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Davies LN, Biswas S, Bullimore M, Cruickshank F, Estevez JJ, Khanal S, Kollbaum P, Marcotte-Collard R, Montani G, Plainis S, Richdale K, Simard P, Wolffsohn JS. BCLA CLEAR presbyopia: Mechanism and optics. Cont Lens Anterior Eye 2024; 47:102185. [PMID: 38796331 DOI: 10.1016/j.clae.2024.102185] [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] [Indexed: 05/28/2024]
Abstract
With over a billion adults worldwide currently affected, presbyopia remains a ubiquitous, global problem. Despite over a century of study, the precise mechanism of ocular accommodation and presbyopia progression remains a topic of debate. Accordingly, this narrative review outlines the lenticular and extralenticular components of accommodation together with the impact of age on the accommodative apparatus, neural control of accommodation, models of accommodation, the impact of presbyopia on retinal image quality, and both historic and contemporary theories of presbyopia.
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Affiliation(s)
- Leon N Davies
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK.
| | - Sayantan Biswas
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK
| | | | - Fiona Cruickshank
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Jose J Estevez
- Caring Futures Institute, College of Nursing and Health Sciences, Optometry and Vision Science, Flinders University, Adelaide, Australia; Flinders Centre for Ophthalmology, Eye and Vision Research, Department of Ophthalmology, Flinders University, Adelaide, Australia
| | - Safal Khanal
- Department of Optometry and Vision Science, The University of Alabama at Birmingham, USA
| | | | | | | | - Sotiris Plainis
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK; Laboratory of Optics and Vision, School of Medicine, University of Crete, Greece
| | | | - Patrick Simard
- School of Optometry, Universite de Montreal, Montreal, Quebec, Canada
| | - James S Wolffsohn
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK
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Wolffsohn JS, Berkow D, Chan KY, Chaurasiya SK, Fadel D, Haddad M, Imane T, Jones L, Sheppard AL, Vianya-Estopa M, Walsh K, Woods J, Zeri F, Morgan PB. BCLA CLEAR Presbyopia: Evaluation and diagnosis. Cont Lens Anterior Eye 2024; 47:102156. [PMID: 38641525 DOI: 10.1016/j.clae.2024.102156] [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] [Indexed: 04/21/2024]
Abstract
It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.
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Affiliation(s)
- James S Wolffsohn
- School of Optometry, Health and Life Sciences, Aston University, Birmingham, United Kingdom.
| | - David Berkow
- Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel
| | - Ka Yin Chan
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
| | - Suraj K Chaurasiya
- Department of Contact Lens and Anterior Segment, CL Gupta Eye Institute, Moradabad, India; Department of Optometry and Vision Science, CL Gupta Eye Institute, Moradabad, India
| | - Daddi Fadel
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, Waterloo, Canada
| | - Mera Haddad
- Faculty of Applied Medical Sciences, Department of Allied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Tarib Imane
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, United States
| | - Lyndon Jones
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong; Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, Waterloo, Canada
| | - Amy L Sheppard
- School of Optometry, Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Marta Vianya-Estopa
- Vision and Hearing Research Centre, Anglia Ruskin University, Cambridge, United Kingdom
| | - Karen Walsh
- CooperVision Inc., San Ramon, CA, United States
| | - Jill Woods
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, Waterloo, Canada
| | - Fabrizio Zeri
- School of Optometry, Health and Life Sciences, Aston University, Birmingham, United Kingdom; University of Milano-Bicocca, Department of Materials Science, Milan, Italy
| | - Philip B Morgan
- Eurolens Research, Division of Pharmacy and Optometry, University of Manchester, United Kingdom
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Plainis S, Panagopoulou S, Charman WN. Longitudinal changes in objective accommodative response, pupil size and spherical aberration: A case study. Ophthalmic Physiol Opt 2024; 44:168-176. [PMID: 37966110 DOI: 10.1111/opo.13250] [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: 08/31/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/16/2023]
Abstract
PURPOSE Previous transverse and a handful of longitudinal studies have shown that the slope of the static accommodation response/stimulus curve declines as complete presbyopia is approached. Changes in pupillary miosis and ocular spherical aberration (SA) are also evident. This study further investigated longitudinal changes in the relationships between the monocular static accommodative response, pupil diameter and SA of a single adult. METHODS A wavefront analysing system, the Complete Ophthalmic Analysis System, was used in conjunction with a Badal optometer to allow continuous recording of the aberration structure of the dominant eye in a low myope for a range of accommodative demands (-0.83 to 7.63 D) over a period of 17 years until the age of 50. Monocular accommodative response was calculated as the equivalent refraction minimising wavefront error. The associated longitudinal changes in pupil size and SA with accommodation were also recorded. RESULTS A decrease in accommodation response with age was found at almost all target vergences, with the changes being greatest for higher vergences. In addition, although absolute pupil diameter decreased with age, the rate of change in pupil diameter with accommodative stimulus remained approximately constant with age. Pupil constriction occurred for near stimuli even in full presbyopia. SA changed linearly with the accommodation response at all ages. CONCLUSIONS The objective amplitude of accommodation declined linearly with age as complete presbyopia was approached, while the slope of the response/stimulus curve also fell. It was hypothesised that the retinal image blur associated with the larger lags of accommodation at higher accommodative stimuli was reduced by pupil constriction and the resulting lower levels of SA.
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Affiliation(s)
- Sotiris Plainis
- Laboratory of Optics and Vision (LOV), School of Medicine, University of Crete, Rethymno, Greece
- Optometry & Vision Science Research Group, Aston University School of Life and Health Sciences, Birmingham, UK
| | - Sophia Panagopoulou
- Laboratory of Optics and Vision (LOV), School of Medicine, University of Crete, Rethymno, Greece
| | - W Neil Charman
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Thakur M, Panicker T, Satgunam P. Refractive error changes and associated asthenopia observed after COVID-19 infection: Case reports from two continents. Indian J Ophthalmol 2023; 71:2592-2594. [PMID: 37322686 PMCID: PMC10418019 DOI: 10.4103/ijo.ijo_2581_22] [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: 10/05/2022] [Revised: 02/27/2023] [Accepted: 03/27/2023] [Indexed: 06/17/2023] Open
Abstract
COVID-19 infection has been linked to various ocular complications and complaints, but not to refractive errors. In this case report, we present ethnically diverse patients who reported asthenopic symptoms shortly after recovering from COVID-19 infection. The hyperopic shift in the refractive error, post-COVID could indicate the ciliary body muscle's inability to sustain accommodation, resulting in asthenopia. Hence, refractive errors should also be considered as a post-COVID complication, even if the magnitude is small, especially when patients have a headache and other asthenopic symptoms. Performing dynamic retinoscopy and cycloplegic refraction will also aid in the better management of these patients.
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Affiliation(s)
- Monika Thakur
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Thanuja Panicker
- Eyelight Optometrists, Unit 11 lot 171, Oasis Motel Premises, Zeerust Road, Tlokweng, Botswana
| | - PremNandhini Satgunam
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Hyderabad Eye Research Foundation, L V Prasad Eye Institute, Hyderabad, Telangana, India
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Takla M, Saadeh K, Tse G, Huang CLH, Jeevaratnam K. Ageing and the Autonomic Nervous System. Subcell Biochem 2023; 103:201-252. [PMID: 37120470 DOI: 10.1007/978-3-031-26576-1_10] [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: 05/01/2023]
Abstract
The vertebrate nervous system is divided into central (CNS) and peripheral (PNS) components. In turn, the PNS is divided into the autonomic (ANS) and enteric (ENS) nervous systems. Ageing implicates time-related changes to anatomy and physiology in reducing organismal fitness. In the case of the CNS, there exists substantial experimental evidence of the effects of age on individual neuronal and glial function. Although many such changes have yet to be experimentally observed in the PNS, there is considerable evidence of the role of ageing in the decline of ANS function over time. As such, this chapter will argue that the ANS constitutes a paradigm for the physiological consequences of ageing, as well as for their clinical implications.
