September 2012

 

CATARACT

 

Complicated cataract cases

Uveitis: Posterior synechiae, lens deposits, CME, prolonged post-op inflammation, and secondary glaucoma


by James P. Dunn, M.D.

 

Kevin Miller, M.D.

This month's "Complicated cataract cases" column takes a look at the subject of uveitis, which is an inflammation of the uveal tract including the iris, ciliary body, and choroid.

Uveitis is a common problem in general ophthalmic practice. In addition to cataract development, it predisposes to complications such as anterior and posterior synechiae, glaucoma, cystoid macular edema, and reduced visual potential. The surgeon must be ready to manage these problems pre-operatively, intraoperatively, and post-operatively.

Pre-op management consists of quieting these eyes in advance of surgery and counseling patients on possible post-op problems, which include pupil irregularity, optic capture, lenticular inflammatory deposits, glaucoma from either the underlying uveitis or the corticosteroid medications used to treat it, epiretinal membrane development, cystoid macular edema, and less-than-perfect visual acuity after surgery. Intraoperative management may entail managing synechiae, miotic pupils, and posterior capsule plaques. Placement of the intraocular lens is an important intraoperative consideration. In synechiae formers, serious consideration should be given to sulcus placement of an appropriately designed lens to keep adhesions from developing post-op between the iris and the residual anterior lens capsule.

Post-op management consists of quieting inflammation and handling any complications that may arise in the days, weeks, and months that follow. Typical post-op problems include keratic precipitates, lenticular precipitates, recurrent synechiae, lens decentration, optic capture, posterior capsule opacification, and cystoid macular edema.

In addition to patients who come to cataract surgery with a known history of uveitis, there are patients who will develop uveitis either de novo or as a complication of surgery. The cataract surgeon must be prepared to handle these eyes as well.

In this issue, James P. Dunn, M.D., shares some study information, clinical pearls, and case examples that ophthalmologists will find useful for brushing up on this very important subject.

Kevin Miller, M.D., Complicated cataract cases editor

 
Direct illumination

Retroillumination

Figure 1. Inflammatory deposits on the anterior surface of the IOL following uveitic cataract surgery as seen with direct illumination (left) and retroillumination (right)

CME in left eye Figure 2A (Case 1). CME in left eye associated with active sarcoid uveitis

Resolution of CME Figure 2B (Case 1). Resolution of CME following sub-Tenon's triamcinolone acetonide injection

Iris bombe Figure 3A (Case 2). Iris bombe due to extensive posterior synechiae

Extensive iris pigment deposits Figure 3B (Case 2). Extensive iris pigment deposits on anterior lens surface caused by recurrent acute anterior uveitis

Resolution of iris bombe Figure 3C (Case 2). Post-op slit lamp photograph of left eye showing resolution of iris bombe

Uveitis following cataract surgery increases the risk of cystoid macular edema (CME), posterior synechiae, and secondary glaucoma, all of which may lead to delayed visual recovery or permanent visual loss. It is important to make the distinction between patients with pre-existing uveitis who undergo cataract surgery and those with no history of intraocular inflammation who develop uveitis after surgery. In the latter group, there typically has been some type of intraoperative complication, although it may not be recognized at the time of surgery, such as a small nuclear fragment that is not aspirated and lodges itself in the angle. A careful clinical examination is essential if such complications are to be identified and treated successfully.

Foster and colleagues popularized the concept of aggressive pre-op suppression of uveitis for at least several months prior to cataract surgery.1 While there are a variety of published regimens using a combination of topical, oral, and periocular corticosteroids as well as oral or topical nonsteroidal anti-inflammatory drugs (NSAIDs), the fundamental principle is to minimize the risk of recurrent uveitis and its sequelae by complete control of inflammation. With uncommon exceptions such as traumatic or phacolytic cataract, cataract surgery should never be performed in an actively inflamed eye. Furthermore, CME should be eliminated or minimized; the same regimen that treats uveitis will often accomplish this goal. A recent report showed patients with posterior uveitis who had undergone placement of an intravitreal fluocinolone implant prior to cataract surgery had better visual outcomes and less uveitis (but also more glaucoma) after surgery compared to eyes undergoing cataract surgery with no fluocinolone implant.2

At the time of surgery, intravenous methylprednisolone 125-500 mg or hydrocortisone 100-400 mg at the start of surgery is given if there are no medical contraindications. Principles of uveitic cataract surgery include minimization of iris trauma (which compromises the blood aqueous barrier and tends to lead to iridocapsular adhesions after surgery), meticulous cortical removal, and careful placement of the intraocular lens within the capsular bag. The literature regarding which IOL material is preferable in such cases is inconclusive, and there are advocates for one-piece or three-piece acrylic lenses as well as three-piece silicone lenses. Intraocular lens deposits following uveitic cataract surgery appear to be less common with hydrophobic acrylic lenses than other lens types, but some clinicians feel that the pre- and post-op medical management of the uveitis and meticulous intraoperative technique are more important factors in the outcome of surgery.

