Cataract surgery in patients with history of uveitis

Abstract

Cataract surgery in patients with uveitis is not as simple as any senile cataract surgery. Recent evidence suggests that useful visual outcome can be achieved in most of the cases if they are handled meticulously. Key factors leading to improved visual outcome are absolute control of preoperative inflammation with diligent use of immunomodulatory drugs, meticulous surgery along with early detection and care of postoperative complications. Modern technologies in the intraocular lens designs and materials have contributed to the success. In this article, we review the literature on this subject with emphasis on the importance of the use of immunomodulatory drugs to control preoperative and postoperative intraocular inflammation and avoid complications.

Introduction

Cataract is a common complication of uveitis and results from chronic intraocular inflammation and corticosteroid use in treating the inflammation. These cataracts are called complicated cataracts and pose several challenges to the surgeon at every step. Difficulties start from the preoperative control of inflammation to intraoperative problems like poor visibility due to band keratopathy, small pupils, posterior synechiae, pupillary membranes, bleeding from abnormal iris vessels, and unusual anterior capsules. The postoperative course can be complicated by recurrence of inflammation, posterior capsular opacification (PCO) and cystoid macular edema (CME). Inspite of all these difficulties, modern surgical techniques, refinement in instrumentation, judicious use of immunomodulatory therapy in control of inflammation and newer technologies in intraocular lens (IOL) development have helped in improving the visual outcome in patients with cataracta complicata. In this review, we discuss the basic principles that we believe should be followed in taking care of patients with uveitic cataracts and also review the current literature on this subject.

Preoperative evaluation

This is the first step in managing patients with uveitic cataract. This involves arriving at an etiological diagnosis of uveitis, selecting appropriate patients who will be benefited from cataract surgery, giving a judicious prognosis and strict preoperative control of inflammation.

Systemic examination and laboratory evaluation

A relevant history, detailed ophthalmic and systemic evaluation and review of medical systems along with laboratory testing often gives a clue to the etiology of uveitis. Eighty three percent of patients with a confirmed diagnosis of uveitis have been shown to have an associated systemic disease.¹⁷ This is an important step, because the etiology and type of uveitis is a guide to preoperative control of inflammation, disease course, treatment response and rate of postoperative complications. Cataracts associated with Fuchs’ heterochromic iridocyclitis have good results and better visual prognosis as compared to other types of anterior uveitis as shown by Tejwani et al. who studied the outcomes of cataract surgery in these patients and found that more than 80% of patients had 20/40 or better visual acuity and no significant postoperative inflammation.⁴² The prognosis is different in case of Juvenile idiopathic arthritis (JIA) associated uveitis. BenEzra and Cohen have shown guarded prognosis of cataract surgery in JIA associated uveitis due to increased postoperative inflammation and increased incidence of irreversible amblyopia.¹⁰ However recent studies have shown that patients with JIA associated uveitis undergoing cataract surgery had improved visual acuities and tolerated IOL implantation provided that they had a strict preoperative and postoperative control of inflammation which may require immunomodulatory therapy.^28,34,43 Cataract surgery in uveitis associated with Behcet’s disease has a guarded prognosis as studied by Berker et al. who found that 20/40 or better visual acuity was achieved in only 45% of patients undergoing cataract surgery. The most common cause of decreased vision in these patients was postoperative macular edema occurring due to severe inflammation and preexisting pathologies like optic atrophy and epiretinal membrane.¹¹

Apart from these autoimmune conditions, infectious causes of uveitis like syphilis, toxoplasmosis, tuberculosis and viral infections should always be kept in mind and treated accordingly. Reactivation of toxoplasmosis after cataract surgery has been seen in a significant number of patients in a study emphasizing the importance of preoperative diagnosis and treatment with antiparasitic agents.¹²

Ophthalmic examination

A complete ophthalmic examination is necessary besides complete systemic examination to rule out associated pathologies in patients with history of uveitis. Uveitis is associated with various complications like glaucoma, CME, retinal neovascularization, optic atrophy, macular scarring. It is important to diagnose these conditions preoperatively for appropriate management and for cautious prognostication of a case. In many of these cases, the view to the posterior segment is not adequate. Appropriate investigations should be used wherever necessary for accurate diagnosis and a careful prognosis in such patients. Techniques like fluorescein angiography (FA) and optical coherence tomography (OCT) can detect macular edema while OCT can also detect macular atrophy, epiretinal membranes and vitreomacular traction. B-scan ultrasonography is a useful tool in assessment of the posterior segment for vitreous opacities, retinal detachment and choroidal thickening/detachment. Potential acuity meter and laser interferometer can be helpful to assess visual potential. A complete ophthalmic examination will help us decide the visual potential and amount of vision loss attributed by cataract, on which are based the prognosis and visual outcome of the surgery.

