You don't have to try to focus. Keep your eyes closed, and gently observe all of your sensations without striving to focus
I think that urge may be a good opportunity to be curious about what’s happening and staying present. What does it feel like? How does your body feel? Your mind? Your breath? Your eyes? What does the discomfort feel like when you don’t open your eyes? Can you sit with it?
I don't think trying to focus too hard is the point of meditation, accept the urge, have a look and then acknowledge the distraction and refocus your attention
I think it is best to go with the flow and open your eyes but to close them again so it doesn't become a battle of will.
I try to focus harder. But you have to do what feels natural to you. Are you wanting to open your eyes because of a distraction? If so, remove the distraction
Acknowledge the fact that you want to open your eyes, but don’t actually do it. Then let the thought go. Refocus on your breathing. If you are a beginner it may be that your brain is trying to fidget. I often use a mental image to help me remain focused on my breathing, like sitting on a dock watching the waves go by. Or place your hand on your chest or belly and focus on the up/down movements of your breathing.