<prompt> Retinopathy of prematurity is commonly predisposed by-Less gestation ageLow birth weightO2 toxicityCarbohydrate excess  <response>: Ans. is less gestation age Ref Nelson, 17e, p 2113, 2114 16e, p. 1925; O.P. Ghai, 6e, p 629 5e, p. 504.There is always the confusion between pre-maturity less gestation age and O2 toxicity, as the predisposing factor Some are also confused with low birth weight.Read these lines from Nelson. They will clear away most of your doubts.Retinopathy of prematurity occurs almost exclusively in pre-term infants.The risk factors associated with ROP are not fully known, but prematurity and the associated retinal immaturity at birth represents the major factors.Hyperoxia is also a major factor but other problems, such as respiratory distress, apnea, bradycardia, heart disease, infection, hypoxia, hypercarbia, acidosis, anemia and the need for transfusion are thought by some to be contributory factors.Crux is Predisposing factor for ROP -Prematurity les gestation age Precipitating factor -Hyperoxia 