Bilateral acute depigmentation of the iris (BADI) and bilateral acute iris transillumination (BAIT): A case series from a center in Brazil.

Bilateral acute depigmentation of the iris and bilateral acute iris transillumination (BAIT) are similar clinical entities. The former causes acute-onset depigmentation of the iris stroma without transillumination, whereas the latter causes depigmentation of the iris pigment epithelium with transillumination. The etiopathogenesis of these conditions is not yet fully understood, but the proposed causes include the use of systemic antibiotics (especially moxifloxacin) and viral triggers. We present a case series of five female patients with a mean age of 41 (32-45) years, all of whom suffered acute onset of bilateral pain and redness of the eyes after moxifloxacin use (oral or topical). It is important for ophthalmologists to be aware of the two forms of iris depigmentation since this case series suggests that SARS-CoV-2 or its empirical treatment with moxifloxacin may trigger iris depigmentation. If this is the case, clinicians will likely see increased incidences of bilateral acute depigmentation of the iris and bilateral acute iris transillumination during and after the COVID-19 pandemic.

Intracameral phenylephrine for surgical mydriasis and intraoperative floppy-iris syndrome: systemic adverse effects and optimal dose.

Phenylephrine, a potent sympathomimetic, induces mydriasis via iris dilator muscle contraction. Intracameral (IC) phenylephrine has been successfully used in cataract surgery for initial mydriasis, maintaining mydriasis, and management of intraoperative floppy-iris syndrome. Serious systemic adverse events (mainly cardiovascular) have been described with topical phenylephrine drops, but we found very little evidence of such adverse events associated with IC phenylephrine use. However, we suspect under-reporting of such adverse events, as they may instead be ascribed to anxiety, positioning, anesthesia, etc. Optimal dosage/concentrations for IC phenylephrine use in different purposes have not been fully studied. In the absence of robust evidence, we suggest that lower but effective IC phenylephrine concentrations are used: a lower concentration (0.31%), in conjunction with an anticholinergic and lidocaine, may be used for initial mydriasis. For management of intraoperative floppy-iris syndrome, 0.31% may be effective, though a higher concentration (1% to 1.25%) may be required.

Prospective analysis of anatomic features predisposing patients to intraoperative floppy iris syndrome.

PURPOSE: To aid preoperative risk assessment by identifying anatomic parameters corresponding with a higher risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery. METHODS: Prospective cohort study of 55 patients with α1-adrenergic receptor antagonist (α1-ARA) treatment and 55 controls undergoing cataract surgery. Anterior segment optical coherence tomography (AS-OCT), video pupilometer, and biometry measurements were performed preoperatively and analyzed regarding anatomic parameters that corresponded with a higher rate of IFIS. Those statistically significant parameters were evaluated with logistic regression analysis and receiver operating characteristic (ROC) curve. RESULTS: Pupil diameter was significantly smaller in patients who developed IFIS compared to those who did not develop IFIS (AS-OCT 3.29 ± 0.85 vs. 3.63 ± 0.68, p = 0.03; Pupilometer 3.56 ± 0,87 vs. 3.95 ± 0.67, p = 0.02). Biometric evaluation revealed shallower anterior chambers in the IFIS group (ACD 3.12 ± 0.40 vs. 3.32 ± 0.42, p = 0.02). Cutoff values for 50% IFIS probability (p = 0.5) were PD = 3.18 mm for pupil diameter and ACD = 2.93 mm for anterior chamber depth. ROC curves of combined parameters were calculated for α1-ARA medication with pupil diameter and anterior chamber depth, which yielded an AUC of 0.75 for all IFIS grades. CONCLUSION: The combination of biometric parameters with history of α1-ARA medication can improve assessment of risk stratification for IFIS incidence during cataract surgery.

Bilateral Acute Iris Transillumination (BAIT): A Rare Syndrome Possibly Associated with COVID-19 and Moxifloxacin Use. A Report of 2 Cases.

Bilateral acute iris transillumination (BAIT) is a rare clinical entity, presumed to be associated with preceding upper respiratory tract infection and/or use of certain antibiotics, marked by bilateral acute loss of iris pigment epithelium with pigment dispersion in the anterior chamber and trabecular meshwork, which can cause elevated intraocular pressure and glaucoma, and with iris transillumination and sphincter paralysis which lead to photophobia and blurry vision. We report the first two cases of BAIT in our center which both had a history of preceding COVID-19 (coronavirus disease 2019) and moxifloxacin use. With more awareness, ophthalmologists might diagnose more cases, and thus gain more information regarding the link between COVID-19 and BAIT, which might be underdiagnosed since it is rare or easily misdiagnosed as some more common diseases with similar features.

Impact of intraoperative floppy IRIS syndrome in cataract surgery by phacoemulsification: Analysis of 622 cases.

