Introduction Previous studies1,2have indicated the existence of ocular temperature gradients. These were of two primary types; the cantral, anterior-posterior gradient across the globe from cornea to orbit and the peripheral, superior-inferior gradient extending across the anterior chamber mainly created by the lids over-riding the superior and inferior limbus. Such factors as head position and lid closure were noted to affect the ocular temperature gradients. During the course of these studies, it became apparent that environmental temperature played a decisive role. A review of the literature showed that no detailed study was available regarding the effect of environmental temperature upon ocular temperature throughout the physiological temperature range. The purpose of this paper, therefore, is to define the effect of environmental temperature upon the central anterior-posterior ocular temperature gradient. A reference temperature for the rabbit lens would thus be obtained which could be used for the culture of the rabbit