i looked up vision in the crystal book for sarah. i found opals.
they help you feel your creativity, furthering clean, true, and spontaneous action, enhancing feeling and allowing release of inhibitions.
opal is used for vision quests and dreamtime.
it can be used to treat disorders of vision and the eyes, to strengthen and clarify sight.

p.s. i also happened upon trilobite. trilobite can be used in treatment of disorders of the eyes, and to correct deficiencies of vitamins a&d.