Dissociated Horizontal Deviation after Traumatic Brain Injury

A 4-year-old boy visited the hospital with exotropia after brain hemorrhage caused by trauma. He had undergone decompressive craniectomy and cranioplasty 18 months prior to presentation at our hospital. An alternate prism cover test showed more than 50 prism diopters (PD) of left exotropia when he was fixing with the right eye and 30 PD of right exotropia when he was fixing with the left eye at near and far distance. On the Hirschberg test, 60 PD of left exotropia was noted in the primary position. Brain computerized tomography imaging performed 18 months prior showed hypodense changes in the right middle cerebral artery and anterior cerebral artery territories. Subfalcian herniation was also noted secondary to swelling of the right hemisphere. The patient underwent a left lateral rectus muscle recession of 7.0 mm and a left medial rectus muscle resection of 3.5 mm. Three weeks after the surgery, the Hirschberg test showed orthotropia. On alternate prism cover testing, 8 PD of left exotropia and 8 PD of right esotropia were noted at distance. We report a patient who developed dissociated horizontal deviation after right subfalcian subdural hemorrhage caused by trauma.

Clinical manifestations and treatment outcomes in dissociated strabismus complex (DSC) patients.

Objective: To demonstrate clinical manifestations and treatment outcomes in dissociated strabismus complex patients. Methods: Charts of patients who attended the Muscle Clinic at Siriraj Hospital from July 1998 to June 2002 were reviewed. Information regarding the patient’s age, sex, eye deviation, visual acuity, binocular function, head posture, degree of dissociated vertical deviation (DVD), dissociated horizontal deviation (DHD), dissociated torsional deviation (DTD), inferior oblique overaction (IOOA) and the treatments were obtained. Results: Seventy-three subjects from 1,335 strabismic patients were included in the study (5.5% of all strabismic patients attended the Muscle Clinic during the study time). The mean age of DSC patients was 8 years old. Among all DSC patients, 65.8% had esodeviation; 23.2% had exodeviation; and, 11% had isolated DSC. Latent nystagmus was found in 11% of the patients. Abnormal head posture was found in 16.4% of the patients. About fifteen percent of DSC patients had binocular function. All DSC patients had DVD but only 5 patients had DHD; no DTD was found. The treatment of DHD was correction of the horizontal deviation that coexisted with vertical deviation. As for DVD, there were many surgical procedures for correction such as superior rectus muscle (SR) recession, inferior oblique muscle (IO) recession, inferior oblique muscle anteriorization and inferior rectus muscle (IR) resection. Both unilateral and bilateral surgeries were performed. Regardless of the procedures, the total success rate was 78.4% (the residual of hyperdeviation was 10 prism diopters (PD) or less).The group of patients, who had surgical correction in only one eye, had a significant deviation in the non-operated eye after the surgical treatment. Conclusions: DSC was composed of DVD, DHD, DTD and latent nystagmus. DVD was the predominant manifestation in most cases of DSC. DSC was usually bilateral and was seen in subnormal binocular function patients. Esotropia was the most common deviation associated with DSC patients. Many surgical procedures were used to correct DVD such as bilateral large SR recession or IO anteriorization. In unilateral surgery, the manifestation of the deviation in the non-operated eye was always be found. Bilateral surgery was suggested but may be performed in asymmetrical degree. In this study, the overall success rate was 78.4%.

Dissociated Horizontal Deviation in the Refractive Accommodative Esotropia with Amblyopia

Dissociated horizontal deviation(DHD) is a rare type of dissociative strabismus. It dose not obey the Hering`s law of equal innervation and is expressed in associated with dissociated vertical deviation or asymmetrical nystagmus blockage syndrome. We observed 6 cases of DHD among the patients with refractive accommodative esotropia associated with amblyopia. The mean age of the patients was 3.6 years and the average refractive error was +5.35D in the dominant eyes and +6.29D in the amblyopic eyes. The average visual acuity was 0.38 with the dominant eyes and 0.17 with the amblyopic eyes. The average angle of deviation was 40.0delta with fixation in the dominant eyes and 24.3delta in the amblyopic eyes. The authors speculate that this difference of angle deviation was caused by the weaker accommodative convergence at the time of fixation by the amblyopic eye that appeared to have decreased accommodative amplitudes.