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Saad A, Steinberg J, Frings A. Repeatability of pupil diameter measurements using three different topography devices. PLoS One 2023; 18:e0290417. [PMID: 37594948 PMCID: PMC10437858 DOI: 10.1371/journal.pone.0290417] [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: 04/16/2023] [Accepted: 08/07/2023] [Indexed: 08/20/2023] Open
Abstract
PURPOSE To evaluate the intra- and inter-device repeatability of pupil diameter measurements using three different devices in patients prior to corneal refractive surgery. METHODS We examined preoperative measurements from a total of 204 eyes (102 patients) scheduled for corneal refractive surgery at two private centers between July and December 2021. Three consecutive scans were performed with three different devices (Sirius anterior segment analyzer, Pentacam HR, IOLMaster 500) in the same session by the same examiner under standardized conditions. To assess the intra- and inter-device repeatability, we calculated the Intraclass Correlation Coefficient (ICC) and demonstrated results using Bland-Altman plots. RESULTS The measurement accuracy (intra-device repeatability) of Sirius and IOLMaster was comparable (ICC = 0.64 and 0.61, respectively), with almost no statistically significant differences. Sirius showed the highest measurement accuracy among the three devices. Pentacam measurements resulted in lower precision, with an ICC of 0.09. The agreement between the pairs of devices (inter-device repeatability) was low (wide LoA ranges, Table 5). CONCLUSION In this study, the intra-device repeatability of Sirius and IOLMaster was higher than that of the Pentacam, although it did not achieve an optimal level across all three devices. The three devices examined cannot be used interchangeably.
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Affiliation(s)
- Amr Saad
- Department of Ophthalmology, University Hospital of Duesseldorf, Duesseldorf, Germany
| | - Johannes Steinberg
- Department of Ophthalmology, University Medical Center, Hamburg, Germany
- Zentrum Sehstärke, Hamburg, Germany
| | - Andreas Frings
- Department of Ophthalmology, University Hospital of Duesseldorf, Duesseldorf, Germany
- Augenheilkunde & Augenlaser Zentrum PD Dr. med. A. Frings, Nuremberg, Germany
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Abstract
Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Alexi Geevarghese
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA; .,Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA.,Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA; .,Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA; .,Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA.,Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA.,Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA
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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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Radhakrishnan H, Jinabhai A, O'donnell C. Dynamics of ocular aberrations in keratoconus. Clin Exp Optom 2021; 93:164-74. [DOI: 10.1111/j.1444-0938.2010.00471.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Hema Radhakrishnan
- Faculty of Life Sciences, Moffat Building, University of Manchester, Manchester, United Kingdom
E‐mail:
| | - Amit Jinabhai
- Faculty of Life Sciences, Moffat Building, University of Manchester, Manchester, United Kingdom
E‐mail:
| | - Clare O'donnell
- Faculty of Life Sciences, Moffat Building, University of Manchester, Manchester, United Kingdom
E‐mail:
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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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Gregory HR, Nti AN, Wolffsohn JS, Berntsen DA, Ritchey ER. Visual Performance of Center-distance Multifocal Contact Lenses Fit Using a Myopia Control Paradigm. Optom Vis Sci 2021; 98:272-279. [PMID: 33771957 PMCID: PMC8007064 DOI: 10.1097/opx.0000000000001665] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The purpose of this study was to examine the visual performance of center-distance MFCLs in nonpresbyopic adults under different illumination and contrast conditions compared with a single-vision contact lens (SVCL). METHODS Twenty-five adult subjects were fit with three different lenses (CooperVision Biofinity D MFCL +2.50 add, Visioneering Technologies NaturalVue MFCL, CooperVision Biofinity sphere). Acuity and reading performance were evaluated. RESULTS A statistically significant difference in high-contrast distance acuity was observed (Biofinity, -0.18 ± 0.06; Biofinity MFCL, -0.14 ± 0.08; NaturalVue MFCL, -0.15 ± 0.03; repeated-measures [RM] ANOVA, P = .02). Under mesopic, high-contrast conditions, MFCLs performed worse than SVCLs (Biofinity, -0.05 ± 0.091; Biofinity MFCL, +0.03 ± 0.09; NaturalVue MFCL, +0.05 ± 0.091; RM-ANOVA, P < .0001). Under low-contrast conditions, MFCLs performed one line worse in photopic lighting and two lines worse under mesopic conditions (RM-ANOVA, P < .0001). Glare reduced acuity by 0.5 logMAR for all lenses (RM-ANOVA, P < .001). A statistically significant difference in near acuity was observed (RM-ANOVA, P = .02), but all lenses achieved acuity better than -0.1 logMAR (Biofinity, -0.16 ± 0.06; Biofinity MFCL, -0.17 ± 0.04; NaturalVue MFCL, -0.13 ± 0.08). Reading performance in words per minute (wpm) was worse with MFCLs (Biofinity MFCL, 144 ± 22 wpm; NaturalVue MFCL, 150 ± 28 wpm) than with SVCLs (156 ± 23 wpm; RM-ANOVA, P = .02) regardless of letter size (RM-ANOVA, P = .13). No difference in acuity between the MFCLs was detected (RM-ANOVA: all, P > .05). CONCLUSIONS Multifocal contact lenses perform similarly to SVCLs for high-contrast targets and display reduced low-contrast acuity and reading speed. Practitioners should recognize that high-contrast acuity alone does not describe MFCL visual performance.
