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Wing Li, Andrew Graham, Thomas Dursch, Diana Yan, Meng C Lin; Worsening contact lens dryness associated with increased rate of cooling in symptomatic contact lens wearers.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3046. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
In this study we examine the rate of cooling over contact lens (CoCL) and subjective symptom ratings over 6 hours of contact lens wear, and determine whether the relationship between changes in CoCL and changes in symptoms differs between symptomatic (Sx) and asymptomatic (Asx) contact lens wearers (CLW).
Nineteen Sx CLW and 21 Asx CLW wore Biofinity CL for six hours at each of 2 visits, separated by at least 1 week. CL comfort and dryness were rated using a visual analog scale after 10 minutes and after 6 hours of wear. Rate of CoCL during each subject’s maximum sustainable inter-blink period was measured using an infrared thermographer (FLIR a655sc). The ΔCoCL, ΔCL comfort and ΔCL dryness are defined as the values obtained after 6 hours of CL wear minus their respective baseline values obtained 10 minutes after insertion.
The mean ΔCoCL rate was -0.020C/s (range: -0.16 to 0.070C/s; a negative ΔCoCL denotes less cooling after 6 hours of CL wear). There was no significant difference in ΔCoCL between Sx and Asx subjects (p=0.83). Using a linear mixed effects model, greater ΔCoCL was associated with increased dryness rating in the Sx group (p=0.01) but not the Asx group (p=0.47). The model estimates that among Sx subjects a 37-point higher dryness rating is associated with the maximum ΔCoCL measured (0.070C/s) compared to the minimum ΔCoCL measured (-0.160C/s). No significant association was found between ΔCL comfort and ΔCoCL in either group.
An increase in CoCL over 6 hours of CL wear was found to be associated with worsening dryness ratings in Sx CL wearers but not in Asx CL wearers, suggesting that sensitization of cold nociceptors may occur in symptomatic patients.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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