Complicated Cataract (Uveitis Cataract)

Key Points of This Disease

• Complicated cataract is a general term for cataracts that occur secondary to uveitis, systemic diseases, or chronic eye diseases.
• The most common cause is uveitis, but many other conditions such as diabetes, atopic dermatitis, and myotonic dystrophy can also lead to complicated cataracts.
• Cataracts occur in about 57% of patients with pars planitis and about 78% of those with Fuchs heterochromic iridocyclitis.
• Complete control of inflammation for at least 3 months before surgery is key to improving surgical outcomes.
• Perioperative management with steroids and NSAIDs is essential to prevent postoperative cystoid macular edema (CME).
• In juvenile idiopathic arthritis (JIA)-associated uveitis, postoperative inflammation tends to be severe, requiring careful judgment.
• The characteristic pattern of lens opacity often allows estimation of the underlying disease.

1. What is Complicated Cataract?

Complicated cataract is a general term for cataracts that occur secondary to various ocular or systemic diseases. The most representative type is that associated with uveitis, but ocular diseases such as retinitis pigmentosa, high myopia, and chorioretinal degeneration, as well as systemic diseases including diabetes, atopic dermatitis, myotonic dystrophy, Wilson disease, and galactosemia, can also cause it. It often presents with characteristic lens opacities different from age-related cataract, and the lens findings may sometimes lead to the discovery of the underlying disease.

The main topic of this article is cataract associated with uveitis (uveitic cataract), but cataracts associated with systemic diseases will also be outlined.

Uveitic cataract is one of the most frequent complications in patients with chronic uveitis. The incidence varies by disease, reaching approximately 57% in pars planitis and about 78% in Fuchs heterochromic iridocyclitis.

The main causes of cataract formation are the following two: first, uncontrolled and persistent intraocular inflammation, and second, long-term use of high-dose topical, periocular, or systemic steroids. In particular, steroid cataracts often appear as posterior subcapsular opacities.

In pediatric non-infectious uveitis, ocular complications including cataract, glaucoma, and macular edema have been reported to occur in up to 76% of all cases ¹⁾.

Q Why does uveitis cause cataracts?

A

Chronic intraocular inflammation worsens the metabolic environment of the lens and promotes opacification. In addition, steroids used to treat inflammation frequently cause posterior subcapsular cataracts. These two mechanisms act in combination.

2. Main symptoms and clinical findings

Subjective symptoms

• Decreased visual acuity: Occurs as lens opacification progresses. In the posterior subcapsular type, central vision is easily impaired from an early stage.
• Photophobia: Caused by both inflammation and opacification.
• Blurred vision: Caused by light scattering due to opacification.
• Decreased contrast sensitivity: Particularly prominent in posterior subcapsular cataract

Clinical Findings

Slit-lamp examination reveals anterior segment changes characteristic of uveitis in addition to the morphology of the cataract.

• Cataract morphology: Posterior subcapsular opacity is common (steroid-induced). Cortical and nuclear cataracts also occur.
• Posterior synechiae: Adhesion between the iris and anterior capsule. Causes poor pupillary dilation.
• Band keratopathy: Common in juvenile chronic iridocyclitis (JIA-associated).
• Iris atrophy and vascular fragility: Risk of intraoperative bleeding
• Angle synechiae: Cause of secondary glaucoma
• Pupillary membrane formation: Particularly common in JIA and VKH disease
• Vitreous opacity: Makes preoperative evaluation difficult in intermediate and posterior uveitis
• Cystoid macular edema (CME): The most important complication limiting postoperative visual prognosis

Disease-specific lens opacity patterns

Disease	Opacity pattern	Characteristics
Uveitis (chronic)	Posterior subcapsular cataract	Opacity just beneath the posterior capsule and in the superficial posterior cortex at the pupillary center
Diabetes mellitus	Cortical cataract	Water clefts in superficial cortex (equator to center)
Wilson disease	Sunflower cataract	Polychromatic granular opacities under anterior capsule radiating outward
Myotonic dystrophy	Vogt type / Fleischer type	Polychromatic granular opacities / Stellate opacities along Y-suture
Atopic dermatitis	Star-shaped cataract	Characteristic morphology in the center of anterior and posterior subcapsular region
Retinitis pigmentosa	Posterior subcapsular cataract	Diameter ≤1 mm, just below the posterior capsule to superficial posterior cortex
Galactosemia	Oil droplet opacity	Starts from the lens nucleus and progresses to total cataract
Hypocalcemia	Tetany cataract	Polychromatic granular opacities in the anterior and posterior superficial cortex

Q Does the appearance of complicated cataract differ from age-related cataract?