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Affiliation(s)
- Hannah R Gregory
- The Ocular Surface Institute, University of Houston College of Optometry, Houston, Texas
| | - Augustine N Nti
- The Ocular Surface Institute, University of Houston College of Optometry, Houston, Texas
| | - James S Wolffsohn
- Optometry and Vision Science Research Group, Department of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | - David A Berntsen
- The Ocular Surface Institute, University of Houston College of Optometry, Houston, Texas
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Rubiño JA, Gamundí A, Akaarir M, Canellas F, Rial R, Nicolau MC. Bright Light Therapy and Circadian Cycles in Institutionalized Elders. Front Neurosci 2020; 14:359. [PMID: 32435176 PMCID: PMC7218138 DOI: 10.3389/fnins.2020.00359] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/24/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Bright light therapy has been found to be an efficient method to improve the main parameters of circadian rhythms. However, institutionalized elders may suffer reduced exposure to diurnal light, which may impair their circadian rhythms, cognitive performance, and general health status. OBJECTIVES To analyze the effects of 5 days of morning exposure for 90 min to bright light therapy (BLT) applied to institutionalized elderly subjects with mild/moderate cognitive impairment. SUBJECTS Thirty-seven institutionalized subjects of both sexes, aged 70-93 years. METHODS The study lasted three consecutive weeks. During the second week the subjects were submitted to BLT (7000-10,000 lux at eye level) on a daily basis. Cognition, attention, and sleep quality were evaluated at the beginning of the first and third week. Circadian variables were recorded continuously throughout the 3 weeks. Non-invasive holders and validated tests were used to analyze the variables studied. RESULTS After BLT we have found significant improvements in general cognitive capabilities, sleep quality and in the main parameters of the subject's circadian rhythms. The results show that merely 90 min of BLT for five days seems to achieve a significant improvement in a constellation of circadian, sleep, health, and cognitive factors. CONCLUSION Bright light therapy is an affordable, effective, fast-acting therapy for age-related disturbances, with many advantages over pharmacological alternatives. We hypothesize these effects were the result of activating the residual activity of their presumably weakened circadian system.
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Affiliation(s)
- José A. Rubiño
- Laboratori de Neurofisiologia del Son i Ritmes Biològics, Institut d’Investigació Sanitária Illes Balears (IDISBA), Universitat Illes Balears (UIB), Palma de Mallorca, Spain
| | - Antoni Gamundí
- Laboratori de Neurofisiologia del Son i Ritmes Biològics, Institut d’Investigació Sanitária Illes Balears (IDISBA), Universitat Illes Balears (UIB), Palma de Mallorca, Spain
| | - Mourad Akaarir
- Laboratori de Neurofisiologia del Son i Ritmes Biològics, Institut d’Investigació Sanitária Illes Balears (IDISBA), Universitat Illes Balears (UIB), Palma de Mallorca, Spain
| | - Francesca Canellas
- Institut d’Investigació Sanitaria Illes Balears (IDISBA), Hospital Universitari Son Espases (HUSE), Palma de Mallorca, Spain
| | - Rubén Rial
- Laboratori de Neurofisiologia del Son i Ritmes Biològics, Institut d’Investigació Sanitária Illes Balears (IDISBA), Universitat Illes Balears (UIB), Palma de Mallorca, Spain
| | - M. Cristina Nicolau
- Laboratori de Neurofisiologia del Son i Ritmes Biològics, Institut d’Investigació Sanitária Illes Balears (IDISBA), Universitat Illes Balears (UIB), Palma de Mallorca, Spain
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Adib-Moghaddam S, Haydar AA, Razi-Khosroshahi M, Soleyman-Jahi S, Tefagh G, Grentzelos MA, Arba-Mosquera S, Kymionis GD. Predictors of Visual Acuity Improvement and Supernormal Vision After Refined Single-Step Transepithelial Photorefractive Keratectomy. J Refract Surg 2019; 35:771-780. [PMID: 31830293 DOI: 10.3928/1081597x-20191025-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/25/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate predicting factors of visual acuity improvement and achieving uncorrected (UDVA) or corrected (CDVA) distance visual acuity supernormal vision (⩾ 15/10; Snellen 20/13) 1 year after refined transepithelial photorefractive keratectomy (TransPRK). METHODS In this retrospective case series, a total of 155 eyes with myopia (mean ± standard deviation = -3.53 ± 1.81 diopters) with and without astigmatism (range = 0.25 to 4.50 diopters) were recruited and observed for 1 year. Patients underwent refined single-step TransPRK using the SCHWIND AMARIS 500 laser (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). The main predicting factors of postoperative supernormal vision and visual acuity improvements were sought by statistical modeling. RESULTS Logistic models showed mesopic contrast sensitivity, high laser fluence, and coma higher-order aberration (HOA) as predicting factors for both UDVA and CDVA super-normal vision. Myopia, astigmatism, dynamic cyclotorsion correction, optical zone, and transitional zone showed associations only in simple models and were not retained in multivariable models. According to the linear regression models, CDVA, mesopic contrast sensitivity, coma HOA, and keratometry were common predictors of both postoperative UDVA and CDVA improvement compared to preoperative UDVA. Astigmatism, optical and transitional zones, and high laser fluence were common predictors only in simple regression models. CONCLUSIONS Through statistical modeling, preoperative CDVA, mesopic contrast sensitivity, coma HOA, and simulated keratometry were found to be the main factors that predicted improvement of both postoperative CDVA and UDVA compared to preoperative CDVA. Furthermore, mesopic contrast sensitivity, coma HOA, and high laser fluence were the common predictors of achieving both CDVA and UDVA supernormal vision 1 year after refined single-step TransPRK. [J Refract Surg. 2019;35(12):771-780.].
