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Abstract
Two independent methods were used to measure the time response of enucleated human eyes to intraocular pressure changes. 1. The phase shift between transmitting and receiving crystals glued on opposing diameters of the enucleated eye was measured and used as an indication of changes in globe dimensions. 2. The change in distance between two white targets glued to the eye was measured using a flying spot micrometer. With the use of continuous-wave ultrasound, experiments up to 50 hours were run on a total of 20 enucleated human eyes. The flying spot micrometer was used on experiments on six pairs of eyes. The results of both of these methods were completely consistent and indicate that the viscoelastic response in enucleated human eyes, as measured externally, decreases rapidly for a given change in pressure over a period of about eight hours. This viscoelastic volume response is large enough to cause significant errors in pressure volume or pressure flow studies performed without monitoring the viscoelastic effect of the outer coats of the eye in some way. The viscoelastic effect on enucleated human eyes which have been stored at low pressures may explain the discrepancies found by different investigators in these types of studies.