スペクトラルドメインOCTによる健常眼の網膜神経線維層厚と視神経乳頭面積の関係

Correlation between retinal nerve fiber layer thickness and optic disc size in healthy eyes measured by spectral domain optical coherence tomography

要約　目的：健常眼の網膜神経線維層厚と視神経乳頭面積（以下，乳頭面積）との関係を屈折別に検討した報告。対象と方法：対象は屈折が－3.0Dより近視度数が大きい近視眼50眼と小さい非近視眼41眼。スペクトラルドメインOCTを用いて視神経乳頭周囲網膜神経線維層厚と乳頭面積を測定。結果：乳頭面積は近視眼のほうが非近視眼より有意に小さかった。近視眼では乳頭面積が小さいほど上側網膜神経線維層が薄く，耳側網膜神経線維層が厚くなり，非近視眼では，乳頭面積が大きいほど鼻側網膜神経線維層が厚かった。結論：健常眼では近視が強いほど乳頭面積は小さくなる。乳頭面積と網膜神経線維層厚との関係は近視眼と非近視眼とでは異なる。

Abstract.　Purpose：To report the correlation between retinal nerve fiber layer（RNFL）thickness and disc size in healthy Japanese eyes measured by spectral domain optical coherence tomography（SD-OCT）. Cases and Method：This study was made on 91 eyes of 51 healthy persons. The age ranged from 25 to 81 years, average 59 years. The refraction ranged from －11.5 to ＋2.5 diopters, average －3.95 diopters. There were 50 eyes with myopia greater than －3 diopters and 41 eyes with lesser or no myopia. All the eyes were evaluated for RNFL thickness and area of optic disc using an SD-OCT. Results：Size of optic disc was negatively correlated with the absolute amount of myopia（r＝＋0.58, p＜0.01）. In eyes with myopia greater than －3 diopters, smaller optic disc showed thinner RNFL superior to the disc and thicker RNFL temporal to the disc. In eyes with myopia less than －3 diopters, larger optic disc showed thicker RNFL nasal to the disc. Conclusion：Size of optic disc is smaller in eyes with greater myopia. Relation between disc size and RNFL thickness differs between eyes with myopia greater than －3 diopters than eyes with lesser or no myopia.