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Radhakrishnan A, Pascual D, Marcos S, Dorronsoro C. Vision with different presbyopia corrections simulated with a portable binocular visual simulator. PLoS One 2019; 14:e0221144. [PMID: 31430328 PMCID: PMC6701771 DOI: 10.1371/journal.pone.0221144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/31/2019] [Indexed: 11/18/2022] Open
Abstract
Presbyopes can choose today among different corrections to provide them with functional vision at far and near, and the outcomes and patient satisfaction depend on the selection. In this study, we present a binocular and portable vision simulator, based on temporal multiplexing of two synchronized tunable lenses allowing see-through and programmable visual simulations of presbyopic corrections. Seventeen binocular corrections were tested: 3 Monofocal (Far, Intermediate, Near), 4 Simultaneous Vision (bifocal, trifocal), 2 Monovision (far and near in either eye) and 8 Modified Monovision corrections (Simultaneous vision in one eye, Monofocal in the other eye). Perceived visual quality was assessed through the simulated corrections in 8 cyclopleged subjects who viewed a composite realistic visual scene with high contrast letters and a landscape at far (4 m) and a high contrast text at intermediate (66 cm) and near (33 cm) distances. Perceptual scores were obtained on a scale of 0 to 5 (low to high perceived quality). Perceptual preference was assessed by judging 36 random image pairs (6 repetitions) viewed through 9 binocular presbyopic corrections using two-interval forced choice procedures. The average score, across far and near distances, was the highest for Monovision (4.4±0.3), followed by Modified Monovision (3.4±0.1), Simultaneous Vision (3.0±0.1) and Monofocal corrections (2.9±0.2). However, the mean difference between far and near was lower for Simultaneous Vision and Monovision (0.4±0.1 PS) than Modified Monovision (1.8±0.7) or monofocal corrections (3.3±1.5). A strong significant correlation was found between the perceptual scores and the percentages of energy in focus, for each correction and distance (R = 0.64, p<0.0001). Multivariate ANOVA revealed significant influence of observation distances (p<10-9) and patients (p = 0.01) on Perceptual Score. In conclusion, we have developed a binocular portable vision simulator that can simulate rapidly and non-invasively different combinations of presbyopic corrections. This tool has applications in systematic clinical evaluation of presbyopia corrections.
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Affiliation(s)
- Aiswaryah Radhakrishnan
- Laboratory of Visual Optics and Biophotonics, Instituto de Óptica, IO-CSIC, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Daniel Pascual
- Laboratory of Visual Optics and Biophotonics, Instituto de Óptica, IO-CSIC, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Susana Marcos
- Laboratory of Visual Optics and Biophotonics, Instituto de Óptica, IO-CSIC, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carlos Dorronsoro
- Laboratory of Visual Optics and Biophotonics, Instituto de Óptica, IO-CSIC, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- * E-mail:
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Lafosse E, Wolffsohn JS, Talens-Estarelles C, García-Lázaro S. Presbyopia and the aging eye: Existing refractive approaches and their potential impact on dry eye signs and symptoms. Cont Lens Anterior Eye 2019; 43:103-114. [PMID: 31445772 DOI: 10.1016/j.clae.2019.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 01/18/2023]
Abstract
Every part of the human body is subject to aging, including the eye. An increased prevalence of dry eye disease with age is widely acknowledged. Aging threatens ocular surface homeostasis, altering the normal functioning of the lacrimal functional unit and potentially leading to signs and symptoms of dry eye. Additional age-related processes take place within the crystalline lens, leading to presbyopia and cataractogenesis. Correction strategies for presbyopia and cataracts may directly or indirectly challenge the ocular surface. Contact lenses disturb the normal structure of the tear film and can interact negatively with the ocular surface, further deteriorating an already unbalanced tear film in presbyopes, however, newer contact lens designs can overcome some of these issues. Moreover, cataract and corneal refractive surgeries sever corneal nerves and disrupt the corneal epithelium and ocular surface, which can influence surgical outcomes and aggravate dryness symptoms in older age groups. This review summarises the current understanding of how the invasive nature of contact lens wear and cataract and refractive surgery influence signs and symptoms of ocular dryness in an aging population.
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Affiliation(s)
- E Lafosse
- Optometry Research Group, Department of Optics & Optometry & Vision Sciences, University of Valencia, Valencia, Spain; Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - J S Wolffsohn
- Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - C Talens-Estarelles
- Optometry Research Group, Department of Optics & Optometry & Vision Sciences, University of Valencia, Valencia, Spain
| | - S García-Lázaro
- Optometry Research Group, Department of Optics & Optometry & Vision Sciences, University of Valencia, Valencia, Spain.
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Padmanaban N, Konrad R, Wetzstein G. Autofocals: Evaluating gaze-contingent eyeglasses for presbyopes. SCIENCE ADVANCES 2019; 5:eaav6187. [PMID: 31259239 PMCID: PMC6598771 DOI: 10.1126/sciadv.aav6187] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 05/22/2019] [Indexed: 05/13/2023]
Abstract
As humans age, they gradually lose the ability to accommodate, or refocus, to near distances because of the stiffening of the crystalline lens. This condition, known as presbyopia, affects nearly 20% of people worldwide. We design and build a new presbyopia correction, autofocals, to externally mimic the natural accommodation response, combining eye tracker and depth sensor data to automatically drive focus-tunable lenses. We evaluated 19 users on visual acuity, contrast sensitivity, and a refocusing task. Autofocals exhibit better visual acuity when compared to monovision and progressive lenses while maintaining similar contrast sensitivity. On the refocusing task, autofocals are faster and, compared to progressives, also significantly more accurate. In a separate study, a majority of 23 of 37 users ranked autofocals as the best correction in terms of ease of refocusing. Our work demonstrates the superiority of autofocals over current forms of presbyopia correction and could affect the lives of millions.
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Levinger E, Levinger S, Mimouni M, Trivizki O, Levinger N, Barequet IS, Rabina G. Unilateral Refractive Lens Exchange with a Multifocal Intraocular Lens in Emmetropic Presbyopic Patients. Curr Eye Res 2019; 44:726-732. [PMID: 30841762 DOI: 10.1080/02713683.2019.1591460] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Purpose: To evaluate the visual outcome and patient satisfaction after a unilateral multifocal IOL implantation in the non-dominant eye of emmetropic patients with presbyopia. Methods: An interventional case series of consecutive patients who underwent unilateral phacoemulsification with femto-laser assisted cataract surgery (FLACS) and refractive lens exchange (RLE), followed by an implantation of a trifocal diffractive IOL (FineVision Micro F), was performed in the non-dominant eyes of emmetropic patients with presbyopia. After 6 months of follow-up, the main outcome measures were uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA). Secondary outcomes included spherical equivalent (SE), refraction, contrast sensitivity, patient questionnaire and presence of visual side effects. Results: A total of 26 eyes of 26 patients, with an average age of 53.8 ± 4.1 years, were included in this study. Preoperative mean UDVA was 0.13 ± 0.04 logMAR (Snellen 20/27), UIVA was 0.46 ± 0.12 logMAR (Snellen 20/58), and UNVA was 0.66 ± 0.17 logMAR (Snellen 20/91), in comparison to postoperative mean UDVA of 0.18 ± 0.32 logMAR (Snellen 20/30) (p = 0.32), UIVA of 0.17 ± 0.21 logMAR (Snellen 20/30) (p < 0.005), and UNVA of 0.02 ± 0.10 logMAR (Snellen 20/21) (p < 0.005). Monocular UNVA of 20/25 or better in the operated eye was achieved in 23 (88%) patients. Twenty-four (96%) patients said they would recommend this procedure to family and friends. There were no intraoperative complications and no IOL exchange was required. Conclusions: A unilateral RLE of the non-dominant eye with FLACS and a trifocal diffractive IOL (FineVision Micro F) implantation in emmetropic, presbyopic patients is provides satisfactory distance, intermediate, and near visual outcomes with no complications reported in this preliminary case series.
