Ординатура / Офтальмология / Учебные материалы / Uveitis Text and Imaging Text and Imaging Text and Imaging 2009

Table 1: Indications for PCIOL implantation in uveitis1

Good to excellent outcome anticipated

•Fuch’s heterochromic iridocyclitis

•Burnt-out or inactive idiopathic anterior uveitis

•HLA-B27 associated uveitis

•Inactive toxoplasmosis

Moderate to good outcome anticipated

•Pars planitis

•Behçet’s disease

•Intermediate uveitis

•Sympathetic ophthalmia

•Birdshot retinochoroidopathy

•Vogt-Koyanagi-Harada syndrome

•Sarcoidosis, inactive infections such as tuberculosis, syphilis and borreliosis

Poor outcome anticipated (IOL contraindicated)

•Juvenile rheumatoid arthritis

•Uveitis in less than 12 years of age

•Hypotony associated with uveitis

•Chronic granulomatous recurrent uveitis

•Advanced disease (VKH, Sympathetic ophthalmia, Behçet’s)

INDICATIONS AND CONTRAINDICATIONS

A PCIOL can be safely implanted in cases of idiopathic non-granulomatous anterior uveitis, HLA-B27 associated uveitis8,15,20-23,36 and Fuchs heterochromic iridocyclitis.3,5 Others have also reported moderate success in VKH,31 sympathetic ophthalmia,38 Behçet’s disease,33 pars planitis9,39 and any burnt out or inactive uveitis (Table 1).

While IOL implantation is the preferred practice in most cases of adult uveitic cataracts, most specialists consider IOL implantation contraindicated in children with JRA-associated uveitis, since the IOL is presumed to act as a scaffold for the formation of intraocular membranes40 further leading to cyclitic membranes,

hypotony and eventual phthisis bulbi. Moreover, visual rehabilitation in these children is difficult due to poor compliance or intolerance to contact lenses or aphakic glasses. Several recent case series describe IOL implantation in children, with mixed outcomes.30,31,41,42 Based on these small case series (Table 2), it appears that the rate of complications following IOL implantation is high. Some experts would agree that more experience and longer periods of follow-up is needed before IOL implantation can be recommended as a safe procedure in these cases.28

However, most of these studies are not recent. The situation has evolved in as much as the type of inflammation suppressive therapy and the expertise in using immunomodulators has become such that we probably can master most of the resistant inflammatory situations. Furthermore, devices to monitor inflammation (laser flare photometry and to measure inflammatory consequences on structures such as the retina (optical coherence tomography) or others allow us to precisely follow inflammatory events. Thus in such inflammatory cases, the question is no more whether the inflammation pattern allows implantation but much more whether the appropriate follow-up can be guarantied in any particular case to readjust therapy timely and appropriately in order to avoid the feared complications.

IOL DESIGNS AND BIOCOMPATIBILITY

The design and material of the intraocular lens also can influence the outcome of surgery. The rigid single piece polymethyl methacrylate (PMMA) was used initially in uveitic cataracts. These lenses appeared to have some benefit over the three-piece lenses since

they did not activate the complement cascade unlike the polypropylene haptics.33 Although heparin- surface-modified (HSM) PMMA lenses have fewer cellular deposits and posterior synechia,43 similar results have not been reported in uveitic cataracts.44 In a prospective randomised trail, Alio et al15 studied the comparative performance of various IOL materials which included hydrophobic acrylic, silicon, PMMA and HSM-PMMA. Their results suggest that acrylic IOLs provided a better visual outcome and lower rate of complications. Amongst the current generation of IOLs, foldable acrylic IOLs (and not silicon) have been shown to have a better biocompatibility and are the preferred lens for uveitic cataracts.46-48

COMPLICATIONS AND MANAGEMENT

Commonly encountered intraoperative complications of cataract surgery (posterior capsular tear, etc.) may occur during this surgery. Additionally, zonular dehiscence may be more frequent due to weakening of zonules from long standing inflammation.48 Certain other complications are peculiar to uveitic cataracts.

