西葛西・井上眼科病院における職業運転手の運転機能評価

Evaluation of professional drivers in the driving assessment clinic in Nishikasai Inouye Eye Hospital

要約　目的：西葛西・井上眼科病院の運転外来にて，視野障害のある職業運転手2例に対して，アイトラッカー搭載ドライビングシミュレータ（DS）を施行した。

症例1：59歳，男性（緑内障）。運送会社のトラック運転手。視力は右（1.0），左（0.4）。Humphrey視野計 中心24-2 SITA standard（HFA24-2）にて，MD値は右−15.42dB，左−26.49dB。中心を含む上半視野障害を認めた。DSを施行したところ，15場面中2場面で事故を起こした（赤信号無視，左からの飛び出し）。リプレイ映像では，上方視野障害により，信号が黄色から赤色に変化していることに気づきにくいことを理解した。

症例2：49歳，男性（網膜色素変性）。ガス会社の営業職。視力は右（1.0），左（1.2）。HFA24-2でのMD値は右−27.46dB，左−27.89dB。輪状暗点を認め，中心視野は10°以内であった。上司の立ち合いのもと，DSを施行したところ，15場面中4場面（すべて左右からの飛び出し）で事故を起こした。求心性視野狭窄により左右の飛び出しに対応できなかったことを理解した。

結論：DSを施行したことで，患者本人や職場の関係者に視野障害による運転の危険性について理解し，納得してもらうことができた。

Abstract　Purpose：We performed a driving simulator（DS）equipped with an eye tracking device on two professional drivers with visual field impairment at the driving assessment clinic in Nishikasai Inouye Eye Hospital.

Case 1：A 59-year-old truck driver consulted our clinic. He had primary open angle glaucoma with best-corrected visual acuity 20/20 in the right eye and 20/50 in the left eye. The mean deviation of his visual field was −15.42 dB in the right eye and −26.49 dB in the left eye, and his superior retinal sensitivity was reduced. In the simulation, he had accidents in 2 out of 15 scenarios. He ignored a red light, and he hit a car coming from the left. Watching a replay of the simulation helped the patient understand that his superior visual field defect seemed to have made it difficult to notice the signal changing from yellow to red.

Case 2：A 49-year-old man with retinitis pigmentosa. His best-corrected visual acuity was 20/20 in the right eye and 20/15 in the left eye. The mean deviation of his visual field was −27.46 dB in the right eye and −27.89 dB in the left eye, with a concentric visual field constriction of 10°. In the simulation, he had accidents in 4 out of 15 scenarios. When the patient and his supervisor viewed the replay, we explained that the patients' visual field constriction made it difficult to notice the hazards coming from the left and right.

Conclusions：The driving assessment clinic allowed us to explain specific accident types that can occur due to a patient's pattern of visual field impairment using the DS. It also helps patients, families, and co-workers understand the dangers they face and specific situations that call for caution.