Scheimpflug Imaging assisted measurement of pre-corneal tear film thickness and its changes after LASIK.

The pre-corneal tear film is an important component of the anatomy and physiology of the eye and performs several functions. It prevents the epithelial cells from dessication, facilitates eyelid movement by lubrication, provides a smooth refracting surface on the cornea, supplies nutrients and oxygen necessary for corneal metabolism, contributes to the ocular antimicrobial defense mechanism, removes metabolic waste products, eliminates foreign bodies from the ocular surface and protects the cornea and conjunctiva from atmospheric and chemical irritants.

The Wavelight Oculyzer is an instrument that uses a rotating camera to image the shape and thickness of the cornea using the Scheimpflug principles. Fluorescein is a dye that is commonly used to study the tear film. By adding fluorescein to the tear film the Wavelight Oculyzer can be used to non-invasively measure the thickness of the tear film.

LASIK (Laser In-Situ Keratomileusis) is one of the most commonly performed cornea refractive surgeries to provide spectacle free vision. It involves creation of a partial thickness flap of the cornea, reflection of the flap, application of excimer laser (wavelength 193 nm) to ab late corneal tissue followed by replacement of the flap.

Aims and Objectives:

(a) To devise a novel method for measuring the pre-corneal tear film thickness.

(b) To study the changes in pre-corneal tear film thickness that occur after LASIK.

(c) To examine the utility of a Scheimpflug Camera based imaging system as a non-invasive objective tool to detect candidates who can potentially develop chronic tear film dysfunction after LASIK.