The Treatment of Uveitic Cataract 8 Arnd Heiligenhaus, Carsten Heinz, Matthias Becker
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The Treatment of Uveitic Cataract 8 Arnd Heiligenhaus, Carsten Heinz, Matthias Becker | Core Messages 8.1 ∑ Preoperative specification of uveitis Introduction aetiology is mandatory for surgical success Cataract formation is an especially common ∑ Any of the decisions on cataract surgery, complication resulting from uveitis. It is rare in including surgical technique, IOL implan- posterior uveitis, but occurs in up to 50% of pa- tation and perioperative medication, tients with anterior and intermediate uveitis rely on proper patient selection [21], and in nearly 80% of patients with Fuchs ∑ Complete quiescence of inflammation heterochromic iridocyclitis (FHC). Duration must be obtained before cataract surgery and intensity of inflammation, and treatment, ∑ The most important general principle e.g.corticosteroids and previous vitrectomy,are for the surgery is to minimise the surgical critical determinants for cataract formation. trauma Compared with the general population, cataract ∑ While IOL implantation is safe in many of formation occurs at an earlier age in uveitis pa- the uveitis patients, it is not recommended tients [36]. in patients of less than 2 years of age, The common prejudices concerning cataract or with active uveitis of any aetiology, surgery in uveitis patients are that the surgery aggressive course of inflammation in spite has a poor final outcome, induces severe post- of high-dose immunosuppression and operative recurrence of uveitis, has a high rate in uncertain uveitis course of ocular hypotony and phthisis and that in- ∑ The postoperative anti-inflammatory traocular lens (IOL) implantation is absolutely treatment must be adjusted according contraindicated. Although a number of typical to the surgical manoeuvres and the inflam- intra- and postoperative problems must be con- matory activity sidered with regard to patient selection for sur- ∑ Although several complications may occur gery, for the surgical technique and the pre- and in the postoperative course, reported func- postoperative care of the patients, the results af- tional results are generally encouraging ter cataract surgery are generally quite good ∑ A major goal in the care of uveitis patients [16]. is the prevention of inflammatory relapses and of cataract formation 8.2 Basics for Cataract Formation in Uveitis Cataract may appear in various clinical forms. Posterior synechiae are often seen with focal ar- eas of anterior capsule necrosis and underlying lens opacities. Fibrin membranes overlying the lens are often accompanied by an opacification 134 Chapter 8 The Treatment of Uveitic Cataract under the anterior capsule. Nevertheless, the fluences the degree of uveal and also of capsular typical form of complicated cataract seen in pa- biocompatibility. Activation of the complement tients with uveitis is posterior subcapsular cascade (primarily the alternative pathway) ini- cataract formation. In rare cases, an anterior tiates the inflammatory response to the artifi- subcapsular opacity can be observed primarily. cial material. Fragments of C3 bind to the sur- Cataract formation at the posterior pole of the face of the implant and C5 is released into the lens can be explained by a missing epithelial aqueous [24]. Chemotactic C5 derived peptides barrier and by the thinnest part of the lens cap- support polymorphonuclear leukocyte (PMN) sule. Inflammatory stimuli or degeneration influx into the AC. PMNs adhere to the surface- might induce proliferation of lens epithelial bound C3 fragments and amplify the adhesion cells (LEC). These abnormal cells produce ex- and aggregation of further cells. Other groups tracellular basal membrane material and extra- proposed that IOLs might not alter the comple- cellular matrix before they degenerate in com- ment levels significantly [30]. bination with surrounding lens fibres [44]. The Some degree of foreign body reaction occurs typical progression of cataract depends on the in all eyes after cataract surgery in order to clear severity of inflammation. In older uveitic pa- debris from the IOL surface. The first cells not- tients, the proliferation potential of LEC is re- ed on the surface are small and spindle-shaped duced and, therefore, it is difficult to distinguish macrophages. Epithelioid or giant cells, resem- from senile subcapsular opacity. bling uni- or multinucleated macrophages, are found at the end of the first week.While most of these cells usually disappear, few cells can be 8.3 found on IOLs years later.An early giant cell re- Basics for the Consideration action with few cells occurs within the first of IOL Implantation month in many patients. The cells clear after some weeks without any clinical significance. The