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Purpose: To determine the dynamic pre- (PLTF) and post-lens (PoLTF) tear film thicknesses using optical coherence tomography (OCT). Methods: Ultra-high resolution OCT was used to image the tear film of 22 subjects before and after contact lens wear. A soft lens with one drop of artificial tears on its concave surface was inserted onto one randomly selected eye. OCT images were taken before insertion, immediately afterwards, and every 2 minutes for 10 minutes. For the contralateral eye, the lens inserted was not pre-wetted on the concave surface. OCT images were taken before insertion, immediately afterwards, and at 3 minutes. Then another drop was instilled and images taken immediately afterwards, and every 2 minutes for 10 minutes. Images were processed by custom software to yield tear film thickness. Results: The thickness of pre-corneal tear film (PCTF) was 1.9 +/- 0.9 mum. The PoLTF was visualized clearly in all cases immediately after lens insertion with one drop on its concave surface. Through the first 6 minutes after insertion, the PoLTF was greater than the PCTF. The PLTF (n = 12) and PoLTF (n = 9) were visualized immediately after lens insertion. After three minutes, the PLTF in most subjects and PoLTF in all subjects were invisible. The thickness of the PLTF increased after the instillation of artificial tears, while the PoLTF did not at any checkpoint for 10 minutes. Conclusions: Ultra-high resolution OCT is a promising tool for measuring the tear film. The PoLTF did not increase after instillation of artificial tears.
PMID: 19933178 [PubMed - as supplied by publisher]