[The neuroretinal rim area and the rim disc areal ratio in normal eyes]

A study of the neuroretinal rim area (NRA) and the rim disc areal ratio (R/D) in normal, suspected low tension glaucoma and low tension glaucoma eyes indicated that NRA had greater variation than did R/D in normal eyes, and NRA was positively correlated with the disc area whereas R/D was not. Meanwhile, R/D was more sensitive to glaucoma than was NRA or the cup and disc ratio, suggesting that R/D was useful in early diagnosis of glaucoma.