Mean ocular temperature measured using a hand-held infrared thermometer was 36.54 degrees C and 36.38 degrees C for the right and left eyes of 51 premature babies; whilst for 54 fullterm controls the corresponding figures were 36.40 degrees C and 36.25 degrees C. As fetal temperature at about 38.0 degrees C is above maternal core temperature this means that the eye of the prematurely born infant experiences a thermal deficit of 1.0 to 2.0 degrees C which is never replaced postnatally. The possibility that this reduction in temperature could influence ocular growth is discussed, with particular regard to the development of myopia which people born prematurely are prone to develop.