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Dong ZM, Wollstein G, Wang B, Schuman JS. Adaptive optics optical coherence tomography in glaucoma. Prog Retin Eye Res 2017; 57:76-88. [PMID: 27916682 PMCID: PMC5350038 DOI: 10.1016/j.preteyeres.2016.11.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/14/2016] [Accepted: 11/19/2016] [Indexed: 02/07/2023]
Abstract
Since the introduction of commercial optical coherence tomography (OCT) systems, the ophthalmic imaging modality has rapidly expanded and it has since changed the paradigm of visualization of the retina and revolutionized the management and diagnosis of neuro-retinal diseases, including glaucoma. OCT remains a dynamic and evolving imaging modality, growing from time-domain OCT to the improved spectral-domain OCT, adapting novel image analysis and processing methods, and onto the newer swept-source OCT and the implementation of adaptive optics (AO) into OCT. The incorporation of AO into ophthalmic imaging modalities has enhanced OCT by improving image resolution and quality, particularly in the posterior segment of the eye. Although OCT previously captured in-vivo cross-sectional images with unparalleled high resolution in the axial direction, monochromatic aberrations of the eye limit transverse or lateral resolution to about 15-20 μm and reduce overall image quality. In pairing AO technology with OCT, it is now possible to obtain diffraction-limited resolution images of the optic nerve head and retina in three-dimensions, increasing resolution down to a theoretical 3 μm3. It is now possible to visualize discrete structures within the posterior eye, such as photoreceptors, retinal nerve fiber layer bundles, the lamina cribrosa, and other structures relevant to glaucoma. Despite its limitations and barriers to widespread commercialization, the expanding role of AO in OCT is propelling this technology into clinical trials and onto becoming an invaluable modality in the clinician's arsenal.
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Affiliation(s)
- Zachary M Dong
- University of Pittsburgh Medical Center (UPMC) Eye Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Ophthalmology and Visual Science Research Center, Pittsburgh, PA, United States.
| | - Gadi Wollstein
- New York University (NYU) Langone Eye Center, NYU Langone Medical Center, Department of Ophthalmology, NYU School of Medicine, New York, NY, United States.
| | - Bo Wang
- University of Pittsburgh Medical Center (UPMC) Eye Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Ophthalmology and Visual Science Research Center, Pittsburgh, PA, United States.
| | - Joel S Schuman
- New York University (NYU) Langone Eye Center, NYU Langone Medical Center, Department of Ophthalmology, NYU School of Medicine, New York, NY, United States; Department of Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, NY, United States.
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This issue at a glance. J Curr Ophthalmol 2016; 28:99-100. [PMID: 27579451 PMCID: PMC4992106 DOI: 10.1016/j.joco.2016.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Mohammadpour M, Heidari Z, Mohammad-Rabei H, Jafarzadehpur E, Jabbarvand M, Hashemi H, Khabazkhoob M. Correlation of higher order aberrations and components of astigmatism in myopic refractive surgery candidates. J Curr Ophthalmol 2016; 28:112-6. [PMID: 27579454 PMCID: PMC4992119 DOI: 10.1016/j.joco.2016.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 12/02/2022] Open
Abstract
Purpose To evaluate the correlation between refractive, corneal, and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates. Methods Three hundred and seventy-five eyes of 188 patients aged 28.2 ± 6.24 years with a predominance of females (62.7%) were enrolled in this study. Refraction, topography (Orbscan IIz, Bausch & Lomb, Rochester, NY, USA), and aberrometry (Zywave, Bausch & Lomb, Rochester, NY, USA) were performed to determine refractive and corneal astigmatism and HOA for all participants. Ocular residual astigmatism was calculated using vector analysis. Results The mean spherical equivalent was −3.59 ± 1.95 D and the mean refractive astigmatism was −1.97 ± 1.3 D. The mean HOA was 0.38 ± 0.15 μm in all cases, which increased with spherical equivalent (p < 0.05). There was a positive significant correlation between both corneal and refractive astigmatism and HOA (p < 0.05), but there was no significant correlation between residual astigmatism and HOA (p = 0.122). Conclusion The results of the study showed significant correlations between corneal and refractive astigmatisms and HOA.
