Geometrical characterization of the corneo-scleral transition in normal patients with Fourier domain optical coherence tomography
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To characterize the geometry at the corneo-scleral transition for a normal population and its correlation with other anatomic parameters of the eyeball.
Transversal epidemiologic study on a sample of 100 individuals (right eye) in different ethnic groups (Africans and Caucasians). All of them were examined with Fourier domain optical coherence tomography, auto-refractometer, topographer, and biometer to obtain the corneo-scleral angle (CSA) and additional clinical parameters. The dataset was analyzed to determine correlations between different anatomical parameters and nasal (CSAn) and temporal CSA (CSAt) values.
The CSAt presents a significant but low correlation with the anterior chamber depth—ACD (r = 0.25; p = 0.024), the white-to-white (W–W) distance (r = 0.27; p = 0.022), and the anterior chamber volume (r = 0.25; p = 0.016). CSAn did not correlate significantly with any clinical variable, with all values being lower than 179° (concave). Ethic groups presented significant differences for pachymetry (Pac) and corneal volume (p = 0.033 and p = 0.014), being greater for Caucasians, and temporal corneo-iridial angle (p = 0.006), being greater for Africans. CSA presented and inverse correlation with age.
The CSAn presents a more concave profile for the normal population, whereas the CSAt presents a planar-convex profile with a great influence of age. In particular, the older the patient, the more convex the CSAt is. This age-related evolution of the CSAt and the concavity on the nasal direction must be considered when prescribing scleral contact lenses or when performing limbal incisions during refractive interventions.
KeywordsCorneo-scleral angle Scleral contact lenses Optical coherence tomography Corneal topography
The author David P Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471. No additional funding was received for the performance of this study.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the ethics committee of the University of Alicante (Alicante, Spain) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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