Uveitic Glaucoma: Techniques and Strategies for MANAGEMENT

Successful treatment depends on appropriate use of medical therapy and laser surgery.

BY AHMAD A. AREF, MD, INGRID U. SCOTT, MD, MPH

The diagnosis and management of uveitic glaucoma heralds a challenge to even the most astute clinicians. The medical and surgical treatment plan for patients suffering from uveitic glaucoma requires a careful, individualized strategy to achieve a successful outcome. Often, a team approach involving more than one ophthalmic subspecialist becomes necessary. This article aims to shed light on considerations in the diagnosis and management of this clinical entity.

Making the Diagnosis

Uveitic glaucoma may be divided into two subtypes based on the status of the anterior chamber angle and underlying pathophysiology: open-angle and closed-angle. Open-angle uveitic glaucomas are often secondary to an underlying process such as sarcoidosis, juvenile idiopathic arthritis, ocular herpetic infection, toxoplasmosis and syphilis, along with specific glaucomatous entities such as Fuchs heterochromic iridocyclitis, and glaucomatocyclitic crisis (Posner-Schlossman syndrome).

Angle-closure glaucoma related to uveitis may result from peripheral anterior synechiae (PAS) occluding the trabecular meshwork, posterior synechiae (Figure 1) or a pupillary membrane (Figure 2) resulting in pupillary block or ciliochoroidal effusions causing anterior displacement of the lens-iris diaphragm, or both. Differentiating among these causes for secondary angle closure is critical to direct appropriate therapy. Often, both open- and closed-angle mechanisms are responsible for increased IOP and subsequent glaucomatous optic neuropathy.

Medical management

The cornerstone of uveitic glaucoma management is adequate control of ocular inflammation. Topical, periocular and systemic corticosteroids are often necessary to combat the inflammatory episode. Intravitreal steroid implants such as the fluocinolone acetonide (Retisert, Bausch + Lomb, Rochester, N.Y.) and dexamethasone (Ozurdex, Allergan Inc., Irvine, Calif.) implants allow for sustained release with minimal systemic absorption. A recent retrospective chart review found no difference in uveitic recurrence rates between patients treated with the Ozurdex and Retisert implants; however, patients treated with Retisert implants were more likely to experience steroid-response glaucoma.¹

Steroid-related IOP rise may require an increase in the patient’s IOP-lowering therapy. However, this outcome alone does not mean one should taper or discontinue steroids, because worsening ocular inflammation often results in a poorer overall outcome. Given the ocular and systemic side-effect profile of chronic steroid treatment, corticosteriod-sparing immunouppressive drugs may also be useful in cases that require maintenance therapy.

Figure 1. Posterior synechiae, iris bombe and secondary angle-closure glaucoma due to a pupillary block mechanism in a 50-year-old Caucasian man with idiopathic sclerouveitis.

Aqueous suppressants commonly accompany medical ocular hypotensive therapy in patients with uveitic glaucoma. Prostaglandin analogs, although a first-line treatment in primary open-angle glaucoma (POAG), pose a theoretical risk of exacerbating a uveitic episode.² Their use in uveitic glaucoma remains controversial and requires further study.^3,4 For this reason, clinicians typically hold prostaglandin analogs in reserve once they exhaust other medical options.

Avoid miotics for uveitic glaucoma. These agents may cause further disruption of the blood-aqueous barrier and subsequently worsen intraocular inflammation.

Laser treatment

Although laser trabeculoplasty is effective in treating POAG and pseudoexfoliative and pigmentary glaucomas, the procedure has no role in managing uveitic glaucoma. Laser trabeculoplasty may incite intraocular inflammation and lead to worsening of uveitic glaucoma — often ciliary body hyposecretion and paradoxical episodes of ocular hypotony. Avoid procedures such as trans-scleral diode laser cyclophotocoagulation because of the risk of unexpected hypotony.

Laser iridotomy may be indicated in cases of uveitic glaucoma and secondary angle closure involving a pupillary block mechanism. Laser iridotomy reverses iridotrabecular apposition. Argon laser pre-treatment followed by Nd:YAG laser penetration decreases the risk of hyphema and also requires less energy than the YAG laser alone. This method may reduce the risk of exacerbating the uveitic episode.

A fibrinous anterior segment reaction may lead to rapid closure of a previously patent iridotomy site. Therefore, more than one large laser iridotomy in different quadrants of the iris may be necessary (Figure 2). A surgical iridectomy may be necessary in cases of repeat laser iridotomy closure. Laser iridotomy is not indicated for angle closure related to PAS or forward displacement of the lens-iris diaphragm, or both. Neither involves a pupillary-block mechanism.

Surgical options

Glaucoma filtration surgery for uveitic glaucoma is often challenging. Episodic ciliary body hyposecretion heightens the risk of postoperative hypotony. Additionally, while complete preoperative treatment of ocular inflammation is ideal, surgery is often indicated before it may be achieved.