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Affiliation(s)
| | | | - Gary Tse
- Kent and Medway Medical School, Canterbury, UK
- University of Surrey, Guildford, UK
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Tavazzi S, Vlasak N, Zeri F. Effects of Lens-Induced Astigmatism at Near and Far Distances. CLINICAL OPTOMETRY 2023; 15:105-117. [PMID: 37181864 PMCID: PMC10171221 DOI: 10.2147/opto.s405472] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/13/2023] [Indexed: 05/16/2023]
Abstract
Purpose To investigate and compare the degradation of visual acuity (VA) in myopic presbyopes due to lens-induced astigmatism at near and at far distance. Patients and Methods Fourteen corrected myopic presbyopes were recruited. VA (logarithm of the minimum angle of resolution) was measured binocularly for different conditions of lens-induced astigmatism: cylindrical powers of -0.25, -0.50, -0.75, -1.00, -1.50, and -2.00 diopters (and positive spherical power of half the cylindrical power) with two axis orientations (with-the-rule WTR and against-the-rule ATR) were added to their optical correction. Measurements were carried out at far and near distance both in photopic and mesopic conditions, and for high and low contrast (HC/LC) stimuli. The paired Wilcoxon signed-rank statistics test was used to evaluate difference between conditions. Results The measured VA as a function of the lens-induced astigmatism was described by regression lines in all investigated experimental conditions. The angular coefficients (slopes) of these lines represent the VA degradation, ie, the variation in logMAR corresponding to the addition of 1.00 diopters of cylindrical power. In photopic HC conditions, the VA degradation is significantly more pronounced at far distance than at near distance (0.22±0.06 diopters-1 vs 0.15±0.05 diopters-1, p = 0.0061 in WTR conditions; 0.18±0.06 diopters-1 vs 0.12±0.05 diopters-1, p = 0.0017 in ATR conditions), although VAs at near and at far with zero cylinder were similar (-0.14±0.10 vs -0.14±0.08, p = 0.824). Conclusion The better tolerance to lens-induced astigmatism blur at near than at far distance in photopic conditions with HC stimuli is tentatively attributed to a possible experience-mediated neural compensation associated to the tendency of the eye toward an inherent astigmatism at near.
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Affiliation(s)
- Silvia Tavazzi
- Materials Science Department, University of Milano-Bicocca, Milam, I-20125, Italy
- University of Milano-Bicocca, COMiB Research Centre in Optics and Optometry, Milan, I-20125, Italy
- Correspondence: Silvia Tavazzi, Department of Materials Science, University of Milano-Bicocca, Via Roberto Cozzi 55, Milan, I-20125, Italy, Tel +39 02 6448 5035, Email
| | | | - Fabrizio Zeri
- Materials Science Department, University of Milano-Bicocca, Milam, I-20125, Italy
- University of Milano-Bicocca, COMiB Research Centre in Optics and Optometry, Milan, I-20125, Italy
- College of Health and Life Sciences, Aston University, Birmingham, B4 7ET, UK
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Gantz L, Stiebel-Kalish H. Convergence insufficiency: Review of clinical diagnostic signs. JOURNAL OF OPTOMETRY 2022; 15:256-270. [PMID: 34963569 PMCID: PMC9537264 DOI: 10.1016/j.optom.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/05/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
Convergence insufficiency (CI) is a common binocular vision (BV) disorder characterized by difficulty in maintaining motor fusion at near, which affects approximately 7.5 percent of the population. Diagnostic criteria for the disorder are inconsistent, ranging from one to many clinical signs. Methodology for clinical tests is inconsistent in measurement technique, visual targets, required repetitions, and normative values. This manuscript demonstrates the inconsistencies amongst published studies, and highlights the importance of consistent clinical diagnostic signs, measurement techniques, visual targets, and cut-off criteria. For each clinical sign, the recommended methodology for the procedure is described. Several studies do not take age into account when diagnosing CI in their cohorts. As such, the review emphasizes changes in diagnostic signs with age. This manuscript highlights the need for consistent and clear procedures and diagnostic criteria amongst clinicians and provides the basis for future studies in terms of diagnostic testing required for CI of varying age groups.
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Affiliation(s)
- Liat Gantz
- Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel.
| | - Hadas Stiebel-Kalish
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv; Felsenstein Research Medical Center; Neuro-Ophthalmology Division, Department of Ophthalmology, Rabin Medical Center - Beilinson Hospital, Petah Tikva, Israel
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8
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Li Z, Meng Z, Qu W, Li X, Chang P, Wang D, Zhao Y. The Relationship Between Age and the Morphology of the Crystalline Lens, Ciliary Muscle, Trabecular Meshwork, and Schlemm's Canal: An in vivo Swept-Source Optical Coherence Tomography Study. Front Physiol 2021; 12:763736. [PMID: 34867468 PMCID: PMC8640208 DOI: 10.3389/fphys.2021.763736] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/29/2021] [Indexed: 01/07/2023] Open
Abstract
Purpose: To evaluate the effects of age on the morphologies of the crystalline lens, ciliary muscle (CM), Schlemm’s canal (SC), and trabecular meshwork (TM) using swept-source optical coherence tomography (SS-OCT). Methods: Images of the crystalline lens and iridocorneal angle were obtained in healthy participants’ eyes using SS-OCT. Morphological parameters of the crystalline lens, CM, and TM/SC were measured, and the relationship between these parameters and age was evaluated. Results: A total of 62 healthy participants were enrolled, with an age range of 7–79 years. With adjustments for the effects of axial length and sex, both the nasal and temporal SC cross-sectional areas (CSA) and the cross-sectional area of the CM (CMA), distance from the scleral spur to the inner apex of the ciliary muscle (IA-SS), and nasal SC volume were negatively correlated with age (P ≤ 0.041). Meanwhile, the lens thickness (LT) (P < 0.001) and lens vault (LV) (P < 0.001) were positively correlated with age, and the radius of the curvature of the anterior lens (ALR) was negatively correlated with age (P < 0.001). Conclusion: Increasing age was associated with a thicker crystalline lens, a steeper anterior lens curvature, an anteriorly located and smaller CM, and a narrower SC. Clinical Trial Registration:https://register.clinicaltrials.gov/prs/app/action/Select Protocol?sid=S000A3JZ&selectaction=Edit&uid=U00019K7&ts=4&cx=-c5xxp8, identifier [NCT04576884].
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Affiliation(s)
- Zhangliang Li
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Ziqi Meng
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Wenyong Qu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Xiuyuan Li
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Pingjun Chang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Dandan Wang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
| | - Yune Zhao
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.,National Clinical Research Center for Ocular Diseases, Wenzhou, China.,Eye Hospital of Wenzhou Medical University Hangzhou Branch, Hangzhou, China
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Karkhanis MU, Ghosh C, Banerjee A, Hasan N, Likhite R, Ghosh T, Kim H, Mastrangelo CH. Correcting Presbyopia With Autofocusing Liquid-Lens Eyeglasses. IEEE Trans Biomed Eng 2021; 69:390-400. [PMID: 34232861 DOI: 10.1109/tbme.2021.3094964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Presbyopia, an age-related ocular disorder, is characterized by the loss in the accommodative abilities of the human eye. Conventional methods of correcting presbyopia divide the field of view, thereby resulting in significant vision impairment. We demonstrate the design, assembly and evaluation of autofocusing eyeglasses for restoration of accommodation without dividing the field of view. METHODS The adaptive optics eyeglasses comprise of two variable-focus liquid lenses, a time-of-flight range sensor and low-power, dual microprocessor control electronics, housed within an ergonomic frame. Subject-specific accommodation deficiency models were utilized to demonstrate high-fidelity accommodative correction. The abilities of this system to reduce accommodation deficiency, its power consumption, response time, optical performance and MTF were evaluated. RESULTS Average corrected accommodation deficiencies for 5 subjects ranged from -0.021 D to 0.016 D. Each accommodation correction calculation was performed in ∼67 ms which consumed 4.86 mJ of energy. The optical resolution of the system was 10.5 cycles/degree, and featured a restorative accommodative range of 4.3 D. This system was capable of running for up to 19 hours between charge cycles and weighed ∼132 g. CONCLUSION The design, assembly and performance of an autofocusing eyeglasses system to restore accommodation in presbyopes has been demonstrated. SIGNIFICANCE The new autofocusing eyeglasses system presented in this article has the potential to restore pre-presbyopic levels of accommodation in subjects diagnosed with presbyopia.
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Deepu S, Kujur ES, Horo S, Priyanka N, Selvin SST, Kuriakose T. Prescription of near addition and its relation to accommodative reserve in presbyopia - The dichotomy between theory and practice. Indian J Ophthalmol 2021; 69:1702-1706. [PMID: 34146010 PMCID: PMC8374824 DOI: 10.4103/ijo.ijo_3160_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Purpose: To study the relationship between the amplitude of accommodation (AA) measured by the Royal Air Force (RAF) rule and near addition (NA) prescribed in presbyopic patients to assess how far practice is different from theoretical recommendations. Methods: Patients, aged 40 to 60 years with best corrected vision of 6/6 N5 were included in this cross sectional observational study. AA was measured using the RAF rule. Refined with near Duochrome chart, the NA was given with the chart at 40 cm. Accommodative reserve was calculated from the measured AA, NA required and the calculated additional accommodation expended by the patient for reading. The percentage of reserve was calculated with and without the correction for depth-of-field. Results: A total of 130 patients were studied. In the patients above 50 years of age, the negative correlation of AA with age was - 0.298 (P = 0.065) and AA and NA was - 0.365 (P = 0.002) was weak. Among the patients aged between 40 and 50 years, the negative correlation of AA with Age and NA were strong; - 0.853 (P < 0.0001) and - 0.823 (P < 0.0001) respectively. When prescribing glasses, 62.01% (CI 58.78 to 65.23) and 90.93% (CI 62.50 to 119.37) of the AA was found to be kept in reserve for patients below and above 50 years of age respectively. Conclusion: Accommodative reserve kept in our study patients when prescribing NA was two to three times the theoretical recommendation. High percentage of accommodation kept in reserve suggest that the measured AA is not activated normally and require higher NA and one should not rely on patient’s ability to generate accommodative power especially in patients over 50 years.
