Lens Shape and Refractive Index Distribution in Type 1 Diabetes

Adnan, Md.; Pope, J. H.; Sepehrband, Farshid; Suheimat, Marwan; Verkicharla, Pavan K.; Kasthurirangan, Sanjeev; Atchison, David A.

doi:10.1167/iovs.15-16430

Cited by 21 publications

(27 citation statements)

References 14 publications

(26 reference statements)

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“…In Type 1 diabetes, lens thickness increases, and the lens surface radii of curvature are reduced (Adnan et al, 2015b). MRI images suggest that, in addition to an increase in lens thickness, diabetes is associated with a reduction in equatorial diameter so that, in effect, diabetic lenses become more spherical (Adnan et al, 2015a). In a comparative analysis of lens biometry in patients with Type 1 or Type 2 diabetes, lens thickening was observed in Type 1 patients only (Wiemer et al, 2008b).…”

Section: Molecular Genetic Insights Into Lens Growth Regulationmentioning

confidence: 99%

The lens growth process

Bassnett

Šikić

2017

Progress in Retinal and Eye Research

102

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The factors that regulate the size of organs to ensure that they fit within an organism are not well understood. A simple organ, the ocular lens serves as a useful model with which to tackle this problem. In many systems, considerable variance in the organ growth process is tolerable. This is almost certainly not the case in the lens, which in addition to fitting comfortably within the eyeball, must also be of the correct size and shape to focus light sharply onto the retina. Furthermore, the lens does not perform its optical function in isolation. Its growth, which continues throughout life, must therefore be coordinated with that of other tissues in the optical train. Here, we review the lens growth process in detail, from pioneering clinical investigations in the late nineteenth century to insights gleaned more recently in the course of cell and molecular studies. During embryonic development, the lens forms from an invagination of surface ectoderm. Consequently, the progenitor cell population is located at the surface and differentiated cells are confined to the interior. The interactions that regulate cell fate thus occur within the obligate ellipsoidal geometry of the lens. In this context, mathematical models are particularly appropriate tools with which to examine the growth process. In addition to identifying key growth determinants, such models constitute a framework for integrating cell biological and optical data, helping clarify the relationship between gene expression in the lens and image quality at the retinal plane.

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Section: Molecular Genetic Insights Into Lens Growth Regulationmentioning

confidence: 99%

The lens growth process

Bassnett

Šikić

2017

Progress in Retinal and Eye Research

102

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“…Full details of the image processing have been described elsewhere [13]. Due to motion and blinking in some participants, MSE images and hence refractive index maps suffered from artefacts.…”

Section: Mri -Data Processingmentioning

confidence: 99%

“…Further details of this procedure together with typical examples of the refractive index profiles obtained for individual lenses can be found in Fig. 2 of our previous publication [13]. As MSE images had in-plane resolution of 0.25 mm and slice thickness of 2 mm, this gave an effective voxel size of 0.375 mm 3 (3 × 0.25 × 0.25 × 2).…”

Section: Mri -Data Processingmentioning

confidence: 99%

Change in human lens dimensions, lens refractive index distribution and ciliary body ring diameter with accommodation

Khan

Pope

Verkicharla

et al. 2018

Biomed. Opt. Express

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Abstract:We investigated changes in ciliary body ring diameter, lens dimensions and lens refractive index distributions with accommodation in young adults. A 3T clinical magnetic resonance imaging scanner imaged right eyes of 38 18-29 year old participants using a multiple spin echo sequence to determine accommodation-induced changes along lens axial and equatorial directions. Accommodation stimuli were approximately 1 D and 5 D. With accommodation, ciliary body ring diameter, and equatorial lens diameter decreased (-0.43 ± 0.31 mm and -0.30 ± 0.23 mm, respectively), and axial lens thickness increased ( + 0.34 ± 0.16 mm). Lens shape changes cause redistribution of the lens internal structure, leading to change in refractive index distribution profiles. With accommodation, in the axial direction refractive index profiles became flatter in the center and steeper near the periphery of the lens, while in the equatorial direction they became steeper in the center and flatter in the periphery. The results suggest that the anatomical accuracy of lens optical models can be improved by accounting for changes in the refractive index profile during accommodation.

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“…The lens dimensions were obtained from an in vivo magnetic resonance imaging (MRI) study on healthy and diabetic participants, from which the former data set was selected. 21 The dimensions for both the 28-and 46-year-old lens were based on the control groups in a study about the lens shape and refractive index distribution in type 1 diabetes. There was no available data for the dimensions of a 7-year-old lens.…”

Section: Geometrical Model Of the Lensmentioning

confidence: 99%