Is it safe to use multipurpose contact lens solution to moisturize my eyes?

Yes: Its just saline solution. Moderation in pouring it in your eyes. Start with one or two drops.

Not exactly: While there are certainly worse things to put in your eyes, the multipurpose contact lens solution is not chemically designed to use as a lubricant for the eyes. The pH and overall chemical composition was designed for the disinfecting of contact lenses; while in very small quantities, it won't harm the eyes, to use them regularly and in larger quantities will irritate the eyes significantly.