Inclusion Criteria:  Preterm infants undergoing screening for ROP, i.e.  infants with GA < 32 weeks and/or BW < 1501 grams infants of greater GA and BW with comorbidities, e.g. sepsis, prolonged need for oxygen supplementation etc., as recommended by the attending neonatologist  Exclusion Criteria:  Unstable clinical condition Severe cardiovascular disease Congenital anomalies Clinical syndromes Inotropes' intake during the week prior to enrollment Traumatic apoptosis of the corneal epithelium Corneal ulcer Anatomical variations of the anterior segment Infants that are outpatients at the commencement of ROP screening