Indications of cataract surgery

Cataract surgery in uveitic patients is not free of risk and so the decision to operate should be made thoughtfully. Various indications for cataract surgery in patients with uveitis include: (1) Phacoantigenic uveitis (active inflammation due to leakage of lens proteins) where cataract removal is obligatory. (2) Visually significant cataract provided that preoperative inflammation is controlled and there is hope of improvement in visual acuity after cataract surgery. (3) Cataract that hampers the assessment of fundus in patients with suspected posterior segment pathologies. (4) Cataract that obscures adequate visualization of the posterior segment where posterior segment surgery is indicated.³⁹

Preoperative control of inflammation

This is the most important step in management of patients with uveitic cataracts. It is generally accepted that the eye should be quiescent and free of inflammation for at least 3 months before surgery. Many surgeons advocate use of topical and systemic preoperative corticosteroids to control inflammation. Corticosteroids have been used with great benefit for control of uveitis for 60 years. They can be administered locally or systemically and are effective in controlling inflammation, but long term treatment with systemic corticosteroids has guaranteed side effects and can vary from weight gain, acne, anxiety, mood changes to more serious complications like aseptic necrosis of head of the femur, pancreatitis, suppression of adrenals, hypertension, diabetes mellitus and psychosis. Children below the age of 15 years are especially prone for growth retardation.³² To combat the side effects of long term corticosteroids, the role of immunomodulatory drugs for controlling inflammation has gained favor. They are especially useful when inflammation is not controlled even after high dose of corticosteroid for 1 month, control of inflammation requires more than 10 mg of steroid daily or development of potential side effects which require stopping or tapering of steroids.²³

Recent evidence suggests that the use of immunomodulatory drugs in controlling inflammation has significantly improved the outcome in cataract surgery in uveitis. Our retrospective case series of cataract surgery in 34 children with uveitis showed improvement in best corrected visual acuity (BCVA) post cataract surgery in 85% of our patients. In this study, 25 of 34 patients had received immunomodulatory therapy for control of inflammation prior to surgery and we noted better vision in patients who received immunomodulatory therapy, though this difference was not statistically significant.³⁴ Zaborowski et al. have shared their experience in treating nine eyes of 6 pediatric patients with uveitic cataract out of which three had JIA associated uveitis. All the patients were treated with cataract extraction and intraocular lens implantation. Immunomodulatory therapy in the form of methotrexate was given to 5 of 6 patients preoperatively as well as postoperatively while 3 patients also received infliximab post operatively and 1 patient received additional mycophenolate mofetil. They have reported up to 20/30 or better visual acuity in all nine eyes.⁴⁴ These above studies show that adequate preoperative and postoperative inflammation control with use of immunomodulatory drugs wherever necessary leads to better visual outcomes even in difficult cases of JIA associated uveitis.

There are many different immunomodulatory drugs available, but there are no set guidelines for the use of these drugs in the control of intraocular inflammation. Immunomodulatory drugs are not free from possible side effects. Galor et al. compared three immunomodulatory drugs namely mycophenolate, azathioprine and methotrexate, which were used in treating ocular inflammatory disorders in a retrospective study of 257 patients. Out of these three, mycophenolate achieved faster control of inflammation, while azathioprine had more side effects and discontinuation rates due to side effects.²⁰ Increased risk of malignancy is a worrisome complication associated with immunomodulatory drugs, although a retrospective study done to evaluate the risk of overall and cancer related mortality in the patients receiving immunosuppressive therapy for ocular inflammatory diseases showed no statistically significant difference between the patients treated with immunosuppressive drugs and those not exposed to them. Tumor necrosis factor inhibitors were associated with significantly increased overall and cancer related mortality, and alkylating agents were also associated with an increase in cancer mortality, but this was not statistically significant.²⁴ The choice of immunomodulatory drugs depends on many different factors such as tolerance of the drug by the patient, control of inflammation, route of administration, side effect profile, general systemic condition of the patient, and cost of the treatment. The basic aim should be intolerance to preoperative and postoperative inflammation with a careful clinical and laboratory assessment for side effects.

