Every seer in David Eddings's Belgariad series is blind; they basically trade first sight for second. Those among the Dals who develop the ability to see the future simply wear blindfolds; others are physically blind.

Are seers blind?

Blindness is the most common deformity among seers and oracles, and it's a metaphor that works on multiple levels. The first is that wisdom has a price -- nothing comes free, especially not the gift of prophecy.

Why are the seers disfigured?

His appearance is deformed, and it is unclear if this is congenital, a result of disease, or even the result of violence. His eyes were either sewn shut or skin grew over his eyes.