Accommodation of the human lens capsule using a finite element model based on nonlinear regionally anisotropic biomembranes

David, Guido; Pedrigi, Ryan M.; Humphrey, Jay D.

doi:10.1080/10255842.2016.1228907

Cited by 23 publications

(21 citation statements)

References 45 publications

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“…1,2 While the etiology of this condition is not fully elucidated, recent research suggests that an increase in lens rigidity is the primary causative mechanism. 3,4 Although corrective measures are available to restore near vision, access to treatment (most often in the form of reading glasses) is limited in some parts of the world. In 2015, 826 million of the 1.8 billion people estimated to have functional presbyopia were found to be living with uncorrected near vision impairment because they had no access to vision correction or were utilizing inadequate correction.…”

Section: Introductionmentioning

confidence: 99%

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Presbyopia – A Review of Current Treatment Options and Emerging Therapies

Katz¹,

Karpecki²,

Dorca³

et al. 2021

OPTH

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Presbyopia is a common age-related vision disorder characterized by a progressive inability to focus on near objects. If uncorrected or under-corrected, presbyopia can significantly impact patients' quality of life. Presbyopia represents an area of considerable unmet need due to its rising prevalence worldwide as the population ages, the high proportion of under-treated individuals in some parts of the world, and the limitations of currently available corrective methods. Progressive or bifocal spectacles are associated with peripheral blur, a restricted visual field and impaired depth perception, which have been linked to an increased risk of falls in the elderly. Contact lens options can be difficult to maintain due to the development of age-related dry eye symptoms and reduced manual dexterity. Other corrective methods involve surgical interventions that modify the optics of the cornea, replace the crystalline lens, or attempt to restore active accommodation. While patients undergoing surgery report satisfactory outcomes post-operatively, many of them eventually require reading glasses. Non-invasive therapies with novel mechanisms of action are currently being investigated; these include miotic agents and UNR844, a lipoic acid choline ester. In this narrative review, available evidence on presbyopia prevalence, quality of life impact and risk factors are described, with a focus on observational studies in nonclinical settings. The diagnosis pathway and patient journey in presbyopia are outlined, and various treatment options are analyzed. The data reviewed herein reveals significant gaps in the provision of vision correction for this common condition, with a paucity of effective, non-invasive treatment options broadly accessible to presbyopic individuals.

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Section: Introductionmentioning

confidence: 99%

“… 1 , 2 While the etiology of this condition is not fully elucidated, recent research suggests that an increase in lens rigidity is the primary causative mechanism. 3 , 4 …”

Section: Introductionmentioning

confidence: 99%

Presbyopia – A Review of Current Treatment Options and Emerging Therapies

Katz¹,

Karpecki²,

Dorca³

et al. 2021

OPTH

View full text Add to dashboard Cite

show abstract

“…On the basis of these experiments, fi nite element models were considered for calculating the shape of the lens and the functioning of the accommodation mechanism [15][16][17][18][19][20][21][22].…”

Section: Discussionmentioning

confidence: 99%

“…Taking into account all the above, it is now clear how correct the widely used schemes for fi xing the lens in the eye with the cross-location of FPF and PPF should be (Figure 17a) [76,77]. Therefore, many researchers today understand how important it is to observe adequate boundary conditions when performing mechanical calculations of the lens shape in various phases of accommodation [20,22,76,77].…”

Section: Biomechanical Interaction Of the Elastic Lens Capsule With The Fi Bers Of The Zonula Of Zinn In Different Phases Of Accommodatiomentioning

confidence: 99%

Theory: Morphological and functional features of the structure of the Zonula Lens Fibers as a key executive link in the mechanism of the human eye accommodation

Koshits¹,

Svetlova²,

Egemberdiev³

et al. 2020

J Clin Res Ophthalmol

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Purpose: Assess morphophysiological and functional features of the structure of the zonula lens fi bers on the basis of an in-depth analysis consistent with the laws of mechanics. Defi ne the purpose and scope of each portion of the zonula lens fi bers. To analyze the results of the research of studies on the structure of the zonula of Zinn in the different authors of the last two centuries. Identify misconceptions about the work of this executive mechanism of accommodation in different phases of accommodation, this includes the uneven accommodation in different meridians. Determine the incorrectness of those theories of accommodation, which are based on erroneous ideas about the functioning of different portions of the zonula fi bers.Methods: Theoretical analysis based on the laws of mechanics and assessment of the results of interdisciplinary research by different authors in the fi eld of structural and functional features of the Zinn's zonule of the lens in different phases of accommodation.Results: The lens's ciliary belt has been found to have three major portions of fi ber that perform different functions. Powerful anterior portion of fi bers is attached to the anterior surface of the lens bag in a segmented mannered a powerful posterior portion of fi bers is attached to the posterior surface of the lens evenly around the circumference and like a cobweb covering the surface of the vitreous chamber. Both these fi laments in the eye don't cross and in all phases of accommodation remain

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“…The balance between order and disorder in the lens capsule leads to a range of complex mechanical properties which may have significant consequences for human visual function, and which have been a topic of research from different perspectives for over a century 3 . Furthermore, the structure of collagen biopolymer networks changes over time, leading to the lens capsule stiffening and consequentially causing a loss of ability to accommodate different focal depths 4,5 .…”

Section: Introductionmentioning

confidence: 99%

Simulation of Defects, Flexibility and Rupture in Biopolymer Networks

Bailey

Wilson

2021

Preprint

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Networks of biopolymers occur often in nature, and are vulnerable to damage over time. In this work, a coarse grained model of collagen IV molecules is applied in a 2D hexagonal network and the mechanisms by which these networks can rupture are explored. The networks are stretched linearly in order to study their structural limits and mechanism of rupture over timescale of up to 100 microseconds. Metrics are developed to track the damage networks suffer over time, and qualitatively analyse ruptures that occur. Further simulations repeatedly stretch the networks sinusoidally to mimic the in vivo strains. Defects of increasing levels of complexity are introduced into an ordered network, and their effect on the rupturing behaviour of the biopolymer networks studied. The effect of introducing holes of varying size in the network, as well as strips of finite width to mimic surgical damage are studied. These demonstrate the importance of the flexibility of the networks to preventing damage.

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Accommodation of the human lens capsule using a finite element model based on nonlinear regionally anisotropic biomembranes

Cited by 23 publications

References 45 publications

Presbyopia – A Review of Current Treatment Options and Emerging Therapies

Presbyopia – A Review of Current Treatment Options and Emerging Therapies

Theory: Morphological and functional features of the structure of the Zonula Lens Fibers as a key executive link in the mechanism of the human eye accommodation

Simulation of Defects, Flexibility and Rupture in Biopolymer Networks

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