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Affiliation(s)
- Mehrdad Mohammadpour
- Farabi Eye Hospital, Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Heidari
- School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hossein Mohammad-Rabei
- Ophthalmic Research Center, Torfeh Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Mahmoud Jabbarvand
- Farabi Eye Hospital, Eye Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Jinabhai A, O'Donnell C, Tromans C, Radhakrishnan H. Optical quality and visual performance with customised soft contact lenses for keratoconus. Ophthalmic Physiol Opt 2014; 34:528-39. [DOI: 10.1111/opo.12133] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 03/18/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Amit Jinabhai
- Faculty of Life Sciences; The University of Manchester; Manchester UK
| | - Clare O'Donnell
- Faculty of Life Sciences; The University of Manchester; Manchester UK
- Optegra Eye Sciences; Optegra Eye Hospital; Manchester UK
- School of Life and Health Sciences; Aston University; Birmingham UK
| | - Cindy Tromans
- Faculty of Life Sciences; The University of Manchester; Manchester UK
- Manchester Academic Health Science Centre; Central Manchester University Hospitals NHS Foundation Trust; Manchester UK
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Lombardo M, Serrao S, Devaney N, Parravano M, Lombardo G. Adaptive optics technology for high-resolution retinal imaging. SENSORS (BASEL, SWITZERLAND) 2012; 13:334-66. [PMID: 23271600 PMCID: PMC3574679 DOI: 10.3390/s130100334] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 12/05/2012] [Accepted: 12/06/2012] [Indexed: 01/18/2023]
Abstract
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of optical aberrations. The direct visualization of the photoreceptor cells, capillaries and nerve fiber bundles represents the major benefit of adding AO to retinal imaging. Adaptive optics is opening a new frontier for clinical research in ophthalmology, providing new information on the early pathological changes of the retinal microstructures in various retinal diseases. We have reviewed AO technology for retinal imaging, providing information on the core components of an AO retinal camera. The most commonly used wavefront sensing and correcting elements are discussed. Furthermore, we discuss current applications of AO imaging to a population of healthy adults and to the most frequent causes of blindness, including diabetic retinopathy, age-related macular degeneration and glaucoma. We conclude our work with a discussion on future clinical prospects for AO retinal imaging.
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Affiliation(s)
- Marco Lombardo
- Fondazione G.B. Bietti IRCCS, Via Livenza 3, 00198 Rome, Italy; E-Mails: (S.S.); (M.P.)
| | - Sebastiano Serrao
- Fondazione G.B. Bietti IRCCS, Via Livenza 3, 00198 Rome, Italy; E-Mails: (S.S.); (M.P.)
| | - Nicholas Devaney
- Applied Optics Group, School of Physics, National University of Ireland, Galway, Ireland; E-Mail:
| | | | - Giuseppe Lombardo
- CNR-IPCF Unit of Support of Cosenza, c/o University of Calabria, Ponte P. Bucci Cubo 31/C, 87036 Rende, Italy; E-Mail:
- Vision Engineering, Via Adda 7, 00198 Rome, Italy
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Uozato H, Shimizu K, Kawamorita T, Ohmoto F. Modulation transfer function of intraocular collamer lens with a central artificial hole. Graefes Arch Clin Exp Ophthalmol 2011; 249:1081-5. [PMID: 21229257 DOI: 10.1007/s00417-010-1602-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 12/04/2010] [Accepted: 12/06/2010] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND A modified implantable collamer lens (ICL) with a central hole (diameter 0.36 mm), "Hole-ICL", was created to improve aqueous humour circulation. The aim of this study is to investigate the effects of ICL power and the relationship between pupil size and modulation-transfer functions (MTFs) in a Hole-ICL in vitro. METHODS The ICL and intraocular lens (IOL) studied were the Collamer ICL (Model ICM, STAAR Surginal) and the monofocal IOL AF-1 (VA-60BBR, HOYA). The ICLs' powers were -20.0 diopters (D), -10.0 D, -5.0 D, +3.0 D, and +10.0 D. A modified ICL with a central hole (diameter 0.36 mm), "Hole-ICL", was created. The monofocal IOL, which was used as an artificial crystalline lens, was +30.0 D in power, and it was 13.0 mm in length with an optic diameter of 6.0 mm. The line-spread function (LSF) was recorded with the OPAL Vector System (Image Science Ltd.), and a model eye (Menicon Co.) was used that consisted of a wet cell. A conventional ICL or Hole-ICL was placed in the posterior chamber of the model eye. The MTF was calculated from the LSF using fast Fourier transform techniques. Furthermore, we investigated the relationship between pupil size and the MTF of the ICL for -5.0 D. The sizes of the effective aperture were 2.0, 3.0, 4.0, and 5.0 mm. RESULTS The in-focus contrasts of the conventional ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 39% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The in-focus contrasts of the Hole-ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 38% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The results for a 2.0-mm effective diameter showed that the in-focus MTF in the Hole-ICL was lower than in the conventional ICL, although the difference was small. CONCLUSION These results suggest that differences in MTF between the Hole-ICL and the conventional ICL for various ICL powers and effective pupil diameters were small and clinically negligible.
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Affiliation(s)
- Hiroshi Uozato
- Department of Orthoptics and Visual Science, Kitasato University School of Allied Health Sciences, 1-15-1 Kitasato, Minami, Sagamihara, 252-0373, Japan.