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Affiliation(s)
- Susmi Deepu
- Optometrist, Lady Willington Hospital, Manali, Himachal Pradesh; Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Evon Selina Kujur
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Saban Horo
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Nancy Priyanka
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu; Optometrist, Salins College of Optometry, Bidar, Karnataka, India
| | | | - Thomas Kuriakose
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
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Regal S, Troughton J, Djenizian T, Ramuz M. Biomimetic models of the human eye, and their applications. NANOTECHNOLOGY 2021; 32:302001. [PMID: 33789258 DOI: 10.1088/1361-6528/abf3ee] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Replicating the functionality of the human eye has been a challenge for more than a century, creating a great wealth of biomimetic and bioinspired devices, and providing ever improving models of the eye for myriad research purposes. As improvements in microelectronics have proceeded, individual components of the eye have been replicated, and models of the optical behaviour of the eye have improved. This review explores both work developed for improving medical components, with an ultimate aim of a fully functioning prosthetic eye, and work looking at improving existing devices through biomimetic means. It is hoped that this holistic approach to the subject will aid in the cross pollination of ideas between the two research foci. The review starts by summarising the reported measurements of optical parameters of various components of the eye. It then charts the development of individual bionic components. Particular focus is put on the development of bionic and biomimetic forms of the two main adaptive components of the eye, namely the lens and the iris, and the challenges faced in modelling the light sensitive retina. Work on each of these components is thoroughly reviewed, including an overview of the principles behind the many different approaches used to mimic the functionality, and discussion of the pros and cons of each approach. This is concluded by an overview of several reported models of the complete or semi-complete eye, including details of the components used and a summary of the models' functionality. Finally, some consideration is given to the direction of travel of this field of research, and which existing approaches are likely to bring us closer to the long term goal of a fully functional analogue of the eye.
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Affiliation(s)
- Simon Regal
- Mines Saint-Etienne, Center of Microelectronics in Provence, Department of Flexible Electronics, F-13541 Gardanne, France
| | - Joseph Troughton
- Mines Saint-Etienne, Center of Microelectronics in Provence, Department of Flexible Electronics, F-13541 Gardanne, France
| | - Thierry Djenizian
- Mines Saint-Etienne, Center of Microelectronics in Provence, Department of Flexible Electronics, F-13541 Gardanne, France
- Al-Farabi Kazakh National University, Center of Physical-Chemical Methods of Research and Analysis, Almaty, Tole bi str., 96A, Kazakhstan
| | - Marc Ramuz
- Mines Saint-Etienne, Center of Microelectronics in Provence, Department of Flexible Electronics, F-13541 Gardanne, France
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12
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Affiliation(s)
- W Neil Charman
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
E‐mail:
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13
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Vincent M, Marin G, Legras R. Subjective Evaluation of Defocus and Astigmatism Combinations Using Image Simulation in Presbyopes. Optom Vis Sci 2021; 98:73-80. [PMID: 33394934 DOI: 10.1097/opx.0000000000001627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
SIGNIFICANCE Image simulation is a useful and efficient tool to explore the impact of defocus and astigmatism combinations on visual acuity and image quality score when accommodation is taken into account. PURPOSE The goal of this experiment was to determine if a simulation is able to predict visual acuity and image quality score (IQS) with defocus and astigmatism combinations in presbyopes. METHODS We measured visual acuity and IQS in five defocus and astigmatism combinations in either real or simulated conditions. In real conditions, the subjects viewed a stimulus through an ophthalmic lens or a deformable mirror. In simulated conditions, subjects viewed images of the same stimulus with simulated blur. The amounts of defocus and astigmatism combinations of a progressive addition lens in near vision were generated through a static correction of the subject's aberrations. We simulated three levels of accommodation: subject could not accommodate (FOC0), subject could accommodate to the less hyperopic focal point (FOC1), or subject could accommodate to the circle of least confusion (FOC2). RESULTS Visual acuity or IQS did not differ between mirror and progressive addition lens conditions. Visual acuity measured in real blur conditions differed significantly from that in FOC0 simulated blur condition but were similar to that in FOC1 and FOC2 simulated blur conditions. Image quality score obtained in real conditions were between scores measured with the FOC0 and FOC1 simulated conditions, suggesting that the subjects were able to produce a low level of accommodation. CONCLUSIONS Accommodation may play a role when comparing optical and simulated defocus and astigmatism combinations. Presbyopic subjects are able to produce a low level of accommodation that may counterbalance a part of the deleterious effect of the astigmatism on image quality. Simulation remains a useful tool if the correct accommodation state is taken into account.
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Affiliation(s)
- Marc Vincent
- Laboratoire Lumière, Matière et Interfaces, CNRS, ENS Paris-Saclay, CentraleSupelec, Université Paris-Saclay, Orsay, France
| | - Gildas Marin
- Essilor International, Research and Development, Vision Science Department, Créteil, France
| | - Richard Legras
- Laboratoire Lumière, Matière et Interfaces, CNRS, ENS Paris-Saclay, CentraleSupelec, Université Paris-Saclay, Orsay, France
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14
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Park SM, Moon BY, Kim SY, Yu DS. Diurnal variations of amplitude of accommodation in different age groups. PLoS One 2019; 14:e0225754. [PMID: 31770414 PMCID: PMC6879161 DOI: 10.1371/journal.pone.0225754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/12/2019] [Indexed: 11/27/2022] Open
Abstract
Clinical assessment of amplitude of accommodation (AA) involves measuring the ability of the eye to change its optical power and focus on near tasks/objects. AA gradually decreases with increasing age. However, details of age-related diurnal changes in AA are not well known. This study compared diurnal changes in AA in the adolescents, the twenties, and the forties age groups. Measurement of AA using the push-up method was performed in six sessions at two-hourly intervals for 154 subjects (48, 56, 50 subjects for the adolescents, twenties, and forties age groups, respectively); the first measurements were taken from 9:00–10:00 a.m. and the final measurements from 7:00–8:00 p.m. The mean AA was 14.67 D (highest: 16.15 D in the 3:00–4:00 p.m. session, lowest: 13.35 D in the 9:00–10:00 a.m. session) for the adolescent group; 11.13 D (highest: 11.69 D in the 3:00–4:00 p.m. session; lowest: 10.61 D in the 9:00–10:00 a.m. session) in the twenties group; and 5.53 D (highest: 5.80 D in the 1:00–2:00 p.m. session, lowest: 5.11 D in the 7:00–8:00 p.m. session) in the forties age group. The measured AA showed significant difference between sessions; however, diurnal variations were greater in the younger groups. The measured AA was low at the beginning of the day in the adolescents and twenties groups and low at the end of the day in the forties age group. All age groups showed a high AA during the afternoon hours of the day (1:00–4:00 p.m.). Since the difference between each session was larger in younger subjects, AA should be evaluated while taking the age-related diurnal variations into account.
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Affiliation(s)
- Sun-Mi Park
- Department of Optometry and Vision Science, Kyungwoon University, Gumi, Korea
| | - Byeong-Yeon Moon
- Department of Optometry, Kangwon National University, Samcheok, Korea
| | - Sang-Yeob Kim
- Department of Optometry, Kangwon National University, Samcheok, Korea
| | - Dong-Sik Yu
- Department of Optometry, Kangwon National University, Samcheok, Korea
- * E-mail:
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15
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Jay DR, Cane D, Howe S. Age Is a Greater Influence on Small Saccades Than Target Size in Normal Subjects on the Horizontal Video Head Impulse Test. Front Neurol 2019; 10:328. [PMID: 31040813 PMCID: PMC6476940 DOI: 10.3389/fneur.2019.00328] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/18/2019] [Indexed: 12/01/2022] Open
Abstract
Objective: This study sought to investigate whether the size of the target used in the horizontal vHIT has an effect on the saccade profile of healthy subjects, and to expand upon previous work linking age to the existence of small vHIT saccades. Methods: Forty eight participants were recruited between 18 and 77 years of age, with no history of vestibular, oculomotor or neurological conditions and a visual acuity of at least 0.3 LogMAR. Participants underwent four consecutive horizontal vHIT trials using the standard target size and three smaller targets. VOR gain and metrics for saccadic incidence, peak eye velocity and latency were then extracted from results. Results: Target size was a statistically significant influence on saccade metrics. As target size increased, saccadic incidence decreased while peak eye velocity and latency increased. However, a potential order effect was also discovered, and once this was corrected for the remaining effect of target size was small and is likely clinically insignificant. The effect of age was much stronger than target size; increasing age was strongly positively correlated with saccadic incidence and showed a medium size correlation with peak velocity, though not with saccadic latency. Conclusion: While this study suggests that target size may have a statistically significant impact on the vHIT saccade profile of normal subjects, age has a greater influence on the incidence and size of small vHIT saccades.
