Clinical Significance of Nasal Step Index in Early Glaucoma

ABSTRACT

Nasal step index(NSI) is an index of light sensitivity of the nasal step area, the early sign of visual field defects in glaucoma. It represents the asymmetry between the upper-nasal and lower-nasal quadrant within 30 degree field. We applied this index to 66 eyes with normal visual field and 204 eyes with mild-to-moderate glaucomatous visual field defect (mean defect(MD)or=1.04), respectively. AUC values related to the validity of this study were NSI-10.38, NSI-2;0.44 and MD;0.83 in early glaucoma patients. But AUC values in high NFBI patients were NSI -1;0.50, NSI -2;0.50, MD;0.82. Therefore, NSI is shown to have lesser diagnostic value than MD in detection of early glaucoma in this study.