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Lombardo M, Lombardo G. Wave aberration of human eyes and new descriptors of image optical quality and visual performance. J Cataract Refract Surg 2010; 36:313-31. [PMID: 20152616 DOI: 10.1016/j.jcrs.2009.09.026] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 09/04/2009] [Accepted: 09/29/2009] [Indexed: 10/19/2022]
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Rae SM, Allen PM, Radhakrishnan H, Theagarayan B, Price HC, Sailaganathan A, Calver RI, O’Leary DJ. Increasing negative spherical aberration with soft contact lenses improves high and low contrast visual acuity in young adults. Ophthalmic Physiol Opt 2009; 29:593-601. [DOI: 10.1111/j.1475-1313.2009.00678.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Caporossi A, Casprini F, Martone G, Balestrazzi A, Tosi GM, Ciompi L. Contrast sensitivity evaluation of aspheric and spherical intraocular lenses 2 years after implantation. J Refract Surg 2009; 25:578-90. [PMID: 19662914 DOI: 10.3928/1081597x-20090610-03] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the quality of vision with aspheric and spherical intraocular lenses (IOLs) in pseudophakic patients after long-term follow-up. METHODS Two hundred eyes of 100 patients with bilateral cataracts were randomly assigned to receive spherical (Acrysof SN60AT [Alcon Laboratories Inc] or Sensar AR40e [Advanced Medical Optics Inc]) or aspheric IOLs (Acrysof SN60WF [Alcon] or Tecnis Z9000 [Advanced Medical Optics]). Ophthalmologic examination, including best spectacle-corrected visual acuity (BSCVA), pupil size, ocular dominance, contrast sensitivity under mesopic and photopic conditions, and wavefront analysis, was performed 2 months and 1 and 2 years after surgery. RESULTS No statistically significant differences among the four groups in terms of age, pupil diameter, postoperative BSCVA, comeal spherical aberration, and posterior capsular opacification were noted. At all followup examinations, contrast sensitivity results showed no significant differences between the two aspheric IOLs at all spatial frequencies. Under photopic conditions, significant differences (P<.05) between spherical and aspheric IOLs were detected for spatial frequencies of 12 and 18 cycles per degree (cpd) at 2 months and 2 years and 12 cpd at 1 year. Under mesopic conditions, significant differences (P<.05) were detected between spherical and aspheric IOLs for all spatial frequencies at 2 months; all spatial frequencies except 18 cpd at 1 year; and spatial frequencies of 3, 12, and 18 cpd at 2 years. In addition, aspheric IOLs had statistical reductions in total spherical aberration at all follow-up examinations (P<.01). CONCLUSIONS This study confirms that implantation of a modified aspheric IOL improves functional visual performance at 2 years postoperative.
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Affiliation(s)
- Aldo Caporossi
- Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy
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Abstract
PURPOSE To investigate the effect on visual acuity of correcting specific Zernike aberrations. METHODS Visual acuity was tested for 12 young subjects using a Freiburg Acuity Test procedure under conditions with wavefront aberrations corrected by an adaptive optics system. The adaptive optics system consists of a Hartmann-Shack wavefront sensor, a deformable mirror, relevant optical channels and closed loop control system. Five aberration correction paradigms were used to correct different Zernike terms. RESULTS With the second order aberration fully corrected, a significant improvement in visual acuity was observed (0.056 logMAR, t = 2.79, p = 0.018). Further correction of third order Zernike aberrations resulted in an additional improvement of 0.041 logMAR (t = 2.63, p = 0.023). But an additional correction of spherical aberration did not produce a significant increase in visual acuity (t = 1.10, NS). Full correction of aberrations achieved the best visual acuity with an improvement of 0.022 logMAR (t = 2.46, p = 0.032). The visual acuity was found to increase with the root mean square values of the residual aberrations with a linear relationship (r = 0.63, p < 0.0001). CONCLUSIONS Correction of monochromatic wavefront aberrations improves visual acuity for normal eyes and the improvement of visual acuity is proportional to the change of root mean square of wavefront aberrations.
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Abstract
PURPOSE Although the effect of spatial sampling on the visibility of grating stimuli is well described and well understood, little research has been conducted into the effects of spatial sampling on the visibility of letter optotypes. The purpose of this study was to investigate whether thresholds for spatially sampled Sloan letters were equal to or significantly smaller than the spacing between spatial samples. METHODS For four visually normal subjects, we measured Sloan letter acuity thresholds, presented on a computer monitor, after the letters had been sampled by sampling arrays with 6.285 elements per square degree, (23.9 min of arc between samples for a square packed array). We used four different sampling arrays: square packed; hexagonally packed; a cone-like array with positive contrast; and a cone-like array with negative contrast. Thresholds were assessed using letter-counting rules and also Probit analysis. RESULTS Although results depended on array type, and the definition of sample spacing, letter acuity thresholds were substantially less than estimates of sample spacing by between 0.290 log units (49% less) (hexagonally sampled Probit thresholds compared with spacing between hexagonal samples) to 0.136 log units (27% less) (positive contrast cone-like sampled letter-counting thresholds compared with spacing between rows of hexagonal samples). CONCLUSIONS Sample spacing is not an absolute limit for Sloan letter thresholds. By comparison with previous measurements of human foveal cone sampling of space, our findings suggest that cone sampling limits for Sloan letters could be as small as 20/4.
