Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

Heilman, Bianca Maceo; Manns, Fabrice; Ruggeri, Marco; Ho, Arthur; González, Alex; Rowaan, Cor; Bernal, Andres; Arrieta, Esdras; Parel, Jean Marie

doi:10.1167/iovs.17-23273

Cited by 4 publications

(4 citation statements)

References 31 publications

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“…Preliminary results obtained on a cynomolgus monkey lens suggest that peripheral lens defocus increases with field angle and simulated accommodation. These results are consistent with previous findings [45,54]. Peripheral lens defocus was measured with respect to a circular entrance pupil at all field angles, where field angles were defined in air.…”

supporting

confidence: 93%

“…Several optical techniques have been used to measure the shape, power or optical aberrations of the in vitro crystalline lens and their changes with age and simulated accommodation [2,25,30,31,[34][35][36][37][38][39][40][41][42][43][44]. In a recent study [45], we described a method based on optical ray tracing to estimate peripheral defocus along one meridian of the monkey crystalline lens.…”

Section: Introductionmentioning

confidence: 99%

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System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens

Ruggeri¹,

Williams²,

Heilman³

et al. 2018

Biomed. Opt. Express

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We present a new in vitro instrument for measuring shape and wavefront aberrations of the primate crystalline lens, both on-and off-axis, while simulating accommodation with a motorized lens stretching system. The instrument merges spectral domain optical coherence tomography (SD-OCT) imaging and ray tracing aberrometry using an approach that senses wavefront aberrations of the lens with the OCT probing beam. Accuracy and repeatability of aberration measurements were quantified. Preliminary experiments on two human and four cynomolgus monkey lenses demonstrate the ability of the system to measure the lens shape, spherical aberration and peripheral defocus, and their changes during simulated accommodation.

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supporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens

Ruggeri¹,

Williams²,

Heilman³

et al. 2018

Biomed. Opt. Express

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“…The effects of accommodation in peripheral refraction have been the subject of research in different studies conducted over the last few years [12,30,31,[40][41][42][43][44]. Lundstrom et al measured peripheral refractions at accommodative demands of 0.50 and 4.00 D and found that myopes did not show a consistent change in peripheral refractive profile while emmetropes became relatively more myopic in the periphery with accommodation [43].…”

Section: Discussionmentioning

confidence: 99%

Peripheral refraction of myopic eyes with spectacle lenses correction and lens free emmetropes during accommodation

2021

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Purpose To measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m (0.50 D) to 0.20 m (5.00 D) in terms of sphere, astigmatism, and spherical equivalent refraction. Methods Refraction was measured at the center, 20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field, binocular, infrared autorefractor (Grand Seiko WAM-5500, Hiroshima, Japan). Fixation target was a Maltese cross set at 2.00, 0.50, 0.33 and 0.20 m from the corneal plane. Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes. Results Off-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance. Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group. This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target. Conclusion Accommodation to very near targets (up to 0.20 m) makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes. A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.

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“…In an effort to get a better understanding of accommodation, the deformation behavior of the crystalline lens during accommodation has mostly been investigated by means of macroscopic changes in the lens thickness, diameter, and curvature assessed with diverse imaging techniques, including ultrasound ( Yoon et al, 2012 ; Zhang et al, 2018 ) and magnetic resonance ( Sheppard et al, 2011 ), but predominantly via optical imaging techniques (Purkinje, Scheimpflug, Optical Coherence Tomography). Other studies have examined the mechanical deformation behavior of the ex vivo crystalline lens under controlled loading conditions, such as during spinning ( Wilde et al, 2012 ; Reilly et al, 2016 ) or while mounted in a lens stretcher ( Marussich et al, 2015 ; Heilman et al, 2018 ; Martinez-Enriquez et al, 2020 ). Due to their ex vivo nature, most of these mechanical characterization studies on crystalline lenses have been conducted in human donor tissues.…”

Section: Introductionmentioning

confidence: 99%

Storage-induced mechanical changes of porcine lenses assessed with optical coherence elastography and inverse finite element modeling

Tahsini,

Gil,

Kling

2024

Front. Bioeng. Biotechnol.

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IntroductionIn an effort of gaining a better understanding of the lens mechanics, ex vivo lenses samples are often used. Yet, ex vivo tissue might undergo important postmortem changes depending on the unavoidable preservation method employed. The purpose of this study was to assess how various storage conditions and the removal of the lens capsule affect the mechanical properties of ex vivo porcine lens samples.MethodsA total of 81 freshly enucleated porcine eyes were obtained and divided into six groups and preserved differently. In the first three groups, the lens within the intact eye was preserved for 24 h by: (i) freezing at −80°C (n = 12), (ii) freezing at −20°C (n = 12), and (iii) refrigeration at +8°C (n = 12). In the remaining groups, the lenses were immediately extracted and treated as follows: (iv) kept intact, no storage (n = 12), (v) decapsulated, no storage (n = 21), and (vi) immersed in Minimum Essential Medium (MEM) at +8°C (n = 12) for 24 h. Frozen lenses were thawed at room temperature. Each lens was compressed between two glass lamella and subjected, first to a period of relaxation during which the compression force was recorded and second to an oscillating micro-compression while the deformation was recorded with a total of 256 subsequent B-scans via optical coherence tomography. The corresponding axial strain was retrieved via phase-sensitive image processing and subsequently used as input for an inverse finite element analysis (iFEA) to retrieve the visco-hyperelastic material properties of the lenses.ResultsAfter freezing at temperatures of −80°C and −20°C, the cortical strains increased by 14% (p = 0.01) and 34% (p < 0.001), and the nuclear strains decreased by 17% (p = 0.014) and 36% (p < 0.001), compared to the lenses tested immediately after postmortem, respectively. According to iFEA, this resulted from an increased ratio of the nuclear: cortical E-modulus (4.06 and 7.06) in −80°C and −20°C frozen lenses compared to fresh lenses (3.3). Decapsulation had the largest effect on the material constant C10, showing an increase both in the nucleus and cortex. Preservation of the intact eye in the refrigerator induced the least mechanical alterations in the lens, compared to the intact fresh condition.DiscussionCombining iFEA with optical coherence elastography allowed us to identify important changes in the lens mechanics induced after different preserving ex vivo methods.

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Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

Cited by 4 publications

References 31 publications

System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens

System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens

Peripheral refraction of myopic eyes with spectacle lenses correction and lens free emmetropes during accommodation

Storage-induced mechanical changes of porcine lenses assessed with optical coherence elastography and inverse finite element modeling

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