The ISNT rule and differentiation of normal from glaucomatous eyes. Academic Article uri icon

Overview

abstract

  • OBJECTIVE: To determine whether the ISNT rule (that normal eyes show a characteristic configuration for disc rim thickness of inferior > or = superior > or = nasal > or = temporal), widely used for clinical evaluation of the optic nerve head, can differentiate normal from glaucomatous eyes. METHODS: All subjects underwent complete eye examination, including achromatic automated perimetry, simultaneous stereoscopic disc photography, and confocal scanning laser ophthalmoscopy. Subjects with normal eyes had no evidence of glaucoma or ocular hypertension and had normal perimetry measurements. Subjects with glaucoma had a reproducible visual field defect. One eye from each subject was randomly enrolled. The ISNT rule was assessed by masked evaluation of disc photographs at the 3, 6, 9, and 12 o'clock positions. RESULTS: Sixty-six subjects with normal eyes (33 black and 33 white individuals) and 43 with open-angle glaucoma (15 black and 28 white individuals) were enrolled. The ISNT rule was intact in 52 (79%) of 66 normal eyes and 12 (28%) of 43 glaucomatous eyes (P<.001). Multiple logistic regression indicated that the odds ratio for glaucoma associated with violation of the ISNT rule was 6.04 (95% confidence interval, 1.74-20.95) after adjustment for age; race was not a confounder of this association. CONCLUSION: The ISNT rule is useful in differentiating normal from glaucomatous optic nerves and is unaffected by race.

publication date

  • November 1, 2006

Research

keywords

  • Diagnostic Techniques, Ophthalmological
  • Glaucoma, Open-Angle
  • Optic Disk
  • Optic Nerve Diseases

Identity

Scopus Document Identifier

  • 33751016786

Digital Object Identifier (DOI)

  • 10.1001/archopht.124.11.1579

PubMed ID

  • 17102005

Additional Document Info

volume

  • 124

issue

  • 11