Cataract surgery in patients with complex anterior-segment anatomy continues to challenge even experienced surgeons, particularly when unexpected signs of intraoperative floppy iris syndrome (IFIS) arise. The case described in this article was a seemingly routine cataract procedure that rapidly evolved into a multifaceted surgical scenario marked by progressive miosis and recurrent iris prolapse. 

Case Presentation

A 71-year-old Black female with a past medical history of hypertension presented for cataract evaluation. Her past ocular history was significant for branch retinal vein occlusion in the right eye, severe chronic angle-closure glaucoma in the right eye, and primary angle closure without glaucoma in the left eye, with her intraocular pressure (IOP) well controlled on latanoprost and brinzolamide/brimonidine tartrate ophthalmic suspension (Simbrinza; Alcon). She denied any history of alpha blocker use, ocular trauma, or prior ocular surgeries.

The Ocular Exam

The patient’s preoperative exam demonstrated the following:

●     Distance visual acuity with correction: 20/40 OD, 20/30+2 OS

●     Manifest refraction:

○     OD: +3.00-1.00 x082 20/30-1, low contrast 20/400

○     OS: +4.00-1.25 x071 20/20, low contrast 20/25

●     IOP (Tono-Pen; Reichert): 21 mmHg OD, 18 mmHg OS

●     Pupils: round and reactive in both eyes, +relative afferent pupillary defect OD

The patient’s slit lamp examination was remarkable for a shallow but quiet anterior chamber (AC) in both eyes and 2+ nuclear sclerosis with 2+ cortical changes in both eyes. The patient’s cup-to-disc ratio was 0.9 in the right eye and 0.75 in the left eye with rim thinning greater in the right eye than the left. She was noted to have shunt vessels in the right eye due to a history of branch retinal vein occlusion, but her exam was otherwise unremarkable.

Relevant preoperative surgical measurements from optic biometry (IOLMaster 500; Zeiss) were as follows:

●     Axial length: 23.67 mm OD, 23.55 mm OS

●     Keratometry:

○     OD: 42.19D

○     OS: K1 41.62 @073 K2 42.08 @163

●     AC depth: 2.60 mm OD, 2.60 mm OS

●     Corneal topography (Pentacam; Oculus):

○     OD: mild irregular against-the-rule astigmatism

○     OS: moderate oblique astigmatism with asymmetric bowtie pattern

●     OCT macula: normal OU

The risks, benefits, and alternatives of cataract extraction with intraocular lens placement (CEIOL) were discussed with the patient in clinic and she elected to proceed with CEIOL in the right eye with plans for a +23.0D SA60WF monofocal IOL (AcrySof Lens, Alcon).

Intraoperative Obstacles

The case began uneventfully, with pupillary dilation to approximately 7 mm, wound creation, capsulorhexis, and hydrodissection were performed. Signs of trouble began during phacoemulsification when pupillary dilation began to wane (Figure 1A). Next, unexpected patient movement occurred, resulting in an iris prolapse through the main incision (Figure 1B). The anterior chamber was decompressed by release of ophthalmic viscosurgical device (OVD) from the sideport incision, and the iris was gently repositioned into the AC with OVD. Phacoemulsification was completed but progressive miosis hindered surgical efficiency.

Attempts to viscodilate the pupil triggered another episode of iris prolapse, prompting the decision to suture the original incision closed with 10-0 nylon and create a new main incision inferiorly. Next, 5 iris hooks were placed to provide pupillary expansion (Figure 1C). Once the pupil was mechanically dilated, cortical material was removed via irrigation/aspiration, the lens capsule was inflated with OVD, and the above-mentioned IOL was inserted into the capsular bag. When iris prolapse was encountered through the new main incision, a new sideport incision was created superiorly and an iris sweep was used to reposition the iris back into the AC (Figure 1D).

The remaining 4 iris hooks were removed, followed by complete OVD removal. Carbachol (Miostat; Alcon) was injected to displace the peripheral iris centrally, away from corneal incisions. The incisions were then hydrated, and the second main incision was sutured using 10-0 nylon. Intracameral moxifloxacin was injected. All incisions were watertight, the IOP was within physiologic range, and the intraocular lens was positioned appropriately at the end of the case.

Intraoperative Floppy Iris Syndrome

Intraoperative floppy iris syndrome (IFIS), first described by Chang and Campbell in 2005, is characterized by iris billowing, iris prolapse through surgical incisions, and progressive miosis.¹ Although IFIS was initially linked to selective α₁-adrenoceptor antagonists such as tamsulosin, current understanding recognizes a broader range of associated risk factors. These include advanced age, male sex, small preoperative pupil size, hypertension, and medications classes such as 5α-reductase inhibitors (e.g., finasteride), angiotensin II receptor blockers, benzodiazepines, and antipsychotics.² Recent literature has highlighted increasing reports of IFIS in female patients, especially those not on α₁-adrenoceptor antagonists, as seen in our patient.^3,4

The overall prevalence of IFIS ranges between 1.1% and 12.6%.^2,4 IFIS is important for ophthalmologists to recognize, because it can complicate phacoemulsification with an elevated risk of iris trauma, posterior capsule rupture, vitreous loss, corneal endothelial loss, elevated IOP, postoperative inflammation, hyphema, macular edema, and longer surgical times.^3,5

