There are two types of ways and reasons why, an individual closes their eyes when vocalizing high-pitch sounds.
(1)Closing of the eyes during a performance as an emotional effect or reaction/feeling to the song
(2)Closing of the eyes because it is hard to let out the voice
The main question is whether you close your eyes consciously or unconsciously.
I can identify which category your fall into if I carefully listen and visually observe your singing.
An important point most vocalists want to achieve, is that their singing can impress an audience.
If you want to impress people, you must display “(1)Closing the eyes as an emotional effect during a performance.”.
In the case of (1) which is closing the eyes consciously, an audience generally feels more comfortable when listening to the song.
(2) Is the case when the eyes are closed unconsciously. This happens when a vocalist cannot completely control high-pitch sounds, by not even realizing or thinking they will close their eyes.
The reason why they close their eyes is because they are afraid of making high-pitch sounds, or lacking confidence in their voice.
The also can be explained in terms of physiology.
Such as, when people feel afraid. When feeling afraid the head’s skin is moved by the frontalis muscle and the occipitalis muscle, in turn making the eyes close.
This is common and happens often unconsciously when singing. People who can control the high-pitched sounds they produce are not feeling afraid so easily or lacking confidence, and do not close their eyes.
Therefore, if you can focus on improving the control you have with your voice when singing high-pitched sounds, you will not unconsciously close your eyes so often anymore when vocalizing.
Note1:This is same concept as shaking of the body unconsciously when letting out high-pitch sounds.
Note2:It is okay to close your eyes for short periods of time when singing ballads, rock or pop music. It is not appropriate and sometimes even frowned upon to close your eyes when singing opera or classic style songs. The only time it is appropriate is periodically and consciously during an emotional part of a performance.
I’ll teach you a training exercise to help in avoiding closing of the eyes.
1:Open your eyes widely.
2:Lift up your eyebrows simultaneously.
3:Keep your eyebrows up high, followed by up in the middle high state and put some muscle into it. These muscle movements are similar just reversed to when closing the eyelids tight.
4:You can blink of course, but no need to close your eyes.
5:Sing a song for only 3 to 5 minutes with above conditions.
You can train like this once per day. In front of a mirror if you like, to watch yourself to see if you close your eyes. This is only temporary training until the issue is fixed, and not meant to be incorporated into your permanent vocal training schedule.
Please use discretion and do not work too hard because you could hurt your muscles, making this training exercise less effective.