Diplopia after limited macular translocation surgery.

Purpose: Full macular translocation surgery relocates the fovea away from choroidal neovascularization, inducing significant postoperative torsional diplopia. In "limited macular translocation," a saline-induced retinal detachment is followed by scleral imbrication with mattress sutures and spontaneous retinal reattachment. In this study, diplopia was characterized in patients treated with limited macular translocation.
Methods: Two surgeons performed retinal translocation surgery on 250 patients over an 18-month time span. The extent and direction of the retinal translocation, and the amount and location of scleral imbrication, were recorded. All patients complaining of diplopia were referred for ocular motility evaluation and treatment.
Results: Thirteen (5.2%) patients complained of occasional or constant diplopia. Imbricating sutures were placed supero-temporally in all cases. Inferior foveal translocation ranged from 200 to 2115 microm (median, 1750 microm). Visual acuity ranged from 20/40 to 20/400 in the operated eye. Prism-and-cover testing underestimated the strabismus when compared with subjective testing. In 3 patients, there was no shift on alternate-cover testing despite binocular diplopia. Excyclotorsion ranged from 0 degrees to 16 degrees. Diplopia resolved in 10 cases with prism; 3 required an occlusive filter for distortion or aniseikonia. One patient underwent successful strabismus surgery to eliminate dependence on prism glasses.
Conclusions: Limited macular translocation only rarely produces symptomatic diplopia. Suprisingly, traditional prism-and-cover testing does not reliably quantify the misalignment. This may result from the combination of a persistent macular scotoma and a repositioned fovea relative to the peripheral retina. Prism therapy is generally satisfactory in the absence of retinal distortion or aniseikonia.