Exophthalmos is defined in Dorland's Medical Dictionary as an "abnormal protrusion of the eyeball; also labeled as proptosis." Proptosis in the same reference is defined as exophthalmos.

Henderson reserves the use of the word exophthalmos for those cases of proptosis secondary to endocrinological dysfunction.[1] Therefore, this dictum will be followed, and non–endocrine-mediated globe protrusion will be referred to as proptosis and exophthalmos will be reserved for protrusion secondary to endocrinopathies. See the image below.

View Image

Bilateral exophthalmos and upper lid retraction secondary to Graves disease.


The etiological basis of proptosis can include inflammatory, vascular, infectious, cystic, neoplastic (both benign and malignant, metastatic disease), and traumatic factors. Some representative examples (not a complete list of proptosis from different causes) include infectious causations such as orbital cellulitis and subperiosteal abscesses. Traumatic causations could be orbital emphysema, retro-orbital hemorrhage, and carotid-cavernous fistula. Vascular causations not traumatically related would be orbital arteriovenous malformation (AVM) varices and aneurysms. Neoplastic causations include adenocarcinoma of the lacrimal gland, pleomorphic adenoma of the lacrimal gland, meningioma, lymphoma, and metastatic disease.

For instance, lymphangiomas, by their histologic nature, can increase in size during viral illnesses and result in an increase in orbital volume. A ruptured lymphangioma can enlarge after its rupture and sequestering of heme, which pathologically is described as a chocolate cyst. Orbital varices can result in proptosis with increased venous pressure in the orbit, as seen with a Valsalva maneuver or change in postural position.

In children, unilateral proptosis is often due to an orbital cellulitis–type picture, and, in bilateral cases, neuroblastoma and leukemia are more likely. Other causes in children include rhabdomyosarcoma, retinoblastoma, capillary hemangioma, dermoid cyst, glioma of the optic nerve, and metastatic disease.

Thyroid orbitopathy, also referred to as thyroid ophthalmopathy, is categorized as an inflammatory process. As it affects the orbit, the author prefers to use thyroid orbitopathy and, more particularly, thyroid-associated orbitopathy, commonly referred to as Graves disease. In adults, it is the most common cause of unilateral and bilateral exophthalmos.

The etiology of the thyroid-related orbitopathy is an autoimmune-mediated inflammatory process of the orbital tissues, predominantly affecting the fat and the extraocular muscles. Lymphocytes, plasma, and mast cells are the cellular constituents in this process. The deposition of glycosaminoglycans and the influx of water increase the orbital contents. Over time, fibrosis can occur.[2, 3] Genetic factors have been associated with Graves disease.[4] Obstruction of the superior ophthalmic vein with resultant diminished venous outflow also contributes to the orbital engorgement.

Nunery has segregated patients with thyroid-related orbitopathy into type I and type II.[5] Those with type I do not have restrictive myopathy, whereas those with type II do. Type I was believed to be caused by a profundity of hyaluronic acid manufactured by the orbital fibroblasts, stimulating lipoid hyperplasia and edema. Patients with type II experience restrictive myopathy and have diplopia within 20° of fixation.

Orbital emphysema can be a significant cause of proptosis and requires emergency treatment.

No matter what the etiology may be, globular protrusion is secondary to the increase in volume within the fixed bony orbital confines. Since the orbit is widest toward its anterior aspect, the orbital contents are displaced anteriorly, resulting in proptosis and exophthalmos.



United States

Bartley et al had reported a frequency of 2.9 cases per 100,000 population per year in men and 16 cases per 100,000 population per year in women. They also observed a bimodal distribution in both sexes, with women showing one peak at age 40-44 years and the other peak at age 60-64 years. In men, the bimodal occurrence was at age 45-49 years and age 65-69 years. Both peaks incidences in men were 5 years later than in women.[6]


Tellez et al, in another small study consisting of 155 patients who were newly diagnosed with Graves ophthalmopathy, 26% were male and 36% were female; however, the prevalence was higher in the Europeans, at a rate of 42% versus 7.7% in Asians. Analysis of the data indicated that Europeans were 6.4 times more likely to have Graves ophthalmopathy than Asians.[7]


Proptosis due to any cause can compromise visual function and the integrity of the eye.




Proptosis occurs in both adults and children at any age. Thyroid orbitopathy and the resultant exophthalmos show a predilection for females aged 30-50 years.

Ahmadi et al showed that with increasing age occurs a "linear reduction in ocular protrusion." With advancing age, there was no asymmetries between the eyes noted.[19]

A US pediatric population showed exophthalmometry measurements that increased with increasing age, as one would expect. The results were stratified into age groups with the following corresponding averages: Younger than 4 years: 13.2 mm

Of the 673 subjects in this study, only 2 had a 2-mm difference between the eyes.[20]

In Tehran, Iran, for the age group 6-12 years, the average was 14.2 mm and for the age group 13-19 years, the average was 15.2 mm.[12]

In Chinese children and adolescents from Xiamen, in the age range from 5-17 years, the average exophthalmometry reading was 14.48 mm.[21]


A meticulous history of the patient's ocular and systemic systems is key in establishing a diagnosis.


Evaluation of the patient with exophthalmos begins with a thorough ophthalmic and medical history. When concomitant sinus disease or an intranasal source is suspected, a speculum or endoscopic intranasal examination is warranted. Special emphasis on the duration and rate of progression of the patient's signs and symptoms is essential. Pain, diplopia, pulsation, change in effect or size with position or Valsalva maneuver, and disturbance of visual acuity are symptoms that should be explored. In general, a difference of more than 2 mm between a person's 2 eyes is abnormal.


Proptosis can be the result of a myriad of disease processes resulting from primary orbital pathology or systemic disease processes. The list below is not comprehensive but can help in forming a differential diagnosis. The list only consists of adult causes since a fair amount of overlap exists in the differential diagnosis of exophthalmos in adults and children.

Laboratory Studies

Imaging Studies

Medical Care

Medical care for patients with exophthalmos is directed at reversing the problem and minimizing ocular complications.


Once the etiology of exophthalmos or proptosis is established, the appropriate specialists should partake in the patient's care.

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Artificial tears (Celluvisc, Murine, Refresh, Tears Naturale)

Clinical Context:  Contains equivalent of 0.9% NaCl and maintains ocular tonicity. Acts to stabilize and thicken precorneal tear film and prolongs tear film breakup time, which occurs with dry eye states.

Class Summary

Keep adequate moisture in eye and prevent dryness.

Further Outpatient Care


Michael Mercandetti, MD, MBA, FACS, Private Practice

Disclosure: Nothing to disclose.


Adam J Cohen, MD, Eyelid and Facial Aesthetic and Reconstructive Surgery, Diseases and Surgery of the Orbit and Lacrimal System, Neuro-ophthalmology

Disclosure: IOP Inc Honoraria Speaking and teaching

Specialty Editors

Brian A Phillpotts, MD, Former Vitreo-Retinal Service Director, Former Program Director, Clinical Assistant Professor, Department of Ophthalmology, Howard University College of Medicine

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

J James Rowsey, MD, Former Director of Corneal Services, St Luke's Cataract and Laser Institute

Disclosure: Nothing to disclose.

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri

Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences

Disclosure: Nothing to disclose.


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Bilateral exophthalmos and upper lid retraction secondary to Graves disease.

Bilateral exophthalmos and upper lid retraction secondary to Graves disease.