Post-cataract surgery rebound iritis

Key Points at a Glance

Post-cataract surgery rebound iritis is a condition in which anterior chamber inflammation recurs during or after tapering of postoperative steroids.
Postoperative inflammation usually peaks within one week and subsides in 2–3 weeks, but rebound can occur in some cases.
The overall incidence of postoperative persistent iritis is reported to be approximately 1.2–1.7% ²⁾.
Diabetes, intraoperative use of pupil dilation devices, and African race are risk factors ¹⁾²⁾.
Treatment is based on restarting topical steroid eye drops and gradual tapering; confirming medication adherence is essential.
Rebound iritis typically persists for 5–6 months and requires long-term follow-up.
In persistent inflammation, it is important to differentiate residual lens fragments, intraocular lens dislocation, and infection.

1. What is Postoperative Rebound Iritis after Cataract Surgery?

Postoperative rebound iritis after cataract surgery is a condition in which anterior chamber inflammation that had subsided after cataract surgery recurs during or after tapering of topical steroids. It is characterized by the reappearance of cells and flare in the anterior chamber.

During cataract surgery, manipulation of the lens disrupts the blood-aqueous barrier, allowing white blood cells and inflammatory mediators to enter the anterior chamber. This inflammation typically peaks within one week after surgery and returns to normal levels within 2 to 3 weeks. Postoperative steroid tapering therapy controls this inflammation well in most cases, but if steroids are tapered too quickly or medication adherence is poor, inflammation can recur (rebound).

This condition is conceptually distinct from “persistent (chronic) iritis,” where inflammation does not resolve within the expected postoperative period, but clinical studies often group both together.

Regarding the incidence of postoperative persistent inflammation, a study using large-scale IRIS Registry data found that 1.68% of cataract surgery patients developed “persistent undifferentiated postoperative pseudophakic iridocyclitis (PUPPI)” within 6 months after surgery ²⁾. The incidence was highest in patients aged 51–60 years (1.80%) and tended to decrease with age ²⁾.

Q What is the difference between rebound iritis and persistent iritis?

Rebound iritis is a recurrence of inflammation that had once subsided, triggered by tapering or discontinuing steroids. Persistent iritis refers to a condition where inflammation continues for several weeks after surgery. However, these two are often confused in clinical studies.

2. Main Symptoms and Clinical Findings

Subjective Symptoms

Symptoms of rebound iritis are similar to those of acute anterior uveitis.

Redness: Severe ciliary injection near the corneal limbus.
Blurred vision (visual changes): Decreased visual acuity due to anterior chamber inflammation.
Eye pain: Pain characteristic of acute anterior uveitis.
Photophobia: Increased sensitivity to light.
Irritation: May complain of foreign body sensation or discomfort.

Clinical Findings (Findings Confirmed by Physician Examination)

The following findings are confirmed by slit-lamp microscopy.

Anterior chamber cells: White blood cells floating in the anterior chamber, reflecting inflammatory activity.
Flare (anterior chamber protein): A sign indicating breakdown of the blood-aqueous barrier, which may or may not be accompanied by cells.
Miosis: Pupillary constriction may occur due to spasm of the iris sphincter muscle.
Intraocular pressure changes: Intraocular pressure often decreases due to reduced ciliary body function.

In severe or persistent cases, attention should be paid to the formation of posterior synechiae. Evaluate for vitreous cells and chorioretinitis on dilated fundus examination to rule out panuveitis or posterior uveitis. If chronic endophthalmitis is suspected, check for vitritis or hypopyon, but these are absent in up to 25% of cases, so a high index of suspicion is important.

3. Causes and Risk Factors

Causes of Rebound Iritis

The essence of rebound iritis is insufficient anti-inflammatory treatment for intraocular inflammation caused by surgical invasion.

Poor medication adherence: Non-compliance with the eye drop schedule is the most common cause. In one study, up to 92.6% of 54 post-cataract surgery patients showed improper eye drop technique.
Inadequate response to tapering schedule: The individual eye’s inflammatory response may not keep up with standard tapering.

Differential Causes of Persistent Iritis

Causes of persistent inflammation that should be differentiated from rebound are as follows:

Residual lens cortex: Detected by gonioscopy or ultrasound biomicroscopy (UBM).
IOL dislocation/malposition: Ciliary sulcus placement of a one-piece acrylic IOL or improper placement of an anterior chamber IOL can be the cause¹⁾.
Latent infection: Chronic endophthalmitis due to Cutibacterium acnes (formerly Propionibacterium acnes) or fungi.
History of uveitis: Recurrence of uveitis that was not recognized preoperatively.
Herpetic eye disease: Reactivation of herpes simplex or varicella-zoster virus.

