Disturbances of ocular motility after retinal detachment surgery

Strabismus After Ocular Surgery

Many types of ocular surgery can cause diplopia, including eyelid, conjunctival, cataract, refractive, glaucoma, retinal, and orbital surgery. Mechanisms include direct injury to the extraocular muscles from surgery or anesthesia, scarring of the muscle complex and/or conjunctiva, alteration of the muscle pulley system, mass effects from implants, and muscle displacement. Diplopia can also result from a loss of fusion secondary to long-standing poor vision in one eye or from a decompensation of preexisting strabismus that was not recognized preoperatively. Treatment, which typically begins with prisms and is followed by surgery when necessary, can be challenging. In this review, the incidence, mechanisms, and treatments involved in diplopia after various ocular surgeries are discussed. [J Pediatr Ophthalmol Strabismus. 2017;54(5):272-281.].

Diplopia and strabismus following ocular surgeries

Postoperative diplopia and strabismus may result from a variety of ocular surgical procedures. Common underlying mechanisms include sensory disturbance, scarring, direct extraocular muscle injury, myotoxicity from injections of local anesthesia or antibiotics, and malpositioning of extraocular muscles by implant materials. The most common patterns are vertical and horizontal motility disturbance. Treatment options include prisms, botulinum, occlusion, or surgery.

Incidence of ocular motility problems following scleral buckling surgery

The incidence and severity of extraocular muscle imbalance after conventional scleral buckling surgery was determined for 70 eyes of 68 patients with primary rhegmatogenous retinal detachment. Fifty-eight eyes had circumferential silicone explants, 10 eyes had radial sponges and 2 had both. Sixty-five per cent of eyes showed some restriction of ocular motility and 72% of patients had diplopia within their field of binocular single vision (BSV). The more extraocular muscles the explant was placed under, the more directions of gaze were likely to be restricted (p = 0.032). In 84% of eyes the restrictions could be related to the position of the explant. In 87% of patients their diplopia could also be related to the position of the explant. A second retinal detachment operation is more likely to cause restricted motility and more likely to cause diplopia within the expected field of BSV (p = 0.0297).

Diplopia after retinal detachment surgery

Diplopia following retinal detachment usually responds to simple measures. Fifteen out of 311 cases developed diplopia lasting more than three months after conventional retinal detachment surgery. Binocular single vision was restored in 12 of the 15 cases (80%). The mean follow-up was four years. Diplopia was eliminated stepwise. If prisms were ineffective, our first surgical procedure was removal of the scleral buckle. If the retina was flat, we were prepared to remove the buckle early. When diplopia persisted after buckle removal, we proceeded to strabismus surgery. Our most consistent results followed strabismus surgery on the untreated eye. Prisms alone restored binocular single vision in six patients (40%), one of whom preferred to adopt a compensatory head posture. Removal of the scleral buckle restored binocular single vision in three patients (20%), with the help of a prism in one case and a compensatory head posture in another. Binocular single vision was restored after buckle removal and strabismus surgery in three further patients (20%), one requiring a prism in addition. Binocular single vision was not restored in three patients (20%).