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Vicente Martín-Montañez, Alberto López-Miguel, Alberto López de la Rosa, Itziar Fernández, Margarita Calonge, Jose Manuel Gonzalez-Meijome, Maria-Jesus J. Gonzalez; Effect of environmental conditions in contact lens wearers. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4669. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the effects of two environmental conditions, recreated within an environmental chamber, in hydrogel (Hy) and silicone-hydrogel (Si-Hy) contact lens (CL) wearers.
Fifty-four subjects were exposed to two environmental conditions: standard (STA): 50% relative humidity (RH), 23°C and 930 mb of pressure (P); and adverse (ADV): 5% RH, 23°C, 750 mb (P) and air flow. Subjects were bilaterally fitted with Hy (Omafilcon A -OMA-) and Si-Hy CL (Comfilcon A -COM-) and were exposed for 90 minutes to each environment in four different visits. Changes in comfort, dryness, blurred vision, visual acuity, osmolarity, NIBUT, phenol red thread test, bulbar and limbal hyperemia, limbal conjunctival and corneal staining and CL dehydration were assessed.
Comfort decreased (p≤0.05) for OMA-STA (pre: 7.81±1.7, post: 7.4±1.7), COM-STA: (pre: 8.45±1.31, post: 7.32±1.99), OMA-ADV (pre: 7.96±1.75, post: 7.22±2.07) and COM-ADV (pre: 8.56±1.48, post: 7.44±1.82). Dryness increased (p≤0.05) for OMA-STA (pre: 2.2±2.23, post: 3.09±2.49), COM-STA (pre: 1.74±1.96, post: 3.49±2.45), OMA-ADV (pre: 1.5±1.8, post: 3.52±2.47) and COM-ADV (pre: 1.37±1.46, post: 3.28±2.41). Blurred vision increased (p≤0.05) in COM-STA (pre: 1.08±1.55, post: 1.66±1.94) and COM-ADV (pre: 1.12±1.61, post: 1.6±1.97). Tear osmolarity decreased (p≤0.001) for OMA-STA (pre: 325.13±23.84, post: 319.72±16.12 mOsm/L) and COM-STA (pre: 325.41±21.46, post: 320.63±19.38 mOsm/L). NIBUT decreased (p≤0.005) in OMA-ADV (pre: 8.15±6.4 s, post: 6.4±2.24 s) and COM-ADV (pre: 7.06±3.06 s, post: 5.91±1.92 s). Dehydration of CL was 13.35±3.48% for OMA-STA, 21.11±2.73% for COM-STA, 15.27±3.37% for OMA-ADV and 22.7±3.36% for COM-ADV (p<0.0001). Hyperemia and staining results are expressed in Table 1.
Environmental chambers can be a useful tool to understand the adverse effects of environment, CL materials or their combined effects in the development of CL discomfort.
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