Trabeculectomy surgery in uveitic glaucoma often requires an adjunctive antifibrotic agent to reduce the risk of failure due to episcleral fibrosis. Unfortunately, even with appropriate adjunctive antifibrotic agents, the risk of surgical failure in this setting is greater compared to other glaucoma types. A long-term retrospective study of trabeculectomy identified a baseline diagnosis of uveitic glaucoma as a risk factor for surgical failure.⁵

Figure 2. This 25 year-old African-American man had a history of uncontrolled uveitic glaucoma secondary to sarcoidosis. Both open- and closed-angle mechanisms were responsible. A fibrinous pupillary membrane caused pupillary block and secondary angle-closure, necessitating laser peripheral iridotomies. Two large iridotomies were created 180° apart to allow for successful reversal of iridotrabecular contact. Persistently uncontrolled IOP required glaucoma drainage implant surgery.

Figure 3. In this 73-year-old African-American woman with a history of uncontrolled uveitic glaucoma secondary to sarcoidosis, characteristic granulomatous keratic precipitates appear in the inferior cornea. She had an Ex-Press mini-shunt (Alcon Labarotories) procedure with adjunctive mitomycin-C. IOP remains controlled 10 months postoperatively.

Some think of the Ex-Press mini-glaucoma shunt (Alcon Laboratories, Fort Worth, Texas) as a modification of conventional trabeculectomy. This procedure involves implantation of a stainless steel device under a scleral flap. The device serves as a conduit for aqueous outflow into the subconjunctival space (Figure 3). The Ex-Press shunt may be less prone to overlying episcleral scar formation and failure in uveitic glaucoma. One study investigating the use of this device with mitomycin-C in neovascular, uveitic and primary open-angle glaucomas reported an average IOP reduction of 40% after a mean follow-up of 9.6 months.⁶

Glaucoma drainage implant (GDI) surgery remains an important option in the setting of uncontrolled uveitic glaucoma (Figure 2). Valved and non-valved devices may achieve long-term success. A retrospective study of 21 eyes with chronic uveitic glaucoma that underwent GDI surgery with the valved Ahmed Glaucoma Valve (New World Medical, Rancho Cucamonga, Calif.) reported an average IOP reduction of 23.7 mm Hg at last follow-up.⁷ All eyes achieved an IOP between 5 and 18 mm Hg after an average of 24.5 months of follow-up. Another study reported a cumulative life-table success rate of 91.7% at 24 months in patients with uveitic glaucoma treated with the non-valved Baerveldt Glaucoma Implant (Abbott Medical Optics, Abbott Park, Ill.).⁸

Even after technically successful glaucoma surgery by a skilled ophthalmic surgeon, the postoperative course is often unpredictable in patients with uveitic glaucoma.We cannot overstate the importance of adequate postoperative care. Frequent visits and proper adjustment of anti-inflammatory and adjunctive ocular hypotensive agents based on an individual’s clinical response allow for the best possible outcome.

Conclusion

The management of uveitic glaucoma requires an approach that carefully balances anti-inflammatory treatment and IOP control while minimizing the risk of hypotony. Once the clinician identifies the underlying disease pathophysiology, a tailored management plan involving medical, laser and surgical therapies can begin. A successful outcome depends on a comprehensive examination, complex medical decision-making and a well-executed surgical strategy. OM

References

1.Arcinue CA, Ceron OM, Foster S. A Comparison between the fluocinolone acetonide (Retisert) and dexamethasone (Ozurdex) intravitreal implants in uveitis. J Ocul Pharmacol Ther. Jan 2013. [Epub ahead of print].

2. Yousufazi SY, Abdel-Latif AA. Prostaglandin F2a and its analog induce release of endogenous prostaglandins in iris and ciliary muscles isolated from cat and other mammalian species. Exp Eye Res. 1996;63:305-310.

3. Warwar RE, Bullock JD. Latanoprost-induced uveitis. Surv Ophthalmol. 1999;43:466-468.

4. Horsley MB, Chen TC. The use of prostaglandin analogs in the uveitic patient. Semin Ophthalmol. 2011;26:285-289.

5. Landers J, Martin K, Sarkies N, Bourne R, Watson P. A twenty-year follow-up study of trabeculectomy: risk factors and outcomes. Ophthalmology. 2012;119:694-702.

6. Reyes M, Sarkisian SR. P200 Express shunt implantation in neovascular glaucoma, uveitic glaucoma, and primary open-angle glaucoma. Invest Ophthalmol Vis Sci. 2010;51: E-Abstract 4438.

7. Da Mata A, Burk SE, Netland PA, Baltazis S, Christen W, Foster CS. Management of uveitic glaucoma with Ahmed Glaucoma Valve implantation. Ophthalmology. 1999;106:2168-2172.

8. Ceballos EM, Parrish RK, Schiffman JC. Outcome of Baerveldt glaucoma drainage implants for the treatment of uveitic glaucoma. Ophthalmology. 2002;109:2256-2260.

Ahmad A. Aref, MD, is with the Illinois Eye & Ear Infirmary, University of Illinois at Chicago School of Medicine. Ingrid U. Scott, MD, MPH, (pictured) is with the Penn State Hershey Eye Center, Penn State University College of Medicine, Hershey, Pa.