Original articleThe Accuracy of the Inferior>Superior>Nasal>Temporal Neuroretinal Rim Area Rule for Diagnosing Glaucomatous Optic Disc Damage
Section snippets
Patients and Methods
The study used a cross-sectional, prospective, observational design.
Results
The 2 experts exhibited complete agreement for all 78 individuals with open-angle glaucoma. The assessment of 5 of the 51 normal individuals initially was discordant; these 5 individuals all had exhibited normal discs and intraocular pressures but manifested apparent field loss that had been designated as early glaucomatous. These 5 individuals each underwent re-examination of the visual field, which yielded a normal outcome in all 5 cases.
The descriptive statistics for the biometric variables
Discussion
The principle observation from this study is the low diagnostic power of the ISNT rule and its variants, for any given segment size, in the diagnosis of open-angle glaucoma exhibiting visual field loss ranging from mild to advanced. Although the comparison of the I>T combined with the S>T (i.e., I>T and S>T combined, indicating normality) rule provided greater diagnostic power, the magnitude of the improvement was of little clinical value.
The limitation of the ISNT rule stems largely from its
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Cited by (29)
The ISNT Rule: How Often Does It Apply to Disc Photographs and Retinal Nerve Fiber Layer Measurements in the Normal Population?
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2015, Glaucoma: Second EditionRetinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity
2014, Journal of OptometryCitation Excerpt :The RNFL thickness distribution in normal eyes was such that the inferior quadrant was the thickest followed by superior, nasal and temporal quadrants. This follows the convention that is often referred to as ISNT rule in glaucoma.24 Analysis of RNFL thickness in the glaucomatous, GS and normal eyes revealed a characteristic double hump pattern with RNFL peaks in the superior and inferior quadrants and troughs in the nasal and temporal quadrants in all groups, although this pattern was quite depressed in glaucomatous eyes, further emphasizing the greater reduction in superior and inferior thickness with more progression of glaucomatous damage.
Manuscript no. 2011-233.
Financial Disclosure(s): The author(s) have made the following disclosure(s):
James E. Morgan - Royalties - Haag Streit, UK (paid into a Cardiff University research account).
Supported by the Wales Office for Research and Development, National Assembly for Wales, Cardiff, United Kingdom (grant no.: SG99/265); and the National Eye Research Center (UK), Bristol Eye Hospital, Bristol, United Kingdom. The funding organizations had no role in the design or conduct of this research.