人間ドック受診者の午前と午後の眼圧の差異

Intraocular pressure in morning and afternoon hours in subjects undergoing a health checkup

　眼圧には日内変動が存在するが，眼圧スクリーニングでは，測定時間は必ずしも考慮されていない。筆者らは，1泊2日の人間ドック受診者1,097例に対して，初日の14時と翌日の9時の2回眼圧を測定し，その差異について検討した。その結果，右眼の平均眼圧は，14時が12.9±2.6mmHg,9時が14.0±2.8mmHgで，9時の眼圧が有意に高く（P＜0.0001），9時の眼圧から14時の眼圧を引いた眼圧差は，9時の眼圧と正の相関を示した（R＝O.419,P＜0.0001）。また，21mmHg以上の眼圧は，14時が7例10眼，9時が20例30眼に記録され，21mmHg以上の眼圧は9時に多かった（χ²検定，P＜0.005）。したがって，眼圧スクリーニングは午前に行うことが望ましいと思われた。

We measured the intraocular pressure (IOP) in 1097 subjects who underwent health checkup under hospitalization. IOP was measured at 1400 hours the first day and at 0900 hours the next morning. At the first measurement, the IOP in the right eye averaged 12.9±2.6mmHg (mean±SD) at 1400 and 14.0±2.8mmHg at 0900. The difference was signifi-cant (p＜0.0001). The difference in IOP between the two measurements was directly proportional to theIOP value at 0900 (R=0.419, p＜0.0001). IOP equal to or greater than 21mmHg was recorded in 10 eyes of 7 subjects at 1400 and in 30 eyes of 20 subjects at 0900. Elevated IOP was more frequently observed at 0900 than at 1400 (chi square test, p＜0.005). These findings show that a large proportion of eyes with elevated IOP in the morning shows a decrease in the afternoon. We recommend tonometry in the morning for IOP screening.