Abstract
Purpose :
Measurement of tear meniscus height (TMH) is one of the important factors for evaluation of dry eye disease. Generally, it is measured the height of tear meniscus stained with fluorescein visually by the slit-lamp observation.
We have developed and reported a non-invasive and quantitative method for measuring TMH with the interferometric image obtained by KOWA DR-1α (Arita, et al. 2017 AAO). In this method, the light interference image was generated in the area where only the tear exists, and its height was defined as the interferometric TMH.
However, it is difficult to recognize the tear area because of its transparency, so that we compared the interferometric TMH with the tear meniscus stained by fluorescein, to verify the tear area recognition algorithm in this method.
Methods :
The subjects were enrolled by 19 eyes of 10 healthy volunteers (mean age ± SD, 45.1 ± 8.3 years). Tear meniscus of subjects were stained with fluorescein and imaged by KOWA DR-1α. First, the interferometric tear meniscus image was recorded by illuminating with a white LED. The interferometric TMH was measured using our method. Next, the fluorescence was excited by switching the illumination light to blue LED and the fluorescent tear meniscus image was recorded. The fluorescent TMH was measured the height of the fluorescent area visually with a commercially available software, ImageJ. And then, we compared the positions of tear area and the TMH obtained by both methods.
Results :
The interferometric tear meniscus lied within the area of the fluorescent tear meniscus area, and both TMH’s has a good correlation (r = 0.88, p<0.01).
The fluorescent TMH (mean ± SD, 405.8 ± 121.4 μm) were significantly larger than the interferometric TMH (285.0 ± 77.8 μm) (p<0.01), as well as the results in the literature, which might be due to the differences of the visualizing methods of tear area.
Conclusions :
We compared the positions and the heights of tear areas obtained by interferometric and fluorescent method. As a result, the interferometric tear areas were placed within the range of the corresponding fluorescent tear areas, which suggests the accuracy of the tear area recognition algorithm in the interferometric method. Thus, interferometric TMH would be alternative to the conventional method and effective in clinical use.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.