Evaluation of the retinal nerve fiber layer in early glaucoma. Physiological and pathological findings

In this study on retinal nerve fiber layer (RNFL) evaluation in early glaucoma we investigated whether the greatest retinal vein width is a usable measure to distinguish physiological findings from beginning pathological defects. Seven normal control eyes and 23 glaucomatous eyes with small relative Octopus defects (greater than 10 db and less than 20 db) were photographed. In the control group 3 eyes had no RNFL loss, 4 eyes had localized defect less than 1 vein width. In the glaucoma group 1 eye had a localized defect less than 1 vein width, 7 eyes had localized defects greater than or equal to 1 vein width and 12 eyes had diffuse defects. Based on the present study it seems reasonable to define small localized defects as pathological if they at any point are greater than or equal to 1 vein width. According to this definition our study showed a specificity of 100% and sensitivity of 95% which means that the method is usable as an extra parameter in the diagnosis of early glaucoma.