Background To examine an effect of intravitreally applied antibodies against epidermal growth factor family members, namely epiregulin, epigen and betacellulin, on ocular axial elongation. Methods The experimental study included 30 guinea pigs (age:3-4 weeks) which underwent bilateral lens-induced myopization and received three intraocular injections of 20 mu g of epiregulin antibody, epigen antibody and betacellulin antibody in weekly intervals into their right eyes, and of phosphate-buffered saline into their left eyes. Seven days after the last injection, the animals were sacrificed. Axial length was measured by sonographic biometry. Results At baseline, right eyes and left eyes did not differ (all P > 0.10) in axial length in neither group, nor did the interocular difference in axial length vary between the groups (P = 0.19). During the study period, right and left eyes elongated (P < 0.001) from 8.08 +/- 0.07 mm to 8.59 +/- 0.06 mm and from 8.08 +/- 0.07 mm to 8.66 +/- 0.07 mm, respectively. The interocular difference (left eye minus right eye) in axial elongation increased significantly in all three groups (epiregulin-antibody:from 0.03 +/- 0.06 mm at one week after baseline to 0.16 +/- 0.08 mm at three weeks after baseline;P = 0.001); epigen-antibody group:from -0.01 +/- 0.06 mm to 0.06 +/- 0.08 mm;P = 0.02; betacellulin antibody group:from -0.05 +/- 0.05 mm to 0.02 +/- 0.04 mm;P = 0.004). Correspondingly, interocular difference in axial length increased from -0.02 +/- 0.04 mm to 0.13 +/- 0.06 mm in the epiregulin-antibody group (P < 0.001), and from 0.01 +/- 0.05 mm to 0.07 +/- 0.05 mm in the epigen-antibody group (P = 0.045). In the betacellulin-antibody group the increase (0.01 +/- 0.04 mm to 0.03 +/- 0.03 mm) was not significant (P = 0.24). Conclusions The EGF family members epiregulin, epigen and betacellulin may be associated with axial elongation in young guinea pigs, with the effect decreasing from epiregulin to epigen and to betacellulin.