Schwartz-Matsuo syndrome is a type of open-angle glaucoma secondary to rhegmatogenous retinal detachment (RRD). It was first reported by Schwartz in 1973, and later Matsuo elucidated the pathophysiology in detail, hence the name. 4)
The essence of the disease is that when aqueous humor flows into the subretinal space through a retinal tear, the detached photoreceptor outer segments (POS) migrate into the anterior chamber. These outer segment particles physically obstruct the trabecular meshwork (TM), causing impaired aqueous outflow and elevated intraocular pressure. 4) The Japanese Glaucoma Society guidelines classify this syndrome as a form of secondary open-angle glaucoma. 2)
It is a form of secondary glaucoma associated with rhegmatogenous retinal detachment. Although rare, it is easily overlooked. If anterior chamber cells are mistaken for inflammation and steroids are administered, intraocular pressure does not decrease, making diagnosis difficult. When a patient with retinal detachment presents with elevated intraocular pressure, this syndrome should always be considered.
The subjective symptoms of this syndrome are a mixture of those due to retinal detachment and those due to elevated intraocular pressure.
This syndrome is characterized by the following three signs.
① Elevated intraocular pressure
Elevated intraocular pressure: Shows moderate to severe elevation of intraocular pressure. It tends to be proportional to the severity of retinal detachment.
Open angle: Gonioscopy reveals an open angle, not angle closure. Aqueous outflow obstruction occurs at the level of the trabecular meshwork.
② Anterior chamber cells
Relatively large cells: Leukocyte-like cells float in the anterior chamber. These are fragments of photoreceptor outer segments, which may be larger and more irregular in shape than inflammatory cells.
Mild flare: Flare (protein turbidity) is often mild compared to inflammatory uveitis.
③ Retinal detachment
Rhegmatogenous retinal detachment: Retinal detachment and a tear can be confirmed on fundus examination.
Correlation between detachment extent and intraocular pressure: The larger the detachment area, the greater the amount of outer segments released into the anterior chamber, and the higher the intraocular pressure tends to be.
The clinical differentiating points between this syndrome and inflammatory uveitic glaucoma are shown below.
| Findings | Schwartz-Matsuo syndrome | Inflammatory uveitis |
|---|---|---|
| Anterior chamber cells | Large, irregular | Small, uniform |
| Flare | Mild | Moderate to severe |
| Retinal detachment | Present (required) | Absent (usually) |
| Steroid response | Ineffective | Effective |
In this syndrome, the cells floating in the anterior chamber are fragments of photoreceptor outer segments, not inflammatory cells. They are larger and more irregular in shape than inflammatory cells, but differentiation can be difficult with slit-lamp microscopy alone. Confirmation of retinal detachment and lack of response to steroids are key to differential diagnosis. See the Diagnosis and Testing Methods section for details.
The underlying cause of this syndrome is the migration of photoreceptor outer segments into the anterior chamber due to rhegmatogenous retinal detachment, leading to physical obstruction of the trabecular meshwork. 4)2)
Photoreceptor outer segments are metabolically active tissues; even under normal conditions, their tips are shed daily and phagocytosed by retinal pigment epithelial cells. When the retina detaches, the shed outer segments are not cleared by the retinal pigment epithelium and flow through the subretinal fluid into the vitreous cavity and anterior chamber. These outer segment particles clog the pores of the trabecular meshwork, causing chronic impairment of aqueous humor outflow.
Risk factors for developing rhegmatogenous retinal detachment are also risk factors for this syndrome.
If retinal detachment is confirmed in a patient with the triad (elevated intraocular pressure, open angle, anterior chamber cells), this syndrome is strongly suspected. The European Glaucoma Society (EGS) guidelines emphasize the importance of gonioscopy in evaluating secondary glaucoma, and the same applies to this syndrome. 1)
The diseases to be differentiated and their characteristics are shown below. 3)
| Differential Diagnosis | Features | Distinguishing Points |
|---|---|---|
| Inflammatory Glaucoma | Anterior chamber inflammation, KP | Steroid responsive |
| POAG | Chronic progressive | No retinal detachment |
| Posner-Schlossman | Recurrent intraocular pressure elevation | Mild inflammation |
Steroid ineffectiveness is an important differential clue. However, definitive diagnosis requires confirmation of retinal detachment by fundus examination or ultrasound. It is advisable to actively search for retinal detachment before attempting steroid response.
