Employee was milling on rack pad (Windy Conditions, Milling, & Sandblasting). Felt discomfort on Saturday 3/21, still feeling discomfort on Sunday 3/22, employee was taken to the ER. The ER treated him for a scratched cornea, referred to an optometrist for a followup visit on Wednesday 3/25. Optometrist discovered an embedded particle, removed with a surgical drill.