Abstract
Purpose :
Understanding the tear film and its dynamic interaction with the cornea and contact lens is vital to improving lens technology and advancing ophthalmology. To this end, we performed an observational clinical study using optical coherence tomography (OCT) to quantify pre- and post-lens tear film (PLTF and PoLTF) thicknesses with different contact lens packaging solutions during the first 60 minutes of lens wear.
Methods :
Ultrahigh resolution OCT was used to image the tear film of nine healthy human subjects wearing contact lenses packaged in solutions containing alternative polymers. A phosphate buffer saline (PBS) solution was used as a control and as the base for three experimental solutions (Solution A, B, C) with different properties (Table 1). Measurements were taken before lens insertion, immediately upon insertion, and at various time points within the first 60 minutes of lens wear. Welch’s unequal variance t-test was used to evaluate data (presented as mean ± SD). Trendlines of exponential form were calculated with a 95% confidence interval. Student’s t-test was used to compare the asymptote and exponential decay constant between solutions. A P-value of <0.05 was considered significant.
Results :
Solution A showed a significantly thicker PLTF (P=0.003) and PoLTF (P=0.0006), 10.53 ± 3.95 μm (range: 5.5-18.7) and 6.21 ± 3.01 μm (range: 0-13.2), respectively, immediately after lens insertion, compared to PBS. PLTF and PoLTF for Solution B at 0 minutes post-insertion were also significantly thicker (P<0.002) with measurements of 11.00 ± 4.54 μm (range: 0-16.5) and 8.29 ± 2.04 μm (range: 4.4-11.0), respectively. These significant differences were sustained through 2 and 4 minutes post-lens insertion for PLTF and PoLTF, respectively, with Solution A, and through 15 minutes for both PLTF and PoLTF for Solution B. A significant difference of the exponential decay constant was found between PBS and Solutions A (P=0.0007, 0.002) and B (P=0.002, 0.002) for both PLTF and PoLTF. Solution C showed PLTF and PoLTF thicknesses similar to PBS, with no significant differences at any time points.
Conclusions :
OCT is a capable tool for assessing thickness and variation of PLTF and PoLTF over time. Using this technology, it has been shown that alternative contact lens packaging solutions can transiently sustain an increased PLTF and PoLTF thickness, when used as a substitute for PBS.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.