HYPHAEMA

Amsler’s sign (bleeding from filiform iris vessels) can be seen in Fuch’s heterochromic iridocyclitis. Other causes of hyphaema include trauma to iris vessels during mechanical stretching of pupils and synechiotomy, and due to bleed from iris new vessels (Figure 7). Hyphaema can be managed on the operating table by tamponading with an air injection or intracameral adrenaline for vasoconstriction. Postoperative hyphaema can either be lysed with tissue plasminogen activator (10 microgram in 0.1 ml of buffered saline) or intense anti-inflammatory therapy alone may suffice. In case of a large clot in the anterior chamber, surgical removal is advisable.

IMMEDIATE POSTOPERATIVE: SEVERE POST-OP INFLAMMATION

Severe post-operative inflammation may develop in some uveitic eyes after surgery, although it is more frequent when the inflammation is not adequately controlled preoperatively (Figures 8A and B). The management includes institution of intense topical corticosteroids and cycloplegics; and oral steroids and

Figure 7: Hyphaema noted on the first postoperative day in an uneventful phacoemulsification in healed anterior uveitis

immunosuppressives if necessary. Recombinant tissue plasminogen activator injection into the anterior chamber has also been reported to disperse the fibrinous reaction.36 The sequelae of severe inflammation include cellular deposits on the IOL, posterior synechia and IOL capture, papillary block glaucoma, inflammatory membranes, hypotony and cystoid macular edema; therefore, control of this inflammation is paramount.

CYSTOID MACULAR EDEMA (CME)

CME is a major cause of reduced postoperative visual acuity. The incidence of postoperative CME depends on the clinical manifestation of the uveitis. Various case series with mixed uveitic aetiologies have reported an incidence ranging from 18 to 56%.20,21,49,50 The management of CME should be done stepwise, starting with a combination corticosteroid drops, non-steroidal drops and acetazolamide, going to injection of periocular corticosteroids (40 mg Triamcinolone acetonide in the sub-tenon space). In refractory CME, oral prednisolone and other immunosuppressive agents (as steroid-sparing) are required.

Intravitreal injection of Triamcinolone (4 mg in 0.1 ml) is another modality that has come into vogue for the management of CME in pseudophakic and uveitis eyes. Secondary ocular hypertension has been reported to occur in about 40% cases following this injection; other complications include endophthalmitis, which was reported in 1:1000 patients. Since most of

Figures 8A and B: Slit photographs showing increased anterior chamber reaction one-week postoperatively in patient with Vogt- Koyanagi-Harada disease

the reported literature consists of case series, this therapy may still be considered experimental until randomised trials are published.51

SECONDARY GLAUCOMA

A transient rise of postoperative IOP is common after surgery. Supplementary therapy should be started immediately with anti-glaucoma medication, including beta-blockers and carbonic anhydrase inhibitors. Miotics and prostaglandin analogues should be avoided.

Pre-existing glaucoma can also be exacerbated in some cases. Other mechanisms of secondary glaucoma include secondary angle closure due to posterior synechia or pupillary block due to inflammatory membranes or IOL capture. A planned peripheral

iridectomy intraoperatively or use of the Nd:YAG laser postoperatively would help; however, the fibrinous reaction can often occlude the laser iridotomy. In cases of glaucoma not controlled medically or by laser, filtering surgery, usually trabeculectomy with antimetabolite or valve implant should be performed earlier rather than later, to prevent glaucomatous optic atrophy.

UVEITIS FLARE-UP

Recurrent episodes of the primary disease may continue to occur after cataract surgery. This could be triggered either by the inflammatory stimuli related to the surgery or as a part of the natural course of the disease. Prompt institution of corticosteroids in full immunosuppressive doses (1 mg/kg body weight or more) is indicated. Postoperative reactivation has been reported to occur in chronic diseases. Reactivation of pars planitis was noted in about 50% of patients following cataract surgery with a mean follow-up of 19.67 months.9 In another study by the same authors,38 reactivation of sympathetic ophthalmia was reported in only 4.5% of patients. Reactivation is also seen in other diseases with a chronic protracted course, like VKH, Behçet’s, JRA and sarcoidosis.