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Aberrometry in clinical practice: Case series. Cont Lens Anterior Eye 2008; 31:207-11. [DOI: 10.1016/j.clae.2008.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/04/2008] [Accepted: 03/02/2008] [Indexed: 11/21/2022]
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Effect of 3rd-order aberrations on human vision. J Cataract Refract Surg 2008; 34:1339-44. [DOI: 10.1016/j.jcrs.2008.04.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 04/13/2008] [Indexed: 11/19/2022]
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Rocha KM, Vabre L, Harms F, Chateau N, Krueger RR. Effects of Zernike Wavefront Aberrations on Visual Acuity Measured Using Electromagnetic Adaptive Optics Technology. J Refract Surg 2007; 23:953-9. [DOI: 10.3928/1081-597x-20071101-17] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Asejczyk-Widlicka M, Pierscionek BK. Fluctuations in intraocular pressure and the potential effect on aberrations of the eye. Br J Ophthalmol 2007; 91:1054-8. [PMID: 17314155 PMCID: PMC1954835 DOI: 10.1136/bjo.2006.109793] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To investigate the fluctuations in intraocular pressure during the day and to see if these are associated with changes in corneal shape and in the patterns of ocular aberrations. METHODS Intraocular pressure, corneal curvature, refractive error, spherical equivalent and aberrations (defocus (sphere); cylinder (astigmatism); coma, trefoil and third order spherical aberration) were measured in 17 healthy subjects three times during the day. The first measurement was made between 9:00 and 9:30, the second at midday (12:30-13:00) and the third in the afternoon (17:00-17:30). Aberrations, corneal shape, refractive error and pupil size (for which correction was made) were measured with an Irx3 Dynamic Wavefront Aberrometer. Intraocular pressures were measured using a non-contact tonometer (Cambridge Instruments Inc.) and calibrated with the Goldmann applanation tonometer. RESULTS Variations in intraocular pressures were unrelated to age or refractive error. Statistically significant differences in intraocular pressure between morning and midday as well as between midday and afternoon were found. Intraocular pressure variations between midday and afternoon were associated with changes in spherical equivalent, corneal radius of curvature and aberrations (defocus, cylinder, coma, trefoil and spherical aberration) over the same time period. Aberration patterns varied between individuals, and no association was found between two eyes of the same subject. CONCLUSIONS Changes in intraocular pressure have no noticeable effect on image quality. This could be because the eye has a compensating mechanism to correct for any effect of ocular dynamics on corneal shape and refractive status. Such a mechanism may also affect the pattern of aberrations or it may be that aberrations alter in a way that offsets any potentially detrimental effects of intraocular pressure change on the retinal image. Variations in patterns of aberrations and how they may be related to ocular dynamics need to be investigated further before attempts at correction are made.
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Affiliation(s)
- M Asejczyk-Widlicka
- School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine BT52 1SA, UK
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Charman WN. The Charles F. Prentice Award Lecture 2005: Optics of the Human Eye: Progress and Problems. Optom Vis Sci 2006; 83:335-45. [PMID: 16772891 DOI: 10.1097/01.opx.0000221389.36278.d0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The history of measurements of ocular aberration is briefly reviewed and recent work using much-improved aberrometers and large samples of eyes is summarized. When on-axis, higher-order, monochromatic aberrations are averaged, undercorrected, positive, fourth-order spherical aberration dominates; other Zernike wavefront aberration coefficients have average values near zero. Individually, however, many eyes show substantial amounts of third-order and other fourth-order aberrations; the value of these varies idiosyncratically about zero. Most normal eyes show only small amounts of axial monochromatic aberration for photopic pupils up to around 3 mm; the limits to retinal image quality are then usually set by diffraction, uncorrected or imperfectly corrected spherocylindrical refractive error, accommodation error, and chromatic aberration. Longitudinal chromatic aberration varies very little across the population. With larger mesopic and scotopic pupils, monochromatic aberration plays a more important optical role, but overall visual performance is increasingly dominated by neural factors. Some remaining problems in measuring and modeling the eye's optical performance are discussed.
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Affiliation(s)
- W Neil Charman
- Optometry and Neuroscience, School of Life Sciences, University of Manchester, Manchester, United Kingdom.
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Tuan KMA, Liang J. Improved contrast sensitivity and visual acuity after wavefront-guided laser in situ keratomileusis: in-depth statistical analysis. J Cataract Refract Surg 2006; 32:215-20. [PMID: 16564995 DOI: 10.1016/j.jcrs.2005.07.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2005] [Indexed: 11/23/2022]
Abstract
PURPOSE To evaluate changes in contrast sensitivity and visual acuity following wavefront-guided laser in situ keratomileusis (LASIK) procedures with the Visx CustomVue system. SETTING Six clinical sites that participated in an Investigational Device Exemption clinical study. METHODS Two hundred seventy-four myopic astigmatic eyes (spherical equivalent range -0.63 to -6.00 diopters) completed 6 months of follow-up examinations. Wavefront-guided procedures using the WaveScan aberrometer and Star S4 excimer laser system with variable spot scanning were performed at 6 clinical locations. Visual acuity and contrast sensitivity under photopic, mesopic, and mesopic-with-glare lighting conditions were tested preoperatively and over a 6-month follow-up period. This study was a retrospective analysis of contrast sensitivity data with controls for the effects of retinal magnification, mesopic pupil size, and the influence of prior soft contact lens wear on visual outcome. RESULTS Patients experienced statistically significant improvements in contrast sensitivity at all spatial frequencies and under all lighting conditions (P<.05, Student t test). Contrast sensitivity under mesopic conditions with glare improved in 40% of patients. There was more improvement at higher (12 cycles per degree [cpd], 18 cpd) than lower (3 cpd) spatial frequencies. No correlation was found between mesopic pupil size and contrast sensitivity. Results stratified by spectacle or soft contact lens wear were similar. Soft contact lens wearers had slightly higher disability glare scores than spectacle wearers. CONCLUSIONS A significant number of patients experienced improved corneal optical quality after wavefront-guided LASIK. The contrast sensitivity in most patients was unchanged. Contrast sensitivity improved in a significant number of patients. There was no correlation between mesopic pupil size and mesopic or mesopic-with-glare contrast performance. Spectacle wearers improved more than soft contact lens wearers.
