED OPTICS 2012; 51:3966-3976. [PMID: 22722270 DOI: 10.1364/ao.51.003966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 04/14/2012] [Indexed: 06/01/2023]
Abstract
A theoretical foundation for the analysis of ocular aberration correction is developed. It enables a comparative study for two different refractive surgical approaches, namely, the conventional and the Q-preserved treatment modalities. A refractive surgical factor is identified that leads to a simple cubic function for the postoperative asphericity factor for the conventional treatment. A formulation is developed that paves the way for the calculation of the induction of spherical aberration for low-order aberration correction in refractive surgery. Opposite to the general belief, the Munnerlyn shape makes myopic LASIK more prolate, not oblate. A Monte Carlo simulation was conducted for 1000 eyes for these two refractive surgical modalities. It was found that, although the postoperative spherical aberration is similar for these surgical modalities, for the induction of spherical aberration from the ablation target shape, the conventional modality appears to be slightly more predictable.
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Madrid-Costa D, Ruiz-Alcocer J, Pérez-Vives C, Ferrer-Blasco T, López-Gil N, Montés-Micó R. Visual simulation through different intraocular lenses using adaptive optics: Effect of tilt and decentration. J Cataract Refract Surg 2012; 38:947-58. [PMID: 22624893 DOI: 10.1016/j.jcrs.2012.01.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/04/2012] [Accepted: 01/05/2012] [Indexed: 01/19/2023]
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Madrid-Costa D, Pérez-Vives C, Ruiz-Alcocer J, Albarrán-Diego C, Montés-Micó R. Visual simulation through different intraocular lenses in patients with previous myopic corneal ablation using adaptive optics: Effect of tilt and decentration. J Cataract Refract Surg 2012; 38:774-86. [DOI: 10.1016/j.jcrs.2011.11.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/28/2011] [Accepted: 11/30/2011] [Indexed: 01/19/2023]
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Total ocular, anterior corneal and lenticular higher order aberrations in hyperopic, myopic and emmetropic eyes. Vision Res 2011; 52:31-7. [PMID: 22100815 DOI: 10.1016/j.visres.2011.10.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 10/14/2011] [Accepted: 10/18/2011] [Indexed: 11/21/2022]
Abstract
Total ocular higher order aberrations and corneal topography of myopic, emmetropic and hyperopic eyes of 675 adolescents (16.9 ± 0.7 years) were measured after cycloplegia using COAS aberrometer and Medmont videokeratoscope. Corneal higher order aberrations were computed from the corneal topography maps and lenticular (internal) higher order aberrations derived by subtraction of corneal aberrations from total ocular aberrations. Aberrations were measured for a pupil diameter of 5mm. Multivariate analysis of variance followed by multiple regression analysis found significant difference in the fourth order aberrations (SA RMS, primary spherical aberration coefficient) between the refractive error groups. Hyperopic eyes (+0.083 ± 0.05 μm) had more positive total ocular primary spherical aberration compared to emmetropic (+0.036 ± 0.04 μm) and myopic eyes (low myopia=+0.038 ± 0.05 μm, moderate myopia=+0.026 ± 0.06 μm) (p<0.05). No difference was observed for the anterior corneal spherical aberration. Significantly less negative lenticular spherical aberration was observed for the hyperopic eyes (-0.038 ± 0.05 μm) than myopic (low myopia=-0.088 ± 0.04 μm, moderate myopia=-0.095 ± 0.05 μm) and emmetropic eyes (-0.081 ± 0.04 μm) (p<0.05). These findings suggest the existence of differences in the characteristics of the crystalline lens (asphericity, curvature and gradient refractive index) of hyperopic eyes versus other eyes.
