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An analysis of the anterior segment of the eye with the Oculus Pentacam Corneo-Scleral Profile Report

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Autoren
1HECHT Contactlinsen GmbH
2HECHT Contactlinsen GmbH
3HECHT Contactlinsen GmbH
4Aalen University
Keywords
Scheimpflug technology
pentacam
limbal sclera contour
corneo-scleral profile
scleral lens
sagittal height
Abstract

Purpose:

This study aims to describe the profile progression from cornea over limbus to sclera using the module CSP-Report (Corneo-Skleral-Profil-Report) of the Oculus Pentacam.

Material and Methods:

Seventy-four left eyes of healthy subjects were evaluated. Data was collected as part of previous research (bachelor-thesis) using the CSP-Report module of the Pentacam Basic. Sagittal height, limbal angle and scleral angle were analyzed over three diameters in eight semimeridians.

Results:

At diameter 10.00 mm the shape of the anterior segment of the eye was nearly rotationally symmetrical, the average sagittal height of the eight semi-meridians was between 1734 μm and 1806 μm. At diameter 12.80 mm the shape was more asymmetrical, average sagittal height ranged from 2797 μm to 3000 μm. At diameter 15.00 mm the asymmetry was most pronounced, the average sagittal height was between 3595 μm and 4033 μm. The average limbal angles at 12.80 mm were in the range of 35.68° and 42.02°. For the scleral angle at 15.00 mm  an values between 34.71° and 43.11° were determined for the eight semi-meridians. The nasal segments always showed smaller sagittal heights, accompanied by smaller limbal and scleral angles compared to the temporal semi-meridians. The same pattern was observed for the superior semi-meridians in relation to the inferior segments. For the nasal semi-meridians, concave transitions of the corneo-scleral profile were observed, whereas temporally a convex course of the CSP was observed.

Conclusion:

The CSP-Report provides a method to describe the shape of the anterior segment of the of the eye. These additional data are useful for fittingscleral lenses.

In den vergangenen 10 Jahren ist die Sklerallinse wieder populärer geworden. Eef van der Worp beschreibt in seinem Leitfaden für die Anpassung von Sklerallinsen, dass neue hochgasdurchlässige Materialien, sowie weiterentwickelte Fertigungsvarianten inzwischen eine immer bessere Versorgungsmöglichkeit, insbesondere bei komplexen Hornhauttopographien wie zum Beispiel fortgeschrittenem Keratokonus, Pellucide Marginale Hornhautdegeneration (PMD) oder nach Keratoplastik, bieten.

Zum aktuellen Zeitpunkt ist es zwar möglich, mittels Topographiesystemen eine präzise Vermessung der Hornhaut zu erstellen, der für die Anpassung relevante sklerale Bereich des vorderen Augenabschnitts stellt Gerätehersteller jedoch vor eine Herausforderung. In der Weiterentwicklung der Messgeräte gibt es unterschiedliche Ansätze, um dieses Defizit zu beheben. Verschiedene Technologieansätze wurden dabei verfolgt, dazu gehören die optische Kohärenztomographie (OCT), die Fourier-basierte Profilometrie oder die Scheimpflug Bildgebung.
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