Purchase this article with an account.
M. F. Haddad, C. Maldonado-Codina, P. B. Morgan; A Novel Technique for Measuring Contact Angles in vivo. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5645.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the feasibility of undertaking contact angle measurements on-eye using a novel, in vivo, sessile drop method.
We have developed a new device for the measurement of in vivo contact angles on contact lenses. This instrument consists of a manual syringe unit mounted on a custom-made XYZ manipulator. This unit includes a microliter syringe (Gastight 1000µl Precision Syringe, DataPhysics, Germany) attached to a flexible nylon dosing tube from which a drop is formed. The probe liquid used is 0.4% sodium hyaluronate mixed with 2% sodium fluorescein to allow visualization of the drop under UV light. The instrument is mounted directly above a headrest on a reclining chair on which a contact lens-wearing subject is supine. A 1.5 µl drop is formed at the tip of the dosing tube which is lowered towards the contact lens until contact is made with the lens surface . A two camera digital video-based system has been developed to record movies of the drop dispensed onto the lens surface. This video set up ensures accurate centration of the drop on the contact lens as well as enabling the measurement of contact angles and the rate of spread of the drop across the lens surface.
This PDF is available to Subscribers Only