In the differential diagnosis from lens-induced endophthalmitis, when late-onset persistent iridocyclitis occurs postoperatively, check for residual lens material. In late-onset endophthalmitis due to C. acnes, white plaque formation on the lens capsule may be seen, but it is often difficult to determine based on clinical findings alone.

Risk factors

Patient Factors

Diabetes: Increases the risk of prolonged postoperative inflammation¹⁾.

African Americans: Tend to have a higher incidence of PUPPI compared to other races²⁾.

Ages 51–60: The incidence is highest in this age group²⁾.

Intraoperative Factors

Use of pupil expansion devices: Increases the risk of postoperative inflammation when used during surgery¹⁾.

History of uveitis: Increases the risk of postoperative inflammation exacerbation, requiring frequent and long-term anti-inflammatory treatment¹⁾.

Q Does diabetes increase the risk of inflammation after cataract surgery?

Diabetic patients have a higher risk of prolonged inflammation and cystoid macular edema after surgery¹⁾. However, some reports indicate that long-term visual outcomes are similar to those of patients without diabetes¹⁾.

4. Diagnosis and Examination Methods

The diagnosis of rebound iritis is based on clinical course and slit-lamp microscopy findings. If anterior chamber inflammation develops within a few months after cataract surgery and there is a history of inflammation that had once subsided, rebound is considered first.

Medical History and Assessment of Medication Adherence

A detailed medical history is essential. The patient’s understanding and adherence to the postoperative eye drop schedule should be confirmed. Causes of non-adherence include carelessness, misunderstanding, improper technique, failure to shake suspensions, and difficulty obtaining medication.

Slit-lamp microscopy

Evaluate cells and flare in the anterior chamber. Grading of anterior chamber inflammation based on the SUN classification is important. Also check for the presence of posterior synechiae.

Dilated fundus examination

Confirm the absence of vitreous cells and chorioretinitis, and rule out panuveitis and posterior uveitis.

Additional tests for differential diagnosis

To exclude other causes of persistent inflammation, consider the following as needed.

Gonioscopy: Detects small lens fragments in the inferior angle.
Ultrasound biomicroscopy (UBM) / long-wavelength OCT: Evaluates residual lens fragments in the ciliary sulcus and intraocular lens malposition.
Culture and PCR of aqueous humor and vitreous: Performed when infection such as C. acnes is suspected.

Differential Diagnosis	Characteristic Findings	Additional Tests
Residual lens cortex	Early to persistent inflammation	Ultrasound biomicroscopy / gonioscopy
Chronic endophthalmitis	Vitritis / white plaque	Anterior chamber fluid culture
Intraocular lens dislocation	Persistent inflammation	Ultrasound biomicroscopy / anterior segment OCT

5. Standard treatment

Pharmacotherapy

Treatment of rebound iritis follows the standard treatment for acute anterior uveitis.

Topical corticosteroids

First-line treatment is 1% prednisolone acetate eye drops. The frequency of instillation is adjusted according to the degree of inflammation, and re-tapering is performed on a slower schedule than the initial taper ¹⁾. 0.1% dexamethasone and 1% prednisolone sodium phosphate are also used.

Since anterior chamber inflammation is often severe at recurrence, betamethasone (Rinderon®) 0.1% ophthalmic solution is recommended three times daily, with adjustments based on the degree of inflammation.

Cycloplegics (mydriatics)

Cycloplegics are used until anterior chamber cells are 0.5+ or less. Mydriasis prevents posterior synechiae formation and reduces pain by relieving ciliary muscle spasm. In Japan, Mydrin P® (tropicamide/phenylephrine combination) is commonly used once daily at bedtime.

NSAID eye drops

Compared to steroids alone, the combination of NSAIDs (ketorolac, nepafenac, etc.) is more effective in preventing inflammation and cystoid macular edema (CME) ³⁾.

Alternative Anti-inflammatory Methods

For patients with poor medication adherence or those who may miss follow-up, the following options are available.

Sub-Tenon corticosteroid injection: Uses long-acting triamcinolone acetonide.
Intracameral steroid/NSAID suspension injection: Being investigated as a newer drug delivery system.

