Glaucoma Pattern Index to Quantify Glaucomatous Visual Field Loss

The visual field indices mean defect (MD), corrected loss variance (CLV). and short-term fluctuation (SF) are statistical summaries that do not incorporate valuable information about typical patterns of glaucomatous visual field loss. We have developed an index sensitive to visual field defects that conform to empirically defined patterns of early glaucomatous visual field loss. One hundred and eleven reliable visual fields of 97 glaucoma patients with localized scotomas were analyzed to define defect patterns. A glaucoma pattern index (GPI) was empirically developed that quantified defects that corresponded to these glaucomatous visual field defects. GPI was then compared to existing indices in a separate group of 75 eyes of 75 patients with early glaucoma and 75 eyes of 75 age-matched normals. GPI had a specificity of 88% and sensitivity of 88%. whereas corresponding values for MD were 80% and 89%; for CLV, 80% and 85%; and for SF, 70% and 81%. GPI had a higher specificity and a higher diagnostic precision than the other indices and may help identify patterns specific for early glaucomatous visual field loss.