PERSISTENT INFLAMMATION

In contrast to recurrence of the primary disease, persistent inflammation refers to those cases where low-grade inflammation persists months after cataract surgery. This could be related to the surgical technique (excessive surgical manipulation), IOL design (three piece lenses with polypropylene haptics30) or IOL position (sulcus fixated, anterior chamber fixated lenses) or due to inadequate treatment. Excessive surgical manipulation may result in severe and prolonged breakdown of the blood-aqueous barrier, with subsequent continued inflammation and accumulation of inflammatory cells, fibrin and debris on the IOL surface.8 Mechanical irritation of the iris in ciliary sulcus-fixated lenses may provide a chronic inflammatory stimulus with cytokine release and inflammatory cell migration at the site of inflammation.52 In these cases, explantation of the IOL may be indicated. Low-grade infection is another cause that should be kept in mind.

POSTERIOR CAPSULAR OPACIFICATION (PCO)

PCO is a common occurrence after surgery for uveitic cataract. In spite of following a meticulous surgical technique by phacoemulsification and careful cortical clean-up and capsule polishing and the use of new generation IOLs with increased biocompatibility, a high incidence of PCO persists. The rates reported vary from one-third15 to nearly half49 of the patients, with approximately one-third49 of the patients requiring Nd:YAG laser capsulotomy. A comparison of the rates of PCO in patients with and without uveitis demonstrated a higher rate in uveitic cases.53

Recurrent and chronic uveitis can also cause the appearance of fibrous membranes and dense fibrosis in certain cases (Figure 9). These have been described in patients with pars planitis39 and may require multiple Nd:YAG laser sessions and higher laser energy. These membranes tend to recur and surgical removal is advocated, with concomitant use of topical or depot steroids.

Overall, in most cases, PCO can be managed by performing an Nd:YAG laser capsulotomy after the inflammation has subsided. Increased topical steroids are required post-procedure, slowly tapering over four to six weeks.

HYPOTONY

Fortunately, not often seen in well controlled uveitis, postoperative hypotony is a grave complication. This

Figure 9: Optic capture and dense pupillary membrane in a patient with chronic posterior uveitis after cataract surgery

Table 3: Uveitis related complications in cataract surgery

Intraoperative

•Small Pupil

•Zonular dehiscence

•Hyphaema (bleed from iris vessels)

Immediate post-operative

•Severe post-operative inflammation

•Secondary glaucoma: secondary angle closure, steroid response

•Flare-up of primary disease

Late post-operative

•Cystoid macular oedema

•Secondary glaucoma

•Uveitis recurrences

•Persistent inflammation

•Posterior capsular opacification

•Hypotony

•Uveitis, glaucoma and hyphaema (UGH) syndrome

•Cyclitic membrane

•Intra-ocular membranes

•Posterior synechia and IOL capture

•Reactivation of HSV, toxoplasmosis

•Epiretinal membrane

•Retinal detachment

•Phthisis bulbi

may be temporary, as a result of ciliary body shutdown secondary to inflammation, in which case there may be a response to intensive anti-inflammatory treatment. Tractional ciliary body detachment may also cause hypotony, for which surgical excision of the membranes and IOL explantation8 combined with pars plana vitrectomy and silicon oil insertion may be necessary. UBM is a useful tool to detect ciliary body detachment.14

SUMMARY

It is possible, in fact even expected, to achieve successful visual outcomes following cataract surgery in uveitis. The predictability has improved primarily because of a higher level of understanding of the uveitic disease among clinicians. Preoperative factors include proper patient selection and counselling and preoperative control of inflammation. It is now well recognised that chronic inflammation, even low grade, can irreversibly damage the retina and optic nerve6 and therefore, inflammatory control both preand postoperatively is vital. The use of immunosuppressive

agents other than steroids also helps control inflammation and has enabled long-term use of these agents especially as steroids sparing medication. Management of postoperative complications, especially inflammation and glaucoma, earlier rather than later, has also contributed to improved outcomes. Still several questions are left unanswered, especially in the area of paediatric uveitis with cataract, which continues to challenge the ophthalmologist to further refine the surgical technique and search for new treatment modalities.