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Affiliation(s)
- Eliya Levinger
- a Division of Ophthalmology, Sourasky Medical Center, Affiliated to the Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.,b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel
| | - Shmuel Levinger
- b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel
| | - Michael Mimouni
- c Department of Ophthalmology, Rambam Health Care Campus, affiliated to the Bruce and Ruth Rappaport Faculty of Medicine , Technion-Israel Institute of Technology , Haifa , Israel
| | - Omer Trivizki
- a Division of Ophthalmology, Sourasky Medical Center, Affiliated to the Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.,b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel
| | - Nadav Levinger
- b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel.,d Department of Ophthalmology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
| | - Irina S Barequet
- b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel.,e Goldschleger Eye Institute, Sheba Medical Center, affiliated to the Sackler School of Medicine , Tel Aviv University , Tel Hashomer , Israel
| | - Gilad Rabina
- a Division of Ophthalmology, Sourasky Medical Center, Affiliated to the Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.,b Department of Ophthalmology , Enaim Refractive Surgery Center , Jerusalem , Israel
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Small-pupil versus multifocal strategies for expanding depth of focus of presbyopic eyes. J Cataract Refract Surg 2019; 45:647-655. [DOI: 10.1016/j.jcrs.2019.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/28/2018] [Accepted: 01/09/2019] [Indexed: 11/23/2022]
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Jarosz J, Molliex N, Chenon G, Berge B. Adaptive eyeglasses for presbyopia correction: an original variable-focus technology. OPTICS EXPRESS 2019; 27:10533-10552. [PMID: 31052911 DOI: 10.1364/oe.27.010533] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
We propose an original variable-focus technology specially designed for presbyopia-correcting adaptive eyeglasses. It has been thought through to offer vision comfort without cutting on aesthetics. It relies on a fluid-filled variable-focus lens (presenting 2 liquids and 1 ultra-thin membrane) assisted by a low-power, high-volume microfluidic actuator. It also features a distance-sensing system to provide automatic focusing. We demonstrate the qualities of this novel technology on our first prototype. Our prototype achieves the necessary 3-diopter-high power variation on a 20-millimeter-wide variable zone with low actuation pressures (~200 Pa at most), and the preliminary optical quality analysis shows the spatial resolution is much better than the one specified by classic eye charts. We discuss further improvements in terms of optics, aesthetics and portability. In particular, we point out that this variable technology is compatible with standard base curves, and we highlight an optimal configuration where the power consumption of our opto-fluidic engine is about 25 mW peak.
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Small Text on Product Labels Poses a Special Challenge for Emerging Presbyopes. Optom Vis Sci 2019; 96:291-300. [DOI: 10.1097/opx.0000000000001362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Charman WN, Liu Y, Atchison DA. Small-aperture optics for the presbyope: do comparable designs of corneal inlays and intraocular lenses provide similar transmittances to the retina? JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:B7-B14. [PMID: 31044949 DOI: 10.1364/josaa.36.0000b7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
The near-vision performance of emmetropic presbyopes can be improved by the monocular surgical implantation of small-aperture corneal inlays or intraocular lenses that contain either an annular or circular stop to increase ocular depth of focus. Ray tracing is used to show that, although different stop designs and positions may produce similar axial imagery and increases in depth of focus, off-axis, the vignetting effects associated with the distance between the stop and the iris aperture result in different field dependences for the pupil transmittance. The implications of these effects, and of implanting a stop in only one eye, are discussed.
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Fernández J, Rodríguez-Vallejo M, Tauste A, Albarrán C, Basterra I, Piñero D. Fast Measure of Visual Acuity and Contrast Sensitivity Defocus Curves with an iPad Application. Open Ophthalmol J 2019. [DOI: 10.2174/1874364101913010015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective:To evaluate the repeatability of the fast measurement of the visual acuity (VADC) and contrast sensitivity (CSDC) defocus curves with a new test as well as the agreement of measurements at far distance obtained with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and the ClinicCSF test for measuring Contrast Sensitivity Function (CSF).Method:Records from fifty-nine subjects implanted with Multifocal Intraocular Lenses (MIOLs) were retrieved from our database. VADC and CSDC were measured from +1.00 D to -4.00 D in 0.50 D steps. The agreement with the ETDRS and the CSF at far distance was assessed in comparison to the 0 D location of the VADC and the CSDC, respectively. The repeatability was evaluated in 34 subjects who consecutively repeated two measures.Results:Median Visual Acuity (VA) was -0.1 logMAR with the VADC at 0 D of defocus and 0 logMAR with the ETDRS (p>0.05). A total of 45.8% of eyes showed no differences between both tests and the difference was less than one line of VA in 96.6% of the eyes. The intrasubject repeatability was under one line of VA along all the defocus curve except for positive defocus levels. The CSDC showed the best agreement with the CSF for 18 cycles per degree. The CSDC was less repeatable than VADC. Mean time spent on completing the VADC and CSDC was 7.81 and 7.98 minutes, respectively.Conclusion:The VADC showed good agreement with the ETDRS and good repeatability despite the short testing time. In contrast, poorer repeatability was found for CSDC. Our method would facilitate the inclusion of VADC in clinical practice as it is a fast test, being also the first one including the measure of CSDC.