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Vaghefi E, Pontre BP, Jacobs MD, Donaldson PJ. Visualizing ocular lens fluid dynamics using MRI: manipulation of steady state water content and water fluxes. Am J Physiol Regul Integr Comp Physiol 2011; 301:R335-42. [DOI: 10.1152/ajpregu.00173.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies using various MRI techniques have shown that a water-protein concentration gradient exists in the ocular lens. Because this concentration is higher in the core relative to the lens periphery, a gradient in refractive index is established in the lens. To investigate how the water-protein concentration profile is maintained, bovine lenses were incubated in different solutions, and changes in water-protein concentration ratio monitored using proton density weighted (PD-weighted) imaging in the absence and presence of heavy water (D2O). Lenses incubated in artificial aqueous humor (AAH) maintained the steady state water-protein concentration gradient, but incubating lenses in high extracellular potassium (KCl-AAH) or low temperature (Low T-AAH) caused a collapse of the gradient due to a rise in water content in the core of the lens. To visualize water fluxes, lenses were incubated in D2O, which acts as a contrast agent. Incubation in KCl-AAH and low T-AAH dramatically slowed the movement of D2O into the core but did not affect the movement of D2O into the outer cortex. D2O seemed to preferentially enter the lens cortex at the anterior and posterior poles before moving circumferentially toward the equatorial regions. This directionality of D2O influx into the lens cortex was abolished by incubating lenses in high KCl-AAH or low T-AAH, and resulted in homogenous influx of D2O into the outer cortex. Taken together, our results show that the water-protein concentration ratio is actively maintained in the core of the lens and that water fluxes preferentially enter the lens at the poles.
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Affiliation(s)
- Ehsan Vaghefi
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Beau P. Pontre
- Centre for Advanced MRI, University of Auckland, Auckland, New Zealand; and
| | - Marc D. Jacobs
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Paul J. Donaldson
- Department of Optometry and Vision Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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de Castro A, Siedlecki D, Borja D, Uhlhorn S, Parel JM, Manns F, Marcos S. Age-dependent variation of the Gradient Index profile in human crystalline lenses. JOURNAL OF MODERN OPTICS 2011; 58:1781-1787. [PMID: 22865954 PMCID: PMC3408875 DOI: 10.1080/09500340.2011.565888] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
PURPOSE: To reconstruct the gradient index (GRIN) profile of human crystalline lenses ex-vivo using Optical Coherence Tomography (OCT) imaging with an optimization technique and to study the dependence of the GRIN profile with age. METHODS: Cross-sectional images of nine isolated human crystalline lenses with ages ranging from 6 to 72 (post mortem time 1 to 4 days) were obtained using a custom-made OCT system. Lenses were extracted from whole cadaver globes and placed in a measurement chamber filled with preservation medium (DMEM). Lenses were imaged with the anterior surface up and then flipped over and imaged again, to obtain posterior lens surface profiles both undistorted and distorted by the refraction through the anterior crystalline lens and GRIN. The GRIN distribution of the lens was described with three variables by means of power function, with variables being the nucleus and surface index, and a power coefficient that describes the decay of the refractive index from the nucleus to the surface. An optimization method was used to search for the parameters that produced the best match of the distorted posterior surface. RESULTS: The distorted surface was simulated with accuracy around the resolution of the OCT system (under 15 µm). The reconstructed refractive index values ranged from 1.356 to 1.388 for the surface, and from 1.396 to 1.434 for the nucleus. The power coefficient ranged between 3 and 18. The power coefficient increased significantly with age, at a rate of 0.24 per year. CONCLUSION: Optical Coherence Tomography allowed optical, non-invasive measurement of the 2-D gradient index profile of the isolated human crystalline lens ex vivo. The age-dependent variation of the changes is consistent with previous data using magnetic resonance imaging, and the progressive formation of a refractive index plateau.
