Measurement of Tear Film Thickness Using Ultrahigh-Resolution Optical Coherence Tomography

Abstract

Our data indicate that the human precorneal tear film can be measured with excellent reproducibility using ultrahigh-resolution optical coherence tomography. This technique may be a valuable tool in the management of dry eye syndrome.

Formulation and process factors influencing product quality and in vitro performance of ophthalmic ointments

“…Nevertheless, this layer of tear film is widely considered as to not only supply all the necessary nutrients to the beneath cornea, but also to reduce friction during eyelid blinking motion (Inatomi et al, 1995), where the eyelid moves across the ocular surface at a very high speed (maximum of 17-20 cm/s (Doane, 1980)) and frequently (15-20 times per minute (Ren and Wilson, 1997)). The reported value for the thickness of the tear film varies depending on the principle of measurement, but is in the range of 3 to 40 µm (Bron et al, 2004;Werkmeister et al, 2013). Based on the eyelid velocity and tear film thickness values, the maximum shear rate exerted by the eyelid on the tear film and/or ointment samples ranges from 10 3 to 10 4 s -1 .…”

Comparison between a supercontinuum source and a titanium sapphire laser in achieving ultrahigh resolution spectral domain optical coherence tomography (SD-OCT)

“…The set-up consisted of a Michelson interferometer and a broadband spectrometer [7,8]. For the presented experiments, two sources, a Ti:Sa laser (Integral OCT, Femtolasers Produktions GmbH, Vienna, Austria) and a supercontinuum source (SuperK Extreme Low noise, 320 MHz, NKT Photonics, Birkerod, Denmark) were employed (Fig.1).…”

Super-resolved thickness maps of thin film phantoms and in vivo visualization of tear film lipid layer using OCT

“…The light source was a Ti:Sapphire laser (Integral OCT; Femtolasers Produktions GmbH, Vienna, Austria) providing 170 nm full-width-at-half-maximum (FWHM) spectral bandwidth at a central wavelength λ c ∼ 800 nm. The spectrometer has already been described in detail elsewhere [18]. The custom acquisition software was done in Labview 2014 (National Instruments, Austin, TX, USA).…”

“…While the aqueous layer can be resolved with OCT [18,19], the lipid layer, which has a thickness estimated to be in the range 40 − 80 nm [34,35] cannot be resolved. The lipid of the tear film has a refractive index estimated to be 1.482 [36], while the aqueous layer has a refractive index close to 1.333 at 800 nm [19].…”