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Affiliation(s)
- David R Jay
- Manchester Head and Neck Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Debbie Cane
- Manchester Centre for Audiology and Deafness, The University of Manchester, Manchester, United Kingdom
| | - Simon Howe
- Manchester Centre for Audiology and Deafness, The University of Manchester, Manchester, United Kingdom.,Department of Audiology, The James Cook University Hospital, South Tees Hospitals NHS Foundation Trust, Middlesbrough, United Kingdom
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16
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Zapata-Díaz JF, Radhakrishnan H, Charman WN, López-Gil N. Accommodation and age-dependent eye model based on in vivo measurements. JOURNAL OF OPTOMETRY 2019; 12:3-13. [PMID: 29573985 PMCID: PMC6318498 DOI: 10.1016/j.optom.2018.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 01/09/2018] [Accepted: 01/20/2018] [Indexed: 06/02/2023]
Abstract
PURPOSE To develop a flexible model of the average eye that incorporates changes with age and accommodation in all optical parameters, including entrance pupil diameter, under photopic, natural, environmental conditions. METHODS We collated retrospective in vivo measurements of all optical parameters, including entrance pupil diameter. Ray-tracing was used to calculate the wavefront aberrations of the eye model as a function of age, stimulus vergence and pupil diameter. These aberrations were used to calculate objective refraction using paraxial curvature matching. This was also done for several stimulus positions to calculate the accommodation response/stimulus curve. RESULTS The model predicts a hyperopic change in distance refraction as the eye ages (+0.22D every 10 years) between 20 and 65 years. The slope of the accommodation response/stimulus curve was 0.72 for a 25 years-old subject, with little change between 20 and 45 years. A trend to a more negative value of primary spherical aberration as the eye accommodates is predicted for all ages (20-50 years). When accommodation is relaxed, a slight increase in primary spherical aberration (0.008μm every 10 years) between 20 and 65 years is predicted, for an age-dependent entrance pupil diameter ranging between 3.58mm (20 years) and 3.05mm (65 years). Results match reasonably well with studies performed in real eyes, except that spherical aberration is systematically slightly negative as compared with the practical data. CONCLUSIONS The proposed eye model is able to predict changes in objective refraction and accommodation response. It has the potential to be a useful design and testing tool for devices (e.g. intraocular lenses or contact lenses) designed to correct the eye's optical errors.
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Affiliation(s)
- Juan F Zapata-Díaz
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Hema Radhakrishnan
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - W Neil Charman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Norberto López-Gil
- Facultad de Óptica y Optometría, Universidad de Murcia, 30100 Murcia, Spain.
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17
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Binocular and accommodative function in the controlled randomized clinical trial MiSight® Assessment Study Spain (MASS). Graefes Arch Clin Exp Ophthalmol 2018; 257:207-215. [PMID: 30196481 DOI: 10.1007/s00417-018-4115-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/27/2018] [Accepted: 08/21/2018] [Indexed: 01/12/2023] Open
Abstract
PURPOSE To evaluate the binocular and accommodative function in children wearing dual focus (DF) MiSight® contact lenses (CLs) for myopia control compared with children wearing single-vision (SV) spectacles. METHODS This was a randomized, controlled clinical trial involving subjects aged 8 to 12, with myopia ranging from - 0.75 to - 4.00D and astigmatism < 1.00D, allocated to MiSight® study CLs group or control group wearing SV. Binocular and accommodative function was determined at baseline, 12-, and 24-month visits, assessed by the following sequence of tests: distance and near horizontal phoria, accommodative convergence/accommodation (AC/A) ratio, stereopsis, accommodative amplitude (AA), and accommodative response (AR) at 33, 25 and 20 cm. RESULTS Seventy-four children completed the study: 41 in the CL group and 33 in the SV group. CLs group did not show any significant differences in binocular and accommodative measurements throughout the study. In control group, distance and near phoria, stereopsis, AC/A and AR at 20 cm did not show any significant change, but AA, AR at 33 cm and AR at 25 cm were greater at 24-month visit compared with baseline (p < 0.05). CONCLUSIONS DF lenses do not change the binocular and accommodative function in children wearing dual focus CLs. TRIAL REGISTRATION NCT01917110.
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18
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Satou T, Ito M, Shinomiya Y, Takahashi Y, Hara N, Niida T. Differences in the Stimulus Accommodative Convergence/Accommodation Ratio using Various Techniques and Accommodative Stimuli. Strabismus 2018; 26:53-61. [DOI: 10.1080/09273972.2018.1459746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Tsukasa Satou
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Misae Ito
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Yuma Shinomiya
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Yoshiaki Takahashi
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Naoto Hara
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Takahiro Niida
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare, Ohtawara, Tochigi, Japan
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19
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Yekta A, Hashemi H, Khabazkhoob M, Ostadimoghaddam H, Ghasemi-Moghaddam S, Jafarzadehpur E, Shokrollahzadeh F. The distribution of negative and positive relative accommodation and their relationship with binocular and refractive indices in a young population. J Curr Ophthalmol 2017; 29:204-209. [PMID: 28913512 PMCID: PMC5587222 DOI: 10.1016/j.joco.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 12/21/2016] [Accepted: 01/01/2017] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To determine the distribution of negative relative accommodation (NRA) and positive relative accommodation (PRA) and its relationship with binocular vision indices in a young population. METHODS In this cross-sectional study conducted in a student population, samples were selected through multistage cluster sampling. All the samples underwent the measurement of uncorrected and corrected visual acuity and refraction. Then far and near cover tests were performed. The near point of convergence (NPC) and accommodation, accommodation facility, PRA and NRA were evaluated in all participants. RESULTS The mean age of the 382 participants was 22.5 ± 4.4 years (18-35 years). Mean NRA and PRA in the total sample was +2.08 ± 0.33 diopter (D) and -2.92 ± 0.76 D, respectively. Mean NRA was highest in hyperopic (P = 0.002) and mean PRA was highest in myopic (P = 0.003) participants. The multiple model showed that NRA had a direct relationship with accommodation facility and spherical refractive error, while PRA had a direct relationship with amplitude of accommodation (AA). CONCLUSION This study provides the normal range of the NRA and PRA and their relationship with accommodation facility, spherical refractive error, and AA in a sample of the Iranian population.
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Affiliation(s)
- AbbasAli Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, 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.,Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Somayeh Ghasemi-Moghaddam
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ebrahim Jafarzadehpur
- Department of Optometry, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran
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20
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Adaptation to Progressive Additive Lenses: Potential Factors to Consider. Sci Rep 2017; 7:2529. [PMID: 28566706 PMCID: PMC5451391 DOI: 10.1038/s41598-017-02851-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 04/20/2017] [Indexed: 11/29/2022] Open
Abstract
People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured. Then, the experiment was repeated after wearing PALs for one month. Linear regression analyses were conducted between the following parameters: near point of convergence, positive fusional vergence at near, vergence facility, net change in the magnitude of phoria adaptation, and the rate of phoria adaptation. The ability to change convergence average peak velocity was significantly greater (p < 0.03) in presbyopic PALs adapters compared to presbyopic PALs non-adapters. The rate of phoria adaptation and vergence facility were significantly greater (p < 0.03) in incipient presbyopic PALs adapters compared to incipient presbyopic PALs non-adapters. Vergence facility and the rate of phoria adaptation may have potential clinical utility in differentiating which patients may adapt to PALs and which ones will have more difficulty.
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21
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Almutairi MS, Altoaimi BH, Bradley A. Accommodation and pupil behaviour of binocularly viewing early presbyopes. Ophthalmic Physiol Opt 2017; 37:128-140. [DOI: 10.1111/opo.12356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/04/2017] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Arthur Bradley
- School of Optometry; Indiana University; Bloomington USA
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22
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Tonic accommodation predicts closed-loop accommodation responses. Vision Res 2016; 129:25-32. [PMID: 27756701 DOI: 10.1016/j.visres.2016.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/24/2016] [Accepted: 08/26/2016] [Indexed: 11/24/2022]
Abstract
The purpose of this study is to examine the potential relationship between tonic accommodation (TA), near work induced TA-adaptation and the steady state closed-loop accommodation response (AR). Forty-two graduate students participated in the study. Various aspects of their accommodation system were objectively measured using an open-field infrared auto-refractor (Grand Seiko WAM-5500). Tonic accommodation was assessed in a completely dark environment. The association between TA and closed-loop AR was assessed using linear regression correlations and t-test comparisons. Initial mean baseline TA was 1.84diopter (D) (SD±1.29D) with a wide distribution range (-0.43D to 5.14D). For monocular visual tasks, baseline TA was significantly correlated with the closed-loop AR. The slope of the best fit line indicated that closed-loop AR varied by approximately 0.3D for every 1D change in TA. This ratio was consistent across a variety of viewing distances and different near work tasks, including both static targets and continuous reading. Binocular reading conditions weakened the correlation between baseline TA and AR, although results remained statistically significant. The 10min near reading task with a 3D demand did not reveal significant near work induced TA-adaptation for either monocular or binocular conditions. Consistently, the TA-adaptation did not show any correlation with AR during reading. This study found a strong association between open-loop TA and closed-loop AR across a variety of viewing distances and different near work tasks. Difference between the correlations under monocular and binocular reading condition suggests a potential role for vergence compensation during binocular closed-loop AR.
