SMALL CASE SERIES

SECTION EDITOR: W. RICHARD GREEN, MD

Three months after the proce- Despite the lack of fusion, he Central Fusion Disruption dure, he continued to have double stated that he was able to function Following Irradiation of vision. On examination, he had 8 PD normally including driving with- Neoplasms in the Pineal of at distance and no de- out difficulty. He was diagnosed with Region viation at near. Double Maddox rod central fusion disruption second- testing showed 5° of excyclotor- ary to pineal tumor irradiation. sion in each eye. There was no ver- Case 2. A 15-year-old previously In 1935, Bielschowsky1 described a tical deviation on head tilt to the healthy boy had a chief symptom of syndrome in which the ability to fuse right or to the left. The patient was double vision. The patient had vis- 2 images was lost because of a long- felt to have bilateral fourth nerve ited a neurologist 2 months before for standing sensory deprivation. The palsies. headaches, vision changes, and vom- main symptom was intractable dip- Owing to persistent double vi- iting. Magnetic resonance imaging of lopia following the removal of the sion, he underwent a second eye the brain revealed a pineal region tu- cause of sensory deprivation. Biel- muscle surgery consisting of bilat- mor with hydrocephalus. He under- schowsky called this syndrome hor- eral Harada-Ito procedures as well went an endoscopic third ventricu- ror fusionis. This syndrome, now as a right inferior rectus recession of lostomy and biopsy of the tumor in known as acquired central fusion 1.0 mm and a left medial rectus re- an outside hospital. The tumor bi- disruption, has been reported fol- cession of 5.0 mm on adjustable su- opsy and markers that were taken lowing cataract extraction,2 apha- tures. Postoperatively, he contin- were inconclusive. Two weeks later, kia,3 severe head trauma,4 and brain ued to have double vision. Prisms he underwent a right occipital cra- surgery.5 We report 2 cases of cen- were prescribed to superimpose the niotomy with transtentorial micro- tral fusion disruption that devel- images as closely as possible. On ex- scopic subtotal resection of the tu- oped after irradiation to the pineal amination 10 years later, corrected mor. Pathological findings were area. was 20/30 OD and consistent with germinoma. Three 20/20 OS with −1.75ϩ0.50ϫ113° days after surgery, he was seen in the Report of Cases. Case 1. A 12-year- OD and −2.25ϩ2.00ϫ85° OS. The ophthalmology clinic with . old boy had a chief symptom of glasses also contained prisms of 3 On examination, uncorrected vi- double vision. One month earlier, the base-out and 3 base-up OD and 3 sual acuity was 20/30 OD and 20/60 patient had visited a neurologist for base-out and 3 base-down OS. On OS. Ductions and versions showed −4 headaches and visual disturbances. A sensorimotor evaluation, the pa- limitation of elevation in all of the biopsy obtained during a third ven- tient had a left eye fixation prefer- horizontal gaze positions, −1⁄2 abduc- triculostomy demonstrated a pineal ence with −3 limitation of eleva- tion deficits in both eyes, and a −2 de- region tumor consistent with germi- tion on the right (scale, 0 to −4 pression deficit in both eyes. In pri- noma. He subsequently received ra- limitation) and −2 limitation on the mary position, he had 10 PD of diation therapy of 2550 cGy (the con- left. Prism and cover testing with cor- esotropia, which increased to 15 PD version of centigray to rad is 1:1) with rection revealed a left of in both left and right gaze. The clini- a 2160 cGy boost in the pineal re- 4 PD at distance and near. Double cal impression was consistent with re- gion. During this treatment, he started Maddox rod testing showed 5° of ex- solving increased intracranial pres- to have diplopia and was referred to cyclotorsion on the right. sure and herniation syndrome our service. On examination, cor- was not detectable by Titmus test and resulting in bilateral sixth cranial rected visual acuity was 20/20 OD and vertical diplopia was found on the nerve palsies. The patient then was 20/20 OS with a manifest refraction Worth 4-dot test. Synoptophore treated with radiation therapy to the of ϩ1.25−2.00ϫ 180° OD and measurements were obtained. The pineal region with a maximum dose plano−0.50ϫ180° OS. Prism and objective angle of the esotropia was of 5040 cGy to the primary tumor site cover testing revealed an intermit- 4.5° (10 PD) and the objective angle and an estimated total dose of 2520 tent of 25 prism diopters of the left hypertropia was 5° (10 cGy to the hypothalamus and (PD) at distance and 16 PD at near. PD). The subjective angle was simi- pituitary. During the following months, the dip- lar but with an additional excyclo- Six months after his initial visit, lopia worsened and finally became torsion of 2° to 4°. Even with the ex- he still had diplopia. On examina- constant. Ten months after the ini- cyclotorsion eliminated and the tion, visual acuity was 20/20 tial visit, the patient was treated with horizontal and vertical OU with a cycloplegic refraction a right lateral rectus recession of 5.0 neutralized, the patient noted only of ϩ2.50ϩ 0.75ϫ 90° OD and mm and a right medial rectus reces- simultaneous perception of the 2 ϩ3.50ϩ0.50ϫ90° OS. He had a sion of 4.0 mm. overlapping images. right eye fixation preference for

