Anterior eye shape in emmetropes, low to moderate myopes, and high myopes

Niyazmand, Hamed; Read, Scott A.; Atchison, David A.; Collins, Michael J.

doi:10.1016/j.clae.2020.08.005

Cited by 16 publications

(20 citation statements)

References 29 publications

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“…Considering that, as expected, a strong positive correlation was present in our study between the axial length and sphere or spherical equivalent, the temporal-nasal asymmetry of the sagittal heights may be a good biomarker of myopic changes. These results are consistent with those obtained in previous studies demonstrating an asymmetric growth of the eye in terms of anterior corneo-scleral geometric data associated with myopia development [4,5]. The more myopic the eye, the less asymmetric was the naso-temporal anterior sclera.…”

Section: Discussionsupporting

confidence: 92%

“…As shown in Tables 1 and 2, the main refractive, aberrometric, topographic, biometric, and tonometric characteristics and the main corneoscleral geometric parameters of the eyes included in the study are consistent with those previously reported using the same instruments in healthy eyes [4,5,[10][11][12][13][14][16][17][18]. Therefore, the current sample was composed of eyes with normal anterior surface geometry, with no peculiarities introducing bias in the outcomes obtained.…”

Section: Discussionsupporting

confidence: 86%

“…These authors also found that the anterior scleral shape was well correlated with the axial length and the refractive power. These results agree with the study from Hamed Niyazmanda et al, who demonstrated that there was less nasal-temporal asymmetry of sagittal height and axial radius of curvature of the anterior sclera in high myopes than in emmetropes [5]. This is in agreement with the asymmetric growth of the eye associated with myopia development.…”

Section: Introductionsupporting

confidence: 93%

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Relationship between Axial Length and Corneo-Scleral Topography: A Preliminary Study

2021

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The main objective of the current study was to investigate further the relationship of the overall length of the eye with a great variety of anterior segment parameters, including scleral geometry. A total of 64 eyes of 32 participants with ages from 12 to 52 years were included in this prospective non-randomized single-center study. All participants underwent a complete eye examination, including an analysis of corneo-scleral shape with a Fourier-domain profilometer. A strong negative correlation was found between axial length and temporal-nasal ocular sagittal height difference for different chord lengths. For the right eye, a consistent and stable linear model was obtained to predict the axial length from the spherical equivalent, the corneal diameter, the high-order aberrations root mean square, and the minimum sagittal height for 13- and 14-mm chord. For the left eye, a model was obtained to predict the axial length from the spherical equivalent and the mean corneal curvature, including other parameters such as corneal diameter or high-order aberrations, depending on the chord length, considered for estimating the sagittal height values. More studies with larger samples are needed to confirm these preliminary outcomes.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 86%

Section: Introductionsupporting

confidence: 93%

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Relationship between Axial Length and Corneo-Scleral Topography: A Preliminary Study

2021

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“…The understanding of ocular surface shape and elevation has been improved by recent advances in anterior segment imaging such as optical coherence tomography (OCT) and corneoscleral profilometry [60,61]. The morphology of the anterior ocular surface varies diurnally [62], during accommodation [63,64], with age [65], refractive error [66,67], and disease [60].While presently there are no evidence-based scleral lens fitting guidelines based on anterior segment imaging to optimise visual and physiological outcomes, toric, quadrant-specific, or customised landing zones can improve scleral alignment and have numerous advantages. Back surface landing zone customisation reduces lens decentration, lens flexure [68], excessive debris [68], the formation of air bubbles, conjunctival prolapse, localised conjunctival vessel blanching [69,70] and lens impingement [71,72].…”

Section: Ocular Surface Shapementioning

confidence: 99%

BCLA CLEAR - Scleral lenses

Barnett

Courey

Fadel³

et al. 2021

Contact Lens and Anterior Eye

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“…A previous study on corneo-scleral topography showed that scleral shape is highly correlated with axial length (r = 0.76, p < 0.001) and moderately correlated with refractive power (r = 0.48, p < 0.01) [44]. The more myopic an eye is the flatter the anterior sclera [44,45]. This finding agrees with the fact that in the current work, the sclera of Asians was found to be flatter than that of Caucasians.…”

Section: Discussionmentioning

confidence: 97%

Anterior Scleral Regional Variation between Asian and Caucasian Populations

Consejo

Abass

2020

JCM

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Purpose: To evaluate the anterior scleral shape regional differences between Asian and Caucasian populations. Methods: The study included 250 Asian eyes and 235 Caucasian eyes from participants aged 22 to 67 years (38.5 ± 7.6). Three-dimensional (3D) corneo-scleral maps were acquired using a corneo-scleral topographer (Eye Surface Profiler, Eaglet Eye BV) and used to calculate sagittal height. For each 3D map, the sclera (maximum diameter of 18 mm) and cornea were separated at the limbus using an automated technique. Advanced data processing steps were applied to ensure levelled artefact-free datasets to build an average scleral shape map for each population. Results: Statistically, Asian and Caucasian sclerae are significantly different from each other in sagittal height (overall sclera, p = 0.001). The largest difference in sagittal height between groups was found in the inferior-temporal region (271 ± 203 µm, p = 0.03), whereas the smallest difference was found in the superior-temporal region (84 ± 105 µm, p = 0.17). The difference in sagittal height between Caucasian and Asian sclera increases with the distance from the limbus. Conclusions: Asian anterior sclera was found to be less elevated than Caucasian anterior sclera. However, the nasal area of the sclera is less elevated than the temporal area, independently of race. Gaining knowledge in race-related scleral topography differences could assist contact lens manufacturers in the process of lens design and practitioners during the process of contact lens fitting.

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Anterior eye shape in emmetropes, low to moderate myopes, and high myopes

Cited by 16 publications

References 29 publications

Relationship between Axial Length and Corneo-Scleral Topography: A Preliminary Study

Relationship between Axial Length and Corneo-Scleral Topography: A Preliminary Study

BCLA CLEAR - Scleral lenses

Anterior Scleral Regional Variation between Asian and Caucasian Populations

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