ESCRS guidelines recommend the combination of NSAIDs and steroid eye drops for the prevention of inflammation and cystoid macular edema after routine cataract surgery ³⁾. In uveitis patients, it is recommended to increase the frequency and prolong the duration of steroids postoperatively ³⁾.

Follow-up

Perform follow-up 7 days after the initial visit.
If anterior chamber cells have decreased appropriately and there is no pain, discontinue cycloplegic agents.
Observe weekly until there are fewer than 5 cells per high-power field.
Reduce the frequency of eye drops and extend follow-up intervals according to improvement.
Rebound iritis usually persists for 5–6 months, so long-term monitoring and medication adherence are essential.

Q How long does rebound iritis last?

Rebound iritis usually persists for 5 to 6 months. During this period, regular follow-up visits and slow tapering of steroids are necessary. For details, see the section on “Standard Treatment”.

6. Pathophysiology and Detailed Mechanism

In cataract surgery, procedures such as corneal incision, phacoemulsification, and use of irrigation fluid physically disrupt the blood-aqueous barrier. This allows inflammatory mediators such as white blood cells, prostaglandins, and cytokines to flow into the anterior chamber, triggering acute traumatic anterior uveitis.

The time course of the inflammatory response is as follows:

Within 1 week after surgery: Inflammation peaks. Anterior chamber cells and flare are most prominent.
2 to 3 weeks after surgery: Under appropriate steroid tapering therapy, inflammation gradually decreases to normal levels.
During tapering to after discontinuation: In some patients, inflammation flares up as the suppressive effect of steroids is lost.

The mechanism of rebound is thought to involve the release of steroid-induced suppression of prostaglandin production, leading to reinflux of inflammatory cells through the blood-ocular barrier that has not yet fully healed.

Rebound inflammation after steroid discontinuation manifests as increased anterior chamber cells and flare, and may progress to cystoid macular edema (CME) ¹⁾. Inflammation is controlled by resuming anti-inflammatory eye drops and slow tapering ¹⁾.

Cataract surgery in patients with uveitis carries a particularly high risk of postoperative inflammation exacerbation ¹⁾. Uveitis specialists recommend a quiescent period of at least 3 months before surgery, and adequate preoperative anti-inflammatory treatment contributes to postoperative inflammation control ¹⁾.

Q Why is postoperative inflammation more severe in patients with a history of uveitis?

In uveitis, the blood-ocular barrier is already compromised, and surgical trauma causes it to break down more easily. Postoperatively, more frequent and longer-term anti-inflammatory treatment is required ¹⁾. A quiescent period of at least 3 months before surgery is recommended ¹⁾.

7. Latest Research and Future Prospects (Research Stage Reports)

Large-Scale Epidemiological Study of Postoperative Undifferentiated Pseudophakic Iridocyclitis (PUPPI)

Using data from the AAO IRIS Registry (approximately 7.51 million patients and 12.46 million eyes), the epidemiology of PUPPI was analyzed²⁾. The patient-level incidence within 6 months post-surgery was 1.68%. Female sex (IRR 1.12), Black race (IRR 1.71), and diabetes (IRR 1.14) were identified as risk factors. This study aims to establish a standard definition that enables future research comparisons by proposing the unified term “PUPPI.”

Anterior Chamber Drug Delivery System

As a new drug delivery method replacing conventional eye drops, the development of an anterior chamber steroid/NSAID suspension injection system is progressing. It is attracting attention as an approach that can fundamentally solve the problem of medication adherence.

Intravitreal Steroid Implants

The ESCRS guidelines suggest that for patients with uveitis undergoing cataract surgery who cannot tolerate systemic steroid therapy, intravitreal steroid injections or steroid implants may be beneficial ³⁾.

8. References

Miller KM, Oetting TA, Tweeten JP, et al.; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the Adult Eye Preferred Practice Pattern. Ophthalmology. 2022;129(1):P1-P126. doi:10.1016/j.ophtha.2021.10.006. PMID:34780842.
Acharya B, Hyman L, Tomaiuolo M, Zhang Q, Dunn JP. Prolonged Undifferentiated Postoperative Pseudophakic Iridocyclitis. Ophthalmology. 2025;132(4):504-506. doi:10.1016/j.ophtha.2024.12.012. PMID:39672310.
European Society of Cataract and Refractive Surgeons (ESCRS). ESCRS Cataract Surgery Guidelines. 2024.

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