Abstract
Purpose: :
To determine changes in lipid tear film by digital sequential interferometry and corneal topography surface indices in healthy subjects.
Methods: :
Sixteen eyes from 8 healthy subjects, 5 females and 3 males, were included. We used a new method based on the Keeler TearScope Plus ® (Windsor, Berks, United Kingdom) interference images captured by a digital camera Sony DSC–W5 to perform sequential tear film interferometry analysis of the pre–corneal tear film. We determined the thickness, pattern and spread time of the lipid tear film. Topographic surface regularity index (SRI) and surface asymmetric index (SAI) were obtained by using Tomey TMS–4N computerized videokeratoscopy (Tomey, Waltman, MA). Additionally, in 5 normal subjects, meibomiam gland secretions were analyzed by mass spectrometer.
Results: :
The mean and standard deviation of lipid tear film thickness was 73.7±15 nm (OD), and 76.25±13 nm (OS) (P: 0.7), and the lipid tear film spread time was 0.60±0.14 sec (OD) and 0.63 sec (OS) (P: 0.1). In all eyes, the lipid tear film interferometry pattern was evenly "wavy". The SRI was 0.39±0.27 (OD) and 0.24±0.13 (OS) (P:0.1) and the SAI was 0.39±0.21 (OD) and 0.40±0.16 (OS) (P: 0.8).
Conclusions: :
In healthy subjects, the digital sequential interferometry images obtained by the Keeler TearScope Plus ® is a consistent and reliable method to evaluate the lipid tear film and is associated with normal corneal topography surface indices.
Keywords: cornea: tears/tear film/dry eye • lipids • cornea: clinical science