Diplopia in blow out fractures.

Sir,

We read with interest the article by Ceylan OM et al.,[1] entitled ′Management of diplopia in patients with blow out fractures′. We would like to congratulate them on their report, and their excellent results regarding diplopia management. We would like to make a few comments on the report.

Diplopia in orbital fracture might result from various causes[2] and because patients' complaints are often too subjective for meaningful comparisons, objective ways to evaluate diplopia are required.[3] To better study the effect of surgery, it is desirable to quantify the amount of diplopia. Reports have utilized quantitative evaluation of binocular visual field (BVF)[2] testing, Hess test (Hess area ratio),[3] and electronystagmography[4] equipment, as newer and innovative measures to quantify diplopia. We appreciate that Ceylan OM et al., utilized Hess screens and BVF, and would like to know if they applied any quantitative value to these tests.

We understand that 6 patients were treated additionally with strabismus surgery or prisms for residual diplopia. We were interested in knowing if the persistent diplopia was less than, or equal to the initial diplopia measured prior to wall repair, and if there was any improvement in the diplopia post orbital repair in these patients.

Though the mean time between trauma and strabismus surgery is mentioned as 10.5 months, the mean time between secondary strabismus surgery and the initial orbital wall reconstruction is not. We were interested in knowing how long should we wait after the primary orbital repair the surgery take place before opting to operate for residual diplopia.

The study states that 7 patients underwent strabismus surgery. Even though the average deviation is mentioned as 14 prism diopters, the direction of deviation is not mentioned. Since the study mentions inferior-rectus recession as the commonest surgery, we infer that most of them had hypotropia in primary gaze. We would like to know if there is a difference in outcome between horizontal and vertical deviations. We wondered if the authors considered strabismus operation in the unaffected eye to resolve diplopia. We also wanted to know if there were any cases of diplopia in down gaze post strabismus surgery.

The study mentions that primary gaze diplopia was eliminated in 73.9% of patients with no complication related to use of the Medpore® (Stryker Company, USA) implant. They also mention the possibility of flap tear in 2 of the patients. We would like to suggest, doing further investigation to find out the cause for the residual diplopia found in 26.1%, post wall repair. Various reports suggest the benefits of a post operative multi-positional high resolution MRI in such situations, to rule out mesh related complications.[5]