Surgical techniques

The surgeon may face various challenges while operating on a cataract in a patient with a history of uveitis because of miotic pupil, posterior synechiae, pupillary membranes, calcified anterior capsules and poor visualization due to band keratopathy.

Extracapsular cataract extraction (ECCE) vs phacoemulsification

Phacoemulsification with intraocular lens is the preferred technique by most surgeons. Studies have compared phacoemulsification with ECCE and have shown that although postoperative visual acuities did not differ in the two techniques, there was a decreased incidence of clinically significant inflammation requiring treatment in phacoemulsification (41%) as compared to extracapsular extraction (51%) as well as a decreased rate of postoperative CME, epiretinal membrane formation and posterior synechiae formation with phacoemulsification technique.^16,19,36 This is probably attributed to the decreased surgical time and minimal tissue handling in phacoemulsification technique.

Pars plana vitrectomy

Cataract extraction and IOL placement has shown improved visual acuities in most of the cases of uveitic cataracts; however those with coexisting posterior segment pathology and significant vitreous opacities may require additional procedure. Androudi et al. has described combined pars plana vitrectomy with phacoemulsification in 34 patients with cataract and posterior segment involvement secondary to chronic uveitis. Out of 34 patients, 22 patients had IOL implantation and 12 were left aphakic. Post operative visual acuity was improved in 72.2% of patients. The most common cause of decreased postoperative visual acuity was macular edema. They also reported complications like IOL dislocation requiring repositioning and intolerance leading to explantation of IOL.⁶ Similarly Soheilian et al. in their series of 19 cases treated with 25 gauge vitrectomy and phacoemulsification with IOL placement have reported improved visual acuity in 63.2% patients and found that macular edema and glaucoma were the common causes of postoperative decreased vision.⁴⁰ Although combined procedure seems feasible in cases with associated posterior segment pathology and significant vitreous opacities, it is not free of complications and has to be tailored according to the patient needs and surgeon comfort.

Surgery in pediatric cases

Most authors have described good outcomes with cataract extraction and IOL placement in adult population of uveitic cataracts; however the scenario is more challenging in children. In young children, the surgery is technically difficult with increased incidence of postoperative inflammation; moreover issues of postoperative amblyopia therapy and visual rehabilitation make it more challenging. Earlier reports suggested lensectomy and pars plana vitrectomy or extracapsular cataract extraction with aphakia to be a safe technique in managing pediatric uveitic cataracts.³⁰ Recently, most authors agree with the idea of IOL placement in pediatric complicated cataracts which was previously thought to be a contraindication.^18,27,33,30 BenEzera and Cohen in their retrospective review of 10 eyes of 10 children, out of which five had JIA associated uveitis have found that the children with JIA associated uveitic cataracts had extended period of postoperative inflammation with tendency for secondary membrane formation, necessitating second surgical intervention. They also found that IOL placement was preferable to correction with contact lenses, as there was poor tolerance to contact lenses leading to discontinuation and resultant amblyopia especially with monocular surgery.¹⁰ In our series of 34 children of which 13 received an IOL, we noted improvement in 92% of patients post IOL implantation. IOL was well tolerated in most of the patients with optimal vision, however JIA associated patients were the most difficult cases and most of these children did not achieve improvement in visual acuity. These patients had a greater tendency to mount postoperative inflammation and so required to be treated aggressively with immunosuppressive therapy.³⁴ Nemet et al. in a multicentre study of 18 patients revealed no significant difference in the postoperative course and complication rate in children with and without JIA associated uveitis. Lam et al. have reported favorable outcomes in 5 patients with JIA associated uveitis undergoing cataract extraction with IOL placement.²⁶

All the above studies have shown that IOL placement is no longer a contraindication for pediatric cataracts associated with uveitis and moreover leads to improved visual function in most of the patients, provided that there is strict control of preoperative and postoperative inflammation with the use of immunomodulatory therapy, wherever necessary. Despite this, we should be aware of the fact that the mere presence of an IOL can act as a trigger for persistent inflammation and can serve as a scaffold for development of inflammatory membranes and cyclitic membrane leading to hypotony and may require IOL explantation to halt further damage.²² Adan et al. have reported two cases of JIA associated uveitic cataracts that required IOL explantation due to severe damage to macula because of persistent and uncontrolled inflammation post cataract surgery and IOL implantation.³ The issue of use of IOL in JIA associated uveitis remains controversial, but if IOL placement is considered, it certainly warrants careful monitoring for potential side effects and timely intense intervention to treat them.

