Digital globe massage has been considered a heroic measure to salvage vision in cases of central retinal artery occlusion (CRAO), an ophthalmologic emergency.1–8 CRAO is one of several diagnoses to consider in the patient with acute painless loss of vision or a visual field. The typical patient is older, between the ages of 50 and 80 years of age, and with significant systemic illnesses. The CRAO is most likely an embolic event secondary to atherosclerotic disease. The vision loss is sudden, monocular, and painless. The outcome for CRAO is poor if treatment is delayed more than 2 hours. Spontaneous remission and recovery of visual function is rare. This condition requires an emergent consultation with an Ophthalmologist for medical management and the consideration of an anterior chamber paracentesis (Chapter 158). Digital globe massage can be used in an attempt to relieve the obstruction or break up the embolus so it moves distally to restore some blood flow to the retina.
The ophthalmic artery is a branch of the carotid artery (Figure 157-1). The first branch of the ophthalmic artery is the central retinal artery. This vessel runs along the optic nerve and enters the optic nerve. The central retinal artery is the main blood supply to the retina. The macula has an independent blood supply from other branches of the ophthalmic artery. An area between the macula and the optic nerve receives collateral circulation from the central retinal artery and the ciliary arteries in a small percentage of the population. This explains why a patient with a complete CRAO may have a normal appearing macula and occasionally an area of perfusing retina adjacent to the optic nerve area.
The anatomy of the eye. (Used with permission from: Riordan-Eva P, Whitcher JP (eds): Vaughan & Asbury's General Ophthalmology, 17th ed. New York: McGraw-Hill, 2008.)
The individual etiology remains unclear in many cases. The main cause of retinal arterial occlusions is an embolic event lodging in the central retinal artery where it narrows to pass through the lamina cribrosa, or in a smaller distal branch arteriole. The embolism may be comprised of aggregated fibrin and platelets arising from an ulcerated vessel wall thrombus, cholesterol from an ulcerated carotid artery plaque, material from cardiac valvular disease, or thrombus formation from giant cell arteritis. The embolus may also result from an invasive procedure such as cardiac angioplasty, carotid angioplasty and stenting, or a carotid endarterectomy.
Abnormal cardiac rhythms are considered an etiology for intracardiac blood clot formation. These may embolize and lodge in the ophthalmic artery or distally in one of the branch arteries. Retrobulbar masses (e.g., a hematoma, neoplasm, or retrobulbar injection) may also lead to an optic nerve and central retinal artery compression.1
Physical Examination Findings