Glaucoma Hemifield Test. Automated visual field evaluation.

We have developed an algorithm, the Glaucoma Hemifield Test (GHT), for automated evaluation of single static threshold visual field test results in glaucoma. The GHT uses empirically determined limits of normality for up-down differences in the Statpac probability maps of the Humphrey Field Analyzer to detect localized visual field loss. It is also constructed to detect field loss that is symmetric around the horizontal meridian. Analysis is done in five corresponding pairs of sectors that are based on the normal anatomy of the retinal nerve fiber layer. Deviations from the age-corrected normal threshold in the most sensitive portions of the visual field are used to detect general reductions of sensitivity or abnormally high sensitivities. The GHT provides brief visual field evaluations printed on the field chart as plain text. The aim of this article is to describe the fundamentals of the analysis program and to provide clinical examples.