A 6-year-old boy from a tribal village in Jharkhand is brought to the eye clinic with a 3-week history of progressive loss of vision and eye pain. On examination, the right eye shows a hazy cornea with a central ulcer measuring 3 mm × 2 mm. The left eye has conjunctival xerosis and Bitot's spots. Intraocular pressure is normal. The child is severely malnourished (weight-for-age < 60% of expected). What is the most appropriate immediate management?