Fiqh-us-Sunnah Volume 2, Supererogatory Prayer, Fiqh 2.092A.

Some say that this act is disliked while others hold that it is allowed, though disliked. Those hadith which state it is disliked are not authentic.

Ibn al-Qayyim said: “The correct position is: if keeping one’s eyes open does not affect one’s attention, then it is preferred to keep them open; however, if there is something in front of the person, such as some ornament or decoration, which could affect his attention, then it is, in no way, disliked to close his eyes. In fact, under such circumstances, to say it is preferred to close one’s eyes is more consistent with the principles and goals of the shar’iah than to say that it is disliked.”