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46.Abela-Formanek C, Amon M, Schild G, Schauersberger J, et al. Inflammation after implantation of hydrophilic acrylic, hydrophobic acrylic, or silicone intraocular lenses in eyes with cataract and uveitis: comparison to a control group. J Cataract Refract Surg 2002;28(7):1153-9.

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INTRODUCTION

Raised intraocular pressure with or without glaucoma is a common and frequently serious complication of uveitis. Uveitic glaucoma is a complex entity which arises from a combination of several biochemical, cellular mechanisms and structural changes inherent in the inflammatory process (Table 1). Inflammatory cells and cytokines, and the corticosteroid therapy used to treat uveitis can participate in the pathogenesis of uveitic glaucoma. Structural changes in the angle can be acute, such as in secondary angle-closure with pupillary block glaucoma, or chronic, such as combined steroid-induced and secondary open-angle

Table 1: Factors influencing IOP in uveitis

IOP-lowering influences:

•Cyclitis reducing aqueous production

•Prostaglandin release increasing uveoscleral outflow

•Cyclitic membrane causing traction and ciliary body detachment

IOP-elevating influences:

•Influence of cytokines on trabeculocytes (IL-1, TGF-β)

•Increased aqueous viscosity when protein levels are elevated

•Increased trabecular resistance following trabecular meshwork hypoperfusion in severe cyclitis

•Trabeculitis

•Corticosteroid-induced trabecular meshword dysfunction

•Angle closure (pupil block, forward movement of the irislens diaphragm, PAS or neovascularisation)

•Pigment deposition / cells / debris / inflammatory nodules in angle

glaucoma.1,2 Diagnostic and therapeutic decisions are guided by careful delineation of the pathophysiology of each case. Standard imaging of the anterior segment of the eye, such as slit-lamp anterior segment photography and gonioscopy are very useful for the diagnosis as well as for the follow-up of patients with uveitic glaucoma. Recently, modern anterior segment imaging modalities, such as ultrasound biomicroscopy, anterior segment OCT (AS-OCT) and in vivo confocal microscopy, have been used in cases with uveitic glaucoma and provide important information for diagnosis and decision making in complicated cases.

SLIT-LAMP EXAMINATION

Biomicroscopic evaluation of the anterior segment is crucial for the diagnosis of uveitic glaucoma and for elucidation of the mechanism responsible for increased intraocular pressure. A detailed examination of the anterior segment may also provide valuable information for certain specific uveitis entities such as in Fuchs uveitis (FU) (Figure 1). Moreover, the presence or absence of aqueous fibrinous exudates or hypopion, iris nodules, the distribution and type of keratic precipitates may indicate the probable type of uveitis.

The inflammatory cells and proteins in the aqueous humour can form adhesions between the posterior iris and the anterior lens, resulting in the formation of posterior synechiae. If they extend for 360 degrees and occlude the aqueous flow through the pupillary aperture (secclusio pupillae), the aqueous becomes trapped in the posterior chamber resulting in anterior bowing of the peripheral iris (iris bombé) with

Figure 1: Fuchs uveitis—diagnostic features. Although it is important to stand back and compare eyes when making the diagnosis of Fuchs uveitis (FU)(A and B), it is important to take other factors into consideration, such as the presence of diffuse iris transillumination in blue-eyed FU (C), the presence of vitreous floaters (C), unilateral cataract or pseudophakia (C). It is also important to examine closely the texture of the iris stroma which will usually differ significantly from the fellow eye. Browneyed FU, does not demonstrate iris transillumination, but occasionally iris nodules may be seen (D) and the iris stromal texture will also differ significantly from the fellow eye (From Shaarawy et al, Glaucoma, Elsevier, 2008, reproduced with the kind permission of Moorfields Eye Hospital)

apposition to the trabeculum and peripheral cornea, causing acute angle-closure glaucoma. In this case, the central part of the anterior chamber is deep. Laser iridotomy or surgical iridectomy should be performed (Figure 2). Such an inflamed iris can stick to the trabeculum and the iridocorneal contact becomes permanent with development of peripheral anterior synechiae (PAS).

