Automated visual field testing [white-on-white (W-on-W) perimetry] and perimetry of short wavelength sensitive mechanisms [blue-on-yellow (B-on-Y) perimetry] were conducted in both eyes of patients with large asymmetries in intraocular pressure (IOP) between eyes (average difference = 19.9 mm Hg). Overall visual field sensitivity was significantly (P < 0.05) depressed in the eyes with higher IOP by an average of 2.33 dB, in spite of the fact that all but two of the eyes with higher IOP demonstrated visual field sensitivities that were within normal limits. None of the eyes with lower IOP were outside of normal sensitivity limits. B-on-Y perimetry revealed similar findings, except that three of the fellow eyes with relatively lower IOP also demonstrated abnormalities. Our results are consistent with the hypothesis that the diffuse loss in visual field sensitivity in glaucoma is related to IOP. In addition, it appears that short wavelength sensitive mechanism may reveal early glaucomatous losses in patients with elevated IOP.