Role of venus in eye ailments explained through simple puranic story.
In one story, Lord Vishnu is born as the Brahmin dwarf-sage Vamana. Vamana comes to take the three worlds as alms from the asura king Bali. Lord Vishnu wanted to deceive the king Bali who was the grandson of the great king Prahlada, in order to help the Devas. The sage Shukracharya identifies him immediately and warns the King. The King is however a man of his word and offers the gift to Vamana. Shukracharya, annoyed with the pride of the king, shrinks himself with his powers and sits in the spout of the Kamandalu, from which water has to be poured to seal the promise to the deity in disguise. Lord Vishnu, in disguise of the dwarf, understands immediately, and picks a straw from the ground and directs it up the spout, poking out the left eye of Shukracharaya. Since this day on, the guru of the asuras has been known to be half blind.
Please refer to link below on role of venus in Cataract surgery.