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23
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Chen Y, Jin W, Zheng Z, Zhang C, Lin H, Drobe B, Bao J, Chen H. Comparison of three monocular methods for measuring accommodative stimulus-response curves. Clin Exp Optom 2016; 100:155-161. [PMID: 27813170 PMCID: PMC5347892 DOI: 10.1111/cxo.12469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 01/07/2016] [Accepted: 07/28/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The aim was to evaluate the repeatability of dynamic measurement of the accommodative stimulus-response curve (ASRC) at three different dioptric speeds using a modified instrument and its agreement with two other methods. METHODS Twenty-nine adults (23.5 ± 2.0 years) were enrolled in the study. ASRC was measured monocularly using three methods: dynamic and static measurement using a motorised Badal system mounted on an open-field auto-refractor (WAM-5500, Grand Seiko Co., Ltd, Japan) and the minus lens technique. Dynamic measurements were conducted at three dioptric stimulus speeds to simulate continuous stimuli for ASRC (0.25, 0.40 and 0.55 D/s), with three repetitions for each speed. All three types of ASRCs were fitted with third-degree polynomial equations. The slope and objective accommodative amplitude of the ASRC were analysed. RESULTS The repeatability of objective accommodative amplitude worsened as the speed of the stimuli increased. The repeatability of the slope was best at a speed of 0.40 D/s and worst at 0.55 D/s. The measurement method significantly influenced the objective accommodative amplitude values and slope (both, p < 0.001). The minus lens technique yielded the highest amplitude of accommodation (6.21 ± 0.84 D) and steepest slope (1.11 ± 0.14), followed by the static Badal method (5.60 ± 0.83 D and 0.89 ± 0.09 D). The objective accommodative amplitude decreased with increasing speed during dynamic measurements. There was no difference between the slopes at 0.25 D and 0.40 D/s (p > 0.05) and the slope was lowest at 0.55 D/s. CONCLUSION The accommodative stimulus-response curve values are method-dependent and the significant differences between three methods used to determine the ASRC based on slope and accommodative amplitude indicate that these methods are non-interchangeable. Using dynamic measurements, accommodative behaviour varies with the speed of dioptric-change of the stimulus. A speed of 0.40 D/s appears to be the best compromise in terms of time, results and repeatability for dynamic ASRC measurement.
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Affiliation(s)
- Yunyun Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
| | - Wanqing Jin
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
| | - Zhili Zheng
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chuanchuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
| | - Huiling Lin
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
| | - Björn Drobe
- WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China.,R&D Optics Asia, Essilor International, Wenzhou, Zhejiang, China
| | - Jinhua Bao
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
| | - Hao Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,WEIRC, WMU-Essilor International Research Centre, Wenzhou, Zhejiang, China
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24
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Pérez-Prados R, Piñero DP, Pérez-Cambrodí RJ, Madrid-Costa D. Soft multifocal simultaneous image contact lenses: a review. Clin Exp Optom 2016; 100:107-127. [PMID: 27800638 DOI: 10.1111/cxo.12488] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/27/2016] [Accepted: 06/12/2016] [Indexed: 11/30/2022] Open
Abstract
Soft multifocal simultaneous image contact lenses have boomed in recent years due to the growing number of presbyopic patients demanding visual solutions, allowing them to maintain their current standard of living. The concept of 'simultaneous image' is based on blur interpretation and/or blur tolerance of superimposed multiple images on the retina formed by various powers of a contact lens. This is the basis for a specific type of multifocal contact lens developed for the compensation of presbyopia. Manufacturers have released a great variety of soft simultaneous image lens designs to meet different patient needs but their fitting is still unsatisfactory in some cases. Some presbyopes discontinue wearing contact lenses due to some limitations in visual quality and comfort that can be overcome with an appropriate contact lens selection based on a comprehensive pre-fitting evaluation. This paper aims to review the different types of soft multifocal contact lenses that are currently available for presbyopic correction and to define the steps and factors crucial for their fitting, such as pupil, aberrations, accommodation and centring. A discussion about useful tools to achieve a customised fitting leading to a successful outcome, such as the defocus curve, power profile and questionnaires, is performed.
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Affiliation(s)
- Roque Pérez-Prados
- Centro Óptico Benalúa, Alicante, Spain.,Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain.,Department of Ophthalmology (Oftalmar), Medimar International Hospital, Alicante, Spain.,Foundation for the Visual Quality (FUNCAVIS, Fundación para la Calidad Visual), Alicante, Spain
| | - Rafael J Pérez-Cambrodí
- Department of Ophthalmology (Oftalmar), Medimar International Hospital, Alicante, Spain.,Foundation for the Visual Quality (FUNCAVIS, Fundación para la Calidad Visual), Alicante, Spain
| | - David Madrid-Costa
- Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
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25
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Abstract
PURPOSE To evaluate whether an induced astigmatism influences the subjective depth of focus. METHODS Fifty-one participants aged 18 to 35 years and with a mean spherical equivalent refractive error of -0.51 ± 2.35 DS participated in the study. The accommodation was blocked with three drops of 1% cyclopentolate. Refractive errors were corrected after subjective refraction with a 4-mm artificial pupil. To evaluate the depth of focus (DoF), defocus curves with a spherical range of ±1.5 DS were assessed. The DoF was calculated as the horizontal distance at a threshold level of +0.1 logMAR from the maximum visual acuity (VA). Defocus curves were estimated binocularly during distance (500 cm) and a near vision (40 cm) for two induced axis (ATR in 0° and WTR in 90°) and for a fixed amount of astigmatic defocus of -0.5 DC. RESULTS The mean natural DoF was 0.885 ± 0.316 D for far vision and 0.940 ± 0.400 D for near vision. With induced astigmatism, the DoF for far vision was significantly increased to 1.095 ± 0.421 D (p = 0.006, ANOVA) for the WTR astigmatism but not for the ATR astigmatism (1.030 ± 0.395 D; p = 0.164, ANOVA). The induced WTR astigmatism enhanced the DoF for near vision significantly to 1.144 ± 0.338 D (p = 0.04, ANOVA), and DoF with induced ATR astigmatism (0.953 ± 0.318 D) was not significantly different (p = 1.00, ANOVA). ATR-astigmatism reduced VA by +0.08 ± 0.08 logMAR (p < 0.01, t-test). CONCLUSIONS With an induced WTR astigmatism of -0.5 DC, the DoF can be enhanced in the near viewing distance with a marginal loss in binocular VA. The approach of using induced WTR astigmatism can lead to novel optical treatments for presbyopia.
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26
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Cardona G, López S. Pupil diameter, working distance and illumination during habitual tasks. Implications for simultaneous vision contact lenses for presbyopia. JOURNAL OF OPTOMETRY 2016; 9:78-84. [PMID: 26481439 PMCID: PMC4811996 DOI: 10.1016/j.optom.2015.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 06/12/2015] [Accepted: 06/13/2015] [Indexed: 05/27/2023]
Abstract
PURPOSE To determine working distance, pupil diameter and illumination in real life conditions in a sample of presbyopic participants performing habitual tasks. METHODS A total of 59 presbyopic subjects (aged between 45 and 63 years) with different occupational backgrounds participated in the study. Participants were first interviewed regarding their habitual tasks with the aid of an ad hoc questionnaire, following which in-office photopic and mesopic pupil diameter was determined. Pupil diameter was also evaluated while participants conducted each of the self-reported habitual tasks by taking a photograph, which was later submitted to image analysis. In addition, working distance was determined with a measuring tape and the illumination that reached the pupil during each of the different tasks was measured, in lux, with a light meter. RESULTS The four most common habitual tasks were computer use, reading, sewing and sports. A high intersubject variability was found in pupil diameter, working distance and illumination conditions while conducting the same task. Statistically significant differences were found between the in-office measured photopic and mesopic pupil diameters and those obtained while participants were conducting their habitual tasks in real life conditions (all p<0.001). CONCLUSIONS Potential multifocal contact lens users may present with different ages, different jobs or hobbies and different preferences regarding lighting conditions and working distances. This results in different pupil size, even within the same task. This information may be critical when selecting a particular lens design and add power. Eye care practitioners are therefore advised to assess pupil diameter in real life conditions.
