Accommodative changes produced in response to overnight orthokeratology

Felipe-Marquez, Gema; Nombela-Palomo, María; Cacho, Isabel; Nieto-Bona, Amelia

doi:10.1007/s00417-014-2865-2

Cited by 31 publications

(18 citation statements)

References 43 publications

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“…Optimal designs could then be used to achieve corrections such as the regulation of myopia progression, by acting on the peripheral defocus 12 or presbyopia correction by improving the depth of field and/or the accommodative response of the eye. 13 Thus, the first goal of the present work was to conduct an objective morphological, topographical and optical characterization of the ortho-k cornea using an algorithm of classification that analyzes the mean curvature from the post-treatment topographic map raw data. Subsequently, the influences of those changes in the optical quality were also investigated.…”

Section: Introductionmentioning

confidence: 99%

Morphology, topography, and optics of the orthokeratology cornea

et al. 2016

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The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median=24 years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between −2.00 and −5.00 diopters (D) (median=−3.41 D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C40) and secondary (C60) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C40 (r=−0.49, p<0.05) and a very strong correlation with C60 (r=0.78, p<0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye’s positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye.

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Section: Introductionmentioning

confidence: 99%

Morphology, topography, and optics of the orthokeratology cornea

et al. 2016

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“…measured increases in mean Zernike defocus for all tested targets distances (0 to 4 D) and stated that this indicated greater accommodation responses and thus reduced lags of accommodation. However a subsequent study suggests that ortho‐k does not alter accommodation function . Continued research into the impact of potential anti‐myopia treatments on accommodation accuracy would be useful.…”

Section: Updatementioning

confidence: 97%

“…However a subsequent study suggests that ortho-k does not alter accommodation function. 54 Continued research into the impact of potential anti-myopia treatments on accommodation accuracy would be useful.…”

Section: Subsequent Related Research and Unanswered Questionsmentioning

confidence: 99%

Differences in the accommodation stimulus response curves of adult myopes and emmetropes: a summary and update

Schmid

Strang

2015

Ophthalmic Physiologic Optic

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This paper has been often cited as evidence that accommodation responses at near may be primarily reduced in adults with progressing myopia and not in stable myopes and/or that challenging accommodation stimuli (negative lenses with monocular viewing) are required to generate larger accommodation errors. As an analogy, animals reared with hyperopic errors develop axial elongation and myopia. Retinal defocus signals are presumably passed to the retinal pigment epithelium and choroid and then ultimately the sclera to modify eye length. A number of lens treatments that act to slow myopia progression may partially work through reducing accommodation errors.

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“…Several studies have examined accommodative changes with orthokeratology. Felipe-Marquez et al 56 conducted a prospective study of 21 young adults wearing spectacles and 51 similar adults wearing orthokeratology lenses. After three months of orthokeratology treatment, there were no significant changes in negative relative accommodation, positive relative accommodation, amplitude of accommodation, accommodative lag, or monocular accommodative facility, and no differences in these accommodative measurements between spectacle and orthokeratology-wearing subjects.…”

Section: Accommodation Changesmentioning

confidence: 99%

Optical changes and visual performance with orthokeratology

Nti

Berntsen

2020

Clinical and Experimental Optometry

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Orthokeratology has undergone drastic changes since first described in the early 1960s. The original orthokeratology procedure involved a series of lenses to flatten the central cornea and was plagued by variable results. The introduction of highly oxygen‐permeable lens materials that can be worn overnight, corneal topography, and reverse‐geometry lens designs revolutionised this procedure. Modern overnight orthokeratology causes rapid, reliable, and reversible reductions in refractive error. With modern designs, patients can wear lenses overnight, remove them in the morning, and see clearly throughout the day without the need for daytime refractive correction. Modern reverse‐geometry lens designs cause central corneal flattening and mid‐peripheral corneal steepening that provides clear foveal vision while simultaneously causing a myopic shift in peripheral retinal defocus. The peripheral myopic retinal defocus caused by orthokeratology is hypothesised to be responsible for reductions in myopia progression in children fitted with these lenses. This paper reviews the changes in orthokeratology lens design that led to the reverse‐geometry orthokeratology lenses that are used today and the optical changes these lenses produce. The optical changes reviewed include changes in refractive error and their time course, high‐ and low‐contrast visual acuity changes, changes in higher‐order aberrations and visual quality metrics, changes in accommodation, and changes in peripheral defocus caused by orthokeratology. The use of orthokeratology for myopia control in children is also reviewed, as are hypothesised connections between orthokeratology‐induced myopic peripheral defocus and slowed myopia progression in children, and safety and complications associated with lens wear. A better understanding of the ocular and optical changes that occur with orthokeratology will be beneficial to both clinicians and patients in making informed decisions regarding the utilisation of orthokeratology. Future research directions with this lens modality are also discussed.

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Accommodative changes produced in response to overnight orthokeratology

Abstract: OK does not induce changes in the ocular accommodative function for either short-term or long-term periods.

Cited by 31 publications

References 43 publications

Morphology, topography, and optics of the orthokeratology cornea

Morphology, topography, and optics of the orthokeratology cornea

Differences in the accommodation stimulus response curves of adult myopes and emmetropes: a summary and update

Optical changes and visual performance with orthokeratology

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