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Show J. Clin. Neuro-ophthalmol. 4: 139-140, 1984. Clinical Feature A Simple Technique for Doppler Ophthalmodynamometry MICHAEL H. ROTBERG, M.D. Abstract A novel method to assess carotid and intraocular blood flow and pulse pressures is presented. This procedure can be performed by personnel not trained in ophthalmoscopy, and is valid in eyes with opaque media. It is noninvasive, requires no elaborate equipment, and may be useful as an adjunct to ophthalmodynamometry. Ophthalmodynamometry is a simple and noninvasive test that can provide useful information about the intracranial and intraocular vasculature. It requires practice, the ability to use an ophthalmoscope, and a cooperative patient with clear ocular media. To ascertain the state of the mograph,l which few ophthalmologists use regularly. The following describes the use of a relatively inexpensive instrument that allows ophthalmic artery pressures to be taken even in eyes with opaque media. The instrument used is a miniature doppler stethoscope (Fig. 1). It consists of an ultrasound transmitter/receiver probe, sensitive to moving material, and which replaces the diaphragm of a stethoscope. The ultrasound signal is transformed into sound, which can then be heard through the earpieces of the stethoscope. No oscilloscope, digital read-out, or recording attachments are included or necessary. With the patient in the supine position, topical anesthetic is placed in the eye. Gonioscopy gel is applied to the tip of the probe, which is then Figure 1. Miniature doppler stethoscope. intraocular pulse in the presence of vitreous blood, corneal opacity, or dense cataract requires elaborate equipment, such as the oculoplethys- From the Duke University Eye Center and McPherson Hospital, Durham, North Carolina. June 1984 gently pressed against the temporal aspect of the globe (Fig. 2). A faint, but audible pulsation can be heard. As pressure on the eye is gradually increased to intraocular diastole, an augmentation in the sound of the pulse can suddenly be heard. Experimentally, if the fundus is simultaneously 139 Doppler Ophthalmodynamometry Figure 2. Technique of measuring retinal artery pressure with doppler stethoscope. observed and auscultated, this increase in amplitude can be seen to coincide with the onset of central retinal artery pulsations. The intraocular pressure that causes the sound of the pulse to change can be quantified by a Schiotz tonometer held on the cornea as one manipulates the probe. Similar ultrasound devices have been used in the past to study flow and pressure characteristics of the ophthalmic artery, but these authors were concerned with side to side comparisons of waveform and amplitude as an index of compromised flow through the carotids. 2 - 4 Rarely was attention paid to specifically ocular blood flow. Maroon used a doppler probe in a single case to document complete lack of flow through an occluded central retinal artery.s He failed to use the instru?,e~t dynamically, however, and did not recogmze It as a way to measure retinal artery pressures. Admittedly, it cannot be proven that the central retinal artery is in fact being directly auscultated; a long posterior ciliary artery directly under the probe may be the pulse one ~ears. As this also originates from the ophthalrrnc artery and has flow which is sensitive to intraocular pressure, this uncertainty is of no practical concern. This procedure has the same contraindications as ophthalmodynamometry; it should not be done soon after intraocular surgery or in other circumstances if pressure on the globe would be dangerous. While this instrument is more costly than an ophthalmodynamometer, it can be used by anyone trained to use a stethoscope, is valid in the presence of opaque ocular media, and can be used to confirm an abnormal OOM reading without resorting to invasive or expensive studies. It may be a useful adjunct to currently available means of evaluating ocular perfusion. References 1. Sanborn, G.E., Miller, N.R., Langham, M.E., and Kumar, AJ.: An evaluation of currently available non-invasive tests of carotid artery disease. Ophthalmology 87: 435-439, 1980. 2. Muller, H.R.: Directional doppler sonography: A new technique to demonstrate flow reversal in the ophthalmic artery. Neuroradiology 5: 91-94, 1973. 3. Kaneda, H., Tadayochi, I., Arita, N., Minami, T., Taneda, M., and Shiraishi, J.: Relationship between ophthalmic artery blood flow and recanalization of occluded carotid artery: Ultrasonic doppler study. Stroke 9: 360-363, 1978. 4. Kammerer, E.: Comparative ophthalmodynographic and doppler sonographic examinations. Klill. MOllatsbl. Augenheilkd. 172: 150-153, 1978. 5. Maroon, I.e., Pieroni, D.W., and Campbell, R.L.: Ophthalmosonometry: An ultrasonic method for assessing carotid blood flow. J. Neurosurg. 30: 238246, 1969. Journal of Clinical Neuro-ophthalmology |