The definitive treatment for this syndrome is surgical repair of the retinal detachment. Reattaching the retina stops the supply of photoreceptor outer segments to the anterior chamber, and intraocular pressure usually normalizes postoperatively. 4)
The choice of surgical procedure depends on the extent of detachment, location of breaks, and presence of proliferative changes.
First-line treatment
Retinal detachment surgery: The only treatment that fundamentally normalizes intraocular pressure. Scleral buckling or vitrectomy is selected according to the condition.
Postoperative course: If proper reattachment is achieved, intraocular pressure often decreases to the normal range within days to weeks after surgery.
Preoperative and waiting-period intraocular pressure management
Aqueous humor suppressants: Beta-blocker eye drops (e.g., timolol) and carbonic anhydrase inhibitors (eye drops or oral) are used. When intraocular pressure is high, they are used as a bridge therapy until surgery.
Prostaglandin-related drugs: Some opinions advise caution because they may exacerbate inflammation.
Steroids are ineffective
Steroid eye drops or oral steroids: Since the anterior chamber cells are photoreceptor outer segments, not inflammatory cells, steroids cannot be expected to lower intraocular pressure.
Risk of inappropriate administration: If steroids are given due to misdiagnosis as inflammatory glaucoma, there is an added risk of steroid-induced intraocular pressure elevation.
In rhegmatogenous retinal detachment, vitreous fluid flows into the subretinal space through the retinal tear. The outer segments of detached photoreceptors (rods and cones) cannot be phagocytosed by the normal retinal pigment epithelium and migrate from the subretinal space into the anterior chamber. The outer segment particles that enter the anterior chamber mix with the aqueous humor and physically block the pores of the trabecular meshwork. 4)2)
The trabecular meshwork is the main outflow pathway for aqueous humor and is composed of trabecular collagen fiber bundles. Disc membrane fragments of photoreceptor outer segments are biologically stable and are slowly degraded and phagocytosed by macrophages. Therefore, outer segment particles accumulate in the trabecular meshwork over a long period, causing sustained outflow resistance. 4)
The degree of intraocular pressure elevation correlates with the amount of outer segments that have migrated into the anterior chamber (i.e., the extent and duration of detachment).
In inflammatory uveitic glaucoma, leukocytes, inflammatory cytokines, and fibrin cause inflammatory infiltration of the trabecular meshwork, and prostaglandins increase aqueous production by the ciliary body. In contrast, in this syndrome, inflammatory mechanisms are not involved, and physical obstruction by outer segment particles is the main cause. This difference in mechanism leads to differences in response to steroids. 3)
Technological innovations in vitreous surgery (27-gauge and 25-gauge small incision systems, wide-angle viewing systems) continue to improve postoperative outcomes of retinal detachment repair. In this syndrome as well, rapid and precise retinal reattachment is expected to minimize secondary and irreversible damage to the trabecular meshwork.
In refractory cases where intraocular pressure does not normalize after retinal reattachment, outflow reconstruction surgery such as trabeculotomy may be considered. MIGS (minimally invasive glaucoma surgery) devices, which have become popular in recent years, are theoretically suitable as a procedure to mechanically open the trabecular meshwork obstructed by outer segment particles, and future application is expected, but evidence specific to this syndrome is currently limited.
In many cases, intraocular pressure normalizes after retinal reattachment. However, if detachment persists for a long time, irreversible damage to the trabecular meshwork may remain, and intraocular pressure may remain high after surgery. Early surgery leads to better intraocular pressure prognosis.
It depends on the duration and severity of intraocular pressure elevation. If retinal detachment is repaired early and intraocular pressure is normalized, irreversible damage to the optic nerve can be minimized. On the other hand, if diagnosis is delayed and high intraocular pressure persists, there is a risk that glaucomatous visual field defects will remain.
