Dakrina is a variation on Dwelle. These two products are formulated for moderate to severe dry eye. They are not viscous, but are formulated with a special combination of polymers which adheres closely to the ocular surface, with the goal of improving its "wettability".
Dakrina is one of the product line developed by eminent ocular surface scientist Frank Holly PhD. Little known during the 1990s when they first became available, they were later popularized on internet forums by patients with severe dry eye, who dubbed them "Dr. Holly's Drops". The other three products developed by Dr. Holly are Dwelle, NutraTear and Freshkote.