Intraocular lens biocompatibility and designs

Intra ocular lens (IOL) biocompatibility depends on the characteristics of the IOL material, design of the lens, surface properties and its resistance to degradation. Host reactions to the IOL material, especially in the uveitic eyes, where there is inherent loss of blood aqueous barrier are equally important. Many authors have studied and compared different IOL materials in their search for the best material and design for the uveitic eyes. In a multicentre study, Alio et al. has compared different IOL materials after phacoemulsification and lens implantation in 140 uveitic eyes. The different materials that they compared were hydrophobic acrylic, silicone, poly methyl methacrylate (PMMA), and heparin-surface-modified PMMA (HSM PMMA). They found that the acrylic lens group had the lowest inflammation and relapse rate at 3 year follow up among all lenses. They also noticed that posterior capsule opacification was a significant problem in silicone lenses as compared to acrylic lenses.⁴ Similar findings were noted by Papiliodis et al. who found that acrylic lenses fared best in terms of post operative inflammation, PCO formation and need for explantation.³¹ Roseal et al. compared the two acrylic materials hydrophobic AcrySof and the hydrophilic Akreos sharp-edged intraocular lenses in patients with uveitis. They found no significant difference between the two lens designs in terms of postoperative inflammation and posterior capsular opacification.³⁷ Recently, Abela-Formanek et al. have compared five different types of IOL materials consisting of hydrophilic acrylic, hydrophobic acrylic, silicone and hydrophilic acrylic with heparin coating. After a follow up for 7 years, they found that the hydrophilic acrylic group had better uveal biocompatibility in uveitic patients as compared to other materials but a slight increased propensity to PCO formation as compared to hydrophobic acrylic lenses.² This finding is consistent with their previous report of comparison of hydrophobic acrylic, hydrophilic acrylic and silicone IOL with control group on a shorter follow up for 6 months. They also noticed that sharp edge lenses have less chance of PCO formation than the round edge lenses.¹ All the above studies indicate that acrylic lenses by the virtue of their uveal biocompatibility should serve best in treating patients with uveitic cataracts.

Postoperative complications

The story does not end with the cataract extraction and IOL placement in uveitic patients as the surgeon is most likely to be confronted with many different complications postoperatively which may include persistent inflammation, posterior capsule opacification, posterior synechiae and macular edema.

Postoperative inflammation

Postoperative inflammation can be treated with topical or oral corticosteroids and sometimes may require immunomodulatory therapy. The key features to decrease postoperative inflammation are preoperative control of inflammation for at least 3 months, minimal manipulation during surgery and in bag placement of intraocular lens. Intravitreal triamcinolone injection at the time of phacoemulsification has been described by some authors to decrease the postoperative inflammation and also as a substitute for systemic steroids, but increase in intraocular pressure is a concern with this procedure.^5,15

Posterior capsule opacification

PCO formation is one of the common postoperative complications in uveitic cataracts. Its incidence ranges from 23% to 96% as seen in different studies.^{16,25,29,35,36} PCO, if visually disturbing often can be treated with Nd YAG laser capsulotomy once inflammation subsides. Commonly, there can be pigment deposition on the IOL, which may be visually disturbing and needs laser polishing of IOL. In cases, such as JIA associated uveitis, severe inflammatory membrane can develop over the IOL as the lens acts as a scaffold for the formation of the inflammatory membrane. These membranes may need repeated Nd YAG laser disruption or at times may need surgical membranectomy.

Cystoid macular edema

Cystoid macular edema is another sight threatening complication of uveitic cataract surgery. Its incidence ranges between 21% and 50%.^16,21,35,36 Belair et al. used optical coherence tomography to determine the incidence of CME after cataract surgery in patients with and without uveitis. At 3 months follow up, the incidence of CME was more in uveitic cataracts as compared to non uveitic cataracts; however a statistically significant decrease in occurrence of macular edema was noted in patients whose inflammation was controlled 3 months prior to surgery and in those who were preoperatively treated with oral corticosteroids.⁹ Initial treatment for post cataract surgery CME includes topical nonsteroidal anti inflammatory drops. Different drug delivery systems have been tried by various authors to treat CME. Roesel et al. has compared the effect of intravitreal and orbital floor triamcinolone acetonide on macular edema and found that intravitreal route was more effective than orbital floor injection in controlling CME and postoperative inflammation in first 3 weeks after surgery. However increase in intra ocular pressure was a concern in both the groups with 2 patients in intravitreal group needing surgical intervention to treat glaucoma.³⁸ Androudi et al. retrospectively studied 20 eyes for the safety and efficacy of intravitreal triamcinolone acetonide in treatment of uveitic macular edema. They reported complete resolution of CME in 50% of patients with persistence or relapse of macular edema in remaining 50% at mean follow up of 34 weeks. They noted that raised IOP was transient and responded to medical treatment.⁷

