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Vision
Special Issues
Physiological Optics of Accommodation and Presbyopia
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Physiological Optics of Accommodation and Presbyopia

A special issue of Vision (ISSN 2411-5150).

Deadline for manuscript submissions: closed (15 April 2019) | Viewed by 21982

Special Issue Editors

Prof. Dr. Leon N. Davies

E-Mail Website
Guest Editor
School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
Interests: physiological optics of accommodation and presbyopia; intraocular lens (IOL) technology; ocular biometry; ophthalmic instrumentation; myopia; visual function following stroke
Dr. Amy L. Sheppard

E-Mail Website
Guest Editor
School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
Interests: ciliary muscle and refractive error; accommodation; presbyopia; biometry; imaging the accommodative apparatu

Special Issue Information

Dear Colleagues,

In this Special Issue, entitled "Physiological Optics of Accommodation and Presbyopia", recent advances in the field will be covered, with a combination of original empirical research and review articles on the following topics:

  • Optics of accommodation and presbyopia

  • Binocular visual function in accommodation and presbyopia

  • Advances in imaging the accommodative structures

  • In vitro and non-human models of accommodation and presbyopia

  • Preservation of accommodative function and risk factors for onset/progression of presbyopia

  • Developments in restoring dynamic accommodation

  • Progress in optical and static surgical methods to correct near vision

  • Theoretical basis of accommodation and presbyopia

Review articles will be invited, although we welcome expressions of interest for further review articles and original studies on topics allied to those listed. Please contact us if you have any queries.

Prof. Dr. Leon N. Davies
Dr. Amy L. Sheppard
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Vision is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • accommodation

  • presbyopia

  • imaging

  • visual function

  • correction of presbyopia

  • restoring near function

  • optics

  • binocular vision

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Published Papers (5 papers)

