More Irregular Eye Shape in Low Myopia Than in Emmetropia

Tabernero, Juan; Schaeffel, Frank

doi:10.1167/iovs.09-3441

Cited by 37 publications

(27 citation statements)

References 24 publications

(23 reference statements)

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“…61, 62 Others have suggested that this individual variation in field curvature is due to individual differences in ocular shape combined with other optical features of the myopic eye. 6063, 64 To obtain a quantitative estimate of this effect to guide the interpretation of our experimental results, we used Atchison’s myopic model eye 60 to compute the change in peripheral relative refractive error (PRM). The model indicated, for example, that PRM at 15° eccentricity from the eye’s optical axis should increase linearly at the rate of 0.06 diopters per diopter of central M in the naked eye.…”

Section: Resultsmentioning

confidence: 99%

Peripheral Refraction With and Without Contact Lens Correction

Shen¹,

Clark²,

Soni³

et al. 2010

Optometry and Vision Science

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Purpose Peripheral refractive error degrades the quality of retinal images and has been hypothesized to be a stimulus for the development of refractive error. The purpose of this study was to investigate the changes in refractive error across the horizontal visual field produced by contact lenses (CLs) and to quantify the effect of CLs on peripheral image blur. Methods A commercial Shack-Hartmann aberrometer measured ocular wavefront aberrations in 5° steps across the central 60° of visual field along the horizontal meridian before and after CLs correction. Wavefront refractions for peripheral lines-of-sight were based on the full elliptical pupil encountered in peripheral measurements. Curvature of field is the change in peripheral spherical equivalent relative to the eye’s optical axis. Results Hyperopic curvature of field in the naked eye increases with increasing amounts central myopic refractive error as predicted by Atchison (2006). For an eccentricity of E degrees, field curvature is approximately E percent of foveal refractive error. Rigid gas permeable (RGP) lenses changed field curvature in the myopic direction twice as much as soft contact lenses (SCLs). Both of these effects varied with CLs power. For all lens powers, SCL cut the degree of hyperopic field curvature in half whereas RGP lenses nearly eliminated field curvature. The benefit of reduced field curvature was partially offset by increased oblique astigmatism. The net reduction of retinal blur due to CLs is approximately constant across the visual field. Conclusions Both SCL and RGP lenses reduced the degree of hyperopic field curvature present in myopic eyes, with RGP lenses having greater effect. The tradeoff between field curvature and off-axis astigmatism with RGP lenses may limit their effectiveness for control of myopia progression. These results suggest that axial growth mechanisms that depend on retinal image quality will be affected more by RGP than by SCL lenses.

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Section: Resultsmentioning

confidence: 99%

Peripheral Refraction With and Without Contact Lens Correction

Shen¹,

Clark²,

Soni³

et al. 2010

Optometry and Vision Science

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“…The details of the refractor have been described elsewhere. 11,12 Briefly, the instrument consists of an infrared photoretinoscope attached to a charged-coupled device camera via a USB cable. 18 Infrared light from the photoretinoscope is reflected off of hot mirror onto the retina, that is rotated and translated simultaneously along a linear stage by two stepping motors.…”

Section: Measurementsmentioning

confidence: 99%

“…To better describe the normal distribution of the relative peripheral refractive errors in a sample of human subjects with low central refractive errors, a newly developed scanning photorefractor was used. 11,12 The advantage of this device is that semicontinuous scans (0.4°angular resolution) can be performed over the central Ϯ45°d egree horizontal field in about 4 s, while the subject keeps the eye in a steady position. Previous studies had more coarse angular resolution, with sampling intervals between 5 and 20°, and they often required the subject to change gaze position for the individual measurements.…”

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confidence: 99%

Peripheral Refraction Profiles in Subjects with Low Foveal Refractive Errors

Tabernero¹,

Ohlendorf²,

Fischer³

et al. 2011

Optometry and Vision Science

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“…If only a few angular positions are sampled, it is hard to fit the shape of the peripheral refraction reliably using a higher-order polynomial. Low sampling density also reduces the chance that local irregularities in eye shape can be detected [11].…”

Section: Introductionmentioning

confidence: 99%

Comparison of two scanning instruments to measure peripheral refraction in the human eye

et al. 2012

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To better understand how peripheral refraction affects development of myopia in humans, specialized instruments are fundamental for precise and rapid measurements of refraction over the visual field. We compare here two prototype instruments that measure in a few seconds the peripheral refraction in the eye with high angular resolution over a range of about ±45 deg. One instrument is based on the continuous recording of Hartmann-Shack (HS) images (HS scanner) and the other is based on the photorefraction (PR) principle (PR scanner). On average, good correlations were found between the refraction results provided by the two devices, although it varied across subjects. A detailed statistical analysis of the differences between both instruments was performed based on measurements in 35 young subjects. Both instruments have advantages and disadvantages. The HS scanner also provides the high-order aberration data, while the PR scanner is more compact and has a lower cost. Both instruments are current prototypes, and further optimization is possible to make them even more suitable tools for future visual optics and myopia research and also for different ophthalmic applications.

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More Irregular Eye Shape in Low Myopia Than in Emmetropia

Abstract: A new setup is presented for obtaining continuous peripheral refraction profiles. It was found that the peripheral retinal shape is more irregular even in only moderately myopic eyes, perhaps because the sclera lost some rigidity even at the early stage of myopia.

Cited by 37 publications

References 24 publications

Peripheral Refraction With and Without Contact Lens Correction

Peripheral Refraction With and Without Contact Lens Correction

Peripheral Refraction Profiles in Subjects with Low Foveal Refractive Errors

Comparison of two scanning instruments to measure peripheral refraction in the human eye

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