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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 2024:102156. [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] [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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Okon MD, Ma Y, Liu J, Roberts CJ. Changes in Central Corneal Thickness With Air-Puff-Induced Corneal Deformation Using a Method to Correct Scheimpflug and Refractive Distortion. J Refract Surg 2021; 37:422-428. [PMID: 34170774 DOI: 10.3928/1081597x-20210219-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To establish a method to determine central corneal thickness (CCT) and anterior chamber depth (ACD) of an air-puff-deformed cornea at the highest concavity (HC) state. METHODS The Fink method for refractive correction of Scheimpflug images of a convex pre-deformed (PRE) cornea was implemented for 155 eyes of 155 participants imaged with the Corvis ST (Oculus Optikgeräte GmbH). This method was subsequently modified for the HC state of deformation. The tracked edges of each participant's cornea were exported at the PRE and HC states. Ten participants who had a visible crystalline lens in the image were selected to determine ACD in both states. The center points on the corneal tracked edges and lens were used to determine uncorrected CCT and ACD, respectively. RESULTS Average undeformed CCTPRE was significantly lower than deformed CCTHC (584 ± 31 and 626 ± 34 µm, respectively) (P < .0001). No significant difference was found for the corrected ACD between the two states. Corrected CCT and ACD were significantly greater than the corresponding uncorrected values for both deformation states (P < .0001). Percent change in CCT was found to be correlated to change in arc length at HC (P < .0001). CONCLUSIONS Distortion in Corvis ST images at the HC state can be corrected using a modified Fink method. CCT was found to increase in the HC state, compared to the PRE state. The CCT change during deformation may be important in the study of the compressive response of the cornea. [J Refract Surg. 2021;37(6):422-428.].
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Ali MH, Javaid M, Jamal S, Butt NH. Femtosecond laser assisted cataract surgery, beginning of a new era in cataract surgery. Oman J Ophthalmol 2016; 8:141-6. [PMID: 26903717 PMCID: PMC4738656 DOI: 10.4103/0974-620x.169892] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The purpose of this article is to analyze and understand the mechanism of action, effectiveness, cost and time benefits, advantages and disadvantages of the femtosecond laser (FSL) assisted cataract surgery. A PubMed search was done using the topic and the keywords. Research shows considerable improvements in corneal incisions, anterior capsulotomy, and phacofragmentation using FSL. We will also discuss and compare FSL with conventional cataract extraction techniques in terms of both short-term and long-term advantages and disadvantages. Limitations of the studies reviewed include small sample size and short-term follow-up. The major dilemma is still considered to be its heavy financial feasibility to date.
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Affiliation(s)
- Muhammad Hassaan Ali
- Department of Ophthalmology, Allama Iqbal Medical College, Jinnah Hospital, Lahore, Pakistan
| | - Mamoona Javaid
- Department of Ophthalmology, Allama Iqbal Medical College, Jinnah Hospital, Lahore, Pakistan
| | - Samreen Jamal
- Department of Ophthalmology, Allama Iqbal Medical College, Jinnah Hospital, Lahore, Pakistan
| | - Nadeem Hafeez Butt
- Department of Ophthalmology, Allama Iqbal Medical College, Jinnah Hospital, Lahore, Pakistan
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Croft MA, McDonald JP, Katz A, Lin TL, Lütjen-Drecoll E, Kaufman PL. Extralenticular and lenticular aspects of accommodation and presbyopia in human versus monkey eyes. Invest Ophthalmol Vis Sci 2013; 54:5035-48. [PMID: 23745002 DOI: 10.1167/iovs.12-10846] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine if the accommodative forward movements of the vitreous zonule and lens equator occur in the human eye, as they do in the rhesus monkey eye; to investigate the connection between the vitreous zonule posterior insertion zone and the posterior lens equator; and to determine which components-muscle apex width, lens thickness, lens equator position, vitreous zonule, circumlental space, and/or other intraocular dimensions, including those stated in the objectives above-are most important in predicting accommodative amplitude and presbyopia. METHODS Accommodation was induced pharmacologically in 12 visually normal human subjects (ages 19-65 years) and by midbrain electrical stimulation in 11 rhesus monkeys (ages 6-27 years). Ultrasound biomicroscopy imaged the entire ciliary body, anterior and posterior lens surfaces, and the zonule. Relevant distances were measured in the resting and accommodated eyes. Stepwise regression analysis determined which variables were the most important predictors. RESULTS The human vitreous zonule and lens equator move forward (anteriorly) during accommodation, and their movements decline with age, as in the monkey. Over all ages studied, age could explain accommodative amplitude, but not as well as accommodative lens thickening and resting muscle apex thickness did together. Accommodative change in distances between the vitreous zonule insertion zone and the posterior lens equator or muscle apex were important for predicting accommodative lens thickening. CONCLUSIONS Our findings quantify the movements of the zonule and ciliary muscle during accommodation, and identify their age-related changes that could impact the optical change that occurs during accommodation and IOL function.
