Bothersome diplopia after surgery is a problem that can be treated successfully temporarily and in most cases, permanently. The immediate remedy for diplopia is obvious: patch one eye constantly or alternate the patch between the two eyes. This type of treatment is often appropriate for the patient who has an early postoperative overcorrection such as esotropia after surgical treatment for an intermittent exotropia. Diplopia persisting more than a few days may require treatment with prisms, either temporary Fresnel prisms or permanent prisms ground into the spectacles. If time and these remedies fail, reoperation to relieve the diplopia may be necessary.

A few patients may have a type of diplopia that is not a complication of surgery but is the patient's own problem. This type of diplopia has been termed central disruption of fusion that can occur after closed head trauma. Other patients have foveas that repel rather than attract with a condition called horror fusionis. Another relentless form of diplopia is caused by bilateral cranial nerve palsies producing secondary deviations in all fields of gaze and making comfortable fusion impossible. Further active treatment may only worsen that problem and the patient should be counseled appropriately. Patching one eye or use of an opaque contact lens or, best of all, establishing the patient's own suppression mechanism could be the only real remedy. Some of the most unfortunate diplopia-plagued patients that I have encountered are those with acquired third cranial nerve palsy, usually with aberrant regeneration, who have their eyes fairly well straightened by surgery but who have constant and incapacitating double vision. Unless these patients can develop suppression, which they often cannot, they may be better off unoperated retaining a larger angle of strabismus or as an alternative, with some form of occlusion.

Some postoperative patients will literally look for diplopia and in the process become agitated. These patients may complain of double vision when reading while lying on their back in bed or while assuming some other extreme position or when looking in extremes of gaze. I tell these patients to assume a more ‘hygienic’ posture for reading and television viewing. It is useful to differentiate diplopia that must be ‘looked for’ and ‘found’ from diplopia that ‘looks for’ and ‘finds’ the patient and in the process disrupts the normal flow of events. The former is an unavoidable part of much strabismus. It can be dealt with by the patient in most cases. The latter may be dealt with by surgical or nonsurgical means but in some cases could be intractable. For the most part, patients seem satisfied by and benefit from this explanation of double vision. Further, it is valuable to tell patients that anyone with two eyes, even those with perfectly normal motility, can experience double vision in certain circumstances. Some patients with longstanding horizontal strabismus and no preoperative fusion potential experience diplopia after their eyes are aligned by surgery. When these patients complain about diplopia, you can offer to put the eyes back in the preoperative state at no charge if the diplopia is more of a detriment than the alignment is beneficial. This would be said with ‘tongue in cheek’ and with the assurance that in nearly every case the diplopia goes away with onset of suppression provided the patient will give the process sufficient time. I know of no patient to date who has exercised this option.