Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

Revista Brasileira de Oftalmologia

Renato Ambrósio Jr²  Isaac Ramos²  Allan Luz¹  Fernando Correa Faria²  Andreas Steinmueller¹  Matthias Krug¹  Michael W. Belin¹  Cynthia Jane Roberts¹ 

[1] ,Instituto de Olhos Renato AmbrósioRio de Janeiro RJ ,Brazil

关键词: Biomechanics;    Cornea;    Corneal topography;    Tonometry;    ocular;    Biomecânica;    Córnea;    Topografia da córnea;    Tanometria ocular;   

DOI  :  10.1590/S0034-72802013000200005

来源: SciELO

【 摘 要 】

OBJECTIVE: To describe a novel technique for clinical characterization of corneal biomechanics using non-invasive dynamic imaging. METHODS: Corneal deformation response during non contact tonometry (NCT) is monitored by ultra-high-speed (UHS) photography. The Oculus Corvis ST (Scheimpflug Technology; Wetzlar, Germany) has a UHS Scheimpflug camera, taking over 4,300 frames per second and of a single 8mm horizontal slit, for monitoring corneal deformation response to NCT. The metered collimated air pulse or puff has a symmetrical configuration and fixed maximal internal pump pressure of 25 kPa. The bidirectional movement of the cornea in response to the air puff is monitored. RESULTS: Measurement time is 30ms, with 140 frames acquired. Advanced algorithms for edge detection of the front and back corneal contours are applied for every frame. IOP is calculated based on the first applanation moment. Deformation amplitude (DA) is determined as the highest displacement of the apex in the highest concavity (HC) moment. Applanation length (AL) and corneal velocity (CVel) are recorded during ingoing and outgoing phases. CONCLUSION: Corneal deformation can be monitored during non contact tonometry. The parameters generated provide clinical in vivo characterization of corneal biomechanical properties in two dimensions, which is relevant for different applications in Ophthalmology.

【 授权许可】

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