Figure 2: Acute angle closure in uveitis. Pupil block in uveitis is often due to a secluded pupil and the defining feature is the deep central anterior chamber and often dramatic surrounding iris bombé (A). Laser iridotomy is usually ineffective in correcting uveitic pupil block due to rapid closure or loculation of aqueous behind the iris. In (B) a patent iridotomy is present (solid arrow) yet there is persistent bombé of the iris and pupil block (transparent arrow). Pupil block must be distinguished from other causes of angle closure in uveitis such as phacomorphic glaucoma (C) or forward movement of the iris-lens diaphragm (D), in this case due to vitreous haemorrhage. In both cases the shallow central anterior chamber is highlighted by the solid arrow (From Shaarawy et al, Glaucoma, Elsevier, 2008, reproduced with the kind permission of Moorfields Eye Hospital)

GONIOSCOPY

Gonioscopy should be preferably performed with a dynamic gonioscopic lens which indents the central cornea and pushes the aqueous into the iridocorneal angle, therefore differentiating appositional from synechial angle closure. It should be performed in all cases of uveitic glaucoma to detect the presence of PAS and the extent of angle closure (Figure 3). Peripheral anterior synechiae may be secondary to inflammation, neovascularization or iris bombé. They are usually broad, but can also be peaked and attached to the anterior trabeculum, and in some cases, to the cornea

Figure 3: Peripheral anterior synechiae in uveitis. Peripheral anterior synechiae (PAS) are common in uveitis. Bridging synechiae from anterior iris surface to Schwalbe’s line (A)(transparent arrow) are relatively uncommon but particularly characteristic of uveitis, These are rarely seen in other types of angle closure, though they may occasionally be confused with Axenfeld’s anomaly. Small PAS (B) (white arrow) are common in uveitis, but are often seen in the presence of other angle abnormalities such as pigment deposition (dark arrow)

(From Shaarawy et al, Glaucoma, Elsevier, 2008, reproduced with the kind permission of Moorfields Eye Hospital)

also. In primary angle-closure glaucoma, PAS usually form superiorly first, whereas PAS of uveitic glaucoma form inferiorly first. Continued PAS formation can

Figure 4: Angle pigmentation in uveitis. Pigmentation of the angle is common in uveitis, more often seen inferiorly than superiorly, as shown in two views of the same angle (A and B). In eyes with severe chronic inflammation, significant pigment deposition may be seen in the inferior angle (C). The mechanism of pigment deposition in the angle is different from that of pigment smudging (D) which results from intermittent iridotrabecular contact. It is not unusual to see a mixture of these as well as PAS in an eye with chronic uveitis (From Shaarawy et al, Glaucoma, Elsevier, 2008, reproduced with the kind permission of Moorfields Eye Hospital)

Figure 5: Angle neovascularization in uveitis. Angle neovascularization is not uncommon in uveitis. It is seen frequently in Fuchs uveitis as fine vessels crossing the angle radially from iris root to peripheral cornea (A). These are only of clinical significance because of their propensity to bleed on surgical decompression of the eye. Inflammatory neovascularization of the angle is often more aggressive and may also cross the irido-corneal angle (B). This appearance contrasts with that seen in ischaemic neovascular glaucoma, where the angle may be completely closed (C) but without visible evidence of vessels in the angle other than on the peripheral iris surface (D)

result in total angle closure. In eyes with PAS less than 360 degrees, the remaining open angle may be compromised by the presence of pigment, which may contribute to trabecular obstruction. Pigment released from the iris may be due to a combination of the uveitis, mydriasis, and previous eye surgery. On gonioscopy, these angles may alternate between PAS and open areas covered by pigment (Figure 4).