A variety of techniques have been described for dealing with small pupils and posterior synechiae, including viscodissection, iris hooks, and pupil maintainers. Remember that trypan blue, which is often invaluable in dealing with uveitic cataracts, will only stain the exposed anterior capsule, so adequate dilation must be obtained prior to staining, whether it is done as a straight injection, under air, or under viscoelastic. Once this step has been achieved and a continuous capsulorhexis performed, the cataract can be removed using whatever technique the surgeon prefers. Complete hydrodissection is essential. Although uveitic cataracts can be quite dense, more often they are relatively soft (because they are more common in younger patients) and are removed with small amounts of phacoemulsification energy.

Glaucoma is common in patients with uveitis and cataracts for a variety of reasons: the use of corticosteroids, outflow compromise from peripheral anterior synechiae, lens-induced mechanisms (phacomorphic glaucoma from tumescent crystalline lenses, IOL chafing, and pupillary block), or retained lens fragments. Progressive iridocapsular adhesions ("zippering up" of the pupil) are a sign of incomplete uveitis control, and cycloplegic therapy should be added. However, laser peripheral iridotomy (LPI) is usually unnecessary and may actually worsen posterior synechiae formation. Flow of aqueous through the pupil is diminished once the LPI has been performed, and the altered flow dynamics cause progressive pupillary block. If the LPI subsequently closes, as is common in eyes with uveitis, acute pupillary block glaucoma can then occur.

Focal edema of the peripheral cornea may indicate a retained lens fragment; goniosocopy is essential for detection. Surgical removal is usually simple and curative. Combined phacoemulsification and either trabeculectomy or tube shunt surgery should be considered in patients with uveitic cataracts and uncontrolled glaucoma. If secondary glaucoma occurs after cataract surgery, corticosteroids should be tapered to the lowest effective dose or discontinued altogether if possible; steroid-sparing immunomodulatory therapy such as methotrexate, mycophenolate, or tumor necrosis factor antagonists may be necessary, particularly in children. Medical management should start with topical beta blockers or carbonic anhydrase inhibitors because of the potential risk of CME from adrenergic agents or worsening of uveitis from prostaglandin analogs. However, these risks are small, and at least a trial of adding such drugs may be preferable to surgical intervention in some patients. Glaucoma surgery has a higher failure rate in patients with uveitis. As with cataract surgery, filtration surgery should be undertaken only after the uveitis has been completely controlled, if possible. Remember that computerized visual field tests may be difficult to interpret in these patients because of CME or epiretinal membrane.

Small pigmented deposits on the IOL surface are not necessarily worrisome, but larger deposits resembling giant cells (Figure 1) are usually a sign of persistent uveitis, even if no inflammatory cells in the aqueous are detected. The deposits have been histopathologically to comprise fibroblast-like and foreign body giant cells.3

Sometimes such deposits will coalesce into a fine anterior pupillary membrane that compromises vision and requires low-power YAG membranotomy. However, it remains necessary to control the uveitis and eliminate reversible causes of the uveitis. If the IOL is in the sulcus or has asymmetric capsular bag/sulcus fixation and the uveitis cannot be controlled easily, consideration should be given to removal of the IOL, allowing the eye to recover, and then consider a secondary IOL at a later date. Obviously, the status of the other eye is critical in determining the best approach in any given situation.

Case 1

A 32-year-old Caucasian woman with unilateral, recurrent granulomatous uveitis of the left eye with a negative workup developed CME that responded to repeated periocular injections of triamcinolone acetonide (Figure 2). However, she developed cataract and steroid-induced glaucoma with IOP as high as 46 mm Hg that responded to medical management. When her cataract became visually significant, she underwent combined phacoemulsification/PC IOL and anti-metabolite trabeculectomy. She recovered 20/20 vision and excellent IOP control without medication. She continued to have intermittent attacks of unilateral uveitis and CME, but tolerated periocular corticosteroid injections without pressure spikes. During follow-up, she developed mild, asymptomatic uveitis in the right eye with peripheral mutton-fat keratic precipitates. On further questioning, she described the recent onset of a skin lesion on her finger that had been biopsied, revealing noncaseating granulomata consistent with sarcoidosis.

Case 2

A 36-year-old man with acute, recurrent HLA B27-associated anterior uveitis in both eyes developed iris bombe from extensive posterior synechiae in the left eye (Figure 3A). There were extensive pigment deposits on the anterior lens surface (Figure 3B). Aggressive control of the uveitis followed by synechiolysis with phacoemulsification and PC IOL placement resulted in resolution of the iris bombe and excellent vision (Figure 3C).

References

1. Foster CS, Fong LP, Singh G. Cataract surgery and intraocular lens implantation in patients with uveitis. Ophthalmology 1989;96:281-88.

2. Sheppard JD, Nguyen GD, Usner DW, Comstock TL. Clin Ophthalmol 2012;6:79-85.

3. Ohara K. Biomicroscopy of surface deposits resembling foreign-body giant cells on implanted intraocular lenses. Am J Ophthalmol 1985;99:304-11.

Editors' note: Dr. Dunn is associate professor of ophthalmology, Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore. He has no financial interests related to this article.

Contact information

Dunn: 410-955-1966, jpdunn@jhmi.edu

Uveitis: Posterior synechiae, lens deposits, secondary glaucoma Uveitis: Posterior synechiae, lens deposits, secondary glaucoma
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