"The Number" is one of the Nerve Fiber Analyzer (GDx)
parameters, which uses trained neural network to consider more than 200
parameters obtained when the image is acquired. The Number is currently under evaluation, but provisionally
the ranges of 0-30, 31-70 and 71-100 are determined to be normal, glaucoma
suspect, and glaucoma, respectively.
In this study, we investigated the clinical effectiveness of the
Number. Twenty-five eyes of 25
normal persons, 9 eyes of 9 ocular hypertensive patients (OHT) and 42 eyes of
42 glaucoma patients were studied.
Three consecutive GDx images were averaged to obtain a mean image. The
24-2 Program of the Humphrey Field Analyzer (HFA) was also performed on each
subject. All glaucoma patients had
either an abnormal glaucoma hemifield test or one of the visual field indices
(MD, CPSD) below the 5% probability level. The average values of the Number were 36.6±}20.4 in normal
group, 42.6±}23.1 in OHT group, and 67.4±}19.2 in glaucoma group, and
significant differences were found between normal and glaucoma groups, and between
OHT and glaucoma groups (p<.01).
Forty-eight percent of normal group and 50% of glaucoma group were in
the Number range of 31-70 and were therefore classified as glaucoma suspects. Using a Number cutoff of 50, the
sensitivities were 81%, 71%, and 88% for all, early, and moderate or advanced
glaucoma patients, respectively, with a specificity of 80%. Conclusions: The Number was the most
promising parameter for diagnosing glaucoma.