Rotation asymmetry of the human sclera

Consejo, Alejandra; Llorens‐Quintana, Clara; Bartuzel, Maciej M.; Iskander, D. Robert; Rozema, J.

doi:10.1111/aos.13901

Cited by 32 publications

(47 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The findings of the current study confirm the belief that the natural shape of the sclera does not exhibit astigmatism patterns like the cornea, but instead is markedly more complex [13]. The results presented here suggest that the sclera is steeper not only at the temporal side as reported by Consejo [29] but also in two other meridians creating angles of nearly 120° between them (Fig 5C and 5D). When Bandlitz [11] measured the limbal scleral radii of 30 subjects, he found that median scleral radii in superior-nasal were the flattest and along temporal direction was the steepest meridian.…”

Section: Discussionsupporting

confidence: 91%

“…In his study, Hall [14] also found that corneal-scleral junctions were the sharpest at the nasal but contradictory he found a progressive significant flattening at temporal, inferior and superior junctions. As the asymmetry evaluation analysis in this study was carried out at all meridians (with 1°intervals) neither at wide sectors as in [29, 30] nor cross-sectional slices as in [15, 45], it provides a detailed overview of the scleral shape up to 3 mm beyond the corneoscleral junction. Comparing the statistical figures of the scleral average raw elevation before and after removing the edge, effect showed an increase in the mean values of raw elevation and a decrease in their standard deviations as a result of removing the effect of artificial lift-off caused by the edges.…”

Section: Discussionmentioning

confidence: 99%

“…Using topography data, Consejo et al . [12] reported that corneal and scleral asymmetry are highly correlated in astigmatic eyes, with the nasal area of the sclera showing less relative elevation than the temporal area, and the inferior area of the sclera was slightly less elevated than the superior area [29]. The relative elevation in their results was calculated as the difference between the scleral raw elevation data and a simple quadratic function fitted to a scleral 2 mm width ring [30].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Artefact-free topography based scleral-asymmetry

Abass¹,

Lopes²,

Eliasy³

et al. 2019

PLoS ONE

View full text Add to dashboard Cite

Purpose To present a three-dimensional non-parametric method for detecting scleral asymmetry using corneoscleral topography data that are free of edge-effect artefacts. Methods The study included 88 participants aged 23 to 65 years (37.7±9.7), 47 women and 41 men. The eye topography data were exported from the Eye Surface Profiler software in MATLAB binary data container format then processed by custom built MATLAB codes entirely independent from the profiler software. Scleral asymmetry was determined initially from the unprocessed topography before being determined again after removing the edge-effect noise. Topography data were levelled around the limbus, then edge-effect was eliminated using a robust statistical moving median technique. In addition to comparing raw elevation data, scleral elevation was also compared through fitting a sphere to every single scleral surface and determining the relative elevation from the best-fit sphere reference surface. Results When considering the averaged raw topography elevation data in the scleral section of the eye at radius 8 mm, the average raw elevations of the right eyes’ sclera were -1.5±1.77, -1.87±2.12, -1.36±1.82 and -1.57±1.87 mm. In the left eyes at the same radius the average raw elevations were -1.62±1.78, -1.82±2.07, -1.28±1.76 and -1.68±1.93 mm. While, when considering the average raw elevation of the sclera after removing the edge effect, the average raw elevations of the right eyes were -3.71±0.25, -4.06±0.23, -3.95±0.19 and -3.95±0.23 mm. In the left eyes at the same radius the average raw elevations were -3.71±0.19, -3.97±0.22, -3.96±0.19 and -3.96±0.18 mm in the nasal, temporal, superior and inferior sides respectively. Maximum raw elevation asymmetry in the averaged scleral raw elevation was 1.6647±0.9015 mm in right eyes and 1.0358±0.6842 mm in left eyes, both detected at -38° to the nasal side. Best-fit sphere-based relative elevation showed that sclera is more elevated in three main meridians at angles -40°, 76°, and 170° in right eyes and -40°, 76°, and 170° in left eyes, all measured from the nasal meridian. Maximum recorded relative elevation asymmetries were 0.0844±0.0355 mm and 0.068±0.0607 mm at angular positions 76° and 63.5° for right and left eyes in turn. Conclusions It is not possible to use corneoscleral topography data to predict the scleral shape without considering a method of removing the edge-effect from the topography data. The nasal side of the sclera is higher than the temporal side, therefore, rotationally symmetric scleral contact lenses are more likely to be translated towards the temporal side. The scleral shape is best described by levelled raw elevation rather than relative elevation.

show abstract

Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Artefact-free topography based scleral-asymmetry

Abass¹,

Lopes²,

Eliasy³

et al. 2019

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Conjunctival hyperaemia and scleral blanching are unwanted phenomena often associated with scleral lens wear. Impingement compression of the conjunctiva to the point where the blood vessels are closed off is an undesirable outcome that will most likely have an effect on wearing time and comfort . Patients that experience discomfort along with conjunctival hyperaemia after extended hours of daily scleral lens wear might eventually reduce wearing time and even develop scleral lens intolerance.…”

Section: Discussionmentioning

confidence: 99%

“…As scleral lenses become more popular, practitioners gain more interest in assessing the anterior scleral shape . Scleral asymmetry, undesired lens seal‐off, and limbal bearing are some of the main fitting challenges associated with scleral contact lenses .…”

Section: Introductionmentioning

confidence: 99%

Scleral asymmetry as a potential predictor for scleral lens compression

Consejo

Behaegel

Hoey

et al. 2018

Ophthalmic Physiologic Optic

Self Cite

View full text Add to dashboard Cite

Purpose: To identify the position and magnitude of lens compression due to short-term miniscleral contact lens wear, as well as evaluating the usefulness of scleral asymmetry as a predictor for scleral lens decentered compression. Methods: Fourteen healthy subjects (mean AE S.D.: 29.2 AE 6.0 years) wore a highly gas-permeable spherical haptic miniscleral contact lens during a 5-h period. Corneo-scleral height Fourier profilometry was captured using an Eye Surface Profiler (www.eaglet-eye.com) before and immediately after lens removal. Scleral asymmetry, lens compression location and magnitude were processed using custom-made algorithms, both globally and for scleral quadrants. Results: Miniscleral contact lenses do not set uniformly on the ocular surface, with the largest decentration seen along the horizontal meridian. The greatest flexural stress exerted by the lens on the ocular surface occurs at the point coinciding with the inner diameter landing point of the lens and not with its overall diameter. Scleral asymmetry was significantly correlated with compression location (R = 0.71, p = 0.002) and compression magnitude (R = 0.81, p < 0.001), showing its potential as compression predictor. Conclusion: Larger amounts of scleral asymmetry will lead to more decentration of spherical haptic scleral lenses. Objective and accurate methods, like the one presented here, could help the practitioner prevent cases of scleral blanching or discomfort due to an excessive compression by the lens.

show abstract

Anatomy and physiology of the eye

Ita¹

2022

Microneedles

View full text Add to dashboard Cite

Rotation asymmetry of the human sclera

Abstract: Human sclera is rotationally asymmetric, and its shape varies considerably between subjects.

Cited by 32 publications

References 20 publications

Artefact-free topography based scleral-asymmetry

Artefact-free topography based scleral-asymmetry

Scleral asymmetry as a potential predictor for scleral lens compression

Anatomy and physiology of the eye

Contact Info

Product

Resources

About