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Man presents with sudden bilateral angle closure and myopic shift
On examination, the anterior chamber was extremely shallow with iris-cornea touch peripherally.
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A 40-year-old male airline pilot with no significant medical or ocular history presented as an urgent walk-in to the Tufts New England Eye Center Comprehensive Ophthalmology Clinic with 18 hours of sudden onset bilateral blurry vision. One day before presentation, he had been flying a commercial airplane from Hong Kong to Los Angeles when his vision became acutely blurry, and he could no longer read the control panels on the airplane. His vision became so hazy that his co-pilot had to take over for the rest of the flight. He had no other ocular symptoms at that time, and his systemic review of symptoms was negative other than an upper respiratory infection 3 weeks prior for which he had taken 5 days of azithromycin.
When he landed in Los Angeles, he went to a local ophthalmologist who noted that his vision had decreased to 20/80 but corrected to 20/20 in both eyes with a refractive error of –5 D. His prior correction was –3 D in each eye. IOP was 28 mm Hg in the right eye and 32 mm Hg in the left eye, and his anterior chambers were very shallow bilaterally. The ophthalmologist recommended urgent bilateral laser peripheral iridotomies (LPIs), but the patient deferred, preferring to be treated in Boston where his family was based. He was started on acetazolamide, dorzolamide, brimonidine and pilocarpine with an adequate improvement in IOP, and the patient then boarded the next flight to Boston.
Examination
Upon examination at Tufts, the patient’s visual acuity was 20/400 in each eye but corrected to 20/25 with –10 D of correction. Pupils were small and pinpoint in either eye due to the pilocarpine. IOP was 16 mm Hg in the right eye and 15 mm Hg in the left eye. The conjunctiva was white and quiet, and the cornea was clear bilaterally. The anterior chamber was extremely shallow with iris-cornea touch peripherally. No angle structures were visible on gonioscopy. The view to the posterior chamber was limited by the very small size of his pupils, but the nerves appeared to have a cup-to-disc ratio of 0.3 bilaterally with pink, healthy nerve tissue and good rims. The macula appeared flat bilaterally.
Images: Werner A
Anterior and posterior segment OCT, ultrasound biomicroscopy and B-scan are shown in Figures 1 to 4.
What is your diagnosis?
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Acute bilateral angle closure
Acute bilateral angle closure associated with a myopic shift can occur when the lens becomes dislocated anteriorly or when the ciliary body becomes rotated anteriorly. Situations in which anterior lens dislocation occurs acutely and bilaterally are limited. It can occur in conditions such as microspherophakia, in which the spherical lens can cause pupillary block, and secondary angle-closure glaucoma. Anterior dislocation of the lens can happen in patients with conditions that cause zonular weakness such Marfan syndrome and homocystinuria; however, simultaneous bilateral lens dislocation without an antecedent history of trauma would be unusual. Conditions associated with anterior rotation of the ciliary body include medication effect (pilocarpine), aqueous misdirection and uveal effusion syndrome. Patients with anatomically narrow angles are susceptible to angle closure after exposure to both mydriatic and miotic agents; however, it is the miotic agents that can induce a myopic shift through rotation of the ciliary body. Spontaneous bilateral aqueous misdirection without a history of ocular surgery is exceedingly unlikely; however, aqueous misdirection is an important consideration in cases of secondary angle closure with induced myopia. Lastly, uveal effusion syndrome is a rare entity that involves exudative detachments of the choroid, ciliary body and retina secondary to impaired posterior segment drainage. It is often a bilateral condition, and when the ciliary body is involved, it can cause a myopic shift.
Our patient was found to have increased choroidal depth visualized on both posterior segment OCT and B-scan. UBM revealed an effusion extending to the ciliary body, causing ciliary body detachment and anterior dislocation of the lens-ciliary body apparatus. Anterior segment OCT revealed the extent of the iris-cornea apposition. These findings were consistent with uveal effusion as a cause of the angle closure and myopic shift. The addition of pilocarpine by the first physician likely compounded the anterior rotation of the ciliary body and was responsible for the second myopic shift (from –5 D to –10 D) experienced by the patient.
Discussion
Uveal effusion occurs when there is a disruption of the normal mechanisms to remove extravasated proteins and fluid from the uveal circulation. Fluid from the choriocapillaris extravasates into the surrounding potential space, causing engorgement and thickening of the choroid or detachment of the choroid, ciliary body and retina. When the effusion extends to the ciliary body, a myopic shift may ensue.
