The effect of timolol on the concentrations of albumin and IgG in the aqueous humor of the human eye.

We investigated albumin and IgG concentrations in the aqueous humor of 41 patients before intracapsular cataract extraction (primary samples) and at the end of surgery (secondary samples). Albumin and IgG concentrations were determined in all samples by means of a quantitative fluoroimmunoassay. A short-term topical application of timolol in 24 eyes was associated with a significant increase in both proteins in the primary aqueous humor samples compared with 17 control samples (P less than .005). The ratios of albumin to IgG--even when corrected for serum levels--were not significantly different in the two groups. Timolol did not affect the change in these ratios in the secondary aqueous humor samples. Thus, we concluded that these findings were not caused by a breakdown of the blood-aqueous barrier, but rather resulted from reduced aqueous humor flow and undisturbed protein filtration.