To the Editor.
—Among the plethora of reports of cup-disc parameters associated with glaucomatous optic nerve damage, the recent article by Balazsi et al1 in the July Archives stands out as a carefully conducted study documenting the potential importance of an intrinsically sensible variable. Given a normal number of retinal nerve fibers, the total neuroretinal rim area should be more resistant to normal variation of the size of the scleral opening than is the cup-disc ratio. The authors found that cases of suspected and early open-angle glaucoma were more closely correlated with neuroretinal rim area than with either vertical or horizontal cup-disc ratio. The following points, however, are worthy of comment:
The authors indicated that corrected neuroretinal rim area (cNRA) "was the only disc parameter in our small sample able to discriminate between the normal subjects, patients with suspected glaucoma, and those suffering from early chronic open-angle glaucoma."
Alfred Sommer. Neuroretinal Rim Area. Arch Ophthalmol. 1984;102(11):1583–1584. doi:10.1001/archopht.1984.01040031283003