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Affiliation(s)
- W Neil Charman
- Biology, Medicine and Health, University of Manchester, Manchester, UK
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Petelczyc K, Byszewska A, Chojnacka E, Jaroszewicz Z, Kakarenko K, Mira-Agudelo A, Ostrowska-Spaleniak A, Składowska A, Kołodziejczyk A, Rękas M. The Light Sword Lens - A novel method of presbyopia compensation: Pilot clinical study. PLoS One 2019; 14:e0211823. [PMID: 30716136 PMCID: PMC6361462 DOI: 10.1371/journal.pone.0211823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/17/2019] [Indexed: 11/19/2022] Open
Abstract
Purpose Clinical assessment of a new optical element for presbyopia correction–the Light Sword Lens. Methods Healthy dominant eyes of 34 presbyopes were examined for visual performance in 3 trials: reference (with lens for distance correction); stenopeic (distance correction with a pinhole ϕ = 1.25 mm) and Light Sword Lens (distance correction with a Light Sword Lens). In each trial, visual acuity was assessed in 7 tasks for defocus from 0.2D to 3.0D while contrast sensitivity in 2 tasks for defocus 0.3D and 2.5D. The Early Treatment Diabetic Retinopathy Study protocol and Pelli-Robson method were applied. Within visual acuity and contrast sensitivity results degree of homogeneity through defocus was determined. Reference and stenopeic trials were compared to Light Sword Lens results. Friedman analysis of variance, Nemenyi post-hoc, Wilcoxon tests were used, p-value < 0.05 was considered significant. Results In Light Sword Lens trial visual acuity was stable in tested defocus range [20/25–20/32], Stenopeic trial exhibited a limited range of degradation [20/25–20/40]. Light Sword Lens and reference trials contrast sensitivity was high [1.9–2.0 logCS] for both defocus cases, but low in stenopeic condition [1.5–1.7 logCS]. Between-trials comparisons of visual acuity results showed significant differences only for Light Sword Lens versus reference trials and in contrast sensitivity only for Light Sword Lens versus stenopeic trials. Conclusions Visual acuity achieved with Light Sword Lens correction in presbyopic eye is comparable to stenopeic but exhibits none significant loss in contrast sensitivity. Such correction method seems to be very promising for novel contact lenses and intraocular lenses design.
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Affiliation(s)
- Krzysztof Petelczyc
- Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
- * E-mail:
| | - Anna Byszewska
- Ophthalmology Department, Military Institute of Medicine, Warsaw, Poland
| | - Ewelina Chojnacka
- Ophthalmology Department, Military Institute of Medicine, Warsaw, Poland
| | - Zbigniew Jaroszewicz
- Institute of Applied Optics, Warsaw, Poland
- National Institute of Telecommunications, Warsaw, Poland
| | - Karol Kakarenko
- Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
| | | | | | - Aleksandra Składowska
- Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | | | - Marek Rękas
- Ophthalmology Department, Military Institute of Medicine, Warsaw, Poland
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Affiliation(s)
- Kyung-Sun Na
- Department of Ophthalmology, Yeouido St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea
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Abstract
SIGNIFICANCE When fit with monovision, most early presbyopes (aged 40 to 50 years) accommodated to near objects by focusing the distance corrected eye, leaving the near corrected eye myopically defocused with reduced image quality. A few were able to switch focus to the near corrected eye retaining a consistently focused image in one eye over a wider range of distances. PURPOSE The aim of this study was to examine accommodation behavior, pupil responses, and resultant image quality of early presbyopes fit with either bilateral or unilateral (monovision) near adds. METHODS Accommodative response and pupil size of 19 subjects (27 to 60 years), including 13 early presbyopes (40 to 50 years), were measured using an aberrometer as a binocularly viewed 20/40 letter E was moved from 2 m to 20 cm. Each subject was fit with different refractive strategies: bilateral distance correction, bilateral +2 diopters (D) near add, and unilateral +2 D near add placed over the measured right eye or unmeasured left eye. Monochromatic image quality was quantified using the Visual Strehl ratio metric. RESULTS With bilateral +2 D near add, all early presbyopes mostly refrained from accommodating (gain = 0.22 D/D) until the target approached closer than the 50-cm far point, and they then accommodated accurately until their maximum accommodative amplitude was reached. With monovision, most (10 of 13 early presbyopes) accommodated to focus the distance corrected eye, leaving the near corrected eye myopically defocused with reduced image quality. As stimulus distance became closer than their distance corrected eye's near point, they continued to exert maximum accommodation. Only two early presbyopes relaxed their accommodation to "switch" focus to the near corrected eye as target distance was reduced, and these two did not experience bilateral drop in image quality as stimulus distance became closer than the near point of the distance corrected eye. CONCLUSIONS Our data suggest that many early presbyopes will not initially adopt an accommodation strategy that optimizes image quality with monovision, but consistently accommodate to focus the distance corrected eye.
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Zeri F, Naroo SA, Zoccolotti P, De Luca M. Pattern of reading eye movements during monovision contact lens wear in presbyopes. Sci Rep 2018; 8:15574. [PMID: 30349058 PMCID: PMC6197269 DOI: 10.1038/s41598-018-33934-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 09/26/2018] [Indexed: 11/12/2022] Open
Abstract
Monovision can be used as a method to correct presbyopia with contact lenses (CL) but its effect on reading behavior is still poorly understood. In this study eye movements (EM) were recorded in fifteen presbyopic participants, naïve to monovision, whilst they read arrays of words, non-words, and text passages to assess whether monovision affected their reading. Three conditions were compared, using daily disposable CLs: baseline (near correction in both eyes), conventional monovision (distance correction in the dominant eye, near correction in the non-dominant eye), and crossed monovision (the reversal of conventional monovision). Behavioral measures (reading speed and accuracy) and EM parameters (single fixation duration, number of fixations, dwell time per item, percentage of regressions, and percentage of skipped items) were analyzed. When reading passages, no differences in behavioral and EM measures were seen in any comparison of the three conditions. The number of fixations and dwell time significantly increased for both monovision and crossed monovision with respect to baseline only with word and non-word arrays. It appears that monovision did not appreciably alter visual processing when reading meaningful texts but some limited stress of the EM pattern was observed only with arrays of unrelated or meaningless items under monovision, which require the reader to have more in-depth controlled visual processing.
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Affiliation(s)
- Fabrizio Zeri
- Ophthalmic Research Group. School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom. .,University of Milano Bicocca, Department of Materials Science, 20125, Milan, Italy.
| | - Shehzad A Naroo
- Ophthalmic Research Group. School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - Pierluigi Zoccolotti
- Neuropsychology Unit, IRCCS Fondazione Santa Lucia, Rome, 00179, Italy.,Department of Psychology, Sapienza University, Rome, 00176, Italy
| | - Maria De Luca
- Neuropsychology Unit, IRCCS Fondazione Santa Lucia, Rome, 00179, Italy
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Wolffsohn JS, Davies LN. Presbyopia: Effectiveness of correction strategies. Prog Retin Eye Res 2018; 68:124-143. [PMID: 30244049 DOI: 10.1016/j.preteyeres.2018.09.004] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 01/04/2023]
Abstract
Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.