The effect of triamcinolone acetonide is transient and macular edema may relapse after the effect of drug wears off. A sustained drug delivery implant could provide long term effect. Chieh et al. reviewed 24 eyes of 21 patients, who underwent a combined phacoemulsification with IOL implantation and a 3 year sustained drug delivery fluocinolone acetonide implant in vitreous cavity for patients with non infectious posterior uveitis or intermediate uveitis with or without iridocyclitis. They reported improvement in visual acuity, decreased rate of recurrence of inflammation and need for systemic immunosuppression with no intraoperative complications. The most common complication was raised IOP and greater than 10 mm Hg increase in IOP was noted in 21% of patients with 15% requiring glaucoma filtering surgery.¹⁴ In the quest of different drugs to treat uveitic macular edema, Willaims et al. studied the effect of surgical placement of intravitreal dexamethasone implant. Patients were randomly assigned to receive 350 μg dexamethasone implant, 700 μg dexamethasone implant and observation. Improved visual acuity and decrease in leakage on fluorescein angiography was observed in both the treatment group, but raised IOP was a significant problem in most of the patients.⁴³

As elevated IOP is a potential sight threatening problem with intraocular steroids, recently intravitreal vascular endothelial growth factor (VEGF) inhibitors have been gaining favor in treatment of uveitic CME. Our retrospective analysis included 29 eyes of 27 patients with refractory uveitic CME of various etiologies of which 13 patients received single intravitreal bevacizumab injection, 6 patients required a repeat intravitreal bevacizumab while 10 patients received a combination of intravitreal bevacizumab and triamcinolone acetonide. We found significant improvement in visual acuity and decreased macular thickness at 1 year follow up.¹³ Soheilian et al. compared intravitreal bevacizumab and intravitreal triamcinolone in treatment of refractory uveitic CME in a prospective randomized study and found that both the drugs were comparable in terms of improved visual acuity; however visual acuity improvement was more in triamcinolone acetonide group when the factor of corticosteroid induced cataract was removed. Moreover significant macular thickness reduction was achieved by the triamcinolone acetonide group.⁴¹ Similar findings were noted by Bae et al. who compared intravitreal bevacizumab (IVB), intravitreal triamcinolone acetonide (IVTA) and posterior subtenons triamcinolone acetonide (PSTA) in refractory uveitic macular edema. They reported better results with IVTA than those with IVB or PSTA, although the difference did not reach statistical significance. They noted that the effect of drug lasted for a period of 16 weeks with IVB, 30 weeks with IVTA, and 12 weeks with PSTA. Increased IOP was a significant problem in steroid group and (0.5 mmHg greater than baseline) was observed in 5 eyes (45.5%) with IVTA, and 4 eyes (40%) with PSTA as compared to1 eye (10%) with IVB.⁸ Intravitreal VEGF inhibitor drugs seem to be a good option in patients at risk of raised IOP due to corticosteroid response, however repeated injections may be required. Post operative CME is the most dreaded complication of uveitic cataract surgery and so it goes without saying that preoperative and post operative control of inflammation, early detection of CME and aggressive management may be helpful in avoiding permanent damage.

Conclusion

Cataract surgery in uveitic patients requires extensive diagnostic evaluation to determine the cause of uveitis, proper patient selection, zero tolerance to preoperative inflammation, vigilant use of immunomodulatory drugs wherever necessary to control preoperative inflammation, meticulous surgery, thoughtful decision for implantation of IOL, control of postoperative inflammation and early detection and aggressive management of complications. Increasing use of immunomodulatory drugs has improved the outcomes in pediatric cases with JIA associated uveitis which however still remains a challenge to the ophthalmologist and appropriate decision to the type of surgery and placement of IOL needs to be done according to the situation.

Further improvement in modes of drug delivery, surgical techniques and refinement of IOL designs will keep influencing the outcomes in cataracts associated with uveitis.