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Affiliation(s)
- A de Castro
- Instituto de Óptica "Daza de Valdés, Consejo Superior de Investigaciones Científicas, C/ Serrano, 121, Madrid, 28006, Spain
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Santhiago MR, Netto MV, Barreto J, Gomes BAF, Oliveira CD, Kara-Junior N. Optical quality in eyes implanted with aspheric and spherical intraocular lenses assessed by NIDEK OPD-Scan: a randomized, bilateral, clinical trial. J Refract Surg 2010; 27:287-92. [PMID: 20672762 DOI: 10.3928/1081597x-20100714-01] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 06/17/2010] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine whether implantation of an intraocular lens (IOL) with an aspheric surface (Akreos AO, Bausch & Lomb Inc) results in reduced ocular aberrations (spherical aberration) and improved Strehl ratio and modulation transfer function (MTF) after cataract surgery. METHODS In an intraindividual, randomized, double-masked, prospective study of 50 eyes (25 patients) with bilateral cataract, an IOL with modified anterior and posterior surfaces (Akreos AO) was implanted in one eye and a biconvex IOL with spherical surfaces (Akreos Fit, Bausch & Lomb Inc) implanted in the fellow eye. Ocular aberrations, Strehl ratio, and MTF curve with 4.5-, 5.0-, and 6.0-mm pupils were measured with a NIDEK OPD-Scan dynamic retinoscopy aberrometer 3 months after surgery. Uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) were also measured. RESULTS No statistically significant difference was noted between eyes in postoperative UDVA and CDVA at 1 month. At 3 months, the Akreos AO IOL group obtained statistically significant lower values of higher order and spherical aberrations with 4.5-, 5.0-, and 6.0-mm pupil diameters than the Akreos Fit IOL group (P<.05). The value of Strehl ratio was statistically significantly higher in eyes with the Akreos AO IOL for 4.5- and 6.0-mm pupils (P<.05). The MTF curve was better in the Akreos AO IOL group in 4.5-, 5.0-, and 6.0-mm pupils (P<.05). CONCLUSIONS The aspheric Akreos AO IOL induced significantly less spherical aberration than the Akreos Fit IOL for 4.5-, 5.0-, and 6.0-mm pupils. Modulation transfer function and Strehl ratio were also better in eyes implanted with the Akreos AO IOL than the Akreos Fit.
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van Gaalen KW, Koopmans SA, Jansonius NM, Kooijman AC. Clinical comparison of the optical performance of aspheric and spherical intraocular lenses. J Cataract Refract Surg 2010; 36:34-43. [PMID: 20117703 DOI: 10.1016/j.jcrs.2009.06.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 06/23/2009] [Accepted: 06/24/2009] [Indexed: 11/18/2022]
Affiliation(s)
- Kim W van Gaalen
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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Scholz K, Messner A, Eppig T, Bruenner H, Langenbucher A. Topography-based assessment of anterior corneal curvature and asphericity as a function of age, sex, and refractive status. J Cataract Refract Surg 2009; 35:1046-54. [PMID: 19465291 DOI: 10.1016/j.jcrs.2009.01.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/09/2009] [Accepted: 01/12/2009] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess corneal asphericity (Q) and evaluate potential factors influencing the shape of the anterior corneal surface. SETTING Medical Optics Research Group, Institute of Medical Physics, University of Erlangen-Nuremberg, Erlangen, Germany. METHODS In this cross-sectional consecutive study, 3 topographic measurements were taken. Eyes were grouped by age in years (A: <or=29; B: 30 to 39; C: 40 to 49; D: 50 to 59; E: 60 to 69; F: >or=70), sex, and refraction. RESULTS The study comprised 487 eyes (205 men, 288 women; age 17 to 81 years). The mean Q of the anterior corneal surface was -0.22 +/- 0.14 (SD) overall, -0.21 +/- 0.12 in Group A, -0.25 +/- 0.11 in Group B, -0.21 +/- 0.15 in Group C, -0.23 +/- 0.14 in Group D, -0.19 +/- 0.17 in Group E, -0.20 +/- 0.15 in Group F, -0.23 +/- 0.13 in men, -0.21 +/- 0.14 in women, -0.19 +/- 0.14 in hyperopes (n = 166; >+0.50 to +6.50 diopters [D]), -0.23 +/- 0.13 in emmetropes (n = 162; -0.50 to +0.50 D), and -0.23 +/- 0.15 in myopes (n = 165; <-0.50 to -8.00 D). There was no significant correlation between Q and age; Q differed significantly between men and women (P = .005), hyperopes and emmetropes (P<.0001), and hyperopes and myopes (P = .001). CONCLUSIONS There were high interindividual variations in the Q value. Thus, proper correction of spherical aberration with intraocular lenses (IOLs) requires sophisticated selection of the asphericity of IOL surfaces based on biometric data and individual corneal Q values.
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Affiliation(s)
- Katja Scholz
- Medical Optics Research Group, Institute of Medical Physics, University of Erlangen-Nuremberg, Erlangen, Germany.