Preoperative Management

A thorough preoperative history is critical for risk stratification and proper surgical planning. Advanced age, small pupil diameter, and hypertension should also raise suspicion for potential IFIS.² Ophthalmologists should obtain a complete medication history, checking for use of not only α₁-adrenoceptor antagonists, but also about 5α-reductase inhibitors, angiotensin II receptor blockers, antipsychotics, and benzodiazepines.² Interestingly, although discontinuing tamsulosin before surgery was initially proposed as preventive, evidence suggests permanent iris dilator muscle atrophy may limit this approach.¹

Pharmacologic prophylaxis can reduce the severity of IFIS. Preoperative administration of atropine and topical NSAIDs like ketorolac has been shown to stabilize the pupil and reduce the incidence of intraoperative miosis.^3-5 Atropine sulfate 1%, administered 40 and 20 minutes prior to surgery, has shown efficacy particularly for mild forms of the syndrome.³

Intraoperative Management

Certain intraoperative strategies are useful when encountering IFIS. The surgeon can consider creating elongated corneal incisions and adjusting phacoemulsification fluid settings to low-flow, low-vacuum parameters.³ OVD, particularly viscoadaptive types like Healon 5, can provide effective iris tamponade and chamber stability, although care must be taken to avoid posterior-chamber entrapment of OVD and resultant iris prolapse.⁵

Intracameral phenylephrine or epinephrine may help maintain dilation and reduce iris mobility, while pupil expansion devices such as iris hooks and rings maintain adequate pupillary dilation and further reduce the risk of iris prolapse.^6-8 Post-IOL implantation iris prolapse can be addressed with intracameral miotics such as carbachol or acetylcholine.³ Mechanical pupil stretching using blunt instruments is discouraged due to the risk of worsening atony and miosis.¹

Postoperative Results

At the patient's postoperative day 1 visit, the patient denied pain. Her distance uncorrected visual acuity without correction was 20/40 PH 20/30+ and IOP 20 mmHg. Her slit lamp exam was remarkable for subconjunctival hemorrhage, sealed corneal incisions with two 10-0 nylon sutures in place, 3+ cell and flare in the AC, and a well-centered posterior-chamber IOL. She was instructed to start her postoperative medications and advised to resume brinzolamide/brimonidine tartrate in her operative eye.

Besides advanced age, our patient did not have any prior history to suggest that she would be at risk of floppy iris syndrome. The placement of iris hooks and new incisions were made to assure proper placement of an IOL. Despite the unexpected challenges, the patient’s outcome was favorable.

The Takeaway

IFIS is a complex, multifactorial intraoperative challenge during cataract surgery. Early identification of high-risk patients through comprehensive preoperative history and evaluation, pharmacologic prophylaxis, and modified surgical technique are key strategies in mitigating its risks and impact. Ophthalmologists should remain vigilant and flexible, adapting both preoperative and intraoperative protocols to optimize outcomes in patients with or at risk of IFIS.

Axel Rivas, BS is a fourth-year medical student at the Kirk Kerkorian School of Medicine at the University of Nevada Las Vegas in Las Vegas. He has no financial or industry disclosures. Reach him at rivasa9@unlv.nevada.edu.

Michelle L. Huynh, MD is a glaucoma fellow at the New England Eye Center and Ophthalmic Consultants of Boston in Boston. She has no financial or industry disclosures. Reach her at michlhuynh8@gmail.com.

Claire Wright, MD is an assistant professor of ophthalmology at The University of Tennessee Health Science Center, Hamilton Eye Institute in Memphis, Tennessee. She has no financial or industry disclosures. Reach her at claire.wright@uthsc.edu.

 References

1. Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg. 2005;31(4):664-673. doi:10.1016/j.jcrs.2005.02.027
2. Christou CD, Esagian SM, Ziakas N, Prousali E, Tzamalis A. Factors predisposing to intraoperative floppy-iris syndrome: an up-to-date meta-analysis. J Cataract Refract Surg. 2022;48(11):1335-1341. doi:10.1097/j.jcrs.0000000000001017
3. Christou CD, Tsinopoulos I, Ziakas N, Tzamalis A. Intraoperative floppy iris syndrome: updated perspectives. Clin Ophthalmol. 2020;14:463-471. doi:10.2147/OPTH.S221094
4. Safir M, Hecht I, Hartstein ME, Mahler O, Einan‑Lifshitz A, Pras E. Preoperative ocular characteristics predicting the development of intraoperative floppy iris syndrome regardless of alpha‑antagonist exposure status. Graefes Arch Clin Exp Ophthalmol. 2021;259(5):1209‑1214. doi:10.1007/s00417‑020‑05060‑5
5. Yang X, Liu Z, Fan Z, Grzybowski A, Wang N. A narrative review of intraoperative floppy iris syndrome: an update 2020. Ann Transl Med. 2020;8(22):1546. doi: 10.21037/atm-20-3214.
6. Nderitu P, Ursell P. Iris hooks versus a pupil expansion ring: operating times, complications, and visual acuity outcomes in small pupil cases. J Cataract Refract Surg. 2019;45(2):167-173. doi: 10.1016/j.jcrs.2018.08.038
7. Tetz MR, Holzer MP, Lundberg K, Auffarth GU, Burk RO, Kruse FE. Clinical results of phacoemulsification with the use of Healon5 or Viscoat. J Cataract Refract Surg. 2001;27(3):416-420. doi:10.1016/s0886-3350(00)00569-1
8. Gurbaxan A, Packard R. Intracameral phenylephrine to prevent floppy iris syndrome during cataract surgery in patients on tamsulosin. Eye (Lond). 2007;21(3):331-332. doi:10.1038/sj.eye.6702172