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Show Journal " f C/ i" iral Nt'llro- o" htlwl",,' logy 1)(. 1): 162- 165, 1991, Upgaze Intraocular Pressure Changes and Strabismus in Graves' Ophthalmopathy Deborah R. Fishman, M. D. and Susan C. Benes, M. D. © 1991 Raven Press, Ltd" New York Graves' thyroid ophthalmopathy primarily affects women in their third through sixth decade. Sixty- seven patients with clinical myopathic ophthalmic Graves' disease examined ( by SCB) between 1982 and 1989 were measured for changes in upgaze intraocular pressure and strabismus. Special attention was paid to " masquerade" symptoms, including pseudosuperior oblique palsies and cyclotorsions. Any correlation between the extent of hypertropia on muscle exam and upgaze intraocular pressure changes is examined. Data suggest that significant changes in introcular pressure in upgaze correlate with more severe extraocular muscle involvement, may represent progression to muscle fibrosis, and occur uniformly in our study of patients who progress to require inferior rectus recession. Key Words: Graves' thyroid ophthalmopathy- Intraocular pressure- Hypotropia. From the Department of Ophthalmology, Ohio State University, Columbus, Ohio, U. S. A. Address correspondence and reprint requests to Dr. Susan C. B: ne~, at Ohio State University, Department of Ophthalmology, " '\''''! T" nth Avcnue. Columbus, OH 43210 U. S. A. 162 Graves' disease is a major cause of exophthalmos and extraocular muscle abnormalities in the adult population, Clinical involvement of the inferior rectus muscle is most common. The pathology of thyroid eye disease includes inflammatory infiltration of the extraocular muscles and surrounding soft tissues with lymphocytes, mast cells, plasma cells, and macrophages. There is eventual progression to intramuscular fibrosis, but degeneration rarely occurs ( 1). Restrictive strabismus has many other etiologies, including orbital trauma, congenital abnormalities, postoperative sequelae, longstanding nonrestrictive deviations, orbital primary and metastatic tumor, and orbital and periorbital inflammation ( 2). Prisms and occlusion therapy are initial treatments of the muscle imbalance of ophthalmic Graves' disease. Surgical treatment of extraocular muscle involvement has traditionally been performed once the strabismus has been stable for 6 months ( 3). Muscle changes are most often restrictive, cicatricial, and noncomitant ( 4). Hypotropia is the most commonly presenting extraocular muscle abnormality; inferior rectus recession is the procedure most often performed ( 3). Thyroid eye disease may present with cyclodeviations-- most often with excyclotorsions. If the torsion is greater than 15°, 100% of the patients are aware of the tilt. At 5°, only 50% of the patients are aware of the tilt until either a compensatory head tilt or double Maddox rod testing brings their attention to it ( 5). Caygill believes that torsion in thyroid patients is the result of the combined effective overaction of restricted inferior rectus and inferior oblique muscles acting as excyclotorters ( 6). With this cyclodeviation, there may be increased hypertropia on adduction, simulating a superior oblique palsy. However, the restrictive hyperdeviation increases on upgaze, differentiating it from a newly- acquired fourth nerve palsy. The normal variation of intraocular pressure in IOP CHANGES IN GRAVES' OPHTHALMOPATHY 163 8 - 7.6 r-- 5.2 - 4.8 - n- l0 n- 9 n- l n- 2 n- 19 Q 1- 2 3- 5 6- 8 9- 11 12- Hypotropia FIG. 1. Prism diopters of hypotropia versus the difference in intraocular pressure between primary and upgaze in patients with recorded measurable hypotropia and dIOP. o 2 4 6 dlOP 10 8 ( 63%), dIOP was greater than or equal to 3 in both eyes. Of the 6 patients ( 9%) with dIOP less than 3, none were noted to have upgaze restriction or chin- up posturing. The correlation between the degree of hypotropia and dIOP ( hypotropic eye) is demonstrated in Fig. 1. Further subdivision of patients with hypodeviation and monocular significant dIOP ( dIOP greater than or equal to 3 in only one eye) is demonstrated in Fig. 2. In patients with upgaze limitation and chin- up posturing, the patient dIOP was based upon the hypotropic eye. In vertical orthophoria, the more significant dIOP was counted. The dIOP was significant in this group of patients, with an average dIOP of 8.3. The difference between dIOP in each category ( monocular upgaze restriction, binocular upgaze restriction, and chin- up posturing) was not significant. Figure 3 demonstrates the correlation between upgaze restriction or chin- up posturing and the ddIOP. In this graph, the ddIOP is defined as the dIOP of the hypotropic eye minus the dIOP of the hypertropic eye; in vertical orthophoria, the larger dIOP minus the smaller dIOP is used. In the 10 patients with cyclodeviation, a significant dIOP was recorded in 100%, with an average dIOP in the hypotropic eye of 7.2. In pseudosuperior oblique palsy, the average dIOP for the hypotropic eye was 6.8. Seven patients ( 10.4%) required inferior rectus recession; the average preoperative dIOP in the hypotropic eye was 7.8. In two patients bilateral recession was performed and the average preoperative ddIOP was 2.0. In those patients undergo- RESULTS The most common strabismus finding was hypotropia, present in 41 patients ( 61 %). Pseudosuperior oblique palsy, defined as a hypertropia greatest in opposite gaze and ipsilateral head tilt, was present in 19 patients ( 28%). Significant torsional deviations ( 100% excyclotorsions) were noted in 10 patients ( 15%); 31 patients ( 46%) presented with some type of chin- up posturing or upgaze restriction. The dIOP was greater than or equal to 3 in at least one eye in 61 patients ( 91 %). In 42 patients The charts of 67 patients with Graves' ophthalmopathy and recorded upgaze intraocular pressures examined by a single observer ( SCB) between 1982 and 1989 were reviewed. Patient age ranged from 21 to 91 years ( mean 53). Motility status was determined by prism/ cover and alternate prism/ cover testing. Severity of inferior rectus involvement was measured by prism diopters of hypertropia in patients with asymmetric orbital fibrosis. In patients with severe bilateral orbitopathy, chin- up posturing or restricted upgaze indicated bilateral restriction. A difference between intraocular pressure in primary and extreme upgaze in mm Hg is referred to as " dIOP." Difference between intraocular pressure ( dIOP) was recorded in at least the " tightest" eye. The symbol " ddIOP" is used to define the difference in dIOP between the hypotropic and hypertropic eye. All tonometry measurements were performed by Goldmann applanation tonometry. Cyclodeviations were measured by double Maddox rod testing when appropriate. MATERIALS AND METHODS vertical gaze positions has been studied. Reader demonstrated the lowest intraocular pressures at 5° downgaze in normals with a linear increase in intraocular pressure in progressive upgaze and downgaze ( 7). Increased intraocular pressures in eccentric gaze positions have been previously documented in thyroid eye disease ( 8,9). Metz postulated that the mechanism involves increased restriction on the globe from thickened and fibrosed extraocular muscles. This increases when the agonist muscle contracts and the antagonist muscle fails to become slack ( 2). This study attempts to correlate upgaze intraocular pressure changes with quantitative parameters indicating extraocular muscle involvement. I Gin Neuro- ophthalmol, Vol. 11, No. 3, 1991 |