outcome of cataract extraction with IOL The late reaction is regarded as a foreign-body implantation in uveitis patients depends largely reaction to the IOL. Groups of multi-nucleated on the biocompatibility of the lens material cells appear usually after the first month and are used. Uniformly, any implanted material acts as often located at the pupillary border. Cells most an artificial surface that may lead to foreign probably originate from the anterior segment body reaction. Reactions on the lens surfaces vessels or from synechiae. were taken as a marker for the degree of bio- The aqueous humour in uveitis patients after compatibility of the implanted lens material. cataract surgery shows abundance of macro- Uveal biocompatibility refers to the relationship phages. While the expressions of the typical to the vascular tissue of eye while capsular bio- macrophage cytokines IL-1 and IL-12 are low or compatibility generally refers to the contact absent, respectively, a shift towards a T helper with the remnant lens epithelial cells [3]. Due to cell type 1 cytokine expression (IL-2 and IFN-g) the different parameters investigated for uveal is found. The data suggested that the long- and capsular biocompatibility one might be ex- standing immunosuppressive therapy or the cellent and the other might be poor. chronicity of the uveitis suppressed or switched off macrophages function [33]. It has been spec- ulated that the alteration of macrophage func- 8.3.1 tions and the modified cytokines in the aqueous Uveal Biocompatibility fluid of uveitis patients may delay the clearing of cells from the AC or may even turn it in the The breakdown of the blood–aqueous barrier opposite direction. (BAB) is the first striking event during or direct- Other studies have shown that the surface of ly after surgery. The average time to re-establish foreign bodies absorbs proteins within seconds the BAB is 3 months [42]. The increase of cells or minutes after AC implantation.These include and cytokines in the anterior chamber (AC) in- fibrinogen, albumin, g-globulin and small 8.4 Patient Selection 135 amounts of fibronectin and coagulation fac- tients with FHC and juvenile idiopathic arthri- tors [4]. The consistence of this initial layer tis (JIA)-associated uveitis. appears to differ with the IOL material and The preoperative evaluation is indicated in may, therefore, explain why uveal and capsular order to specify the aetiology of uveitis. The biocompatibility depends on the lens material ophthalmological examination should always [27]. include visual acuity tests, slit-lamp evaluation, tonometry, and ophthalmoscopy. Additional tests may be indicated, such as interferometry, 8.3.2 sonography, fluorescence angiography, visual Capsular Biocompatibility field assessment or electrophysiological tests. A comprehensive review of systems, clinical eval- The capsular biocompatibility is characterised uations by consulting physicians, laboratory by lens epithelial cell (LEC) migration, by ante- and radiological investigations must be includ- rior capsule opacification (ACO) and posterior ed. capsule opacification (PCO). These parameters also depend on the above mentioned mecha- nism of BAB breakdown and protein absorption 8.4.1 of the IOL. Absorption patterns differ extreme- Aetiology of Uveitis ly between the lens materials. Linnola and co- authors [27] showed that fibronectin is respon- The management of uveitic cataract is princi- sible for the IOL attachment to the capsular bag. pally dependent on the underlying aetiology of This bioactive bond between lens and capsule uveitis, since the diverse types of uveitis differ may reduce lens epithelial cell migration, being extremely in their typical postoperative compli- one reason for a lower PCO rate.Due to a severe- cations and courses of visual loss. The recom- ly damaged BAB and changed cytokines in mendations and evidence that are published uveitic eyes, LEC may loose their ability to at- must be considered when selecting the surgical tach to the lens surface [27]. Therefore, the cap- method for the individual patient. For example, sular biocompatibility of one IOL material also while IOL implantation can be recommended in depends on the intraocular environment. patients suffering from FHC, it is generally con- traindicated in patients with JIA uveitis. Summary for the Clinician ∑ Any IOL material may lead to a foreign body reaction 8.4.2 ∑ Uveal biocompatibility influences Indications and Contraindications the degree of cell deposits on the IOLs in Cataract Surgery ∑ Capsular biocompatibility influences the opacification of the anterior and posterior The indications for the treatment of uveitic capsule cataracts differ profoundly between the pa- tients: 1. The major cause for surgery is mostly poor 8.4 vision. However, the contribution of cataract Patient