4 mm
Aged 9-12 years: 15.2 mm
Aged 13-17 years: 16.2 mm
Of the 673 subjects in this study, only 2 had a 2-mm difference between the eyes.
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.
In Chinese children and adolescents from Xiamen, in the age range from 5-17 years, the average exophthalmometry reading was 14.48 mm.
A meticulous history of the patient's ocular and systemic systems is key in establishing a diagnosis.
The ophthalmic history should address the duration and the rate of onset of the proptosis. The patient should be queried about pain, change in visual acuity or refraction, diplopia, and decreased fields of vision. Transient visual loss or blackout periods may signify optic nerve compromise and may call for rapid intervention.
Complaints of foreign body sensation or dry gritty eyes are symptoms that may indicate corneal decompensation.
In performing a thorough medical history and a review of systems, the ophthalmologist should consider orbital involvement secondary to systemic pathology.
Past trauma and family history also may aid in the 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.
A complete ophthalmic examination is paramount. Periorbital changes can be noted easily on gross examination in a well-illuminated examination room.
Hypertelorism, exorbitism, eyeball protrusion (proptosis), eyelid lesions or edema, chemosis, and engorged conjunctival vessels are several periorbital signs.
Blepharoptosis, lagophthalmos (incomplete lid closure), and interpalpebral fissure distance are additional signs to be considered during the examination.
Palpation of the anterior orbit can assess the level of tenderness, texture, and mobility of the mass.
Tenderness may denote an inflammatory process or neural invasion by a neoplasm.
Attention should be paid to regional lymph nodes.
Tactile inspection of the globe may reveal pulsations secondary to arteriovenous communications or physiological intracranially pulsations transmitted through a bony defect of the orbit, such as an encephalocele.
Protrusion of the eye is an important clinical manifestation of orbital disease. In addition to proptosis, one should note the displacement of the eye in planes other than the anteroposterior dimension (eg, downward, lateral).
Hertel exophthalmometry is a well-accepted tool to quantitate proptosis. The base is determined by the interlateral canthal space. The transection of the central cornea by the premarked millimeter ruler records the amount of anterior displacement of the globe. Its use requires intact lateral orbital rims. If the rim is not intact, a Luedde exophthalmometer.
Relative protrusion can be observed by simply standing behind a seated patient and gazing downward toward the chin from the forehead to assess the displacement of one globe as compared to the contralateral side.
Auscultation of the orbit may detect a high flow state in the orbit or intracranially. The bell is useful for this examination. If a high-flow lesion is suspected (eg, carotid cavernous fistula), arteriography should be sought to further qualify these lesions. It is important to have the contralateral eye remain fixated on a target while auscultating the orbit.
Decreased visual acuity, change of refraction, and pupillary abnormalities should be noted.
Extraocular motility dysfunction and diplopia should be carefully assessed and documented.
Forced duction testing may qualify the dysfunction as restrictive or neurogenic in nature. Intraocular 