Transforming growth factor beta (TGF-beta) plays an important role in anterior segment wound healing, by controlling the cell proliferation and differentiation, angiogenesis, extracellular matrix composition and mediating the immunosuppressive properties of the aqueous humor. The present study was undertaken to clarify the possible changes of aqueous humor TGF-beta(1) levels after excimer laser photoablation. Twenty-eight New Zealand rabbits were divided into four groups of 7 rabbits each. Group 1 served as control, the central 7 mm of corneal epithelium was removed in groups 2, 3 and 4. We performed 50-mu m corneal photoablation in group 3, and 100-mu m ablation in group 4. After 48 h we measured the TGF-beta(1) levels of the aqueous humor by ELISA method. The mean TGF-beta(1) value of the aqueous humor was found to be 162.94 +/- 13.73 pg/ml in the control group. Mechanical deepithelialization did not change the TGF-beta(1) levels of the aqueous humor (p>0.05). There was no significant difference between the 50-mu m photoablated group and the controls (p>0.05), but the TGF-beta(1) levels of the 100-mu m photoablated group were found to be significantly higher than those of both the control group and 50-mu m photoablated group (p<0.05). Many factors and cytokines may induce corneal haze and myopic regression after excimer laser photoablation; our study demonstrated that TGF-beta(1) is one of these factors and there is a positive correlation between the depth of corneal photoablation and aqueous TGF-beta(1), concentrations.