ABSTRACT
The eye and the brain are hemodynamically linked by the carotid artery and the autonomic nervous system. A number of case reports are presented that show hemodynamic increase or decrease in the eye secondary to independently proven pathological changes in the carotid, the brain, sympathetic nervous system, and the heart.
Subject(s)
Carotid Stenosis/complications , Eye/blood supply , Intracranial Embolism and Thrombosis/complications , Adolescent , Adult , Aged , Blood Flow Velocity/physiology , Cardiac Output , Embolism/complications , Female , Humans , Intraocular Pressure , Middle AgedABSTRACT
Precise instantaneous digital measurement of intraocular pressure done non-invasively is a clinical window to the vascular physiology of the eye. This technique has been used to study the pulse amplitude/intraocular pressure curve in 2 distinct clinical entities. The first is amaurosis fugax before and after carotid endarterectomy. This demonstrates the effects of high vascular resistance external to the eye on the ocular blood flow. The second is a patient with long-standing arteriosclerotic cardiovascular disease. This is an illustration of increased vascular resistance within the eye.
Subject(s)
Eye/blood supply , Vascular Resistance , Blood Flow Velocity , Blood Pressure , Humans , Intraocular Pressure , Pulsatile FlowABSTRACT
A relationship has been derived between intraocular pressure and pulsatile blood flow in the eye. Measurements of intraocular pressure show a time variation that is associated with the pulsatile component of arterial pressure. Experimental results provide a means of transforming intraocular pressure changes into ocular volume changes. The eye is represented by a chamber with elastic walls, a pulsatile incoming flow of incompressible fluid (blood), and a steady outgoing flow of blood. Under these conditions, the rate of pulsatile blood flow through the eye can be approximated from the instantaneous intraocular pressure measurements. Data from a healthy human eye are used to illustrate the analysis.
Subject(s)
Eye/blood supply , Intraocular Pressure , Pulsatile Flow , Rheology , Blood Flow Velocity , Eye/anatomy & histology , Humans , Time FactorsSubject(s)
Carotid Arteries/surgery , Endarterectomy/methods , Aged , Female , Hospitals, Community , Humans , Male , Maryland , Middle AgedSubject(s)
Computers , Eye Movements , Animals , Diagnosis, Computer-Assisted , Electrooculography/instrumentation , HaplorhiniSubject(s)
Cerebral Cortex/physiology , Geniculate Bodies/physiology , Vision, Ocular , Animals , Behavior, Animal , Cerebral Cortex/surgery , Conditioning, Psychological , Discrimination, Psychological , Form Perception , Haplorhini , Luminescent Measurements , Occipital Lobe/surgery , Reward , Visual Cortex/physiologySubject(s)
Form Perception , Temporal Lobe/physiology , Touch , Animals , Haplorhini , PsychophysiologyABSTRACT
Thirteen normal monkeys (Macaca mulatta) trained to discriminate between transilluminated figures of equal area and different luminance, and consequently different luminous flux, made similar numbers of errors during training on a new problem with the same luminance values but with targets equated for luminous flux. These findings together with results of "critical trials" suggest that the significant cue in the original problem was luminous flux. This behavior is strikingly similar to what has been reported for the monkey following exclusion of the geniculostriate system.
