Eye Shape Using Partial Coherence Interferometry, Autorefraction, and SD-OCT

Clark, Christopher A.; Elsner, Ann E.; Konynenbelt, Benjamin J

doi:10.1097/opx.0000000000000453

Cited by 9 publications

(11 citation statements)

References 39 publications

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“…The increase in axial length alone is sufficient to lead to large individual differences, and the eye shape does not necessarily change in an identical manner for all subjects (Chen, Elsner, Burns et al, 1992; Clark, Elsner,& Konynenbelt, 2015). Further, the retina does not stretch in an identical manner across the retina (Chui, Song, & Burns, 2008b).…”

Section: Introductionmentioning

confidence: 99%

Distribution differences of macular cones measured by AOSLO: Variation in slope from fovea to periphery more pronounced than differences in total cones

et al. 2017

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Large individual differences in cone densities occur even in healthy, young adults with low refractive error. We investigated whether cone density follows a simple model that some individuals have more cones, or whether individuals differ in both number and distribution of cones. We quantified cones in the eyes of 36 healthy young adults with low refractive error using a custom adaptive optics scanning laser ophthalmoscope. The average cone density in the temporal meridian was, for the mean ± SD, 43216 ± 6039, 27466 ± 3496, 14996 ± 1563, and 12207 ± 1278 cones /mm2 for 270, 630, 1480, and 2070 microns from the foveal center. Cone densities at 630 microns retinal eccentricity were uncorrelated to those at 2070 microns, ruling out models with a constant or proportional relation of cone density to eccentricity. Subjects with high central macula cone densities had low peripheral cone densities. The cone density ratio (2070 : 630 microns) was negatively correlated with cone density at 630 microns, consistent with variations in the proportion of peripheral cones migrating towards the center. We modelled the total cones within a central radius of 7 deg, using the temporal data and our published cone densities for temporal, nasal, superior, and inferior meridians. We computed an average of 221,000 cones. The coefficient of variation was 0.0767 for total cones, but higher for samples near the fovea. Individual differences occur both in total cones and other developmental factors related to cone distribution.

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Section: Introductionmentioning

confidence: 99%

Distribution differences of macular cones measured by AOSLO: Variation in slope from fovea to periphery more pronounced than differences in total cones

et al. 2017

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“…As such, any system is then dependent upon how reliable the subject is at fixating. Research‐grade systems do exist to reduce the time and fixation problem by having scanning systems, although subject fixation can still vary …”

Section: Potential Sources Of Differences In Peripheral El Measurementmentioning

confidence: 99%

“…Jansson reported the EL to change 0.1 mm with a change in alignment of about 5°. The data collected on many of these devices can have errors due to the location of the reflection off the retina in the axial direction, that is, whether the reflection is off the photoreceptor interface or from the inner limiting membrane …”

Section: Potential Sources Of Differences In Peripheral El Measurementmentioning

confidence: 99%

“…Research-grade systems do exist to reduce the time and fixation problem by having scanning systems, although subject fixation can still vary. 82 Most optical technologies tend not to be accurate in eyes with poor fixation, ocular opacities, or significant corneal pathology. Moreover, accommodation changes the thickness and refraction of the light beam which can affect the conversion of the optical length.…”

Section: Potential Sources Of Differences In Peripheral El Measurementmentioning

confidence: 99%

“…The data collected on many of these devices can have errors due to the location of the reflection off the retina in the axial direction, that is, whether the reflection is off the photoreceptor interface or from the inner limiting membrane. 82 Factors such as the distance measured, the refractive indices of the eye, and the calibration of the instrument can influence the measurement process. 64,86 As an example, the optical method measures the distance from anterior corneal vertex to the retinal pigment epithelium, whereas the ultrasound EL is measured up to the inner limiting membrane layer.…”

Section: Potential Sources Of Differences In Peripheral El Measurementmentioning

confidence: 99%

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Peripheral eye length measurement techniques: a review

Mekountchou

Conrad

Sankaridurg

et al. 2020

Clinical and Experimental Optometry

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Along with the rising myopia epidemic is the increasing interest in any ocular parameter that might inform understanding of myopia progression. The relationship between eye length and myopia has long been established but the recent interest in the central and peripheral retina, eye shape, retinal contour, and refractive error development is attracting more clinical and research interest in peripheral eye length measurements. Therefore, peripheral eye length measurements are an important step in the ongoing research involving the peripheral retina. Since the first measurement of peripheral eye length reported in 1991, many techniques and methods have been developed, which vary in many aspects. These techniques involve custom‐built or modified commercially available instruments, with the use of off‐axis targets and other considerations such as eye or head turn of the subject. The wide range of methods and instruments used for peripheral eye length measurements make it difficult to compare results and may account for some of the variations in the reported results. Specifications of the different methods are presented along with their advantages and disadvantages. Although researchers acknowledge a good agreement between the modified commercially available optical biometers for peripheral eye length measurement, the Lenstar LS 900 appears to offer better results. Nevertheless, the introduction to the market of an instrument specially designed for peripheral eye length might overcome the issues noted with other methods and could allow for more insights in future research involving the peripheral retina. Moreover, future studies may be able to track peripheral eye length changes and its relationship to the progression of myopia and find out if those changes are responsible for or correlated with important eye conditions.

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