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Affiliation(s)
- James S Wolffsohn
- Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
| | - Leon N Davies
- Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
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From Presbyopia to Cataracts: A Critical Review on Dysfunctional Lens Syndrome. J Ophthalmol 2018; 2018:4318405. [PMID: 30050689 PMCID: PMC6040261 DOI: 10.1155/2018/4318405] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/05/2018] [Indexed: 01/19/2023] Open
Abstract
Dysfunctional lens syndrome (DLS) is a term coined to describe the natural aging changes in the crystalline lens. Different alterations in the refractive properties and transparency of the lens are produced during the development of presbyopia and cataract, such as changes in internal high order aberrations or an increase in ocular forward scattering, with a potentially significant impact on clinical measures, including visual acuity and contrast sensitivity. Objective technologies have emerged to solve the limits of current methods for the grading of the lens aging, which have been linked to the DLS term. However, there is still not a gold standard or evidence-based clinical guidelines around these new technologies despite multiple research studies have correlated their results with conventional methods such as visual acuity or the lens opacification system (LOCS), with more scientific background around the ocular scattering index (OSI) and Scheimpflug densitometry. In either case, DLS is not a new evidence-based concept that leads to new knowledge about crystalline lens aging but it is a nomenclature change of two existing terms, presbyopia and cataracts. Therefore, this term should be used with caution in the scientific peer-reviewed literature.
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Fernandes P, Amorim-de-Sousa A, Queirós A, Escandón-Garcia S, McAlinden C, González-Méijome JM. Light disturbance with multifocal contact lens and monovision for presbyopia. Cont Lens Anterior Eye 2018; 41:393-399. [PMID: 29576438 DOI: 10.1016/j.clae.2018.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/07/2018] [Accepted: 03/18/2018] [Indexed: 12/11/2022]
Abstract
Dysphotopsia affects a significant number of patients, particularly after visual correction with multifocal optical designs. PURPOSE Evaluate light distortion (LD) in two modalities of contact lens (CL) wear: multifocal (MF) and monofocal (MV). METHODS This was a randomized, double-masked, crossover study involving 20 presbyopic patients. Patients were randomized first into either MF or MV for 15 days of use with a 1 week wash-out period between each lens type. The LD was evaluated with the Light Distortion Analyzer (LDA, University of Minho) under monocular and binocular conditions. The light distortion index (LDI, %), among other parameters were analyzed. Subjective quality of vision was assessed with the Quality of Vision (QoV). RESULTS The LD showed an increase in all parameters in both CL modalities being significant for MV in the non-dominant eye (p < 0.030, for all LD parameters). For the MF, there was also a significant increase in LDI (p = 0.016) and in BFCrad (p = 0.022) in the non-dominant eye. After 15 days of MF lens wear, there was a significant decrease in all LD parameters (p < 0.002) in the dominant eye. Binocularly, a significant improvement from 1 to 15 days was observed for LDI (p = 0.009) and BFCrad (p = 0.0013) with MF. The QoV questionnaire showed no significant changes with neither CL. CONCLUSIONS Adaptation to light disturbances induced by MF CL is more effective compared to MV. Practitioners will have greater success if they prepare their patients for the adaptation required as their vision will get better and have less of an issue with light disturbance.
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Affiliation(s)
- Paulo Fernandes
- Clinical and Experimental Optometry Research Laboratory (CEORLab) Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal.
| | - Ana Amorim-de-Sousa
- Clinical and Experimental Optometry Research Laboratory (CEORLab) Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal
| | - António Queirós
- Clinical and Experimental Optometry Research Laboratory (CEORLab) Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal
| | - Santiago Escandón-Garcia
- Clinical and Experimental Optometry Research Laboratory (CEORLab) Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal
| | - Colm McAlinden
- University Hospitals Bristol, NHS Foundation Trust, Bristol, UK
| | - José Manuel González-Méijome
- Clinical and Experimental Optometry Research Laboratory (CEORLab) Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal
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Charman WN. Virtual Issue Editorial: Presbyopia - grappling with an age-old problem. Ophthalmic Physiol Opt 2018; 37:655-660. [PMID: 29044672 DOI: 10.1111/opo.12416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- W Neil Charman
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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69
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Hipsley A, Hall B, Rocha KM. Scleral surgery for the treatment of presbyopia: where are we today? EYE AND VISION (LONDON, ENGLAND) 2018; 5:4. [PMID: 29497624 PMCID: PMC5827891 DOI: 10.1186/s40662-018-0098-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 01/28/2018] [Indexed: 11/28/2022]
Abstract
Presbyopia corrections traditionally have been approached with attempts to exchange power, either at the cornea or the lens planes, inducing multifocality, or altering asphericity to impact the optical system. Treatments that affect the visual axis, such as spectacle and contact lens correction, refractive surgeries, corneal onlays and inlays, and intraocular lenses are typically unable to restore true accommodation to the presbyopic eye. Their aim is instead to enhance 'pseudoaccommodation' by facilitating an extended depth-of-focus for which vision is sufficient. There is a true lack of technology that approaches presbyopia from a treatment based or therapy based solution, rather than a 'vision correction' solution that compromises other components of the optical system. Scleral surgical procedures seek to restore true accommodation combined with pseudoaccommodation and have several advantages over other more invasive options to treat presbyopia. While the theoretical justification of scleral surgical procedures remains controversial, there has nevertheless been increasing interest and evidence to support scleral surgical and therapeutic approaches to treat presbyopia. Enormous progress in scleral surgery techniques and understanding of the mechanisms of action have been achieved since the 1970s, and this remains an active area of research. In this article, we discuss the historic scleral surgical procedures, the two scleral procedures currently available, as well as an outlook of the future for the scleral surgical space for treating presbyopia.
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Affiliation(s)
| | | | - Karolinne M. Rocha
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC USA
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70
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The effect of ageing on the ocular surface parameters. Cont Lens Anterior Eye 2018; 41:5-12. [DOI: 10.1016/j.clae.2017.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 02/03/2023]
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71
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Balgos MJTD, Vargas V, Alió JL. Correction of presbyopia: An integrated update for the practical surgeon. Taiwan J Ophthalmol 2018; 8:121-140. [PMID: 30294526 PMCID: PMC6169332 DOI: 10.4103/tjo.tjo_53_18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Presbyopia results from loss or insufficiency of the eye's accommodative ability, and clinically manifests as the inability to focus near objects on the retina. It is one of the most common causes of visual impairment worldwide especially in adults of productive or working age. Various means of compensating for the loss of accommodative ability have been devised from optical tools such as spectacles and contact lenses, to topical medications and to surgical procedures. A comprehensive search on journal articles about topical and surgical correction of presbyopia was undertaken. The various techniques for presbyopia correction, as enumerated in these articles, are discussed in this paper with the addition of our personal experience and perspective on the future of these techniques.
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Affiliation(s)
| | | | - Jorge L Alió
- VISSUM Alicante, Spain.,Division of Ophthalmology, Universidad Miguel Hernández, Spain
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72
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Almaguer C, Acosta E, Arines J. Pupil size stability of the cubic phase mask solution for presbyopia. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-8. [PMID: 29297211 DOI: 10.1117/1.jbo.23.1.015002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
Presbyopia correction involves different types of studies such as lens design, clinical study, and the development of objective metrics, such as the visual Strehl ratio. Different contact lens designs have been proposed for presbyopia correction, but performance depends on pupil diameter. We will analyze the potential use of a nonsymmetrical element, a cubic phase mask (CPM) solution, to develop a contact or intraocular lens whose performance is nearly insensitive to changes in pupil diameter. We will show the through focus optical transfer function of the proposed element for different pupil diameters ranging from 3 to 7 mm. Additionally, we will show the images obtained through computation and experiment for a group of eye charts with different visual acuities. Our results show that a CPM shaped as 7.07 μm*(Z33-Z3-3)-0.9 μmZ20 is a good solution for a range of clear vision with a visual acuity of at least 0.1 logMar from 0.4 to 6 m for pupil diameters in the 3- to 7-mm range. Our results appear to be a good starting point for further development and study of this kind of CPM solution for presbyopia.
