Abstract
Purpose :
To determine the factors that influence the satisfaction of the “ISNT” rule (neural rim width: inferior(I)>=superior(S)>=nasal(N)>=temporal(T)) in normal and glaucomatous eyes.
Methods :
Medical records of patients attending Seoul National University Hospital were reviewed. Each group of normal and glaucomatous eyes was divided into subgroups of whether or not they satisfied the ISNT rule. ISNT rule assessment was done by measuring the rim width in stereoscopic optic disc photographs using ImageJ software. Logistic regression analysis was performed to identify the factors affecting the satisfaction of the ISNT rule.
Results :
Seventy seven normal eyes and ninety seven glaucomatous eyes were included. The ISNT rule was intact in fifty nine eyes (76.6%) in normal eye group and was violated in seventy one eyes (73.2%) in glaucomatous eye group. Logistic regression analysis revealed significant influence of the axial length (OR 0.548, P = 0.034) in violation of the ISNT rule in the normal eye group while MD value (OR 1.352, P = 0.045) was a significant factor in the glaucomatous eye group.
Conclusions :
The ISNT rule may not be as effective in detecting early glaucoma. Cautious application of the ISNT rule should be performed when evaluating normal eyes with long axial lengths.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.