Importance of visual field score and asymmetry in the detection of glaucoma

The visual fields and intraocular pressures (IOP's) of 115 normal volunteers and 107 suspect/diagnosed early glaucoma subjects were recorded by Friedmann static perimetry and noncontact tonometry or applanation tonometry. The visual field data were analyzed statistically and quantified numerically by a microcomputer. The readings obtained from the suspect/diagnosed early glaucoma subjects were compared to those from an age-matched control group according to four criteria: (1) highest field score; (2) field score asymmetry; (3) highest IOP; and (4) IOP asymmetry. A combined field score and asymmetry analysis was found to be more sensitive, 86%, than a combined IOP and IOP asymmetry analysis, 56%. The combined field score and field score asymmetry analysis also gave a clear bimodal separation of subjects with early visual field defects from those with normal visual function.