Assessing enophthalmos is critical in facial trauma patients, and there are many ways to do so. We have reviewed the various devices for measuring enophthalmos over the last 155 years. Knowing the benefits and drawbacks of each instrument is important in obtaining accurate results and interpreting them. We have reviewed the evolution of enophthalmos definitions and surgical indications. Although 2 mm of enophthalmos is commonly used as a cutoff for clinical significance, one should take into account individual patient factors, measurement techniques used, symptoms and/or the patient's aesthetic concerns. The decision to operate must also be balanced with the risks of surgery, which may cause or worsen symptoms, such as diplopia, soft tissue deformities related to the surgical approach, and possibly blindness. We question whether enophthalmos greater than 2 mm should be considered the main criteria for corrective surgery.