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Affiliation(s)
- Genís Cardona
- Optics and Optometry Department, Technical University of Catalonia, Spain.
| | - Sílvia López
- Optics and Optometry Department, Technical University of Catalonia, Spain
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Abstract
PURPOSE The purpose of this study is to determine the relationship between target clarity and the magnitude of accommodative lag using the metric accommodative gain (AG). METHODS Monocular accommodative responses were measured with Grand Seiko autorefraction using both proximal and minus lens techniques in 139 subjects aged 5 to 35 years. Subjects viewed a 1.5-mm letter at 13 discrete distances (range, 40 to 3.33 cm) for the proximal technique and fixed at 33 cm through minus lenses of increasing power for the lens technique. Subjects were instructed to keep the target clear and report when it blurred. The AG was calculated (accommodative response/accommodative demand) for the four greatest consecutive demands perceived clear (termed conditions 1 to 4) and the first demand perceived blurry (termed condition 5). RESULTS Multivariate planned contrast, including age as a predictor, revealed that mean AG was significantly larger when the target was clear (range, 0.71 to 0.77 for conditions 1 to 4 across techniques) versus blurry (0.59 and 0.68 for condition 5 across techniques) (p < 0.001 for proximal and p < 0.036 for lens). Age was only a contributing factor for the proximal technique, with the youngest subjects having the largest decrease in AG when the target changed from clear to blurry (p = 0.017). CONCLUSIONS These data suggest that across age and technique, the AG is relatively constant when the target is perceived clear but drops below approximately 70%, on average, once the target is perceived as blurry for subjects aged 5 to 35 years. The AG may be a useful metric to compare accommodative responses across a range of demands and to identify accommodative responses that may not be sufficient to perceive a clear target.
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Park A, Chung SA. Comparison of Manifest Refraction and Cycloplegic Refraction Using Retinoscopy or an Autorefractor in Children. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2016. [DOI: 10.3341/jkos.2016.57.8.1274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Aram Park
- Department of Ophthalmology, Ajou University School of Medicine, Suwon, Korea
| | - Seung Ah Chung
- Department of Ophthalmology, Ajou University School of Medicine, Suwon, Korea
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Hashemi H, Khabazkhoob M, Asharlous A, Soroush S, Yekta A, Dadbin N, Fotouhi A. Cycloplegic autorefraction versus subjective refraction: the Tehran Eye Study. Br J Ophthalmol 2015; 100:1122-7. [PMID: 26541436 DOI: 10.1136/bjophthalmol-2015-307871] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 10/15/2015] [Indexed: 11/04/2022]
Abstract
AIM To compare cycloplegic autorefraction with non-cycloplegic subjective refraction across all age and refractive error groups. METHODS In a cross-sectional study with random stratified cluster sampling, 160 clusters were chosen from various districts proportionate to the population of each district in Tehran. Following retinoscopy and autorefraction with the 0.25 D bracketing (Topcon KR-8000, Topcon, Tokyo, Japan), all participants had a subjective refraction. Then all participants underwent cycloplegic autorefraction. RESULTS The final analysis was performed on 3482 participants with a mean age of 31.7 years (range 5-92 years). Based on cycloplegic and subjective refraction, mean spherical equivalent (SE) was +0.31±1.80 and -0.32±1.61 D, respectively (p<0.001). The 95% limits of agreement (LoA) between these two types of refraction were from -0.40 to 1.70 D. The largest difference between these two types of refraction was seen in the age group of 5-10 years (1.11±0.60 D), and the smallest difference was in the age group of >70 years (0.34±0.45 D). The 95% LoA was -0.52 to 0.89 D in patients with myopia and -0.12 to 2.04 D in patients with hyperopia. We found that female gender (coefficients=0.048), older age (coefficients=-0.247), higher education (coefficients=-0.043) and cycloplegic SE (coefficients=-0.472) significantly correlated with lower intermethod differences. CONCLUSIONS The cycloplegic refraction is more sensitive than the subjective one to measure refractive error at all age groups especially in children and young adults. The cyclorefraction technique is highly recommended to exactly measure the refractive error in momentous conditions such as refractive surgery, epidemiological researches and amblyopia therapy, especially in hypermetropic eyes and paediatric cases.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mehdi Khabazkhoob
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Amir Asharlous
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Sara Soroush
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - AbbasAli Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nooshin Dadbin
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Abstract
Purpose To obtain experimental values of the depth-of-field (DOFi) of the human eye for different accommodative states. Methods First, the monochromatic ocular wavefront of seven eyes from young subjects (mean [±SD] age, 29.7 [±7.7] years) was measured at eight different accommodative demands (ADs) (from −1 to 6 diopters [D] in steps of 1 D). Then, in a second part, accommodation was paralyzed and an adaptive optics system was used to correct the aberrations of the paralyzed eye and to simulate, with the aid of an artificial pupil, the wavefront of the accommodated eye. The simulation was performed for each AD measured in the first part of the experiment. A Badal system was used to modify the stimulus vergence so as to obtain three repeated measurements of the subjective DOFi, based on the criterion of an objectionable blur. Results When increasing AD from 0 to 6 D, the mean intersubject pupil diameter and DOFi changed from 5.70 to 4.62 mm and from 0.85 ± 0.26 D to 1.07 ± 0.19 D, respectively. All subjects presented a similar DOFi for all AD (intrasubject SD never exceeded 0.23 D). Paraxial accommodation response showed a lag that increased with the AD. For the lowest (0 D) and the highest (6 D) values of AD, the refractive state of the eye was close to the nearest and furthermost ends of the DOFi, respectively. Conclusions The visual system takes advantage of the DOFi to change the refractive state less than necessary to form the paraxial image at the retina when it comes to focusing a near target (5 to 6 D of AD). This indicates that the main purpose of accommodation is not to maximize retinal image quality but to form one that is good enough.
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Sayegh RR, Dohlman CH, Greenstein SH, Peli E. The Boston keratoprosthesis provides a wide depth of focus. Ophthalmic Physiol Opt 2014; 35:39-44. [DOI: 10.1111/opo.12181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/03/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Rony R. Sayegh
- University Hospitals Eye Institute; University Hospitals Case Medical Center; Case Western Reserve University School of Medicine; Cleveland USA
- Schepens Eye Research Institute; Massachusetts Eye and Ear Infirmary; Harvard Medical School; Boston USA
| | - Claes H. Dohlman
- Schepens Eye Research Institute; Massachusetts Eye and Ear Infirmary; Harvard Medical School; Boston USA
| | - Scott H. Greenstein
- Schepens Eye Research Institute; Massachusetts Eye and Ear Infirmary; Harvard Medical School; Boston USA
| | - Eli Peli
- Schepens Eye Research Institute; Massachusetts Eye and Ear Infirmary; Harvard Medical School; Boston USA
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Abstract
PURPOSE To compare visual and optical quality of the Crystalens HD intraocular lens (IOL) with that of a monofocal IOL. METHODS The wavefront aberration patterns of the monocular Akreos Adapt AO IOL and the single-optic accommodating Crystalens HD IOL were measured in a model eye. The Crystalens IOL was measured in its nonaccommodative state and then, after flexing the haptic to produce 1.4 mm of movement, in its accommodative state. Using an adaptive optics system, subjects' aberrations were removed and replaced with those of pseudophakes viewing with either lens. Monocular distance visual acuity (DVA) at high (100%), medium (50%), and low (10%) contrast and contrast sensitivity (CS) were measured for both IOL optics. Near VA (NVA) and CS were measured for the Crystalens HD IOL in its accommodative state. Depth of focus around the distance and near focus was also evaluated for the Crystalens HD IOL. Modulation transfer function (MTF), point spread function (PSF), and Strehl ratio were also calculated. All measures were taken for 3- and 5-mm pupils. RESULTS The MTF, PSF, and Strehl ratio showed comparable values between IOLs (p > 0.05). There were no significant differences in DVA and CS between IOLs for all contrasts and pupils (p > 0.05). When spherically focused, mean DVA and NVA with the Crystalens HD IOL were ≥20/20 at 100 and 50% contrasts for both pupils. Monocular DVA, NVA, and CS were slightly better with 3- than 5-mm pupils, but without statistically significant differences. The Crystalens HD IOL showed about 0.75 and 0.50 D of depth of focus in its accommodative state and nonaccommodative state, respectively. CONCLUSIONS The optical and visual quality with the nonaccommodatied Crystalens HD IOL was comparable to that of a monofocal IOL. If this lens can move 1.4 mm in the eye, it will provide high-quality optics for near vision as well.
