網膜症のない糖尿病の網膜神経線維層

Retinal nerve fiber layer in diabetic persons without retinopathy

要約　目的：網膜症のない糖尿病患者での網膜神経線維層厚の臨床的要因による検索。対象と方法：年齢を調整した後，対象を網膜症のない糖尿病150眼，コントロールを正常眼66眼と正常眼圧緑内障47眼とした。このうち1年後に，糖尿病60眼と正常26眼を再測定した。網膜神経線維層厚は光干渉断層計OCT3で測定し，乳頭全周とその4方向を検索した。結果：糖尿病群の網膜神経線維層厚は正常に比べやや薄く（p＜0.05），1年後にはさらに減少した（p＜0.05）。網膜神経線維層厚は加齢により減少し，その程度は正常よりも糖尿病群でやや強い（p＜0.001）。網膜神経線維層厚は糖尿病の罹患年数と負の相関があり，HbA1cとの相関は低い。糖尿病者での網膜神経線維層厚の下限値は，正常眼圧緑内障での上限値と重複した。結論：網膜症のない糖尿病者では網膜神経線維層厚が減少し，正常眼圧緑内障を発症する可能性があり，鑑別を要する。

Abstract.　Purpose：To evaluate the thickness of retinal nerve fiber layer（RNFL）in diabetic patients without retinopathy. Cases and Method：This study was made on 150 eyes of 150 diabetics. Diabetic retinopathy was not present by routine ophthalmological examinations. Other groups of 66 normal eyes and 47 eyes with normal-tension glaucoma served as control. Sixty diabetic eyes and 26 normal eyes were examined again after one year. An optical coherence tomograph（OCT 3）was used to measure the thickness of RNFL around the optic disc in 4 quadrants. Results：Thickness of RNFL was significantly less than in normal. The difference became more pronounced one year later. Thickness of RNFL in diabetics decreased along with increase in age and was not related with serum HbAlc. The lower limit of thickness of RNFL in diabetics overlapped the upper limit of normal-tension glaucoma. Conclusion：Thickness of retinal nerve fiber layer（RNFL）decreases in diabetic patients without retinopathy. There may be a risk in these eyes to develop normal-tension glaucoma.