<p>Comparison and Evaluation of Prelens Tear Film Stability by Different Noninvasive in vivo Methods</p>

Abstract

Purpose Prelens tear film stability of soft contact lens (SCL) play an important role for contact lens discomfort. In this study, we investigated the association between two types of noninvasive methods and evaluated the tear film stability with SCL using the methods. Patients and Methods In experiment 1, images of ring mire were recorded with a keratograph after focusing the pigment located at the front or back of the SCL. Interferometry and videokeratoscopy were used for the assessment of tear film stability in the right eye of 10 women, with two different cosmetic daily disposable SCLs: polymacon and etafilcon A with polyvinylpyrrolidone. Time to first distortion by noninvasive keratograph break up time (NIKBUT-first) was compared to noninvasive interferometry break up time (NIBUT). In experiment 2, ten normal females wore two different daily disposable SCLs: samfilcon A and narafilcon A. NIKBUT-first and NIBUT were compared between the lenses after 8 hours of SCL wearing. Results In experiment 1, NIBUT-first without SCL was significantly correlated to NIBUT without SCL (r=0.445, P=0.0488, Pearson’s correlation coefficients). However, NIKBUT-first with SCL was not significantly correlated with NIBUT with SCL. In experiment 2, although NIKBUT-first was not significantly different between SCLs, samfilcon A had significantly longer NIBUT than narafilcon A (P=0.0315, paired t -test). Conclusion NIKBUT-first with SCL could be related to tear film stability between the lens and the corneal surface, but not to prelens tear film stability. NIIBUT could be a suitable method to evaluate prelens tear stability.

Role of the Water Gradient Structure in Inhibiting Thin Aqueous Layer Break in Silicone Hydrogel-Soft Contact Lens

“…TALB is known to occur immediately after eye-opening when there is no lipid layer on the SCL surface due to a thin aqueous layer tear, and rarely observed in bare eye. 24 In our study, we found a significant decrease in TALB among the SH-SCL delefilcon A lens wearers compared to the SCL narafilcon A lens wearers. The conventional SH SCLs (narafilcon A) has a low water content of 30% to 40% in all the layers such that the SCL surface is water-repellent, and tears evaporate immediately and easily from the surface.…”

“… 21 Another study by Guillon et al 35 showed that the mean NIBUT of delefilcon A was longer (9.2 seconds) than that of narafilcon A (5.1 seconds, P = 0.006). The recent study by Itokawa et al 24 showed that the NIBUT measured by Keratograph 5M did not correlate to that measured by DR-1α in the eyes with SCL and proposed the possibilities that Keratograph 5M frequently captures the tear dynamics in the posterior but not the anterior surface of SCL, resulting in inaccurate NIBUT values. In our measurements, Keratograph 5M was unstable as reported by Itokawa et al; thus, we used DR-1α measurements for the NIBUT analysis.…”

“…Using the tear interferometer DR-1α (Kowa, Tokyo, Japan), the break up pattern with SCLs was classified into six patterns consist of area break (AB), line break (LB), thin aqueous layer break (TALB), spot break (SB), dimple break (DB), and random break (RB), as previously reported by Yokoi et al 23 , 24 For these break-up pattern, the three videos captured using the DR-1α were judged in a masked manner. A total of nine judgments comprising three videos by three researchers per one eye were used, and the majority of the break-up patterns were adopted.…”

Stabilization of comfort and visual quality after the insertion of soft contact lenses

“…Despite scientific evidence supporting the evaluation of in vivo wettability by corneal topography during soft contact lens wear [18,19,22,23], this technique has limitations that should be explored in future studies. In this sense, a study by Itokawa et al [24] reported no correlation between the in vivo wettability measured by videokeratoscopy (objective) and interferometry (subjective) using two soft contact lenses. Additionally, they showed that the videokeratoscopy showed differences between both contact lenses, while not the interferometry.…”

Ophthalmological Approach for the Diagnosis of Dry Eye Disease in Patients with Sjögren’s Syndrome

“…This allows the measurement of noninvasive breakup time which is more unambiguous to interpret than the one measured with fluorescein (as the FBUT might be related with local thinning of the tear film rather than with actual breakup event) and has been shown as potentially having a stronger correlation with patient discomfort. Furthermore, noninvasive techniques can be readily used by a broader range of medical personnel, such as technicians and nurses, which allows for more rapid and broadly available diagnostics of DED [87][88][89][90].…”