You could spend considerably more and wind up with a solution less practical than this design.
The Down Range Gear Night Vision - Tactical Lanyard System is designed to prevent the loss of the AN/PVS-14A mounted to helmets using PASGT/MICH/ACH and Ops-Core VAS mounting plates. It relies on a proven, two piece system running a snap-hook tethered to the optic with elastic cord and anchoring to a D-ring on the helmet. The hardware is simple, robust and non-mechanical, leaving very little that can break or go wrong. All the components are replaceable and meant to be easily switched out if damaged. The low profile D-ring is robust and unobtrusive when not in use. Durable elastic cord keeps the assembly under elastic tension to reduce snag hazards. Compatibility is strictly limited to AN/PVS-14A Mil-spec housing with standard PASGT/MICH/ACH and Ops-Core VAS mounts as pictured. Kits can be purchased with extra components to pair multiple helmets to a single optic or multiple optics to a single helmet.