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Affiliation(s)
- Citlalli Almaguer
- Universidade de Santiago de Compostela, Facultade de Óptica e Optometría, Dept. Física Aplicada, San, Spain
| | - Eva Acosta
- Universidade de Santiago de Compostela, Facultade de Óptica e Optometría, Dept. Física Aplicada, San, Spain
| | - Justo Arines
- Universidade de Santiago de Compostela, Facultade de Óptica e Optometría, Dept. Física Aplicada, San, Spain
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73
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Novillo-Díaz E, Villa-Collar C, Narváez-Peña M, Martín JLR. Fitting success for three multifocal designs: Multicentre randomised trial. Cont Lens Anterior Eye 2017; 41:258-262. [PMID: 29258836 DOI: 10.1016/j.clae.2017.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine if the discontinuation of commercially-available simultaneous vision Multifocal Soft Contact Lenses is independent from the multifocal design. To determine causes for discontinuation and psychosocial factors involved. METHODS Multicentre single-blinded randomised controlled trial with external blinded evaluation for a three months follow-up period for three intervention groups. 150 single-vision soft wearers were randomly assigned a spherical near centred lens (S-CN), distance centred lens (CD) or aspherical near centred lens (A-CN). Cases of discontinuation, anxiety and quality of life were measured at one week and one month. RESULTS 120 females and 30 males were included with an age range of 40-62 (48.79 ± 5.23). At one month, the S-CN design had a statistically significant higher risk of discontinuation than the other two OR: 6.12 (95%CI 2.5-14.9). Twenty-eight subjects discontinued wearing S-CN at first week (56%), while discontinuation of CD and A-CD were 15 (30%) and 11 (22%), with a statistically significant difference between S-CN design and the other two (p = 0.001). There were not statistically significant differences when direct comparison between discontinuation of CD and A-CN was made (p = 0.36). Thirty-two percent discontinued the use because of poor distance vision and 28% because of both poor distance and near vision. Psychosocial factors were not statistically significant. CONCLUSIONS Discontinuation of Multifocal Soft Contact Lenses is dependent on the design. Most common cause for discontinuation is poor distance vision. Psychosocial factors do not impact on discontinuation rates.
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Zeri F, Berchicci M, Naroo SA, Pitzalis S, Di Russo F. Immediate cortical adaptation in visual and non-visual areas functions induced by monovision. J Physiol 2017; 596:253-266. [PMID: 29071723 DOI: 10.1113/jp274896] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/18/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Monovision is an optical correction for presbyopes that consists of correcting one eye for far distance and the other for near distance, creating a superimposition of an in-focus with a blurred image. Brain adaptation to monovision was studied in unexperienced observers by measuring visual evoked potentials from 64-channels. The first clear effect of monovision on visual evoked potentials was the C1 amplitude reduction, indicating that the unilateral blurring induced by monovision reduces feed-forward activity in primary visual area. Monovision led also to an increased amplitude of the P1 and pP1 components, with the latter originating in prefrontal regions. This effect probably works as an attentional compensatory activity used to compensate for the degraded V1 signal. ABSTRACT A common and often successful option to correct presbyopia with contact lenses is monovision. This is an unbalanced correction across the two eyes where one eye is corrected for far vision and the other eye is corrected for near vision. Monovision is therefore a form of acquired anisometropia that causes a superimposition of an in-focus image with a blurred image. In spite of this visual anisometropia, monovision has been successfully used for many decadesl however the brain mechanism supporting monovision is not well understood. The present study aimed to measure the visual evoked potentials with a high-density electrode array (64-channel) in a group of presbyopes and to provide a detailed spatiotemporal analysis of the cortical activity after a short period of adaptation to monovision with contact lenses. When compared with a balanced eye near correction, monovision produced both a clear reduction of the earliest visual evoked potential components, the C1 and the N1, and an amplitude increase of the P1 and pP1. These results indicate that the unilateral blurring induced by wearing monovision contact lenses reduces feed-forward activity in the primary visual area and feedback activity in extrastriate areas (C1 and N1 reduction). Interestingly, other brain activities in both extrastriate visual areas (the P1 component) and in the anterior insula (the pP1 component) appear to compensate for this dysfunction, increasing their activity during monovision. These changes confirm the presence of fluid brain adaptation in visual and non-visual areas during monocular interferences.
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Affiliation(s)
- Fabrizio Zeri
- Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Marika Berchicci
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Shehzad A Naroo
- Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Sabrina Pitzalis
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy.,IRCCS Santa Lucia Foundation Rome, Italy
| | - Francesco Di Russo
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy.,IRCCS Santa Lucia Foundation Rome, Italy
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75
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An Italian Translation and Validation of the near Activity Visual Questionnaire (NAVQ). Eur J Ophthalmol 2017; 27:640-645. [DOI: 10.5301/ejo.5000957] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Purpose To validate the Near Activity Vision Questionnaire (NAVQ) in Italian to allow the assessment of presbyopia corrections in Italian-speaking patients. Methods An Italian version of the NAVQ was arranged through several steps: an initial forward translation (from English to Italian), a backward translation (from Italian to English), and finally a consensual version to check against the original NAVQ. This prospective study enrolled native Italian-speaking presbyopic patients with corrected distance visual acuity of 0.20 logMAR or better in each eye and free of ocular anomalies. Six different groups of patients were asked to complete the questionnaire: emerging presbyopic patients, reading spectacle users, multifocal spectacle users, multifocal contact lens (CL) wearers, monovision CL wearers, and monofocal intraocular lens patients. Subjects were asked to answer the questionnaire again 2 weeks after the first completion. Results A total of 207 subjects completed the questionnaire. Data analysis showed good internal consistency (Cronbach α = 0.93) and factorial validity with only one factor explaining 62.0% of the variance. Test-retest reliability was extremely good (ICC = 0.92) as well as discriminatory power of the questionnaire's ability to discriminate between subjects with different forms of presbyopic correction. Conclusions The Italian version of the NAVQ matches the properties of the original English version. It is a valid instrument to evaluate near activity visual quality of presbyopic Italian speakers.
