[A study of neuroretinal rim morphology in physiologic large cups and early glaucoma]

To find the differences of the physiologic large cups from the optic cup of early glaucoma.

The morphology of neuroretinal rim was studied. The subjects were divided into two groups: (1) 54 cases 88 eyes with physiologic large cups defined by cup/disk (C/D) ratio more than 0.6, optic disk areas more than 2.8 mm2, without neuroretinal rim loss within 3-6 years of follow-up, normal intraocular pressure and visual field. (2) 68 cases 89 eyes with early glaucoma defined by visual field defects, neuroretinal rim loss in follow-up and C/D ratio less than 0.8. The indexes of neuroretinal rim related to morphology are a series of rim widths and a parameter of cupping morphology which is a ratio of the vertical C/D over the horizontal C/D.

The characteristics of a physiologic large cup are a large optic disk, a horizontal elliptic cupping and the widest neuroretinal rim at the inferior, followed by superior, nasal and temporal, while the characteristics of optic nerve head of glaucoma are normal size of optic disk, vertical elliptic cupping and the widest rim not at the inferior, since the inferior rim is subject to glaucomatous damage.

To differentiate a physiologic large cup from a glaucomatous one, the most effective way is to apply the parameter of cupping morphology in combination with neuroretinal rim area and optic disk area in the multivariate discrimination.