Will Ignis See Again?

Ignis had lost his sight. ... While his sight never returned, his other senses grew sharper by the day. Before long, he had remastered everything from cooking to combat, all without use of his eyes. With the newly returned Noctis at his side, the Hand of the King heads home to Insomnia to help his liege reclaim his throne.

Why did Ignis become blind?

Ignis doesn't go down without a fight and reveals that he stole the ring of the Lucii back in Altissia and puts it on, burning his eyes and going blind.

Should I take Ignis or leave him?

Ignis will ask you if you are ready to go (Take Ignis along, Leave Ignis Behind). No matter what choice you make, Ignis will still be coming with you. Ignis walks slowly, so you also have to move at a slower pace for Ignis to catch up. Gladiolus will warn you if you stray too far from the party.