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Research

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14 pages, 3350 KiB  
Article
Factors Influencing Pseudo-Accommodation—The Difference between Subjectively Reported Range of Clear Focus and Objectively Measured Accommodation Range
by Sandeep K. Dhallu, Amy L. Sheppard, Tom Drew, Toshifumi Mihashi, Juan F. Zapata-Díaz, Hema Radhakrishnan, D. Robert Iskander and James S. Wolffsohn
Vision 2019, 3(3), 34; https://doi.org/10.3390/vision3030034 - 28 Jun 2019
Cited by 9 | Viewed by 4281
Abstract
The key determinants of the range of clear focus in pre-presbyopes and their relative contributions to the difference between subjective range of focus and objective accommodation assessments have not been previously quantified. Fifty participants (aged 33.0 ± 6.4 years) underwent simultaneous monocular subjective [...] Read more.
The key determinants of the range of clear focus in pre-presbyopes and their relative contributions to the difference between subjective range of focus and objective accommodation assessments have not been previously quantified. Fifty participants (aged 33.0 ± 6.4 years) underwent simultaneous monocular subjective (visual acuity measured with an electronic test-chart) and objective (dynamic accommodation measured with an Aston open-field aberrometer) defocus curve testing for lenses between +2.00 to −10.00 DS in +0.50 DS steps in a randomized order. Pupil diameter and ocular aberrations (converted to visual metrics normalized for pupil size) at each level of blur were measured. The difference between objective range over which the power of the crystalline lens changes and the subjective range of clear focus was quantified and the results modelled using pupil size, refractive error, tolerance to blur, and ocular aberrations. The subjective range of clear focus was principally accounted for by age (46.4%) and pupil size (19.3%). The objectively assessed accommodative range was also principally accounted for by age (27.6%) and pupil size (15.4%). Over one-quarter (26.0%) of the difference between objective accommodation and subjective range of clear focus was accounted for by age (14.0%) and spherical aberration at maximum accommodation (12.0%). There was no significant change in the objective accommodative response (F = 1.426, p = 0.229) or pupil size (F = 0.799, p = 0.554) of participants for levels of defocus above their amplitude of accommodation. Pre-presbyopes benefit from an increased subjective range of clear vision beyond their objective accommodation due in part to neural factors, resulting in a measured depth-of-focus of, on average, 1.0 D. Full article
(This article belongs to the Special Issue Physiological Optics of Accommodation and Presbyopia)
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11 pages, 882 KiB  
Article
Cognitive Demand and Accommodative Microfluctuations
by Niall J. Hynes, Matthew P. Cufflin, Karen M. Hampson and Edward A. H. Mallen
Vision 2018, 2(3), 36; https://doi.org/10.3390/vision2030036 - 6 Sep 2018
Cited by 6 | Viewed by 4408
Abstract
Previous studies have shown cognition to have an influence on accommodation. Temporal variation in the accommodative response occurs during the fixation on a stationary target. This constantly shifting response has been called accommodative micro-fluctuations (AMFs). The aim of this study is to determine [...] Read more.
Previous studies have shown cognition to have an influence on accommodation. Temporal variation in the accommodative response occurs during the fixation on a stationary target. This constantly shifting response has been called accommodative micro-fluctuations (AMFs). The aim of this study is to determine the effects of increasing task cognitive demand on the ocular accommodation response. AMFs for 12 myopes and 12 emmetropes were measured under three conditions of varying cognitive demand and comprising reading of numbers (Num), simple arithmetic (SA), and complex arithmetic (CA). Fast Fourier transforms were used to analyze the different frequency band components of the AMFs. Other aspects of AMFs including root mean square accommodation values and chaos analysis was applied. A repeated measures ANOVA revealed a significant main effect of cognition in the mean power of the high frequency component (HFC) (F2,44 = 10.03, p < 0.005). Pairwise analyses revealed that these differences exist between SA and CA tasks (p < 0.005) and the Num and CA (p < 0.005) tasks with the HFC power being the highest for the CA condition. It appears that the difficulty of a task does affect active accommodation but to a lesser extent than other factors affecting accommodation. Full article
(This article belongs to the Special Issue Physiological Optics of Accommodation and Presbyopia)
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14 pages, 4661 KiB  
Article
Validation of Novel Metrics from the Accommodative Dynamic Profile
by Nicola Szostek, Hetal Buckhurst, Christine Purslow, Thomas Drew, Avril Collinson and Phillip Buckhurst
Vision 2018, 2(3), 34; https://doi.org/10.3390/vision2030034 - 21 Aug 2018
Cited by 3 | Viewed by 3985
Abstract
Objective and subjective methods of assessing time taken for accommodative change (ToAC) include accommodative dynamics (AD) and accommodative facility (AF). This study investigates the validity of novel metrics derived from the AD-profile and explores their relationship with AF. AD were assessed using a [...] Read more.
Objective and subjective methods of assessing time taken for accommodative change (ToAC) include accommodative dynamics (AD) and accommodative facility (AF). This study investigates the validity of novel metrics derived from the AD-profile and explores their relationship with AF. AD were assessed using a modified open-field autorefractor in 43 healthy adults. Non-linear regression curves were fitted to the data to derive: latency-of-accommodation (nLoA) and -disaccomodation (nLoD), Time-for-accommodation (ToA) and -disaccommodation (ToD), and objective-ToAC (oToAC). Latencies were also calculated through visual inspection of the AD data as in previous studies (pLoA and pLoD). AF was used to assess subjective-ToAC. Statistical analysis explored the relationships between the AD-metrics and AF. Subjects were assessed on three visits to examine intra- and inter-observer repeatability. nLoA and nLoD were greater than pLoA (p = 0.001) and pLoD (p = 0.004) respectively. nLoA and nLoD also demonstrated greater intra- and inter-observer repeatability than pLoA and pLoD. AF demonstrated a moderate, inverse correlation with ToA (p = 0.02), ToD (p = 0.007), and oToAC (p = 0.007). ToD was the single best accommodative predictor of AF (p = 0.011). The novel method for deriving latency was more repeatable, but not interchangeable with the techniques used in previous studies. ToD was the most repeatable metric with the greatest association with AF. Full article
(This article belongs to the Special Issue Physiological Optics of Accommodation and Presbyopia)
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13 pages, 1125 KiB  
Article
Optical Coherence Tomography Reveals Sigmoidal Crystalline Lens Changes during Accommodation
by George A. Gibson, Fiona E. Cruickshank, James S. Wolffsohn and Leon N. Davies
Vision 2018, 2(3), 33; https://doi.org/10.3390/vision2030033 - 21 Aug 2018
Cited by 3 | Viewed by 3811
Abstract
This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18–25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) [...] Read more.
This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18–25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) images were captured along the 180° meridian (Visante, Zeiss Meditec, Jena, Germany) under stimulated accommodative demands (0–4 D). Images were analysed and lens thickness (LT) was measured, applying a refractive index correction of 1.00. Accommodative responses were also measured sequentially through a Badal optical system fitted to an autorefractor (Shin Nippon NVision-K 5001, Rexxam, Japan). Data were compared with Dubbelman schematic eye calculations. Significant changes occurred in LT, anterior chamber depth (ACD), lens centroid (i.e., ACD + LT/2), and AS length (ASL = ACD + LT) with accommodation (all p < 0.01). There was no significant change in CT with accommodation (p = 0.81). Measured CT, ACD, and lens centroid values were similar to Dubbelman modelled parameters, however AS-OCT overestimated LT and ASL. As expected, the accommodative response was less than the demand. Interestingly, up until approximately 1.5 D of response (2.0 D demand), the anterior crystalline lens surface appears to be the primary correlate. Beyond this point, the posterior lens surface moves posteriorly resulting in an over-all sigmoidal trajectory. he posterior crystalline lens surface demonstrates a sigmoidal response with increasing accommodative effort. Full article
(This article belongs to the Special Issue Physiological Optics of Accommodation and Presbyopia)
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Review

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9 pages, 1443 KiB  
Review
A Review of Depth of Focus in Measurement of the Amplitude of Accommodation
by David H. Burns, Peter M. Allen, David F. Edgar and Bruce J. W. Evans
Vision 2018, 2(3), 37; https://doi.org/10.3390/vision2030037 - 6 Sep 2018
Cited by 14 | Viewed by 4565
Abstract
The aim of this review is to investigate the role of depth of focus (DoF) as a potential confounding variable in the measurement of the amplitude of accommodation (AoA). The role of DoF in human vision is briefly summarised, and it is noted [...] Read more.
The aim of this review is to investigate the role of depth of focus (DoF) as a potential confounding variable in the measurement of the amplitude of accommodation (AoA). The role of DoF in human vision is briefly summarised, and it is noted that the prevalent method of measuring AoA is the push-up method. Factors influencing the effect of DoF on the push-up and other methods of measuring AoA are reviewed in detail. DoF is shown to add substantial measurement error in the routine assessment of accommodation when the AoA is measured by methods involving subjective judgement of an object’s clarity. Reliable compensation for this source of error is not realistically possible because of the complexity of the aetiology of DoF, and its inter-individual and intra-individual variation. The method of measurement also influences the extent of the error. It is concluded that methods of measurement of AoA that exclude DoF should be preferred. Full article
(This article belongs to the Special Issue Physiological Optics of Accommodation and Presbyopia)
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