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Ophthalmic Plast Reconstr Surg. 2009 Mar-Apr;25(2):123-5. doi: 10.1097/IOP.0b013e31819a41d5.

Hess area ratio and diplopia: evaluation of 30 patients undergoing surgical repair for orbital blow-out fracture.

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Department of Ophthalmology, University of Rome La Sapienza, Rome, Italy.



To determine if the Hess area ratio is effective in predicting postoperative diplopia in patients undergoing surgery for orbital blow-out fracture.


Our retrospective, interventional case series study involved 30 consecutive cases affected by orbital fractures and diplopia undergoing surgical correction within 7 days after injury. To evaluate ocular motility disturbance, we measured the involved ocular motility range by use of a manual Hess screen test before and 4 months after surgery. The percentage of Hess area ratio % was used to express the range of ocular motility in a numerical value.


All patients with preoperative Hess area ratio >85% had no postoperative diplopia, and most patients (57%) having a preoperative Hess area ratio <65% had postoperative diplopia. When the Hess area ratio was between 65% and 85%, surgical outcomes were variable and most patients (55%) described no problematic diplopia in the peripheral visual field.


The Hess area ratio is a useful procedure to convert Hess graphic representation in a numerical value so that Hess chart data can be compared among clinicians and used to predict surgical outcomes in patients undergoing surgery for orbital blow-out fractures.

[Indexed for MEDLINE]

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