Purpose: To investigate the inflammatory response of the ocular surface with different soft contact lens (CL) replacement frequencies and materials.
Methods: Twenty soft CL wearers were required to wear three lens types: reusable Acuvue® 2 (A2), reusable Acuvue® Oasys® (AO) and daily disposable Acuvue® Oasys® (AODD), for one week in random sequence in one eye with the non-lens wearing eye acting as a control. Three methods were used to assess sub-clinical response: tear cytokine evaluation, in vivo confocal microscopy (IVCM), and impression cytology.
Results: Of 13 cytokines investigated, differences were observed only for IL-12p70 which was present in greater concentrations for A2 (interocular difference 8.8pg/ml, 95% confidence interval 5.5-12.1) and AO (8.9 [5.7-12.1]) compared with AODD (3.7 [0.6-6.8]). For IVCM, corneal presumed dendritic cell density was lower for AODD (interocular difference 1.9 [-0.1-3.9] cells/mm2) than for both A2 (9.3 [7.2-11.4]) and AO (10.6 [8.6-12.6]). This trend was the same for the other five IVCM measures evaluated. Proportion of CD45+ cells in the bulbar conjunctiva was lower for AODD (0.6 [-0.3-1.5]%) compared with A2 (4.6 [3.7-5.6]) and AO (4.8 [3.9-5.8]). Similar findings were observed for cells in the upper lid margin.
Conclusion: This work has demonstrated for the first time that daily disposable CL wear produces a minimal sub-clinical inflammatory response compared to no lens wear over one week. In contrast, this inflammatory response is up-regulated with reusable lenses but appears to be similar between hydrogel and silicone hydrogel materials over this short time-frame.