SCHWARTZ-MATSUO SYNDROME

Introduction:

Schwartz-Matsuo syndrome is a rare condition characterized by the triad of rhegmatogenous retinal detachment (RRD) (usually with peripheral breaks or oral dialysis), elevated intraocular pressure (IOP) with marked fluctuation, and cells in the anterior chamber. In cases of retinal detachments not associated with Schwartz-Matsuo syndrome, there is usually low IOP secondary to increased outflow by active pumping of aqueous humor through the exposed retinal pigment epithelium. However, IOP in Schwartz-Matsuo syndrome is elevated.

The syndrome was first described by Schwartz in 1973. He described the classic findings of elevated IOP and apparent iridocyclitis associated with RRD and open AC angles. In 1986 Matsuo et al. discovered photoreceptor outer segments on electron microscopy of the aqueous humor and theorized that the free photoreceptor outer segments blocked the trabecular outflow leading to elevated IOP.

Electron microscopy of aqueous humor in such patients has demonstrated photoreceptors outer segments. The photoreceptor outer segments and/or retinal pigment epithelium (RPE) pigment pass through a retinal break, leading to outflow obstruction in the trabecular meshwork. 

The syndrome presents with, or mimics, severe open-angle glaucoma. It can be mistaken for uveitis or uveitic glaucoma, but it does not respond to corticosteroids. There are no features of inflammation such as pain, redness or ciliary flush.

Following retinal detachment repair, IOP typically normalizes and prognosis is favorable.

Symptoms:

Patients typically present with complaints of unilateral blurry vision, eye pain, and nausea associated with the elevated IOP, as well as floaters, photopsia, and scotoma secondary to the retinal detachment. 

Risk Factors:

Shallow RRD involving the vitreous base (a shallow detachment allows for constant sloughing of dying photoreceptor outer segments and involvement of the vitreous base allows for the photoreceptor outer segments to gain access to the anterior chamber. An intact hyaloid would not allow them to reach the anterior segment).

Other risk factors include:

• Retinal dialysis or retinal tears at the ora serrata. 
• History of ocular trauma or surgery.
• Myopia, or lattice degeneration.

Diagnosis:

On examination, IOP is elevated, with marked fluctuation in pressures. Pigmented aqueous cells are present in varying number, but there are usually no other signs of uveitis. On gonioscopy, the anterior chamber angles are typically open; however, angle recession may indicate prior ocular trauma. Finally, there is retinal detachment with tears most commonly located at the ora serrata or non-pigmented epithelium of the pars plana or pars plicata. The retinal detachment is often shallow and involves a wide area, including the macula.

Identification of photoreceptor outer segments in the aqueous humor by electron microscopy assists in the diagnosis. OCT will demonstrate the presence of subretinal fluid indicative of retinal detachment.

Systemic examination (Marfan's syndrome or atopic dermatitis may help identify patients who are at risk of a retinal break around the ora serrata).

Routine assessment of the visual acuity and monitoring of IOP should be done.

Gonioscopy will show an open angle and can rule out other etiologies of increased IOP: angle recession, angle closure, peripheral anterior synechiae, neovascularization, and others.

Differential diagnosis:

1. Iritis: The anterior chamber findings in Schwartz-Matsuo syndrome are not inflammatory. The presence of anterior synechiae and keratic precipitates indicates an inflammatory condition which would rule out this condition. It should also be noted that the aqueous cells in Schwartz-Matsuo syndrome are unresponsive to corticosteroid treatment.
2. Open-angle or other secondary glaucomas should be considered, especially if it occurs in a patient with a history of blunt trauma.
3. Posner-Schlossman syndrome shows very mild anterior chamber inflammation with few cells and little flare, few fine keratic precipitates, and responds to steroid treatment.

Management:

Schwartz-Matsuo syndrome should be managed as a secondary cause of glaucoma, with first line treatment including repair of the retinal detachment and washout of the AC cellular debris. Typically, IOP returns to normal following retinal detachment repair. 

Immediate glaucoma management includes maximizing medical therapy before retinal surgery with oral carbonic anhydrase inhibitors with or without pilocarpine. Pilocarpine may help to open the trabecular meshwork pores but is associated with miosis and increased risk of retinal detachments.

Similar to the treatment of pigmented cells seen in pigment dispersion syndrome, laser trabeculoplasty should lower the IOP, but may not achieve satisfactory results. Additionally, laser trabeculoplasty may place patients at higher risk for post-operative IOP spikes given their compromised trabecular function. 

A tube shunt is preferred over trabeculectomy given the possible conjunctival scaring following retinal surgery and the risk of hypotony maculopathy with the use of antifibrotic agents in young, highly myopic patients. Tube shunts may induce diplopia via restrictive strabismus when combined with sclera buckle. An additional consideration is the timing of the tube shunt implantation, whether at the time of retinal surgery or not.

Prognosis:

Is usually good, with IOP returning to normal following successful RRD surgery.