Table 4

Results of ATP assay: mean percentage of cell viability reduction (SD) following 2 hours of incubation with test agent. 50% serum reduced the viability of cultured cells significantly less than unpreserved hypromellose (p = 0.04). 100% serum maintained cellular ATP levels better than 50% serum (p = 0.11) and serum of patients on systemic immunosuppressive therapy was less toxic than serum of healthy normal individuals (p = 0.08) although these trends did not reach statistical significance

% Viability reduction p Value (in comparison with negative control) p Value for other tests
Hypromellose 0.3% unpreserved (n = 4 tests)87 (14)0.03
50% serum (serum diluted 1:1 v/v with 0.5% chloramphenicol eye drops, n = 5 patients)58 (25)0.0460.04 (v Hypromellose 0.3%)
100% serum of normal individual (n = 6)34 (10)0.030.11 (v 50% serum)
100% serum of patients with dry eyes treated with autologous serum (n = 4)24 (22)0.72
100% serum of immunosuppressed patients (n = 8)26 (7)0.170.08 (v serum of normal individuals)