Glaucoma patient presents with eye pain, blurred vision

On examination, iris atrophy and peripheral anterior synechiae were seen.

Priti Batta

Namrata Nandakumar

A 62-year-old Chinese woman presented to our clinic with a 1-day history of right eye pain, redness and blurry vision. She also described a bilateral frontal headache as well as dizziness.

Her ocular history was significant for chronic angle-closure glaucoma in both eyes, secondary to anatomically narrow angles, for which she underwent laser peripheral iridotomies many years ago. She was subsequently diagnosed with plateau iris configuration, and she underwent bilateral gonioplasty. Her IOP remained poorly controlled, particularly in the left eye. She underwent a trabeculectomy with 5-fluorouracil in the left eye 10 years ago followed by a double-plate Ahmed valve with cataract extraction 8 years ago. She is currently taking Cosopt (dorzolamide hydrochloride, timolol maleate, Merck), Lumigan (bimatoprost ophthalmic solution, Allergan) and Pred Forte (prednisolone acetate ophthalmic suspension 1%, Allergan) eye drops in both eyes. Her IOP has generally been well-controlled over the years, although for the past year she has had some elevated pressures on routine clinic visits.

Her medical history was significant for hypertension, for which she took atenolol. She had a family history of glaucoma.

Examination

On examination, the patient’s best corrected visual acuity was 20/70 in the right eye and 20/30 in the left eye, with no improvement on pinhole refraction in either eye. The direct pupillary response was sluggish in the right eye but brisk in the left eye. She did not have an afferent pupillary defect. Her IOPs by applanation were 60 mm Hg in the right eye and 16 mm Hg in the left eye.

Figure 1. Anterior segment photograph of the left eye depicting iris atrophy and stromal splitting. Images: Bhavsar K and Mattox C

Anterior segment examination of the right eye revealed 1+ diffuse injection of the bulbar conjunctiva, as well as 2+ diffuse microcystic corneal edema. The anterior chamber was markedly shallow. There was 360· of peripheral iridocorneal touch, as well as diffuse anterior stromal iris atrophy, with the ends of the anterior iris stromal fibers free-floating in the anterior chamber. Anterior segment examination of the left eye was notable for a double-plate Ahmed tube shunt with the tube appropriately positioned in the anterior chamber. Iris atrophy in the left eye was seen inferotemporally (Figure 1).

Gonioscopy of both eyes revealed diffuse peripheral anterior synechiae with no angle structures visible. Dilated funduscopic examination of both eyes showed a cup-to-disc ratio of 0.4 in the right eye and 0.8 in the left eye.

Visual field testing was suggestive of an early superior arcuate defect in the right eye and dense superior nasal step and inferior arcuate defect in the left eye. Optical coherence tomography revealed a retinal nerve fiber layer thickness of 110 µm in the right eye and 53 µm in the left eye, with generalized thinning in the left eye.

What is your diagnosis?

Acute angle-closure with iris atrophy

The differential diagnosis for acute on chronic angle-closure glaucoma associated with iris atrophy includes iridoschisis, Axenfeld-Rieger syndrome and iridocorneal endothelial syndrome.

Progressive angle closure with chronic peripheral anterior synechiae (PAS) formation occurs with iridoschisis, iridocorneal endothelial (ICE) syndrome and Axenfeld-Rieger syndrome. These clinical entities can be differentiated based on laterality, age of onset and specific anterior segment exam characteristics. Iridoschisis and Axenfeld-Rieger syndrome are typically bilateral, whereas ICE syndrome presents unilaterally. Iridoschisis generally manifests in the seventh decade of life, in contrast to ICE syndrome, which presents in the fourth decade, and Axenfeld-Rieger syndrome, which is a congenital disorder. Moreover, iridoschisis has a characteristic splitting of anterior iris stroma from the posterior stroma. The anterior stromal strands can be seen waving freely in the aqueous of the anterior chamber. This is distinct from the stromal atrophy and hole formation seen in both ICE syndrome and Axenfeld-Rieger syndrome. Additionally, Axenfeld-Rieger syndrome is associated with other systemic anomalies including teeth, facial and musculoskeletal malformations. Our patient was diagnosed with acute on chronic angle-closure glaucoma secondary to PAS formation from iridoschisis, given her age of presentation, bilateral disease and hallmark exam findings.

Discussion and management

Initial management was aimed at acutely lowering IOP. Oral acetazolamide as well as topical agents Alphagan P (brimonidine tartrate, Allergan), Cosopt and pilocarpine 2% were administered. One hour later, the patient’s IOP was 69 mm Hg in the right eye. A laser peripheral iridotomy was performed, but 30 minutes later the IOP was unchanged. Given lack of improvement after these measures, an anterior chamber paracentesis was done, which reduced IOP to 24 mm Hg. The patient was placed on Cosopt, Alphagan and oral acetazolamide therapy overnight. The patient underwent cataract extraction and Ahmed valve shunt placement the next day (Figures 2 and 3). The patient’s postoperative course was successful, with an IOP of 15 mm Hg achieved in the right eye after shunt surgery.

Figures 2 and 3. Anterior segment photographs of the right eye after Ahmed tube shunt placement depicting resolution of iridocorneal touch and peripheral anterior chamber deepening.

Iridoschisis is a rare condition characterized by local cleavage of iris stroma presenting as iris atrophy. The majority of case reports are described in individuals age 70 years and older. There is no clear established genetic or gender predilection. The pathophysiology of iridoschisis has not been elucidated, and it is typically labeled as an idiopathic iris atrophy of age. Some case reports note an association between syphilitic interstitial keratitis and keratoconus. Glaucoma is seen in cases of iridoschisis in 65% of reported cases. Approximately 40% of those cases are coupled with acute angle-closure glaucoma.

The exact mechanism is unknown, but some studies suggest that chronic PAS formation in iridoschisis causes progressive angle closure. Blockage of the trabecular meshwork with pigment may also have a role in the pathogenesis of IOP elevation. Based on the association of iridoschisis and glaucoma, patients with this rare disorder should be closely followed, and examination should include gonioscopy. In those with acute angle-closure, therapy should be directed at acute IOP lowering. In some cases, definitive treatment may require tube shunt surgery to achieve long-term IOP control.

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• Kavita Bhavsar, MD, and Cynthia Mattox, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.

• Edited by Priti Batta, MD, and Namrata Nandakumar, MD. Drs. Batta and Nandakumar can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.
• Disclosure: No products or companies are mentioned that would require financial disclosure.