Answered by Shaykh Faraz Rabbani
Are you allowed to close your eyes in Salah with the intention of increasing your concentration??
It is recommended to keep your eyes open in prayer, looking down towards your place of prostration while standing, your feet while bowing, your nose while prostrating, and between your thighs when sitting.
However, if you cannot maintain concentration, then it is not disliked to close your eyes. Some scholars held that one should still close your eyes, for it is the outward practice of the Prophet (Allah bless him and give him peace), while others argued that it would be BETTER to close one’s eyes in such a case, for the inward practice of the Prophet (Allah bless him and give him peace), and the essence of the prayer, is attentiveness (khushu`) and presence of heart with Allah.
And Allah knows best.