A

Complicated cataracts often have characteristic opacity patterns, and slit-lamp examination may help identify the underlying cause. For example, Wilson disease shows sunflower-like opacities, and myotonic dystrophy shows Vogt or Fleischer type specific opacities. In contrast, age-related cataracts typically present as nuclear, cortical, or posterior subcapsular types, and diagnosis is made by combining history and opacity pattern.

3. Causes and Risk Factors

Cataract due to Uveitis

The risk of developing uveitic cataract varies depending on the type of underlying disease and treatment method.

• High-risk diseases: Juvenile idiopathic arthritis-associated uveitis, granulomatous anterior uveitis, pars planitis, posterior uveitis, panuveitis
• Low-risk diseases: Fuchs heterochromic iridocyclitis (postoperative inflammation is relatively mild and prognosis is good)
• Steroid cataract: Long-term use of topical or systemic steroids. Often presents as posterior subcapsular cataract
• Disease activity: Poorly controlled inflammation directly promotes lens opacification

In juvenile idiopathic arthritis-associated uveitis, the incidence of both cataract and glaucoma is significantly higher than in idiopathic uveitis³⁾.

Complicated Cataract Associated with Systemic Diseases

• Metabolic disorders: Diabetes mellitus, galactosemia, Fabry disease, hypocalcemia/hypoparathyroidism, Wilson disease
• Musculoskeletal disorders: Stickler syndrome (cortical cataract in young individuals, nuclear cataract in 30s-40s), Wagner syndrome
• Skin diseases: Atopic dermatitis (most common cause of cataract in young individuals), Werner syndrome (posterior subcapsular cataract)
• Renal diseases: Alport syndrome (cataract associated with spherophakia and lenticonus), Lowe syndrome (lens dysplasia)
• Neurological diseases: Myotonic dystrophy (cataracts in over 90% of cases), Neurofibromatosis type 2
• Eye diseases: Retinitis pigmentosa (cataracts in about half of cases), Retinochoroidal degeneration, High myopia

Prevention and daily care

• Continuing treatment for uveitis and suppressing inflammation as much as possible can help prevent cataract formation.
• If you are using steroid eye drops or oral steroids, have regular eye check-ups.
• If you notice changes in your vision, see an eye doctor early.

Q Can atopic dermatitis cause cataracts?

A

Atopic dermatitis is the most common cause of cataracts in young people. Cases can occur from the late teens onward, presenting with a characteristic star-shaped opacity in the central anterior and posterior subcapsular region. The main mechanism is thought to be lens epithelial cell damage due to eye rubbing behavior and intraocular inflammation.

4. Diagnosis and Examination Methods

Preoperative Evaluation

Thorough ophthalmic evaluation is essential before surgery. Assessment of intraocular inflammation activity is the highest priority, and anterior chamber cell grading is performed according to the SUN (Standardization of Uveitis Nomenclature) criteria ⁶⁾.

• Slit-lamp microscopy: Check for cataract morphology, posterior synechiae, corneal degeneration, and the presence of cystoid macular edema.
• Ultrasound (A/B mode): Used to evaluate posterior segment structures when direct observation is difficult due to media opacities.
• Optical coherence tomography (OCT): Detects macular edema, epiretinal membrane, macular hole, and choroidal neovascularization.
• Fluorescein angiography: Useful for evaluating cystoid macular edema.
• Potential acuity meter (PAM) / Laser interferometer: Selectively used to predict postoperative visual acuity.

It is important to infer the causative disease from characteristic lens opacity patterns. If a sunflower cataract is observed, Wilson disease is suspected; if Vogt or Fleischer type, myotonic dystrophy is suspected. When specific patterns are found, systemic examination for the underlying disease (in collaboration with internal medicine, dermatology, etc.) is necessary.

Q What is the most important examination before cataract surgery in patients with uveitis?

A

Assessment of intraocular inflammation activity is the highest priority. Evaluate the degree of anterior chamber cells and flare using SUN criteria, and plan surgery only after confirming inflammation has been quiet for at least 3 months. If vitreous opacity is present, evaluate the posterior segment with B-mode ultrasound, and check for cystoid macular edema using OCT.

5. Standard Treatment

Preoperative Management: Inflammation Control

Complete inflammation control (no cells in the anterior chamber, minimal vitreous inflammation) is required at least 3 months before surgery. Preoperative inflammation control reduces the risk of postoperative cystoid macular edema ²⁾.

Preoperative management differs depending on the type of uveitis as follows.

