In vivo measurement of the human crystalline lens equivalent refractive index using extended-depth OCT

Chang, Yeon S.; Mesquita, Gabrielle Monterano; Williams, Siobhan; Gregori, Giovanni; Cabot, Florence; Ho, Arthur; Ruggeri, Marco; Yoo, Sonia H.; Parel, Jean Marie; Manns, Fabrice

doi:10.1364/boe.10.000411

Cited by 23 publications

(24 citation statements)

References 32 publications

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“…Previous and our study showed that the ACD significantly increased and the LT significantly decreased after cycloplegia, including the elderly. 17 – 19 Our results of an increase in ALR (<60 years) after cycloplegia corresponded with the results shown by Zhang et al (31.05 ± 5.84 years, +0.609 mm). 28 Changes in ALR in subjects older than 60 years were not statistically significant.…”

Section: Discussionsupporting

confidence: 92%

“…11 , 18 , 21 Despite Chang et al and Kasthurirangan et al suggested that the PLR increases with age, whereas most previous studies and our study agreed that the PLR is not related with age. 9 , 19 Most studies did not find age-dependent changes of LV, but our study noted that the LV increases with age (+0.009 mm/y before and after cycloplegia). Römkens et al and Gavin et al also found the positive correlation between the LV and age; however, they only included subjects older than 40 years.…”

Section: Discussioncontrasting

confidence: 53%

See 1 more Smart Citation

Effect of age and cycloplegia on the morphology of the human crystalline lens: swept-source OCT study

Huang

et al. 2022

J Cataract Refract Surg

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Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 53%

Effect of age and cycloplegia on the morphology of the human crystalline lens: swept-source OCT study

Huang

et al. 2022

J Cataract Refract Surg

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“…Figure 1 shows the dimensions of the different components of the FE model in the non-accommodated state standardised for a 29-year-old subject. Lens dimensions were obtained from the OCT study of Chang et al, 27 with a radius of curvature of the anterior (r a ) and posterior (r p ) lens surfaces of 11.00 and 6.10 mm, respectively, sagittal thickness of the lens (T L ) of 3.44 mm and an anterior chamber depth (ACD) of 3.03 mm. As the lens equatorial diameter cannot be obtained by OCT, it was extracted from the MRI work of Kasthurirangan et al 29 with the value of 9.04 mm being obtained.…”

Section: Finite Element Modelmentioning

confidence: 99%

A validated finite element model to reproduce Helmholtz’s theory of accommodation: a powerful tool to investigate presbyopia

Cabeza-Gil

Grasa

Calvo

2021

Ophthalmic Physiologic Optic

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Accommodation is a dynamic change in the dioptric power of the eye that allows a change in focus from distant to near objects. This process is achieved by changing the shape of the lens, following contraction of the ciliary muscle, thereby releasing the zonular tension around the lens equator, according to the widely accepted accommodation theory of Helmholtz. 1 Numerous authors have confirmed this theory over time, including Fincham, 2 who demonstrated the ability of the elastic lens to round up after the release of zonular tension, and Glasser and Kaufmann, 3 who showed relaxation of the zonules due to ciliary muscle contraction along with other investigators. 4 The ciliary muscle is the engine that drives the accommodation process. It consists of three groups of muscle fibres (i.e., longitudinal, radial and circular), although their

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“…In the crystalline lens, horizontal radius is steeper than the vertical one. Furthermore, cortical lamella is mostly not concentric so it makes some different refractive indexes in the different meridians of the crystalline lens 16,19. Astigmatisms that are iatrogenic or related to some illnesses usually have a greater dioptric power and are more irregular.…”

Section: Different Classifications Of Astigmatismmentioning

confidence: 99%

<p>Posterior corneal astigmatism: a review article</p>

Mohammadi¹,

Khorrami-Nejad²,

Hamidirad³

2019

OPTO

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Most human eyes show at least a small degree of corneal astigmatism and it can arise from both surfaces of the cornea. The shape of the anterior corneal surface provides no definitive basis for knowing the toricity of the posterior surface. In the previous studies, average astigmatism of the posterior corneal surface was −0.26 to −0.78 diopter. The radius of the posterior corneal surface is less than the radius of the anterior corneal surface. Most studies have found a clear correlation between the anterior and posterior corneal asphericities and the asphericity of the posterior surface is independent of the vertex radius of curvature, refractive error and gender. In contrast to the anterior corneal surface, the asphericity of the posterior corneal surface varies significantly between meridians. The anterior and posterior corneal surface would have approximately parallel principal meridians and both of these surfaces are often flatter in the horizontal meridian than the vertical one. This is especially true in the higher degrees of corneal astigmatism, and then about 10% of any anterior corneal astigmatism is neutralized by an astigmatism arising from the posterior corneal surface. Although the second corneal surface only contributes to about 10% of the total refractive power of the eye, a precise knowledge of its morphology is needed for the correct diagnosis and monitoring the corneal diseases or the surgical interventions and in many eyes neglecting the posterior corneal surface measurement may lead to significant deviations from the corneal astigmatism estimation. In this article, we have reviewed the shape and the toricity of the posterior corneal surface and also the effect of age on it. We investigated the contribution of posterior corneal astigmatism to the total corneal astigmatism and evaluated the accuracy of corneal astigmatism estimation by neglecting the posterior corneal surface measurement.

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In vivo measurement of the human crystalline lens equivalent refractive index using extended-depth OCT

Cited by 23 publications

References 32 publications

Effect of age and cycloplegia on the morphology of the human crystalline lens: swept-source OCT study

Effect of age and cycloplegia on the morphology of the human crystalline lens: swept-source OCT study

A validated finite element model to reproduce Helmholtz’s theory of accommodation: a powerful tool to investigate presbyopia

<p>Posterior corneal astigmatism: a review article</p>

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