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Trueb PR, Albach C, Montés-Micó R, Ferrer-Blasco T. Visual acuity and contrast sensitivity in eyes implanted with aspheric and spherical intraocular lenses. Ophthalmology 2009; 116:890-5. [PMID: 19410947 DOI: 10.1016/j.ophtha.2008.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/26/2008] [Accepted: 12/02/2008] [Indexed: 10/20/2022] Open
Abstract
PURPOSE To compare visual acuity and contrast sensitivity (CS) in eyes implanted with aspheric and spherical intraocular lenses (IOLs) after cataract surgery. DESIGN Randomized, prospective study. PARTICIPANTS Five hundred twenty-four eyes from 262 cataract surgery patients implanted with 2 IOL models: the AcrySof IQ (262 eyes) and AcrySof SN60AT (262 eyes; Alcon Laboratories, Fort Worth, TX). METHODS High-contrast photopic best-corrected distance visual acuity (BCVA) and CS under photopic (85 cd/m(2)) and mesopic (6 cd/m(2)) conditions were measured. Pupil diameter was analyzed for distance vision under both lighting conditions. Follow-up was carried out for 6 months in all patients. MAIN OUTCOMES MEASURES Best-corrected distance visual acuity and photopic and mesopic CS after implantation under monocular and binocular conditions. RESULTS No statistically significant differences in BCVA were found between either IOL (0.06+/-0.06 and 0.05+/-0.07 logarithm of the minimum angle of resolution units for AcrySof SN60AT and AcrySof IQ groups, respectively; P = 0.091). One hundred percent of patients achieved BCVA of 20/32 or better in both groups. The percentage of patients who achieved BCVA of 20/25 or better was 86.3%. The AcrySof IQ IOL group showed better monocular and binocular CS at 6, 12, and 18 cpd under photopic conditions and at 3, 6, 12, and 18 cpd under mesopic conditions (P<0.001). CONCLUSIONS Eyes implanted with the aspheric AcrySof IQ IOL showed better photopic and mesopic CS at medium and high spatial frequencies than eyes implanted with the spherical AcrySof SN60AT IOL. High-contrast photopic BCVA was similar between both IOLs. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Peter R Trueb
- Ambulante Augenchirurgie Zürich, Talstrasse 65, Zürich, Switzerland.
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Su PY, Hu FR. Intraindividual Comparison of Functional Vision and Higher Order Aberrations After Implantation of Aspheric and Spherical Intraocular Lenses. J Refract Surg 2009; 25:265-72. [PMID: 19370821 DOI: 10.3928/1081597x-20090301-05] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Pei-Yuang Su
- Far-Eastern Memorial Hospital, Taipei, Taiwan, Republic of China
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Analysis of the possible benefits of aspheric intraocular lenses: Review of the literature. J Cataract Refract Surg 2009; 35:172-81. [PMID: 19101441 DOI: 10.1016/j.jcrs.2008.09.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 08/09/2008] [Accepted: 09/06/2008] [Indexed: 11/23/2022]
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Lee JS, Yoon TJ, Ahn JH. Comparison of the Clinical Effects of Implantation of Aspheric and Spherical Intraocular Lenses. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2009. [DOI: 10.3341/jkos.2009.50.10.1514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jong Soo Lee
- Department of Ophthalmology, School of Medicine, Pusan National University, Busan, Korea
| | - Tae-Jin Yoon
- Department of Ophthalmology, School of Medicine, Pusan National University, Busan, Korea
| | - Jin Hwan Ahn
- Department of Ophthalmology, School of Medicine, Pusan National University, Busan, Korea
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Navarro R. The Optical Design of the Human Eye: a Critical Review. JOURNAL OF OPTOMETRY 2009; 2:3-18. [PMCID: PMC3972707 DOI: 10.3921/joptom.2009.3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 01/12/2009] [Accepted: 01/14/2009] [Indexed: 05/18/2023]
Abstract
Cornea, lens and eye models are analyzed and compared to experimental findings to assess properties and eventually unveil optical design principles involved in the structure and function of the optical system of the eye. Models and data often show good match but also some paradoxes. The optical design seems to correspond to a wide angle lens. Compared to conventional optical systems, the eye presents a poor optical quality on axis, but a relatively good quality off-axis, thus yielding higher homogeneity for a wide visual field. This seems the result of an intriguing combination of the symmetry design principle with a total lack of rotational symmetry, decentrations and misalignments of the optical surfaces.
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Affiliation(s)
- Rafael Navarro
- Corresponding author: Facultad de Ciencias, Plaza San Francisco s/n, 50009 Zaragoza (Spain).
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