• Non-granulomatous anterior uveitis / Fuchs heterochromic iridocyclitis: Starting 1% prednisolone acetate eye drops (every 6 hours) 3 to 7 days before surgery may be sufficient.
• JIA, granulomatous anterior uveitis, panuveitis, history of CME: In addition to topical therapy, start systemic prednisone (0.5–1.0 mg/kg/day) 3–7 days before surgery. Sub-Tenon triamcinolone acetonide 40 mg may be an alternative to systemic administration.
• Herpetic (HSV-1, VZV) uveitis: Start acyclovir 2 g/day or valacyclovir 1–3 g/day at least 1 week before surgery. Continue prophylactic doses (acyclovir 600–800 mg/day) for at least 4 weeks after surgery.
• If band keratopathy is present: Perform 1–2% EDTA chelation therapy or excimer laser calcium removal before surgery, and perform cataract surgery after corneal epithelial healing.

For all uveitis patients, it is recommended to start topical NSAIDs (nepafenac 0.1%, ketorolac 0.4%, or bromfenac 0.09%) at least 3 days before surgery and continue for at least 6–8 weeks after surgery⁴⁾.

The ESCRS guidelines recommend increased frequency and extended duration of steroid use in uveitis patients⁴⁾.

Surgical Technique

Small incision cataract surgery (MICS) and phacoemulsification via corneal incision are recommended ⁹⁾.

• Mydriasis: Synechialysis, pupillary membranectomy, sphincterotomy, or use of iris retractors may be necessary.
• Capsulorhexis (CCC): Maintain a diameter of 5–6 mm. A smaller size increases the risk of capsular contraction and IOL decentration.
• Ultrasound energy: Minimize to avoid excessive inflammation, corneal endothelial damage, and posterior capsule rupture.
• Posterior capsule protection: Keeping the posterior capsule intact and placing the IOL in the capsular bag is key to success.
• Intraoperative steroids: After corneal wound closure, intracameral injection of preservative-free dexamethasone phosphate 400 mcg may be considered.

Selection of Intraocular Lens (IOL)

In adult uveitis patients, hydrophobic acrylic IOL or heparin surface-modified PMMA (HSM PMMA) IOL is recommended ¹⁰⁾. Hydrophobic acrylic IOL is associated with lower inflammation levels and posterior capsule opacification rates at 6 months postoperatively. In principle, in-the-bag placement (both optic and haptic within the capsule) is preferred.

In patients with JIA-associated uveitis, there is a risk of serious complications such as secondary glaucoma, extensive fibrosis, and cyclitic membrane formation associated with IOL implantation, so the feasibility of IOL implantation must be carefully considered.

As a treatment principle for cataracts associated with systemic diseases, treatment of the underlying disease takes priority. In galactosemia, dietary therapy (galactose restriction) may improve opacification. In advanced cases, phacoemulsification and IOL implantation are performed. In cases complicated by retinitis pigmentosa, caution is needed due to the high risk of postoperative cystoid macular edema.

Precautions in Treatment

• In Behçet’s disease, ocular inflammatory attacks may be induced postoperatively, and a flare-free period of 6 months or more is desirable.
• In JIA-associated uveitis, severe inflammation with fibrin exudation may occur postoperatively, leading to pupillary membrane formation and hypotony. The decision to insert an IOL should be made carefully.
• Attention should also be paid to secondary glaucoma and steroid-induced glaucoma associated with long-term steroid use.

Postoperative Management

Immediately after surgery, start topical steroids (1% prednisolone acetate every hour), topical NSAIDs (nepafenac 0.1% every 8 hours, bromfenac 0.09% every 24 hours), and broad-spectrum topical antibiotics (every 6 hours).

To prevent posterior synechiae, administer short-acting mydriatics (1% tropicamide every 6 hours) for 10–14 days postoperatively. In patients on oral steroids, maintain the target dose for 1 week, then taper to a maintenance dose (ideally ≤10 mg/day).

Q What is the most serious postoperative complication?

A

Postoperative exacerbation of intraocular inflammation is the most feared complication. It may present as severe anterior chamber inflammatory cells, fibrin membrane, or hypopyon. It tends to be particularly severe in JIA and VKH disease. Cystoid macular edema occurs in 33-56% of cases and is a major cause of visual loss ¹¹⁾. Epiretinal membrane is reported in 15-56% of cases.

6. Pathophysiology and Detailed Mechanisms

Lens Opacification Due to Uveitis

In chronic intraocular inflammation, disruption of the blood-aqueous barrier leads to increased cytokines, inflammatory mediators, and oxidative stress substances in the aqueous humor. These directly act on lens epithelial cells and lens fibers, causing structural changes and precipitation of proteins (crystallins) that maintain transparency. Additionally, direct lens contact due to posterior synechiae causes anterior subcapsular opacification.

Steroid-Induced Cataract

Steroids specifically induce posterior subcapsular cataract (PSC). The mechanism is thought to involve steroids promoting migration of lens epithelial cells, and accumulation of epithelial cells under the posterior capsule forming opacities.

