You can run games at higher resolutions for better image quality. If e.g. currently you run the game at 1920×1080, you might want to try to set 2560×1440 in the game’s video/graphics options, which should come close to the pixel density of your headset.
The higher the game resolution, the crisper the image. You have to find a balance between resolution and performance though. Higher resolution also means more work for your PC, so you may have to dial down details when you increase the resolution.
If your monitor does not support 2560×1440, please check the ‘Custom Resolutions’ section in the vorpX help. It explains step-by-step how to add unsupported resolutions to your PC.