Static and dynamic crystalline lens accommodation evaluated using quantitative 3-D OCT

Gambra, Enrique; Ortíz, Sergio; Pérez-Merino, Pablo; Gora, Michalina J.; Wojtkowski, Maciej; Marcos, Susana

doi:10.1364/boe.4.001595

Cited by 41 publications

(50 citation statements)

References 48 publications

(28 reference statements)

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“…8(c) and 8(d)). The ranges of radii of curvature, ACD and lens thickness in the accommodated state, as well as their change with accommodative demand, are consistent with those reported in the literature [35]. On average, the standard deviation across subjects and accommodative states in axial distances were 0.028 mm in ACD and 0.027 mm in lens thickness.…”

Section: Changes In Anterior Segment Geometry and Biometry With Accomsupporting

confidence: 88%

“…In previous studies, we described image-processing tools for distortion correction, denoising, segmentation and merging of volumes [27][28][29][30][32][33][34][35]. The quantification capabilities of the OCT have been validated ex vivo with artificial model eyes with known dimensions, and in vivo comparing with other imaging techniques (videokeratography, Scheimpflug and non-contact profilometry) [30].…”

Section: Oct Image Processingmentioning

confidence: 99%

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OCT-based crystalline lens topography in accommodating eyes

Pérez-Merino¹,

Velasco-Ocaña²,

Martinez-Enriquez³

et al. 2015

Biomed. Opt. Express

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Custom Spectral Domain Optical Coherence Tomography (SD-OCT) provided with automatic quantification and distortion correction algorithms was used to measure anterior and posterior crystalline lens surface elevation in accommodating eyes and to evaluate relationships between anterior segment surfaces. Nine young eyes were measured at different accommodative demands. Anterior and posterior lens radii of curvature decreased at a rate of 0.78 ± 0.18 and 0.13 ± 0.07 mm/D, anterior chamber depth decreased at 0.04 ± 0.01 mm/D and lens thickness increased at 0.04 ± 0.01 mm/D with accommodation. Threedimensional surface elevations were estimated by subtracting best fitting spheres. In the relaxed state, the spherical term accounted for most of the surface irregularity in the anterior lens (47%) and astigmatism (70%) in the posterior lens. However, in accommodated lenses astigmatism was the predominant surface irregularity (90%) in the anterior lens. The RMS of high-order irregularities of the posterior lens surface was statistically significantly higher than that of the anterior lens surface (x2.02, p<0.0001). There was significant negative correlation in vertical coma (Z 3 1 ) and oblique trefoil (Z 3 3 ) between lens surfaces. The astigmatic angle showed high degree of alignment between corneal surfaces, moderate between corneal and anterior lens surface (~27 deg), but differed by ~80 deg between the anterior and posterior lens surfaces (including relative anterior/posterior lens astigmatic angle shifts, 10-20 deg).

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Section: Changes In Anterior Segment Geometry and Biometry With Accomsupporting

confidence: 88%

Section: Oct Image Processingmentioning

confidence: 99%

OCT-based crystalline lens topography in accommodating eyes

Pérez-Merino¹,

Velasco-Ocaña²,

Martinez-Enriquez³

et al. 2015

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…Use of anterior segment spectral domain OCT effectively gives a time series of meridional sections of the anterior eye. After correction for refractive distortion effects, measurement in each section of surface curvatures and separations, together with the assumption of a suitable eye model, allows an estimate of the instantaneous ocular power to be made …”

Section: Later Workmentioning

confidence: 99%

Microfluctuations in accommodation: an update on their characteristics and possible role

Charman

Heron

2015

Ophthalmic Physiologic Optic

113

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Purpose: Following the recognition, some 80 years ago, that the accommodation of the eye is not stable but fluctuates over a range of about AE0.5 D, mainly at frequencies of up to a few Hz, there has been a continuing interest in the characteristics of these microfluctuations (MFs) and their possible role in the control of accommodation. This paper reviews relevant work carried out since 1988, when we previously reviewed the same topic (Charman WN, Heron G. Fluctuations in accommodation: a review. Ophthalmic Physiol Opt 1988; 8: 153-164). Recent findings: Studies relating to the effects on the MFs of stimulus form, luminance and vergence are described, together with those of pupil diameter, age and ametropia. Important advances in the understanding of the links between the characteristics of the MFs and those of the cardiopulmonary system, higher-order aberrations and ocular depth-of-focus are outlined. Only limited progress has been made in understanding the role of MFs in accommodation control. Summary: While the dependence of the characteristics of the MFs in relation to observing conditions is now reasonably well understood, their involvement in accommodation control still needs clarification. The current consensus appears to be that any role is more likely to be concerned with maintaining an appropriate response, rather than in initiating responses to abrupt changes in stimulus vergence. Fluctuations at lower temporal frequencies (<0.6 Hz) are probably important to the control process, which may make use of the associated changes in the contrast and spatial frequency spectrum of the retinal image.

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“…The lens surface radii of curvature, and their changes with age and accommodation have been extensively measured both ex vivo, using, among other techniques, shadowphotography [11] and Optical Coherence Tomography (OCT) [12,13], and in vivo, using Purkinje imaging [14][15][16], Scheimpflug imaging [14,17], magnetic Resonance Imaging [18,19] and OCT [20]. Data ex vivo and in vivo differ primarily because the isolated lens appears in its maximally accommodated state, and therefore the young lens shows large steepening ex vivo.…”

Section: Introductionmentioning

confidence: 99%

“…This technique was used for measurements of corneal elevation maps in vivo [38], biometry and lens alignment [39], dynamic measurement of crystalline lens radii of curvature with accommodation [20] and crystalline lens surfaces elevation maps in vivo [40].…”

Section: Introductionmentioning

confidence: 99%

OCT 3-D surface topography of isolated human crystalline lenses

Sun

Birkenfeld

Castro

et al. 2014

Biomed. Opt. Express

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Quantitative 3-D Optical Coherence Tomography was used to measure surface topography of 36 isolated human lenses, and to evaluate the relationship between anterior and posterior lens surface shape and their changes with age. All lens surfaces were fitted to 6th order Zernike polynomials. Astigmatism was the predominant surface aberration in anterior and posterior lens surfaces (accounting for ~55% and ~63% of the variance respectively), followed by spherical terms, coma, trefoil and tetrafoil. The amount of anterior and posterior surface astigmatism did not vary significantly with age. The relative angle between anterior and posterior surface astigmatism axes was on average 36.5 deg, tended to decrease with age, and was >45 deg in 36.1% lenses. The anterior surface RMS spherical term, RMS coma and 3rd order RMS decreased significantly with age. In general, there was a statistically significant correlation between the 3rd and 4th order terms of the anterior and posterior surfaces. Understanding the coordination of anterior and posterior lens surface geometries and their topographical changes with age sheds light into the role of the lens in the optical properties of the eye and the lens aging mechanism.

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Static and dynamic crystalline lens accommodation evaluated using quantitative 3-D OCT

Cited by 41 publications

References 48 publications

OCT-based crystalline lens topography in accommodating eyes

OCT-based crystalline lens topography in accommodating eyes

Microfluctuations in accommodation: an update on their characteristics and possible role

OCT 3-D surface topography of isolated human crystalline lenses

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