Assessment of the ISNT Rule on Publicly Available Datasets

AimsTo evaluate the accuracy of the ISNT rule (I=inferior, S=superior, N=nasal, T=temporal) and its variants with neuroretinal rim width and retinal nerve fibre layer (RNFL) thickness measurements differentiating normal from glaucomatous eyes.MethodsThe diagnosis accuracy of the ISNT rule and its variants was evaluated in a population-based study. Neuroretinal rim widths were measured on monoscopic optic disc photographs with an image-processing program. RNFL thickness measurements were obtained with spectral-domain optical coherence tomography (SD-OCT).ResultsIn this study including 940 normal subjects and 93 patients with glaucoma, the sensitivity of the ISNT rule with optic disc photographs was 94.1% (95% CI 90.2 to 98.1), whereas its specificity was 49.2% (46.9 to 51.6). When using the IST rule, the sensitivity decreased to 69.9% (62.1 to 77.6) with a higher specificity, 87.0% (85.3 to 88.6). All the diagnosis indicators were somewhat lower for the different rules using RNFL thickness: the sensitivity of the ISNT rule was 79.4% (72.6 to 86.2) and its specificity was 34.1% (31.9 to 36.4). With the IST rule, the sensitivity decreased to 50.0% (41.6 to 58.4) while the specificity increased to 64.9% (62.7 to 67.2).ConclusionsThe ISNT and IST rules applied to neuroretinal rim width measurement by optic disc photographs are useful and simple tools for differentiating normal from glaucomatous eyes. The translation of these rules to RNFL thickness by SD-OCT is of limited value.

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An automatic glaucoma screening algorithm using cup-to-disc ratio and ISNT rule with support vector machine

IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society ◽

10.1109/iecon.2015.7392152 ◽

2015 ◽

Author(s):

W. Ruengkitpinyo ◽

P. Vejjanugraha ◽

W. Kongprawechnon ◽

T. Kondo ◽

P. Bunnun ◽

...

Keyword(s):

Support Vector Machine ◽

Support Vector ◽

Glaucoma Screening ◽

Screening Algorithm ◽

Isnt Rule ◽

Cup To Disc Ratio

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Use of the ISNT rule for optic disc evaluation in 40 to 79 year old patients seen in optometric practice

Scandinavian Journal of Optometry and Visual Science ◽

10.5384/sjovs.vol3i1p16 ◽

2010 ◽

Vol 3 (1) ◽

pp. 16-22 ◽

Cited By ~ 1

Author(s):

Per O. Lundmark ◽

Göran B. Skjöld ◽

Paal A. Nævdal ◽

Ole K. Volden ◽

Morten Belgum

Keyword(s):

Optic Disc ◽

Old Patients ◽

Isnt Rule

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ISNT rule satisfaction in Korean non-glaucomatous subjects

European Journal of Ophthalmology ◽

10.1177/1120672119876824 ◽

2019 ◽

pp. 112067211987682

Author(s):

Yoon Pyo Lee ◽

Jin Woo Ro ◽

Kayoung Yi ◽

Dong Gyu Choi

Keyword(s):

Medical Records ◽

Neuroretinal Rim ◽

Fundus Photographs ◽

Isnt Rule

Purpose: To evaluate the efficacy of the ISNT rule in normal eyes of Koreans. Methods: We retrospectively reviewed medical records of 890 subjects with fundus photographs and evaluated the presence of the cup and ISNT rule satisfaction. If the ISNT rule was violated, the quadrants in which the neuroretinal rim was thinnest and thickest, respectively, were evaluated. Results: Among 890 eyes, 84.7% showed the cup. The subjects without the cup were significantly younger and more hyperopic. Among 754 eyes with the cup, 53.5% showed ISNT rule satisfaction. In 351 eyes violating the ISNT rule, the most common quadrant showing the thickest neuroretinal rim was the inferior (65.5%), and the thinnest, the temporal (98.3%). Conclusion: The cup was absent in 15% of the assessed eyes. Only about half of eyes with the cup showed ISNT rule satisfaction. Even in eyes violating ISNT rule, the inferior was the most common quadrant with the thickest neuroretinal rim and the temporal, the thinnest.

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