Exodeviation following monocular myopic regression after laser in situ keratomileusis

Abstract

We report a 44-year-old woman with intermittent left exotropia of 35 prism diopters at distance who initially exhibited alignment of both eyes after bilateral laser in situ keratomileusis (LASIK). The exophoria was not preserved due to myopic regression in the dominant eye. An uneventful LASIK treatment was performed to correct -11.00 -0.50 x 130 in the right eye and -13.50 -1.50 x 145 in the left eye. The aim was to achieve emmetropia in both eyes. Although an examination revealed exophoria at near and distance during the 6 months following refractive surgery, the tropic aspect of the divergent deviation appeared in the right eye following the myopic regression. Laser in situ keratomileusis is an effective option to achieve binocular visual quality in myopic anisometropic patients. However, myopic regression after LASIK may disrupt the binocular visual quality.

Refractive surgery and strabismus

“…If strabismus is present with refractive error, refractive surgery should normally be performed first because it may have an effect on the strabismus angle. Some time should pass to allow for regression of the refractive effect before the strabismus is assessed for realignment surgery 21 . If strabismus surgery is performed first, the so‐called fornix approach is better because it enables normal microkeratome suction.…”

Unexpected outcomes associated with laser in situ keratomileusis: Ptosis, anisocoria, and “curing” of exotropia

“…Decompensation of exodeviations have also been reported after refractive surgery, however, and can result in secondary strabismus surgery. 10,11 We are aware of only 1 report in which exotropia improved after LASIK. In that report, the proposed mechanism was resolution of anisometropia, with subsequent improvement of binocular function.…”

Impact of laser refractive surgery on ocular alignment in myopic patients

“…Some studies have described cases with postoperative diplopia retrospectively, or included a pre-selected population with various manifest strabismus. [7][8][9][10][11][12][13][14][15]18 Moreover, the impact of myopic refractive surgery on exodeviation has been reported to vary among reports. 2,4,6,18 We identified that corneal refractive surgery for low to moderate myopia in general did not appear to have an impact on ocular alignment.…”

“…[2][3][4][5][6] Conversely, although 10-year follow-ups have demonstrated that the technique is safe and predictable, 1 refractive surgery can cause strabismus and binocular diplopia. 2,[7][8][9][10][11][12][13][14][15] Patients with preexisting strabismus or anisometropiacausing aniseikonia, and those hoping to achieve monovision are at higher risk for postoperative strabismus and diplopia. 7 Therefore, refractive surgery might be a means of treatment for strabismus and a cause of strabismus.…”

“…4,6,18,19 In contrast, there were some case reports with decompensation of exodeviation after laser surgery. 8,11,14,15 To address this, we have performed a prospective study to determine whether myopic keratorefractive surgery affects ocular alignment.…”