In many cases, uveal effusion is secondary to underlying inflammatory conditions or hydrostatic abnormalities. In inflammatory conditions such as posterior scleritis or uveitis, effusion is caused by increased choroidal permeability. In contrast, ocular or systemic conditions that disrupt the normal hydrostatic milieu can also produce uveal effusions. These conditions include hypotony, myxedema, amyloidosis, multiple myeloma, nephropathy and dural arteriovenous fistula. When no obvious cause of the effusion exists, the term uveal effusion syndrome (UES) is applied. UES is divided into two categories, nanophthalmic and idiopathic. It should be considered a diagnosis of exclusion.
It appears that UES involves a primary abnormality of the sclera. There are multiple histologic studies illustrating that the sclera of patients with UES has abnormal arrangements of collagen fibrils and glycosaminoglycans and that it is abnormally thick. Shaffer and colleagues were the first to propose a hypothesis regarding the mechanism of UES. They suggested that the thickened sclera compresses the vortex vein, causing a backup of fluid, and their treatment focused on surgical decompression of the vortex veins. Later, Gass suggested that the abnormal sclera causes reduced scleral outflow of proteins, leading to choroidal effusion via increased osmotic pressure. He found that sclerotomies and scleral windows without decompression of the vortex veins improved uveal effusions. Subsequent studies using scleral tissue samples to test transscleral diffusion rates determined that it is likely both vein compression and reduced scleral outflow mechanisms may be at play to varying degrees in any individual.
There are some patients with UES who do not appear to have an underlying scleral abnormality. It is likely that these patient have some previously unrecognized cause of increased choroidal permeability. There have been reports of UES associated with viral infections such as HIV and, recently, H1N1. While there are no pathologic specimens to confirm this, the presumed underlying mechanism in these cases is thought to be increased vascular permeability secondary to cytokines released by viral-infected macrophages. Medication exposures are also linked to UES, possibly via an inflammatory pathway. The most notorious of these drug exposures is topiramate, but also includes other sulfa-based drugs such as acetazolamide, Bactrim (sulfamethoxazole and trimethoprim) and escitalopram.
In cases associated with drug exposure, treatment focuses on removing the offending agent. Similarly, when associated with a viral or systemic process, the UES should resolve with treatment of the underlying issue. Various medical therapies, primarily steroids and carbonic anhydrase inhibitors, have been reported to be helpful, although with highly variable degrees of success. For refractory cases, resolution of the effusion focuses on relieving the mechanical outflow obstruction via scleral window surgery. Patient selection is key for surgical intervention, and scleral windows seem to be effective in true scleral outflow obstruction due to scleral abnormalities. Patients with abnormal scleral histology and patients with nanophthalmos are most likely to benefit from this procedure, whereas patients with eyes of normal axial length and normal histology do not derive benefit, likely because the mechanism of UES in these patients is not an outflow issue.
Clinical course continued
Our patient underwent bilateral LPIs the day of his initial visit. Pilocarpine was discontinued, and treatment with topical cyclopentolate, dorzolamide and prednisolone acetate was initiated. He was continued on oral acetazolamide. Given the diagnosis of UES, the patient underwent further testing to determine the etiology of his condition. A-scan showed axial lengths of 24.05 mm and 24.01 mm, ruling out nanophthalmos. Fluorescein angiography and indocyanine green angiography were unremarkable. The patient underwent a systemic workup that included HIV, CBC with differential, complete metabolic panel, ANA and ANCA, total serum protein levels and serum peptide electrophoresis (SPEP). Total protein levels were mildly elevated, and the SPEP showed a small monoclonal spike. The patient was evaluated by hematology, which felt this did not represent monoclonal gammopathy of undetermined significance, amyloid or multiple myeloma. It was thought this was more likely to represent a post-viral inflammatory response. Over the next 4 weeks, the patient’s effusions resolved, and his myopic correction returned to baseline. He will have repeat evaluation by hematology in 6 months to ensure resolution of serum protein and electrophoresis abnormalities.
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- For more information:
- Astrid Werner, MD, Alan Barlow, MD, and Caroline Baumal, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.
- Edited by Jessica Moon, MD, and Emily C. Wright, MD. They can be reached at the New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.