Abstract
Purpose :
Wind stimulation is an environmental factor that causes contact lens (CL) discomfort. We investigated the changes in ocular surface temperature and blood flow resulting from wind stimulation in soft CL (SCL) wearers.
Methods :
We recruited 21 SCL wearers (21 eyes; mean age, 25.3±4.2 years) who wore two 1-day disposable silicone hydrogel lens (narafilcon A and delefilcon A). We measured the conjunctival blood flow, ocular surface temperature, and non-invasive tear break-up time (NIBUT) with/without SCLs after wind stimulation, which was created by a fan that directed wind at the rate of 3.0 meters/second to the volunteers’ faces for 10 minutes while wearing and not wearing SCLs. The blood flow was measured as the mean blur rate (MBR) using laser speckle flowgraphy (LSFG-OAS, Softcare). The temperature and NIBUT measurements were conducted using ocular surface thermography (TG-1000, Tomey) and tear film interferometry (DR-1 Alpha, KOWA), respectively. Dryness was evaluated using the visual analog scale (VAS), with 0 indicating no symptoms.
Results :
After wind stimulation, the NIBUT and VAS score for dryness symptoms with the delefilcon A lens (3.7±1.7 seconds and 29.4±16.9, respectively) were significantly (P<0.01 for both comparisons, paired t-test) longer and lower than with the narafilcon A lens (2.3±1.7 seconds and 35.9±17.0, respectively). Compared with no SCL, the corneal and bulbar conjunctival temperatures with SCLs decreased significantly (P<0.01 for both comparisons). The temperature difference between with/without the delefilcon A lens (-0.36±0.35°C) was significantly (P<0.01) lower than with the narafilcon A lens (-0.60±0.42°C). Although the bulbar conjunctival blood flow with the narafilcon A lens increased significantly (P<0.05) compared with no SCL (174.3±39.6 vs 158.7±33.2), that with the delefilcon A lens (156±42.3) did not reach significance. The rate of blood flow after wearing the narafilcon A lens (1.11±0.21) was significantly (P<0.05) higher than with the delefilcon A lens (0.99±0.19).
Conclusions :
CLs with a lower NIBUT and more dryness show significantly greater changes in blood flow and temperature after wind stimulation. The wind stimulation test may be useful as a stress test for CL wear.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.