<prompt> Credes method refers to instillation of:1 silver nitrate1 methyl cellulose1 chloramphenicol1 saline wash  <response>: Ans. a 1 silver nitrate Ref: AK Khurana, 3rd ed, p. 98; 4th ed, p. 72.1 silver nitrate solution instillation into the eye of the babies immediately afterbirth is known as Credes method. Its a post natal measure against ophthalmia neonatorum.Ophthalmia neonatorum is the name given to bilateral inflammation of conjunctiva in infants 30 days old. It is important to know the I.P depending on the different types of agents causing ophthalmia neonatorum:-Causative agentIncubation period1. Chemical4-6 hours2. Gonococcal2-4 days3. Other bacterial4-5 days4. Neonatal inclusion conjunctivitis5-14 days5. Herpes simplex5-7 daysRemember: Blanket antibiotic therapy - application of 1 tetracycline eye ointment twice daily for 5 days in a month for 6 months for endemic trachomai.e., prevalence 5 