PURPOSE. To measure the oscillation phase delay between retinal arterioles and venules in order to analyze pulse wave propagation in the ocular circulation of vasospastic and nonvasospastic subjects and a change thereof during the cold pressor test in another group of healthy subjects. METHODS. Twenty-four young, healthy women, 12 vasospastic and 12 nonvasospastic, were analyzed. A retinal vessel analyzer was used to obtain 1-minute recordings of the ocular fundus. A phase delay between the arteriole and venule pulsations was assessed at three sites, one (proximal) in the close retinal vicinity of the disc, one (middle) 1 to 2 disc diameters away from the disc, and a third (distal) 3 to 4 disc diameters away from the disc; and, assuming that venules are counterphased to the choroidal circulation, a choroid-to-retina pulse delay was calculated. In addition, the change in these parameters was analyzed during the modified cold-pressor test in 10 healthy subjects (five women, five men). RESULTS. Pulse oscillations in arterioles led those in venules by 95.0°Ϯ 39.0°, 60.5°Ϯ 57.5°, and 47.5°Ϯ 64.0°in vasospastic subjects, and 76.0°Ϯ 58.0°, 31.5°Ϯ 60.0°, and 2.5°Ϯ 80.5°in nonvasospastic subjects in the proximal, middle, and distal measuring sites, respectively. Calculated choroid-to-retina pulse delays in vasospastic subjects were 0.20 Ϯ 0.10, 0.28 Ϯ 0.14, and 0.30 Ϯ 0.11 seconds and in nonvasospastic subjects 0.25 Ϯ 0.15, 0.35 Ϯ 0.11, and 0.43 Ϯ 0.2 seconds at the proximal, middle, and distal measuring sites, respectively. The difference was significant between vasospastic and nonvasospastic subjects (P ϭ 0.033) and among the measuring sites (P ϭ 0.0023). During exposure to cold, the choroid-to-retina pulse delays changed from 0.31 Ϯ 0.08, 0.40 Ϯ 0.16, and 0.51 Ϯ 0.26 seconds to 0.26 Ϯ 0.12, 0.30 Ϯ 0.10, and 0.33 Ϯ 0.14 seconds at the proximal, middle, and distal measuring sites, respectively (P ϭ 0.024 for the change from baseline to cold exposure, and P ϭ 0.022 for measuring sites). CONCLUSIONS. Retinal vessels in vasospastic subjects demonstrate an altered pattern of oscillation phase delay between arterioles and venules. Vessels in vasospastic subjects seem to conduct pulse waves faster and are thus stiffer than those in nonvasospastic subjects. The pattern of oscillation demonstrates changes during the cold pressor test in healthy subjects, indicating faster pulse-wave propagation. (Invest Ophthalmol Vis Sci. 2006;47:4019 -4025 10 Evaluation of vascular pulsations in the eye has been mostly limited to the choroidal circulation. 16,17 An actual pulse-wave propagation from the heart to the ophthalmic artery and choroidal circulation has been estimated at 4.08 m/s in a study of healthy subjects by Michelson et al. 11,20 The retinal vessel analyzer (Retinal Vessel Analyzer [RVA]; IMEDOS GmbH, Weimar, Germany) offers high spatial vessel width resolution 21 ; high reproducibility of measurements METHODS Subjects Forty healthy nonsmoking women were screened for the study. After approval by the ethics committee, we obtained informed consent from the subjects, in accordance with the guidelines of the Declaration of Helsinki. A notification in the University Eye Clinic of Basel informed potential volunteers (collaborators, students, parents, and friends of patients) of the opportunity to participate in a scientific research project. Subjects were screened for ocular and systemic diseases. A detailed medical and ophthalmic history was recorded, and all subjects completed an ophthalmic examination. Included were individuals with no history of ocular or systemic disease, no history of chronic or current systemic or topical medication, and no history of drug or alcohol abuse Further inclusion criteria were a normal systolic (100 -140 mm Hg) and diastolic (60 -90 mm Hg) blood pressure, a best corrected visual acuity 20/25 or better in both eyes, ametropia within Ϫ3.0 to ϩ3.0 D of spherical equivalent and less than a 1-D astigmatism in each eye, intraocular pressure (IOP) lower than 20 mm Hg in each eye by (Goldmann) applanation tonometry, and no pathologic findings in slit lamp examination and indirect funduscopy. Subjects were classified as having vasospasm if they related a clear history of frequently cold hands (answering "yes" to the questions: "do you always have cold hands, even during the summer?" and "do other people tell you that you have cold hands?") and as healthy subjects if they reported n