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Affiliation(s)
- Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53792-3220, USA.
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The Influence of Diabetes Mellitus Type 1 and 2 on the Thickness, Shape, and Equivalent Refractive Index of the Human Crystalline Lens. Ophthalmology 2008; 115:1679-86. [DOI: 10.1016/j.ophtha.2008.03.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 03/17/2008] [Accepted: 03/18/2008] [Indexed: 11/18/2022] Open
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Wiemer NGM, Dubbelman M, Hermans EA, Ringens PJ, Polak BCP. Changes in the internal structure of the human crystalline lens with diabetes mellitus type 1 and type 2. Ophthalmology 2008; 115:2017-23. [PMID: 18718668 DOI: 10.1016/j.ophtha.2008.06.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/25/2008] [Accepted: 06/25/2008] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To investigate the effect of diabetes mellitus (DM) type 1 and type 2 on the internal structure of the lens. DESIGN Observational cross-sectional study. PARTICIPANTS AND CONTROLS One hundred seven patients with DM type 1, 106 patients with DM type 2, and 75 healthy control subjects. METHODS Scheimpflug photography was used to image the lens of the right eye of 213 patients with DM and 75 healthy control subjects. The densitogram of the Scheimpflug image was used to indicate the nucleus and the different layers of the cortex of the lens. Lenses with cataract were excluded. MAIN OUTCOME MEASURES The size of the nucleus and the different layers of the cortex of the lens. RESULTS The nucleus and the different cortical layers of the DM type 1 lenses were significantly thicker compared with those of the control group (P<0.001). A significant association was found between the duration of DM type 1 and both the anterior and posterior cortex, its different layers, and the nucleus (P<0.001). The increase in the anterior and posterior cortex with the duration of DM was comparable with that of the nucleus. No important differences in the internal structure of the lens were found between the patients with DM type 2 and the control group. CONCLUSIONS Diabetes mellitus type 1 has a significant effect on the internal structure of the lens. The difference in effect of DM type 1 and type 2 on internal lens structure suggests an essential difference in pathogenesis. Furthermore, the results of the present study may indicate that the increase in the size of the lens with DM type 1 is the result of a generalized swelling of the lens, affecting all its different parts.
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Affiliation(s)
- Nanouk G M Wiemer
- Department of Ophthalmology, VU University Medical Center, Amsterdam, The Netherlands
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Fink W, Micol D. simEye: Computer-based simulation of visual perception under various eye defects using Zernike polynomials. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:054011. [PMID: 17092160 DOI: 10.1117/1.2357734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We describe a computer eye model that allows for aspheric surfaces and a three-dimensional computer-based ray-tracing technique to simulate optical properties of the human eye and visual perception under various eye defects. Eye surfaces, such as the cornea, eye lens, and retina, are modeled or approximated by a set of Zernike polynomials that are fitted to input data for the respective surfaces. A ray-tracing procedure propagates light rays using Snell's law of refraction from an input object (e.g., digital image) through the eye under investigation (i.e., eye with defects to be modeled) to form a retinal image that is upside down and left-right inverted. To obtain a first-order realistic visual perception without having to model or simulate the retina and the visual cortex, this retinal image is then back-propagated through an emmetropic eye (e.g., Gullstrand exact schematic eye model with no additional eye defects) to an output screen of the same dimensions and at the same distance from the eye as the input object. Visual perception under instances of emmetropia, regular astigmatism, irregular astigmatism, and (central symmetric) keratoconus is simulated and depicted. In addition to still images, the computer ray-tracing tool presented here (simEye) permits the production of animated movies. These developments may have scientific and educational value. This tool may facilitate the education and training of both the public, for example, patients before undergoing eye surgery, and those in the medical field, such as students and professionals. Moreover, simEye may be used as a scientific research tool to investigate optical lens systems in general and the visual perception under a variety of eye conditions and surgical procedures such as cataract surgery and laser assisted in situ keratomileusis (LASIK) in particular.
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Affiliation(s)
- Wolfgang Fink
- California Institute of Technology, Visual and Autonomous Exploration Systems Research Laboratory, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA.
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