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Vu LT, Chen CCA, Shum PJT. Analysis on multifocal contact lens design based on optical power distribution with NURBS. APPLIED OPTICS 2017; 56:7990-7997. [PMID: 29047788 DOI: 10.1364/ao.56.007990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/03/2017] [Indexed: 06/07/2023]
Abstract
This paper aims to develop and analyze the design method of multifocal contact lenses to obtain curvature continuity in the optical surfaces with the high addition (Add) powers by adjusting non-uniform rational B-spline (NURBS) curves. The paper has developed mathematical formulae to generate the optical power distributions in which the powers continuously change from either near or distant center to the opposite focal length in the periphery of the optical region with different change rates and Add power values. This developed method can efficiently adjust and optimize three parameters, including control points, weight, and knots of the NURBS, to be anterior optical lens surface profiles to adapt for these given power profiles. The result shows that the proposed contact lenses not only achieve smooth and continuous anterior optical surfaces, but also satisfy various optical power distributions with high Add power values for different pupil diameters. Then, these designs of contact lenses can be feasibly converted to the computer-aided design format for analysis and manufacture for molding or single-point diamond turning. Experimental results of this method have been tested and proven when both the power distributions of simulation of lenses and the actual machined samples match the original specified powers provided by clinical demands of a multifocal contact lens. Future integration with variant clinical demands and optimization rules of lens design can be explored for a progressive contact lens.
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77
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Jia Z, Xu K, Fang F. Measurement of spectacle lenses using wavefront aberration in real view condition. OPTICS EXPRESS 2017; 25:22125-22139. [PMID: 29041501 DOI: 10.1364/oe.25.022125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/28/2017] [Indexed: 06/07/2023]
Abstract
A wavefront aberration analysis method for measuring spectacle lenses in real-view condition is proposed and verified using experimental apparatus based on the eye-rotation model. Two strategies-feedback positioning and posture adjustment of incident beams and Hartmann-Shack wavefront-aberration sensor calibration at each measurement subarea-are applied to improve measurement accuracy. By simulating the real-view condition, wavefront aberration and user power on the vertex sphere can be obtained. Comparison experiments demonstrate the validity and accuracy of the proposed method and experimental apparatus. Freeform progressive addition lenses are also measured and the results analyzed. The findings provide a possible approach for optimizing the design of spectacle lenses and evaluating their manufacturing and imaging quality.
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78
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Optical quality of rotationally symmetrical contact lenses derived from their power profiles. Cont Lens Anterior Eye 2017; 40:346-350. [PMID: 28522252 DOI: 10.1016/j.clae.2017.05.005] [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: 01/30/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile. METHODS Simulated rotationally symmetrical power profiles corresponding to different CLs designs (monofocal, two-zone center-near bifocal, and four-zone center-distance bifocal) were used to calculate the wavefront error profile by means of numerical integration. Then, each lens wavefront error profile was spun around the center to obtain the lens wavefront error surface. From the surface, monochromatic optical transfer functions (OTF), simulated images and the visual Strehl ratio based on the OTF (VSOTF) were obtained for different distances and pupil sizes (3 and 5.5mm) after performing a through-focus. RESULTS VSOTF variations, taking into account both vergence and pupil size, were presented for the three CLs designs. The monofocal design showed excellent optical quality only for far vision, whereas the bifocal designs exhibited good optical quality for far and near vision. Modulation transfer function (MTF) from each lens design, pupil size, and work distance agreed with the previous results. CONCLUSIONS The methodology presented here allows for a rapid and thorough assessment of the optical quality of rotationally symmetrical CLs by means of optical quality metrics, with a special interest in simultaneous image contact lenses. This methodology may be useful for choosing the most suitable lens for each subject's visual demands.
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79
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Radhakrishnan H, Charman WN. Optical characteristics of Alvarez variable-power spectacles. Ophthalmic Physiol Opt 2017; 37:284-296. [DOI: 10.1111/opo.12361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/25/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Hema Radhakrishnan
- Division of Pharmacy and Optometry; Faculty of Biology, Medicine and Health; University of Manchester; Manchester UK
| | - W. Neil Charman
- Division of Pharmacy and Optometry; Faculty of Biology, Medicine and Health; University of Manchester; Manchester UK
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80
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Personalized Progressive Addition Lenses: Correlation between Performance and Design. Optom Vis Sci 2017; 94:208-218. [DOI: 10.1097/opx.0000000000001016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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81
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Arines J, Almaguer C, Acosta E. Potential use of cubic phase masks for extending the range of clear vision in presbyopes: initial calculation and simulation studies. Ophthalmic Physiol Opt 2017; 37:141-150. [DOI: 10.1111/opo.12348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/22/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Justo Arines
- Departamento de Física Aplicada (área de Optometría); Facultade de Óptica e Optometría; Universidade de Santiago de Compostela; Santiago de Compostela Spain
| | - Citlalli Almaguer
- Departamento de Física Aplicada (área de Optometría); Facultade de Óptica e Optometría; Universidade de Santiago de Compostela; Santiago de Compostela Spain
| | - Eva Acosta
- Departamento de Física Aplicada (área de Óptica); Facultade de Física; Universidade de Santiago de Compostela; Santiago de Compostela Spain
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82
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Papadatou E, Del Águila-Carrasco AJ, Esteve-Taboada JJ, Madrid-Costa D, Cerviño-Expósito A. Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses. Int J Ophthalmol 2017; 10:103-108. [PMID: 28149785 DOI: 10.18240/ijo.2017.01.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/18/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS The power distribution of the lenses was affected by pupil size differently. One of the lenses showed a significant spread in refractive power distribution, from about -3 D to 0 D. Generally, the power distribution of the lenses expanded as the pupil diameter became greater. The surface of the lens dedicated for each distance varied substantially with the design of the lens. CONCLUSION In an experimental basis, our results show how the lenses power distribution is affected by the pupil size and underlined the necessity of careful evaluation of the patient's visual needs and the optical properties of a multifocal contact lens for achieving the optimal visual outcome.
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Affiliation(s)
- Eleni Papadatou
- Optometry Research Group, University of Valencia, Valencia 46100, Spain
| | | | | | - David Madrid-Costa
- Optics II Department, Optics and Optometry Faculty, Complutense University of Madrid, Madrid 28037, Spain
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83
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Affiliation(s)
- W Neil Charman
- Division of Pharmacy and Optometry; Faculty of Biology, Medicine and Health; University of Manchester; Manchester UK
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84
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Finding routes towards understanding and the successful correction of presbyopia. Cont Lens Anterior Eye 2016; 39:401. [PMID: 27863717 DOI: 10.1016/j.clae.2016.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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85
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Papadatou E, Del Águila-Carrasco AJ, Marín-Franch I, López-Gil N. Temporal multiplexing with adaptive optics for simultaneous vision. BIOMEDICAL OPTICS EXPRESS 2016; 7:4102-4113. [PMID: 27867718 PMCID: PMC5102541 DOI: 10.1364/boe.7.004102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/17/2016] [Accepted: 08/19/2016] [Indexed: 05/27/2023]
Abstract
We present and test a methodology for generating simultaneous vision with a deformable mirror that changed shape at 50 Hz between two vergences: 0 D (far vision) and -2.5 D (near vision). Different bifocal designs, including toric and combinations of spherical aberration, were simulated and assessed objectively. We found that typical corneal aberrations of a 60-year-old subject changes the shape of objective through-focus curves of a perfect bifocal lens. This methodology can be used to investigate subjective visual performance for different multifocal contact or intraocular lens designs.
