Figure 2.

In vivo release of diadenosine tetraphosphate from silicon contact lenses and effect on tear secretion. (A) In vivo release of Ap₄A from non-ionic and ionic silicon contact lenses together with a topical application of 1 mM Ap₄A (10 μl) (n = 3). (B) Variation of tear secretion, induced by Ap₄A released from non-ionic and ionic silicon contact lenses together with a topical application of 1 mM Ap₄A (10 μl) (n = 3). Zero represents the baseline tear secretion which corresponded to a Schirmer score of 12 ± 1 mm.