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McLellan JS, Prieto PM, Marcos S, Burns SA. Effects of interactions among wave aberrations on optical image quality. Vision Res 2006; 46:3009-16. [PMID: 16697435 PMCID: PMC2790163 DOI: 10.1016/j.visres.2006.03.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 02/28/2006] [Accepted: 03/03/2006] [Indexed: 11/23/2022]
Abstract
Wave aberrations degrade the optical quality of the eye relative to the diffraction limit, but there are situations in which having slightly aberrated optics can provide some relative visual benefits. This fact led us to consider whether interactions among aberrations in the eye's wavefront produce an advantage for image quality relative to wavefronts with randomized combinations of aberrations with the same total RMS error. Total ocular wave aberrations from two experimental groups and corneal wave aberrations from one group were measured and expressed as Zernike polynomial expansions through the seventh-order. In a series of Monte Carlo simulations, modulation transfer functions (MTFs) for the measured wave aberrations were compared to distributions of artificial MTFs for wavefronts created by randomizing the sign or orientation of the aberrations, while maintaining the RMS error within each Zernike order. In a control condition, "synthetic" model eyes were produced by choosing each individual aberration term at random from individuals in the experimental group, and again MTFs were compared for original and randomized signs. Results were summarized by the MTF ratio: real MTF/mean simulated MTF, as a function of spatial frequency. For a 6mm pupil, the mean MTF ratio for total ocular aberrations was greater than 1.0 up to 60 cycles per degree, suggesting that the eye's aberrations are not independent and that there may be a positive functional consequences to their interrelations. This positive relation did not hold for corneal aberrations alone, or for the synthetic eyes.
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Affiliation(s)
- J S McLellan
- Schepens Eye Research Institute and Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
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Lombardo M, Lombardo G, Serrao S. Interocular high-order corneal wavefront aberration symmetry. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2006; 23:777-87. [PMID: 16604757 DOI: 10.1364/josaa.23.000777] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The interocular symmetry of the high-order corneal wavefront aberration (WA) in a population of myopic eyes was analyzed before and after photorefractive keratectomy (PRK). The preoperative and one-year postoperative corneal aberration data (from third to seventh Zernike orders) for 4- and 7-mm pupils from right and left eyes were averaged after correcting for the effects of enantiomorphism to test for mirror symmetry. Also, the mean corneal point-spread function (PSF) for right and left eyes was calculated. Preoperatively, a moderate and high degree of correlation in the high-order corneal WA between eyes was found for 4- and 7-mm pupils, respectively. Myopic PRK did not significantly change the interocular symmetry of corneal high-order aberrations. No discernible differences in the orientation PSF between eyes were observed one year after surgery in comparison with the preoperative state over the two analyzed pupils.
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Affiliation(s)
- Marco Lombardo
- Department of Experimental and Clinical Medicine, University Magna Graecia, Viale Europa, Catanzaro, Italy.
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Tuan KMA. Visual experience and patient satisfaction with wavefront-guided laser in situ keratomileusis. J Cataract Refract Surg 2006; 32:577-83. [PMID: 16698475 DOI: 10.1016/j.jcrs.2006.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Accepted: 02/11/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine the correlation between patient perception and clinical measurements after wavefront-guided laser in situ keratomileusis (LASIK). SETTING Multicenter clinical trial. METHODS In this retrospective analysis of clinical study results in 274 eyes, wavefront-guided LASIK procedures were performed in 274 myopic-astigmatic eyes at 6 sites. Comprehensive evaluations of vision and ocular health were conducted preoperatively and for 6 months postoperatively. Visual acuity and contrast sensitivity were measured, and questionnaires were administered. Questionnaire responses were compared with clinical measurements. RESULTS The overall distribution shifted toward "more satisfied." The "very satisfied" population increased by as much as 70% in all areas. There was no significant change in frequency of visual symptoms. Patients were more expressive about visual decline than visual improvement. Perception of changes in vision appeared to be related to mesopic contrast sensitivity and mesopic contrast sensitivity under glare. Mesopic pupil diameter was not a major predictor of patient satisfaction. Contact lens wearers were more satisfied with postoperative vision than were spectacle wearers. Men were more likely to report visual symptoms and to complain about night vision, although their changes were the same as those of the women. Residual refractive error was a major predictor for most questionnaire items. CONCLUSION Most patients were as satisfied or more satisfied with their postoperative uncorrected visual acuity than with their preoperative best corrected visual acuity. By continuing to minimize postoperative refractive error through the use of nomograms and improved technology, visual complaints such as night glare and halo could be diminished or even eliminated. The study shows that subjective experience affected satisfaction with results. Some dissatisfaction might be mitigated by being sure patients are educated and have realistic expectations before surgery.
