Norm of Oculopneumoplethysmography (OPPG)
Difference between ophthalmic artery pressures should be <5 mm Hg. Ophthalmic artery pressure divided by the higher brachial systolic pressure should be >0.67.
Usage of Oculopneumoplethysmography (OPPG)
Ataxia, carotid bruits of asymptomatic origin, carotid endarterectomy monitoring, carotid occlusive disease, syncope, and transient ischemic attacks.
Description of Oculopneumoplethysmography (OPPG)
A vacuum applied to the sclera allows adjustment of intraocular pressure and a recording of ocular pressure waveform. Ophthalmic artery pressures are compared with the higher brachial pressure and with each other.
Professional Considerations of Oculopneumoplethysmography (OPPG)
Consent form IS required.
Corneal abrasion, erythema, hematoma (scleras).
Anticoagulant therapy, conjunctivitis, enucleation, retinal detachment or history, uncontrolled glaucoma, eye surgery within the previous 2–6 months, increased intracranial pressure.
- Obtain anesthetic eye drops such as 0.5% proparacaine, an eyecup, suction vacuum apparatus, a plethysmograph, a sphygmomanometer, and a stethoscope.
- Instill the anesthetic eye drops.
- Attach the eyecup to the scleras of the eyes.
- Apply a vacuum of 300 mm Hg to each eye so that the pulse disappears. Then gradually release the suction until the pulse returns.
- Take both brachial pressures.
- The higher systolic brachial pressure is compared with the ophthalmic artery pressures.
- Observe for ocular pain or photophobia, which may indicate corneal abrasion.
Client and Family Teaching
- Transient loss of vision when suction is applied is not unusual.
- Anesthetic eye drops may cause slight temporary burning.
- Do not rub the eyes or insert contact lenses for 2 hours after the test.
- Continued pain should be reported to the physician.
Factors That Affect Results
- Constant blinking, hypertension, nystagmus, and poor cooperation prevent accurate measurement.
- Results may be difficult to interpret if the client has a history of hypertension.
- Cardiac dysrhythmias may alter the results.
- This method is more accurate than oculoplethysmography.
- See also Oculoplethysmography (OPG).