Following unilateral carotid artery ligation in the rabbit, immersion hypothermia resulted in decreases in rate of secretion of aqueous humor in both eyes. Comparative tonometric and tonographic studies suggested an exponential fall on both sides of 11 to 12 percent per degree centrigrade decline in rectal temperature. At hypothermic temperatures aqueous flow remained approximately 35 to 40 percent lower on the operated side than on the nonligated side. Intraocular pressure also decreased exponentially on both ligated (3.9 percent per degree centigrade) and nonligated sides (3.7 percent per degree centigrade). Ocular rigidity, as measured with 5.5 and 7.5 gram weights, remained unchanged following carotid ligation and during hypothermia. During hypothermia no statistical differences were found between the rectal and intraocular temperatures nor did the carotidligated and nonligated sides differ in temperature. At normal body temperature, however, the mean temperature of the anterior chamber was about 2 °C lower than that found in the vitreous or by rectal measurement. Unilateral preganglionic sympathectomy did not change intraocular pressure or alter the effects on intraocular pressure of lowering body temperature as compared with the unoperated side. Ocular blood flow, as measured from a cut vortex vein, fell exponentially with the decline in body tempeature in a very similar fashion to the decrease in aqueous secretion. Following unilateral carotid ligation both homolateral and contralateral eyes demonstrated 12 to 13 percent decreases in blood flow per degree centigrade fall in body temperature. At hypothermic temperatures vortex vein blood flow remained approximately 50 to 55 percent lower on the ligated side than in the opposite eye. This suggested a possible role of ciliary body blood flow as a factor in the effects of hypothermia on aqueous secretion.
|Original language||English (US)|
|Number of pages||9|
|Journal||American journal of ophthalmology|
|Issue number||5 PART 2|
|State||Published - May 1 1961|
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