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Aldaba M, Vilaseca M, Arjona M, Pujol J. Age-related changes in accommodation measured with a double-pass system. Ophthalmic Physiol Opt 2013; 33:508-15. [PMID: 23448348 DOI: 10.1111/opo.12038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/07/2013] [Indexed: 11/28/2022]
Abstract
PURPOSE To measure the accommodative response in a wide age range population using the retinal image quality assessments provided by a double-pass system. METHODS The accommodative response was measured using a custom-built double-pass setup in 84 patients from 15 to 55 years of age. Patients were classified in four groups (A: 15-25 year old; B: 26-35; C: 36-45; D: 46-55). Accommodation was stimulated from 0 to 5 dioptres (D) with the push up method using an open field fixation test. The total accommodative response in the stimulated range, the accommodative stimulus-response curve, the slope and the progression of optical quality with accommodation were measured. RESULTS The total accommodation obtained in groups A and B was high, with a mean value of 4 D or higher, whereas values in older individuals were significantly lower. The accommodative stimulus-response curve and the slope were also high with a sudden decrease in patients over 35 years of age. The optical quality of the eye during accommodation did not change significantly. CONCLUSIONS Participants aged 15-35 years showed a good accommodative response. Thereafter, a significant decrease of the response in the total accommodation, stimulus response curve and slope was observed. The younger groups showed a larger accommodative response than previously published.
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Affiliation(s)
- Mikel Aldaba
- Centre for Sensors, Instruments, and Systems Development (CD6), Universitat Politecnica de Catalunya (UPC), Barcelona, Spain.
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Aldaba M, Vilaseca M, Díaz-Doutón F, Arjona M, Pujol J. Measuring the accommodative response with a double-pass system: Comparison with the Hartmann-Shack technique. Vision Res 2012; 62:26-34. [DOI: 10.1016/j.visres.2012.03.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/14/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
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Beirão M, Matos E, Beirâo I, Costa PPE, Torres P. Anticipation of presbyopia in Portuguese familial amyloidosis ATTR V30M. Amyloid 2011; 18:92-7. [PMID: 21591979 DOI: 10.3109/13506129.2011.576719] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The aim of this study was to evaluate if Portuguese patients with familial amyloidosis, liver transplanted and not, have an earlier development of presbyopia compared with a normal population and its relation with the presence or the absence of anterior capsule opacification of the lens. This study was performed to evaluate if Portuguese patients with familial amyloidosis and in a blood donors population (control group). Three hundred and fifty-six subjects, 144 amyloidotic patients and 212 healthy individuals, were evaluated for the need of plus lenses for normal near reading (Jaeger chart 1 at 33 cm). In familial amyloidosis patients, the value of the add-power was related to age, liver transplantation status, and presence of visible anterior capsule opacification of the lens. In both groups, the value of add-power was positively correlated with age (r=0.91; P<0.005). Familial amyloidosis patients require more add-power than control individuals of similar age, and need to use reading glasses at earlier ages. The age of onset of presbyopia in familial amyloidosis patients was significantly lower than in control individuals (32 years vs. 42 years). Adjusting for age, no significant difference was observed in add-power values between liver transplanted and not transplanted amyloidotic patients, suggesting that liver transplantation has no influence on presbyopia evolution in these patients. Familial amyloidosis patients had an earlier onset of presbyopia, probably related to amyloid deposition on the anterior capsule of the lens, which is not halted by liver transplantation.
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Affiliation(s)
- Melo Beirão
- Opthalmology, Centro Hospitalar do Porto, Porto, Portugal.
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Gispets J, Arjona M, Pujol J, Vilaseca M, Cardona G. Task oriented visual satisfaction and wearing success with two different simultaneous vision multifocal soft contact lenses. JOURNAL OF OPTOMETRY 2011; 4. [PMCID: PMC3974383 DOI: 10.1016/s1888-4296(11)70046-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Purpose A longitudinal prospective, cross-over, double masked study was designed to evaluate task oriented visual satisfaction and wearing success with two types of simultaneous vision multifocal soft contact lenses. Methods Twenty-two presbyopic subjects followed two 14-day trial periods in which they were alternatively and randomly fitted with two types of multifocal lenses. Habitual tasks were described in terms of observation distance, visual demand level and time allocation. Subjects graded visual satisfaction with each pair of lenses and each habitual task at different times during each trial. Overall satisfaction was evaluated after completion of the two trial periods. Wearing success was determined by the percentage of subjects opting to continue multifocal lens wear and by the number of subjects still wearing their lenses six months later. Results Viewing distance and visual demand level were found to influence visual satisfaction (p < 0.001). Visual satisfaction decreased for tasks involving higher visual demands and for near and far viewing distances, rather than for intermediate vision or a combination of near and far vision. A combined effect of lens type and evaluation time was discovered (p = 0.046). Although 78% of subjects decided to continue lens wear, only one subject was wearing them on a daily basis 6 months after the completion of the study. Insufficient quality of vision was reported as the main reason for multifocal contact lens discontinuation. Conclusions A task oriented visual satisfaction evaluation may prove helpful in lens design selection, as well as in predicting wearing success.
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Affiliation(s)
- Joan Gispets
- University Vision Centre, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
| | - Montserrat Arjona
- Centre for Sensors, Instruments and Systems Development (CD6), Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
| | - Jaume Pujol
- Centre for Sensors, Instruments and Systems Development (CD6), Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
| | - Meritxell Vilaseca
- Centre for Sensors, Instruments and Systems Development (CD6), Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
| | - Genís Cardona
- University Vision Centre, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
- Corresponding author. Escola Universitària d’Òptica i Optometria de Terrassa, Violinista Vellsolà 37, 08222 Terrassa, Barcelona, Spain.
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Wee SH, Yu DS, Moon BY, Cho HG. Comparison of presbyopic additions determined by the fused cross-cylinder method using alternative target background colours. Ophthalmic Physiol Opt 2010; 30:758-65. [DOI: 10.1111/j.1475-1313.2010.00780.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Visual accommodation plays a critical role in one's visual perception and activities of daily living. Age-related accommodation loss poses an increased risk to older adults' safety and independence. Although extensive effort has been made towards understanding the effect of age on steady-state accommodation, dynamic aspects of accommodation is still unknown. A study was therefore conducted to investigate age-related dynamic accommodative characteristics utilising a modified autorefractor. Ten individuals from each of three age groups (i.e. younger group: 20 to 29 years old; middle-aged group: 40 to 49 years old; older group: 60 to 69 years old) were recruited and their dynamic accommodation responses were examined. The laboratory experiment was designed to assess dynamic accommodation associated with an abrupt change from a constant far target (400 cm, 50 cd/m(2)) to a near target (70 cm, 100 cd/m(2) or 20 cd/m(2)), which aimed to simulate car dashboard reading behaviour while driving. The results of the study indicated that age and target intensity both had a significant impact on dynamic accommodation. These effects were attributed to both the age-related physiological limitation of the eye as well as to central neural processing delay. A method of measuring dynamic accommodation and the implications of the study are discussed. STATEMENT OF RELEVANCE: The results of the study indicate that age and target intensity both have a significant impact on dynamic accommodation. These effects are attributed to age-related physiological limitation of the eye as well as central neural processing delay and to decreased sensitivity of the cone photoreceptors. To enhance the visual performance of the ageing population involving dynamic accommodation, target distance and target light intensity should be carefully evaluated to facilitate effective viewing.
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Affiliation(s)
- Thurmon E Lockhart
- Grado Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, USA.
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Yao P, Lin H, Huang J, Chu R, Jiang BC. Objective depth-of-focus is different from subjective depth-of-focus and correlated with accommodative microfluctuations. Vision Res 2010; 50:1266-73. [DOI: 10.1016/j.visres.2010.04.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 03/11/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
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Vasudevan B, Ciuffreda KJ, Wang B. Objective Blur Thresholds in Free Space for Different Refractive Groups. Curr Eye Res 2009; 31:111-8. [PMID: 16500761 DOI: 10.1080/02713680500514669] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The aim of the current study was to measure the objective depth-of-focus (DOF) of myopes (MYO) in free space and compare them with emmetropic (EMM) and hyperopic (HYP) cohorts. The objective DOF was measured in 35 visually normal, young adults including 16 MYO, 13 EMM, and 6 HYP using the Power Refractor (PR II). The DOF was larger in the MYO and HYP than in the EMM. The larger objective DOF found in the MYO subgroup is in agreement with previous studies assessing the DOF subjectively. This finding is consistent with current thinking that increased amounts of retinal-defocus integrated over extended time may be myopiogenic. In agreement with earlier clinical and computer simulation studies, hyperopes demonstrate a relative resistance to increased retinal defocus.
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Affiliation(s)
- Balamurali Vasudevan
- Department of Vision Sciences, SUNY/State College of Optometry, New York, New York 10036, USA.