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Affiliation(s)
- Eleni Papadatou
- Optomety Research Group, Facultad de Física, Universidad de Valencia, Spain
| | | | - Iván Marín-Franch
- Optomety Research Group, Facultad de Física, Universidad de Valencia, Spain
- CiViUM Research Group, Facultad de Óptica y Optometría, Universidad de Murcia, Spain
| | - Norberto López-Gil
- CiViUM Research Group, Facultad de Óptica y Optometría, Universidad de Murcia, Spain
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86
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Pościk A, Jachowicz M. Mechanical properties of protective spectacles fitted with corrective lenses. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2016; 23:440-446. [PMID: 27649581 DOI: 10.1080/10803548.2016.1234131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The majority of commercially available corrective spectacles used by workers do not provide effective eye protection against mechanical hazards in the workplace. One of the risks commonly occurring during work is hitting the head on some protruding elements, such as components of machines, buildings or tree branches in a forest. Because of the considerable weight of the human head and the speed of movement during impact, this type of accident may be very serious. This article presents a method of testing the mechanical strength of corrective lenses, simulating the results of an impact of the head on elements of workplaces. The results of tests of commercially available materials used for the construction of corrective and protective spectacles are also presented and discussed.
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Affiliation(s)
- Adam Pościk
- a Central Institute for Labour Protection - National Research Institute (CIOP-PIB) , Poland
| | - Marcin Jachowicz
- a Central Institute for Labour Protection - National Research Institute (CIOP-PIB) , Poland
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87
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Charman WN. François Pourfour du Petit (1664-1741): pioneer in ocular biometry. Ophthalmic Physiol Opt 2016; 36:428-38. [DOI: 10.1111/opo.12303] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/11/2016] [Indexed: 12/30/2022]
Affiliation(s)
- W Neil Charman
- Faculty of Life Sciences; University of Manchester; Manchester UK
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88
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Ruggeri M, de Freitas C, Williams S, Hernandez VM, Cabot F, Yesilirmak N, Alawa K, Chang YC, Yoo SH, Gregori G, Parel JM, Manns F. Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging. BIOMEDICAL OPTICS EXPRESS 2016; 7:1351-64. [PMID: 27446660 PMCID: PMC4929646 DOI: 10.1364/boe.7.001351] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 05/21/2023]
Abstract
Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence. The image sequences were processed to extract dynamic morphological data from the crystalline lens and the ciliary muscle. The synchronization between the OCT systems allowed the precise correlation of anatomical changes occurring in the crystalline lens and ciliary muscle at identical time points during accommodation. To describe the dynamic interaction between the crystalline lens and ciliary muscle, we introduce accommodation state diagrams that display the relation between anatomical changes occurring in the accommodating crystalline lens and ciliary muscle.
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Affiliation(s)
- Marco Ruggeri
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carolina de Freitas
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Siobhan Williams
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Victor M. Hernandez
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Florence Cabot
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nilufer Yesilirmak
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Karam Alawa
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Yu-Cherng Chang
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Sonia H. Yoo
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Giovanni Gregori
- Quantitative Imaging Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
- Vision Cooperative Research Centre, Sydney, NSW, Australia
- Brien Holden Vision Institute, Sydney, NSW, Australia
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
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89
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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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90
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Serra P, Chisholm C, Sanchez Trancon A, Cox M. Distance and near visual performance in pseudophakic eyes with simulated spherical and astigmatic blur. Clin Exp Optom 2016; 99:127-34. [PMID: 26840890 DOI: 10.1111/cxo.12350] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Increased depth-of-focus after cataract surgery is dependent on various ocular characteristics, including refractive astigmatism. This work studied the influence of meridional blur produced by astigmatism, and spherical blur, on distance and near visual performance in pseudophakic eyes. METHODS Visual performance was assessed monocularly in 59 pseudophakes (mean ± standard deviation, 66.9 ± 7.53 years) at distance (3.0 m) and near (0.33 m) using high- (HC: 94%) and low-contrast (LC: 10%) visual acuity (VA) charts. Reading performance (maximum reading speed [MRS], threshold print size [TPS] and reading acuity [RA]) was evaluated at near using a reading chart. Four refractive conditions at distance and near were monocularly simulated using the following trial lenses: distance (in-focus: ± 0.00 DS, with-the-rule [WTR] astigmatism: +2.00 × 180; against-the-rule [ATR] astigmatism: +2.00 × 90; spherical defocus: +1.00 DS) and near (in-focus: +3.00 DS, WTR astigmatism: +2.00 × 180; ATR astigmatism: +2.00 × 90, spherical blur: ±0.00 DS). RESULTS Distance high- and low-contrast VA were degraded by spherical and astigmatic blur in comparison to the distance in-focus condition (p < 0.001 for all), with astigmatism in either of the forms being more harmful than spherical blur (p < 0.001 for all). At near, best HC- and LCVA were attained with full near correction (p < 0.001 for all) followed by the ATR and WTR astigmatism. For all conditions, the VA measured was independent of whether the astigmatism was WTR or ATR. However, MRS was higher with +3.00 DS and ATR astigmatism compared to the other conditions. RA and TPS significantly strengthened the weak pattern seen with HCVA at near, with ATR astigmatism allowing significantly better RA and TPS than WTR astigmatism (p < 0.001 for all). CONCLUSIONS Simple myopic astigmatism improved near visual performance in pseudophakic eyes at the expense of some deterioration in distance performance. ATR astigmatism degraded VA at distance marginally more than WTR astigmatism and provided a marginally better VA at near. However, the benefit at near was more explicit when measured by reading performance, confirming the role of blur orientation on visual performance.
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Affiliation(s)
- Pedro Serra
- Bradford School of Optometry and Vision Sciences, University of Bradford, United Kingdom. .,Faculty of Health Sciences, University of Beira Interior, Portugal.