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 distance and near. Pupils were no- Comment. Central fusion disrup- fering prism therapy to affected table for light-near dissociation. Duc- tion refers to an acquired defi- patients. tions and versions showed limita- ciency in fusion caused by intracra- The possible complication of cen- tion of elevation in all of the nial insult or prolonged visual tral fusion disruption is considered horizontal gaze positions. Prism and deprivation. Characteristically, pa- when planning interventions in pa- cover testing revealed 4 PD of left hy- tients with central fusion disrup- tients who have had prolonged vi- pertropia at distance and near. The tion experience diplopia in all po- sual deprivation or who require sur- patient was fitted with prisms in an sitions of gaze associated with gery to areas surrounding the attempt to reduce his diplopia. strabismus of any angle.4 If the eyes midbrain, cerebellum, or connect- One year later, he returned for are aligned with prisms, patients can ing pathways. Our cases extend this evaluation and had persistent double experience transient superimposi- caution to interventions in the pi- vision despite prism use. Examina- tion of images but not fusion. Sup- neal region and raise the possibility tion revealed an exotropia of 12 PD pression does not occur by subjec- that neurons in this area contribute along with a right hypertropia of 6 tive report or on objective testing. to central fusion. Furthermore, the PD at distance and near. Double In both of our patients, eye muscle possibility that radiation alone can Maddox rod testing showed 5° of ex- surgery reduced the strabismus and damage these areas, even in the ab- cyclotorsion on the right and 3° of torsion sufficiently to have allowed sence of surgical transection, is im- excyclotorsion on the left. Three fusion to take place with prisms if portant to note. normal fusional mechanisms had months after the initial visit, he was Sashank K. Reddy, PhD treated with a right inferior oblique been intact. To our knowledge, our patients Cristian M. Salgado, MD disinsertion and an adjustable right David G. Hunter, MD, PhD lateral rectus recession of 2.5 mm. represent the first reported cases of central fusion disruption associated The patient was then lost to fol- Correspondence: Dr Hunter, De- with irradiation to the pineal area. low-up until 1 year and 5 months partment of Ophthalmology, Chil- Gruzensky and Palmer5 reported 1 postoperatively, when he continued dren’s Hospital Boston, 300 Long- case of central fusion disruption fol- to have double vision. On examina- wood Ave, Fegan 4, Boston, MA lowing surgical resection of a pineal tion, corrected visual acuity was 20/20 02115 (david.hunter@childrens teratoma. While both of our patients OD and 20/20 OS with a manifest re- .harvard.edu). ϩ ϫ had surgical biopsies and 1 of them Author Contributions: Drs Reddy fraction of plano 0.50 90° OD and had a therapeutic resection of his tu- ϩ0.25ϩ0.50ϫ19° OS. He had a right and Salgado contributed equally to mor, the patient whose tumor was not this work. eye fixation preference for distance resected did not have persistent and near. Ductions and versions Financial Disclosure: None re- double vision until after radiation ported. showed −2 limitation of elevation in therapy had been completed. In the all of the horizontal gaze positions. Funding/Support: This work was other patient, there was double vi- supported by the Research to Pre- Prism and cover testing revealed 6 PD sion immediately after surgery ow- of exotropia and 6 PD of left hyper- vent Blindness Walt and Lily Dis- ing to transient abducens nerve pal- ney Research Award (Dr tropia at distance and 12 PD of exo- sies, but the diplopia never resolved tropia and 4 PD of left hypertropia at Hunter), the Medical Scientist Train- despite resolution of the abduction ing Program (Dr Reddy), and the near. Double Maddox rod testing limitation. showed 2° of incyclotorsion on the Children’s Hospital Ophthalmol- Once central fusion is dis- ogy Foundation (Dr Salgado). right and 4° of excyclotorsion on the rupted, it is rarely regained.2 Al- left. Stereopsis was not detectable and though prisms did not restore fu- 1. Bielschowsky A. Congenital and acquired defi- diplopia was found on Worth 4-dot sion in either of our cases, the ciencies of fusion. Am J Ophthalmol. 1935;18: testing. Using prisms, the patient was 925-937. patients were most comfortable 2. Pratt-Johnson JA, Tillson G. Intractable diplo- able to superimpose both images but when the 2 images were maximally pia after vision restoration in unilateral cataract. unable to fuse them. Prisms were pre- superimposed. In our clinical expe- Am J Ophthalmol. 1989;107(1):23-26. 3. Lyle TK. The importance of orthoptic investi- scribed as they improved his com- rience, this has been the case in pa- gation before contact lens fitting in unilateral fort, but he remains unable to fuse im- tients with central fusion disrup- aphakia: a preliminary report. Trans Ophthal- ages into a single visual impression. mol Soc U K. 1953;73:387-398. tion of any cause, contrary to the 4. Pratt-Johnson JA, Tillson G. Acquired central dis- The patient was diagnosed with clinical teaching that it is easier for ruption of fusional amplitude. Ophthalmology. central fusion disruption second- patients to ignore double images 1979;86(12):2140-2142. 5. Gruzensky WD, Palmer EA. Intractable diplo- ary to pineal tumor irradiation and when they are not nearly superim- pia: a clinical perspective. Graefes Arch Clin Exp surgery. posed. We therefore recommend of- Ophthalmol. 1988;226(2):187-192.

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