Gonioscopy may also reveal angle neovascularization in long-standing chronic uveitis.3 In most cases, this neovascularization is not of the florid type found secondary to severe retina ischaemia, such as that associated with ischaemic central retinal vein occlusion, proliferative diabetic retinopathy and ocular ischemic syndrome. However, contraction of the fibrovascular tissue may result in secondary PAS formation. Rubeosis iridis should not be confounded with the fine vessels seen in Fuchs uveitis, which are arranged either radially or concentrically and cross the angle (Figure 5). Severe inflammation can result in engorgement of the normal blood vessels in the iris stroma and irido-corneal angle, which should be also differentiated from rubeosis iridis.

MODERN ANTERIOR SEGMENT

IMAGING MODALITIES

Evaluation of the anterior segment structures may not be possible by standard clinical examination in eyes with uveitic glaucoma because of opaque media. The cornea may reveal band keratopathy, corneal stromal scarring or epithelial edema which may accompany acutely elevated IOP or corneal decompensation, thus preventing adequate imaging of the anterior segment structures with either slit-lamp examination or gonioscopy. Moreover, evaluation of the retro-lenticular and retroiridal space is not readily accessible with routine examination methods, and information about these spaces may be valuable in inflammatory diseases.

Ultrasound biomicroscopy and AS-OCT are useful tools for anterior segment imaging.4 They can be used whenever corneal opacities are present and/or to detect atypical angle closures as well as for the followup of patients presenting with uveitis and angle closure.5 It is helpful for diagnosis and guiding

Figure 6A: Ciliochoroidal effusion (UBM). Ultrasound biomicroscopy (UBM) imaging of ciliochoroidal effusion. The ciliary body (CB) is anteriorly displaced, pushing forward the iris and closing the angle (white arrow). Strands are crossing the suprachoroidal space (short white arrow). Note that, with UBM, the CB and choroid are more clearly delineated compared to AS-OCT (Figure 6B). Personal collection of Dr Bagnoud M., Department of Ophthalmology, Geneva University Hospitals, Switzerland

treatment in cases of angle-closure complicating Vogt- Koyanagi-Harada syndrome.6-8

The main disadvantage with the use of UBM is that it is cumbersome and time consuming, requiring direct contact with the eye and an experienced technician to obtain the images. For these reasons its use has been limited to a few clinical and to research centres. It has a significant advantage, however, of being able to provide images of the position, angulation and anatomical variants of the ciliary body and peripheral iris, which have been instrumental in furthering knowledge of mechanisms of angle closure, such as in cases which are secondary to uveitis-related ciliochoroidal effusion5, 9, 10 (Figure 6A).

By contrast, AS-OCT has the advantages of being a non-contact, fast technique that does not require much technical skill to perform. Passage of infrared light, however, is limited by the posterior pigmented layer of the iris and therefore structures posterior to the iris, including the ciliary body or suprachoroidal space are not as well delineated as they are by the means of UBM (Figure 6B).

Using the B-scan ultrasound mode, UBM has a high frequency transducer, which emits sound waves through ocular tissues and detects their reflection from tissue interfaces. At this higher frequency, detailed

Figure 6B: Ciliochoroidal effusion (AS-OCT). Horizontal highresolution corneal scan obtained with Visante OCT showing a ciliochoroidal effusion. Yellow arrows indicate the ciliary body and part of the choroid detached and separated from the sclera by a hyporeflective space (small white arrow) corresponding to supraciliary fluid (A). Same image as in (A) with images colors inverted. Blue arrows indicate the ciliochoroidal detachment separated from the sclera by the presence of fluid (blue arrowhead) (B). Personal collection of Dr Bagnoud M., Department of Ophthalmology, Geneva University Hospitals, Switzerland

images of the anterior chamber, iridotrabecular angle and ciliary body can be obtained with an axial resolution of about 25 μm and a lateral resolution of about 50 μm.11 These images can provide clinicians with information about the structures contributing to angle configuration which are not visible with gonioscopic examination. The transducer requires the eye to be immersed in a water bath of saline usually housed in an eye cup placed directly on the globe with the patient lying down. More recent generations of the Paradigm UBM model (Paradigm Medical Industries Inc., Salt Lake City, Utah, USA) incorporate the water bath around the probe into a hand piece which can be applied with the patient in the sitting position using a coupling gel between the globe and the probe.