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Atchison DA, Charman WN. Influences of reference plane and direction of measurement on eye aberration measurement. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2005; 22:2589-97. [PMID: 16396018 DOI: 10.1364/josaa.22.002589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We explored effects of measurement conditions on wave aberration estimates for uncorrected, axially myopic model eyes. Wave aberrations were initially referenced to either the anterior corneal pole or the natural entrance pupil of symmetrical eye models, with rays traced into the eye from infinity (into the eye) to simulate normal vision, into the eye from infinity and then back out of the eye from the retinal intercepts (into/out of the eye), or out of the eye from the retinal fovea (out of the eye). The into-the-eye and out-of-the-eye ray traces gave increases in spherical aberration as myopia increased, but the into/out-of-the-eye ray trace showed little variation in spherical aberration. Reference plane choice also affected spherical aberration. Corresponding residual aberrations were calculated after the models had been optically corrected, either by placing the object or image plane at the paraxial far point or by modifying corneas to simulate laser ablation corrections. Correcting aberrations by ablation was more complete if the original aberrations were referenced to the cornea rather than to the entrance pupil. For eyes corrected by spectacle lenses, failure to allow for effects of pupil magnification on apparent entrance pupil diameter produced larger changes in measured aberrations. The general findings regarding choice of reference plane and direction of measurement were found to be equally applicable to eyes that lacked rotational symmetry.
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Affiliation(s)
- David A Atchison
- Centre for Health Research, Queensland University of Technology, Victoria Park Road, Kelvin Grove, Q 4059, Australia.
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Yi AY, Raasch TW. Design and fabrication of a freeform phase plate for high-order ocular aberration correction. APPLIED OPTICS 2005; 44:6869-76. [PMID: 16294960 DOI: 10.1364/ao.44.006869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In recent years it has become possible to measure and in some instances to correct the high-order aberrations of human eyes. We have investigated the correction of wavefront error of human eyes by using phase plates designed to compensate for that error. The wavefront aberrations of the four eyes of two subjects were experimentally determined, and compensating phase plates were machined with an ultraprecision diamond-turning machine equipped with four independent axes. A slow-tool servo freeform trajectory was developed for the machine tool path. The machined phase-correction plates were measured and compared with the original design values to validate the process. The position of the phase-plate relative to the pupil is discussed. The practical utility of this mode of aberration correction was investigated with visual acuity testing. The results are consistent with the potential benefit of aberration correction but also underscore the critical positioning requirements of this mode of aberration correction. This process is described in detail from optical measurements, through machining process design and development, to final results.
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Affiliation(s)
- Allen Y Yi
- Ohio State University, Columbus, Ohio 43210, USA.
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Abstract
After outlining what is meant by wavefront aberration, the history of the field of wavefront technology is sketched and methods for measuring ocular wavefront aberration are briefly described. The variations in aberration of the normal eye with the individual and their pupil size, accommodation and age are summarised. Potential contact lens applications are outlined, including the design and on-eye performance of single-vision lenses, lenses for presbyopes and keratoconics, orthokeratology, tear film studies, and the design and performance of customised contact lenses intended to minimise residual lens-eye wavefront error.
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Affiliation(s)
- W N Charman
- Department Optometry and Neuroscience, Faculty of Life Sciences, University of Manchester, P.O. Box 88, Manchester M60 1QD, UK.
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Legras R, Chateau N, Charman WN. Assessment of just-noticeable differences for refractive errors and spherical aberration using visual simulation. Optom Vis Sci 2004; 81:718-28. [PMID: 15365392 DOI: 10.1097/01.opx.0000144751.11213.cd] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate the threshold levels of aberration change that a typical reference eye is able to detect. METHODS The method involved simulation of the foveal vision of a typical eye in polychromatic light through optics affected by different levels of the various chosen monochromatic aberrations. The reference eye had the following monochromatic wavefront characteristics based on the aberrations of a population of young adults: no spherical defocus, astigmatism -0.37D oriented at 0 degrees celsius, coma -0.17 D/mm oriented at 270 degrees celsius, and spherical aberration -0.12 D/mm. Average amounts of longitudinal and transverse chromatic aberration were assumed, and allowance was made for the Stiles-Crawford effect. The pupil diameter of the simulated eye was kept fixed at 6 mm. Three observers each compared, 100 times, a simulated image as seen through the standard reference eye with a variant "aberrated" image. The varying parameter was the value of a chosen additional aberration affecting the variant image in the reference eye. The test was repeated for varying amounts of spherical defocus, astigmatic defocus, and spherical aberration. For each of these aberrations and each observer, the discrimination probability as a function of the aberration level in the variant image was determined. The just-noticeable difference in aberration (JNDA) was derived from each discrimination curve as the difference between the aberrations corresponding to discrimination probabilities of 75% and 25%. The JNDA values obtained were expressed in the form of root mean square (RMS) wavefront error thresholds. RESULTS It was found that 0.04 microm of RMS aberration should be considered as the threshold of just-noticeable image change, in good agreement with the Maréchal criterion. CONCLUSIONS The results imply that in normal viewing conditions (e.g., a 3-mm pupil size), optical corrections should be in the range of +/-0.15 D in sphere and cylinder from the target prescription if perceptible change in the quality of the perceived images is to be avoided. The design of conventional soft contact lenses of high negative power or positive power should aim to produce -0.07 D/mm of spherical aberration, with a tolerated interval between -0.15 to +0.01 D/mm for a 6-mm pupil size.
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Affiliation(s)
- Richard Legras
- Université Paris Sud, Laboratoire Aimé Cotton, Orsay, France.
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