Mechanisms of Cataract Development Due to Systemic Diseases

• Diabetes mellitus: Polyol accumulation via the sorbitol pathway → osmotic cell swelling → swelling and opacification of lens fibers
• Hypocalcemia: Impaired calcium ion transport → dysfunction of lens epithelial cells
• Wilson disease: Copper deposition in the lens → formation of sunflower cataract
• Myotonic dystrophy: CTG repeat expansion in the DMPK gene → nuclear accumulation of RNA → splicing defects in lens epithelial cells

Association with Elevated Intraocular Pressure

In uveitis, elevated intraocular pressure occurs frequently. Mechanisms include trabecular meshwork clogging, trabeculitis, angle nodules, peripheral anterior synechiae, steroid-induced myocilin induction, neovascularization, and pupillary block.

7. Latest Research and Future Prospects

For Patients: Please Read

The following content is currently under research or in clinical trials and is not standard treatment available at general hospitals. It is reference information for professionals regarding future medical developments.

Persistent Pseudophakic Uveitis after Cataract Surgery (PUPPI)

Analysis of large-scale data from the IRIS Registry (7,513,604 cases) reported that the incidence of chronic uveitis within 6 months after uncomplicated cataract surgery was 1.68% at the patient level ⁵⁾. Risk factors identified included female sex (IRR 1.14), diabetes (IRR 1.87), and bilateral surgery (IRR 1.10). This inflammation is due to patient-related factors rather than surgical errors or infection, with an incidence of over 4% in high-risk groups ⁵⁾.

Use of Intravitreal Steroid Implants

For patients who cannot tolerate systemic steroids, intravitreal steroid injections or implants have been reported to be useful for controlling postoperative inflammation ^{7, 8)}.

Management of Refractory Postoperative Cystoid Macular Edema

Postoperative cystoid macular edema in uveitis patients may be resistant to conventional treatment ²⁾. Research is ongoing on the optimal combination of intravitreal injections, implants, and immunomodulatory therapy ^{7, 8)}.

Combination with Biologic Agents

Adalimumab (anti-TNF agent) is used for non-infectious uveitis refractory to existing treatments and has been shown to have a steroid-sparing effect. Research on its impact on perioperative management of cataract surgery is also accumulating.

8. References

1. Cann M, et al. Complications of paediatric non-infectious uveitis in a UK tertiary unit. Pediatr Rheumatol. 2018;16:51.

2. Chen JL, Bhat P, Lobo-Chan AM. Perioperative management of uveitic cataracts. Adv Ophthalmol Optom. 2019;4:325-339. PMID: 31788579. PMCID: PMC6884361. doi:10.1016/j.yaoo.2019.04.014.

3. Llop SM, Papaliodis GN. Cataract surgery complications in uveitis patients: a review article. Semin Ophthalmol. 2018;33(1):64-69.

4. ESCRS Cataract Guideline (Draft version, September 2024). European Society of Cataract and Refractive Surgeons. Section 7.6: Medication for ocular comorbidities in cataract surgery.

5. Acharya B, Hyman L, Tomaiuolo M, et al. Prolonged undifferentiated postoperative pseudophakic iridocyclitis. Ophthalmology. 2024.

6. Standardization of Uveitis Nomenclature (SUN) Working Group. Standardization of uveitis nomenclature for reporting clinical data. Am J Ophthalmol. 2005;140(3):509-516. PMID: 16196117. PMCID: PMC8935739. doi:10.1016/j.ajo.2005.03.057.

7. Ratra D, Barh A, Banerjee M, Ratra V, Biswas J. Safety and efficacy of intravitreal dexamethasone implant for refractory uveitic macular edema in adults and children. Ocul Immunol Inflamm. 2018;26(7):1034-1040. PMID: 29394119. doi:10.1080/09273948.2018.1424342.

8. Fan S, Shi XY, Zhao CF, Chen Z, Ying J, Yu SP, et al. Efficacy and safety of single-dose intravitreal dexamethasone implant in non-infectious uveitic macular edema: a systematic review and meta-analysis. Front Med (Lausanne). 2023;10:1126724. PMID: 36873888. PMCID: PMC9982842. doi:10.3389/fmed.2023.1126724.

9. Ram J, Gupta A, Kumar S, et al. Phacoemulsification with intraocular lens implantation in patients with uveitis. J Cataract Refract Surg. 2010;36(8):1283-1288.

10. Foster CS, Rashid S. Management of coincident cataract and uveitis. Curr Opin Ophthalmol. 2003;14(1):1-6.

11. Bélair ML, Kim SJ, Thorne JE, et al. Incidence of cystoid macular edema after cataract surgery in patients with and without uveitis using optical coherence tomography. Am J Ophthalmol. 2009;148(1):128-135.