If your eyes need be clean but don't have eye drops by side, you can use a soft and clean washcloth and warm water to help the eyes. Just rinse the cloth in warm water, and then, put the cloth on your eyes. Just keep it stay for a while. Or you can gently rub the area of eyes with the warm washcloth. It can help you clean your eyes and relieve from uncomfortable of the eyes.
Yes, sometimes, you need to clean your eyes for some reasons. Usually, If you suffers from some debris in your eyes, you may need clean your eyes. And except common eye drops, some people even need chemical eyewash or medical attention. If you suffer eye problems and don't have eye drops by hand to clean your eyes, you can use clean water or saline solution to clean your eyes.