| | - Catharine Chisholm
- Bradford School of Optometry and Vision Sciences, University of Bradford, United Kingdom
| | | | - Michael Cox
- Bradford School of Optometry and Vision Sciences, University of Bradford, United Kingdom
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91
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Atchison DA, Blazaki S, Suheimat M, Plainis S, Charman WN. Do small-aperture presbyopic corrections influence the visual field? Ophthalmic Physiol Opt 2015; 36:51-9. [DOI: 10.1111/opo.12265] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/06/2015] [Indexed: 11/29/2022]
Affiliation(s)
- David A. Atchison
- Institute of Health & Biomedical Innovation, School of Optometry & Vision Science, Queensland University of Technology; Brisbane Australia
| | - Stella Blazaki
- Institute of Vision and Optics; University of Crete; Heraklion Crete Greece
| | - Marwan Suheimat
- Institute of Health & Biomedical Innovation, School of Optometry & Vision Science, Queensland University of Technology; Brisbane Australia
| | - Sotiris Plainis
- Institute of Vision and Optics; University of Crete; Heraklion Crete Greece
- Faculty of Life Sciences; University of Manchester; Manchester UK
| | - W. Neil Charman
- Faculty of Life Sciences; University of Manchester; Manchester UK
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92
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Xu R, Bradley A. IURead: a new computer-based reading test. Ophthalmic Physiol Opt 2015; 35:500-13. [PMID: 26303446 DOI: 10.1111/opo.12233] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/06/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE To develop a computer-based single sentence reading test especially designed for clinical research enabling multiple repeat trials without reusing the same sentences. METHODS We initially developed 422 sentences, with an average of 60 characters and 12 words. Presentation controls were improved by employing computer-based testing and the oral reading was recorded by visual inspection of digital audio recordings. Variability in reading speed of normally sighted adults between sentences, between charts, between subjects, between formats, and between display devices was quantified. The impact of display size and pixel resolution on test geometry was assessed, and the impact of reduced retinal image quality and retinal illuminance were compared for reading and standard letter acuities. Eleven visually normal subjects (age: 18-60 years) participated in this study. RESULTS Stopwatch timing of sentences reliably underestimated reading times by about 0.3 s, and exhibited coefficients of repeatability 17 times larger than those estimated from visual inspection of digital recordings. A slight relaxing of the lexical content constraints had no effect on reading speed; neither did sentence format (single vs three lines) or display size or distance. Within subject standard deviations of reading speed for different sentences were small (between 6% and 9% of the mean speed) requiring only small samples sizes to achieve typical statistical reliability and power when comparing conditions within individual subjects. The greater variability associated with stopwatch timing necessitates larger sample sizes. As defocus and light level were varied, reading acuity and standard letter acuity were highly correlated (r(2) = 0.99), and reading acuity was slightly better. DISCUSSION A computer-based IURead reading test provides a useful reading speed and reading acuity tool for clinical research involving multiple conditions and repeat testing of individual subjects. Ready to use IURead files for use with a computer, tablet or cell phone can be downloaded from our lab website (https://www.opt.indiana.edu/Bradley/Downloads.aspx).
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Affiliation(s)
- Renfeng Xu
- Indiana University School of Optometry, Bloomington, USA
| | - Arthur Bradley
- Indiana University School of Optometry, Bloomington, USA
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Elliott DB, Hotchkiss J, Scally AJ, Foster R, Buckley JG. Intermediate addition multifocals provide safe stair ambulation with adequate 'short-term' reading. Ophthalmic Physiol Opt 2015; 36:60-8. [PMID: 26307152 PMCID: PMC4737269 DOI: 10.1111/opo.12236] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/24/2015] [Indexed: 11/30/2022]
Abstract
Purpose A recent randomised controlled trial indicated that providing long‐term multifocal wearers with a pair of distance single‐vision spectacles for use outside the home reduced falls risk in active older people. However, it also found that participants disliked continually switching between using two pairs of glasses and adherence to the intervention was poor. In this study we determined whether intermediate addition multifocals (which could be worn most of the time inside and outside the home and thus avoid continual switching) could provide similar gait safety on stairs to distance single vision spectacles whilst also providing adequate ‘short‐term’ reading and near vision. Methods Fourteen healthy long‐term multifocal wearers completed stair ascent and descent trials over a 3‐step staircase wearing intermediate and full addition bifocals and progression‐addition lenses (PALs) and single‐vision distance spectacles. Gait safety/caution was assessed using foot clearance measurements (toe on ascent, heel on descent) over the step edges and ascent and descent duration. Binocular near visual acuity, critical print size and reading speed were measured using Bailey‐Lovie near charts and MNRead charts at 40 cm. Results Gait safety/caution measures were worse with full addition bifocals and PALs compared to intermediate bifocals and PALs. The intermediate PALs provided similar gait ascent/descent measures to those with distance single‐vision spectacles. The intermediate addition PALs also provided good reading ability: Near word acuity and MNRead critical print size were better with the intermediate addition PALs than with the single‐vision lenses (p < 0.0001), with a mean near visual acuity of 0.24 ± 0.13 logMAR (~N5.5) which is satisfactory for most near vision tasks when performed for a short period of time. Conclusions The better ability to ‘spot read’ with the intermediate addition PALs compared to single‐vision spectacles suggests that elderly individuals might better comply with the use of intermediate addition PALs outside the home. A lack of difference in gait parameters for the intermediate addition PALs compared to distance single‐vision spectacles suggests they could be usefully used to help prevent falls in older well‐adapted full addition PAL wearers. A randomised controlled trial to investigate the usefulness of intermediate multifocals in preventing falls seems warranted.
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Affiliation(s)
- David B Elliott
- Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - John Hotchkiss
- Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - Andrew J Scally
- School of Allied Health Professions and Sport, Faculty of Health Studies, University of Bradford, Bradford, UK
| | - Richard Foster
- Sport, Health and Performance Enhancement (SHAPE) Research Group, Department of Sport Science, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - John G Buckley
- Division of Medical Engineering, Faculty of Engineering, University of Bradford, Bradford, UK
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Charman WN. Developments in the correction of presbyopia II: surgical approaches. Ophthalmic Physiol Opt 2014; 34:397-426. [PMID: 24716827 DOI: 10.1111/opo.12129] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/05/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To discuss the various static and dynamic surgical approaches which attempt to give presbyopes good vision at far, intermediate and near viewing distances. CONTENT Static methods broadly adopt the same optical techniques as those used in presbyopic contact lens correction and aim to satisfy the needs of the presbyope by increasing binocular depth-of-focus, often using monovision as well as simultaneous-imagery. Dynamic methods generally attempt to make use of at least some of the still-active elements of the accommodation system. They include procedures which are supposed to modify the relative geometry of the ciliary muscle and lens, or which reduce the stiffness of the presbyopic lens either by replacing it with other natural or man-made material or by subjecting it to femtosecond laser treatment. Alternatively the natural lens may be replaced by some form of intraocular lens which changes power as a result of forces derived from the still-active ciliary muscle, zonule and capsule, or other sources. CONCLUSIONS At present, multifocal intraocular lenses appear to offer the most consistent and reliable surgical approach to surgical presbyopic correction. They have obvious advantages in convenience and stability over optically-similar, simultaneous-image presbyopic contact lenses but this must be balanced against their relative inflexibility in cases of patient dissatisfaction. Dynamic methods remain largely experimental. Although some approaches show promise, as yet no method has demonstrated a reliable, long-term ability to correct distance refractive error and to appropriately change ocular power in response to changes in viewing distance over the normal range of interest.
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Affiliation(s)
- W Neil Charman
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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Stem Cells and the Ocular Lens: Implications for Cataract Research and Therapy. STEM CELL BIOLOGY AND REGENERATIVE MEDICINE 2014. [DOI: 10.1007/978-1-4939-0787-8_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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