光干渉断層計アンギオグラフィを用いた正常眼の中心窩無血管野の評価

Foveal avascular zone in healthy eyes evaluated by en face optical coherence tomography angiography

要約　目的：光干渉断層計アンギオグラフィを用いて正常眼の中心窩無血管野（FAZ）の形状を評価した。

対象と方法：屈折異常と加齢白内障以外に眼科的異常のない日本人44名72眼に対し，AngioVue^TMを用いて黄斑内層のangioflow像を取得し，ImageJでFAZの大きさや面積を算出した。また，形状を分類した。

結果：FAZ面積は平均0.280±0.097（平均値±標準偏差）mm²で，有効直径は平均0.597mmであった。FAZ面積と中心窩網膜厚との間に相関はなかった。両眼が正常である対象者のうちで，FAZ面積の左右差が10％未満で，かつ両眼同形は25％であった。

結論：FAZは正常眼でも変化に富む。

Abstract　Purpose：To report findings of foveal avascular zone（FAZ）in healthy eyes evaluated by en face optical coherence tomography angiography.

Cases and Method：This study was made on 72 eyes of 44 Japanese adults who were seen by us for 5 months through August 2015 and who showed no ocular lesions except mild refractive anomalies and senile cataract. The age ranged from 20 to 83 years, average 55 years. They were evaluated regarding angioflow image of superficial macular layer by AngioVue^TM. The size and area of FAZ was evaluated using ImageJ.

Findings：The shape of FAZ was classified to either round, oval, or irregular. Area of FAZ averaged 0.280±0.097 mm². Its effective diameter averaged 0.597 mm. Area of FAZ was correlated neither with age, refraction, axial length, nor thickness of central fovea. In the present series of normal eyes, only 25％ of the cases showed the same shape of FAZ with less than 10％ of difference in its diameter between both eyes.

Conclusion：The size and shape of FAZ are widely variable even in normal eyes.