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Bulson RC, Ciuffreda KJ, Hung GK. The effect of retinal defocus on golf putting. Ophthalmic Physiol Opt 2008; 28:334-44. [DOI: 10.1111/j.1475-1313.2008.00575.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Leffler CT, Davenport B, Rentz J, Miller A, Benson W. Clinical predictors of the optimal spectacle correction for comfort performing desktop tasks. Clin Exp Optom 2008; 91:530-7. [PMID: 18537986 DOI: 10.1111/j.1444-0938.2008.00288.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The best strategy for spectacle correction of presbyopia for near tasks has not been determined. METHODS Thirty volunteers over the age of 40 years were tested for subjective accommodative amplitude, pupillary size, fusional vergence, interpupillary distance, arm length, preferred working distance, near and far visual acuity and preferred reading correction in the phoropter and trial frames. Subjects performed near tasks (reading, writing and counting change) using various spectacle correction strengths. Predictors of the correction maximising near task comfort were determined by multivariable linear regression. RESULTS The mean age was 54.9 years (range 43 to 71) and 40 per cent had diabetes. Significant predictors of the most comfortable addition in univariate analyses were age (p<0.001), interpupillary distance (p=0.02), fusional vergence amplitude (p=0.02), distance visual acuity in the worse eye (p=0.01), vision at 40 cm in the worse eye with distance correction (p=0.01), duration of diabetes (p=0.01), and the preferred correction to read at 40 cm with the phoropter (p=0.002) or trial frames (p<0.001). Target distance selected wearing trial frames (in dioptres), arm length, and accommodative amplitude were not significant predictors (p>0.15). The preferred addition wearing trial frames holding a reading target at a distance selected by the patient was the only independent predictor. Excluding this variable, distance visual acuity was predictive independent of age or near vision wearing distance correction. The distance selected for task performance was predicted by vision wearing distance correction at near and at distance. CONCLUSIONS Multivariable linear regression can be used to generate tables based on distance visual acuity and age or near vision wearing distance correction to determine tentative near spectacle addition. Final spectacle correction for desktop tasks can be estimated by subjective refraction with trial frames.
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Affiliation(s)
- Christopher T Leffler
- Department of Ophthalmology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond VA 23298-0438, USA.
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Fernández-Vega L, Alfonso JF, Montés-Micó R, Amhaz H. Visual acuity tolerance to residual refractive errors in patients with an apodized diffractive intraocular lens. J Cataract Refract Surg 2008; 34:199-204. [DOI: 10.1016/j.jcrs.2007.10.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
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Radhakrishnan H, Charman WN. Age-related changes in static accommodation and accommodative miosis. Ophthalmic Physiol Opt 2007; 27:342-52. [PMID: 17584285 DOI: 10.1111/j.1475-1313.2007.00484.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An attempt was made to explore the validity of the Hess-Gullstrand and Duane-Fincham models of presbyopia development, on the assumption that accommodative miosis could be used as an indicator of ciliary muscle effort. Monocular accommodation response and pupil size were measured as a function of accommodation demand over the range 0-4 D, in 48 normal subjects with ages between 17 and 56 years. The slope of the response/stimulus curve was found to decrease only slowly with age up to about 35 years and then to decline more rapidly. Accommodative miosis per dioptre of accommodation response did not change systematically with age up to about 35 years, this being apparently more in accord with the Hess-Gullstrand model. However, accommodative miosis varied very widely between younger subjects of similar age and accommodative amplitude (from zero to around 1 mm per dioptre of accommodation response for subjects in their twenties). It is concluded that miosis does not necessarily accompany accommodation and that its magnitude is not related in any simple general way to ciliary muscle contraction. Hence it cannot be used to support or refute particular theories of presbyopia.
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Affiliation(s)
- Hema Radhakrishnan
- Optometry and Neuroscience, Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, UK.
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Cufflin MP, Hazel CA, Mallen EAH. Static accommodative responses following adaptation to differential levels of blur. Ophthalmic Physiol Opt 2007; 27:353-60. [PMID: 17584286 DOI: 10.1111/j.1475-1313.2007.00491.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the effects of two levels of blur adaptation on visual resolution and steady-state accommodation responses in emmetropes and myopes. METHODS Eleven emmetropes (mean refractive error +0.01 +/- 0.31 DS) and 11 early-onset myopes (EOM, mean refractive error -4.44 +/- 1.64 DS) fixated monocularly at 4 m in three trials of 45 min duration with either: optimal refractive correction, +1 DS defocus, or +3 DS defocus. Monocular logMAR visual acuity (VA) was measured at 10 min intervals during each trial, and immediately following completion of the trial. Accommodative stimulus-response function (ASRF), refractive error and pupil size were measured before and after each trial. RESULTS Blur adaptation was found to have no effect on pupil size or baseline refraction, irrespective of the power of the blurring lens. Adaptation to +1 DS of defocus yielded an improvement in VA of -0.16 +/- 0.07 logMAR and -0.17 +/- 0.11 logMAR in the emmetropes and myopes respectively. An improvement in VA of -0.20 +/- 0.18 logMAR in the emmetropes and -0.26 +/- 0.17 logMAR in the myopes was observed following adaptation to +3 DS of defocus. The changes in acuity became significant following 30 min of exposure to defocus. Blur adaptation was found to have no effect on the ASRF gradient or individual steady-state accommodative responses. CONCLUSIONS Following blur adaptation, visual resolution was found to increase in both emmetropes and myopes. The magnitude of the blur level did not produce significantly different increases in resolution. Blur adaptation failed to affect either the steady-state responses to an accommodative stimulus or ASRF gradient.
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Affiliation(s)
- Matthew P Cufflin
- Department of Optometry, University of Bradford, Richmond Road, Bradford, West Yorkshire BD7 1DP, UK
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Luo X, Kymes SM, Gordon MO, Bassnett S. Lens fluorescence and accommodative amplitude in pre-presbyopic and presbyopic subjects. Exp Eye Res 2007; 84:1013-7. [PMID: 17359974 PMCID: PMC2682368 DOI: 10.1016/j.exer.2007.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 01/17/2007] [Accepted: 01/18/2007] [Indexed: 01/08/2023]
Abstract
Accommodative amplitude (AA; the difference, measured in diopters, between the near and far points of vision) declines steadily with age such that, by midlife, most individuals are unable to focus clearly on near objects and, thus, are said to be presbyopic. Conversely, intrinsic lens fluorescence (LF) increases steadily with age. Previous studies have suggested that AA and LF are negatively correlated, independent of age. Were this to be the case, it might suggest that the biochemical modifications underlying increased tissue fluorescence (for example, glycation of lens proteins) contribute to presbyopia. We used quantitative techniques to re-evaluate the relationship between AA and LF in 161 healthy volunteers aged between 25 and 70. Our data confirmed that AA decreases with age, becoming essentially zero by age 55, and LF increases with age. However, in marked contrast to previous reports, statistical analysis failed to detect any correlation between LF and AA independent of age. Thus, the biochemical processes responsible for increased LF observed in the aged lens are unlikely to contribute directly to presbyopia.
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Affiliation(s)
- Xianmin Luo
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
| | - Steven M. Kymes
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
- Division of Biostatistics, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
| | - Mae O. Gordon
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
- Division of Biostatistics, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
| | - Steven Bassnett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, St. Louis MO 63110
- Corresponding author. Tel: (314) 362-1604,
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Wang B, Ciuffreda KJ, Vasudevan B. Effect of blur adaptation on blur sensitivity in myopes. Vision Res 2006; 46:3634-41. [PMID: 16697436 DOI: 10.1016/j.visres.2006.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 03/14/2006] [Accepted: 03/14/2006] [Indexed: 10/24/2022]
Abstract
Although blur adaptation in myopia has been investigated, knowledge regarding its effect on blur sensitivity remains unknown. In the present study, changes in three blur thresholds (i.e., noticeable, bothersome, and non-resolvable blur) were assessed monocularly after 1h of blur adaptation in myopes. A Badal optical system was used to present either an isolated 20/50 Snellen E or 20/50 lines of text, with the full text field used in the latter condition for all blur judgments. Eight visually normal adult myopes were tested with paralyzed accommodation. All subjects exhibited blur adaptation, with a significant improvement in group mean visual acuity of -0.16 LogMAR. There was a consistent and concurrent significant decrease of 0.15-0.19 D in all blur thresholds for the isolated 20/50 E. However, there was no significant effect of blur adaptation on blur thresholds for the 20/50 text, with large intersubject variability evident. The enhanced blur sensitivity for the isolated E target may in part be attributed to the increased visual resolution following blur adaptation. Differences found in the blur thresholds for the two targets may be related to a variety of neuroperceptual phenomena, in particular lateral masking.
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Affiliation(s)
- Bin Wang
- SUNY/State College of Optometry, Department of Vision Sciences, New York, NY 10036, USA.
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Abstract
The depth-of-focus, or the perceptual tolerance of the human eye to retinal defocus, is important to and imbedded in many aspects of clinical refraction and physiological optics. Although the depth-of-focus is a common concept in classical optics, there is relatively little detailed discussion of its implications as related to normal vision function and to vision anomalies. With current advances in refractive surgery and ophthalmic lens design, the demand for knowledge in this topic is both timely and important. This review of our current understanding of the depth-of-focus should prove to be useful to clinicians, researchers, and students as an introduction to the subject. Two areas will be considered: 1) basic definitions of and factors affecting the depth-of-focus, and 2) its contemporary clinical implications.
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Affiliation(s)
- Bin Wang
- Department of Vision Sciences, SUNY/State College of Optometry, 33West 42nd Street, New York, NY 10036, USA
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