BACKGROUND: Small pupil syndromes, including IFIS, increase the risk of complications during cataract surgery if proper surgical planning is not performed. Tamsulosin is associated with a very significant increase in the risk of IFIS, due to the prolonged inactivation of alpha-1 adrenergic receptors in the smooth muscle fiber of the iris. MATERIAL AND METHODS: Single-center prospective observational study, carried out at the Hospital de l'Esperança - Parc de Salut Mar. RESULTS: 622 eyes of 502 patients were included, of which 337 (62%) were women. The mean age of the sample is 74.8 years. 61 cases of IFIS (11%) were observed, of which 13 received treatment with Tamsulosin and 1 with Doxazosin. 23 cases of IFIS were observed in female patients. The female:male ratio was approximately 1:3. 19 cases (3%) of severe IFIS were observed, of which 6 received treatment with alpha-antagonists, with no statistically significant correlation. The mean surgical time was 13.80 min (Standard Deviation - SD: 4.01 min) in patients without IFIS and 16.93 min (SD: 4.32 min) in patients with IFIS. The relationship between the duration of the surgical procedure in minutes and the presence of IFIS was statistically significant, applying a 'two-tailed' or bilateral t-Student test with a p value of 0.01. CONCLUSION: Regardless of the degree of severity, the diagnosis of IFIS lengthens the surgical time in cataract surgery. This represents yet another piece of evidence that supports the use of less selective alpha-1 adrenergic antagonist treatments than Tamsulosin or the performance of cataract surgery before starting these treatments.

Floppy iris syndrome associated with specific medication intake: A narrative review.

Intraoperative floppy iris syndrome (IFIS) is a cataract surgery complication that remains a challenge for eye surgeons. It is caused by the antagonism of alfa-1-adrenergic receptors within the dilator muscle of the iris, thus preventing the iris from dilation during a cataract surgery. The long-term blocking alfa-1 adrenergic receptors by the chronic use of a number of systemic medications may lead to permanent anatomical atrophy of the dilator muscle of the iris. The most common drugs associated with the development of IFIS are tamsulosin and other alpha-1 adrenergic receptor antagonists prescribed to patients with low urinary tract symptoms (LUTS). There are other systemic medications that have been reported to have increased risk for IFIS. It is crucial for the ophthalmologist to identify the high-risk patients prone to develop IFIS. Its presence may complicate the course of cataract surgery, ultimately negatively affecting visual outcome. Cataract surgery should be performed by an experienced eye surgeon using alternative pharmacological and surgical techniques. Interdisciplinary cooperation is essential to mitigate potential complications. Patients should be informed by their physicians about the need to report a medication history to their eye specialists, especially before cataract surgery.

Bilateral Acute Depigmentation of Iris (BADI) and Bilateral Acute Iris Transillumination (BAIT)-An Update.

Bilateral acute depigmentation of the iris (BADI) and bilateral acute iris transillumination (BAIT) are relatively new clinical entities characterized by acute pigment dispersion from the iris stroma or iris pigment epithelium, respectively. While BADI presents with diffuse or geographic areas of iris stromal depigmentation without transillumination, BAIT cases typically develop diffuse iris transillumination and mydriatic atonic pupils. Prolonged pigment dispersion and ocular hypertension are more common in BAIT. Although the exact etiopathogenesis is still unknown, moxifloxacin toxicity appears to be a probable/likely cause. The underlying cause of BADI or BAIT in patients who were not exposed to fluoroquinolone antibiotics remains unexplained. Systemic viral infections, including coronavirus disease 2019, may be the triggering event in several cases.

Alpha Blocker-Associated Intraoperative Floppy Iris Syndrome.

Objective To evaluate the literature related to the use of alpha1-blockers and the risk of intraoperative floppy iris syndrome (IFIS), particularly in cataract surgery. IFIS is characterized by floppiness or billowing of the iris, iris prolapse, and progressive miosis, possibly leading to severe complications. It is thought to be associated with adrenergic alpha-1 receptor antagonists commonly used to treat lower urinary tract symptoms in patients with benign prostatic hyperplasia. Data Sources A literature search was conducted in Pubmed, EMBASE, and Web of Science through May 2021 with MeSH terms and keywords 'intraoperative floppy iris syndrome,' ' adrenergic alpha-1 receptor antagonists,' and 'cataract surgery.' Study Selection and Data Extraction Relevant articles were reviewed and included. In addition, reference lists from identified publications were reviewed to identify additional reports and studies of interest. Data Synthesis Numerous reports have linked IFIS to multiple risk factors including age, gender, hypertension, and the use of adrenergic alpha-1 receptor antagonists, most notably tamsulosin. Tamsulosin selectively blocks the adrenergic alpha-1 receptor in the iris dilator muscle, preventing mydriasis during cataract surgery. Other adrenergic alpha-1 receptor antagonists, including terazosin, doxazosin, alfuzosin, and sildosin, have also been linked to IFIS; however, their relationship to IFIS is not as well defined. Conclusion Patients should be educated regarding potential adverse effects and discuss this with their health care providers prior to cataract surgery. In addition, health care providers should be aware of the adverse effect and take steps to reduce the risk of surgical complications.

[Intraoperative floppy iris syndrom (IFIS) associated with tamsulosin]. / Intraoperatives Floppy Iris Syndrom (IFIS) bei Tamsulosineinnahme.

BACKGROUND: Tamsulosin is one of the most commonly prescribed alpha-1A antagonists for the treatment of benign prostatic syndrome (BPS). Patients treated with tamsulosin often develop intraoperative floppy iris syndrome (IFIS) during cataract surgery. This leads to increasing miosis and an undulating iris, which increases the risk of complications significantly and can cause permanent damage. AIM OF THE WORK: The aim is to raise awareness for the effects of tamsulosin intake before cataract surgery. MATERIAL AND METHODS: We conducted a critical review of publications on the association of IFIS in cataract surgery with alpha-receptor blockers. RESULTS AND DISCUSSION: Tamsulosin has a risk of complications of up to 80 %, whereas doxazosin and alfuzosin only have a 15-20 % chance of complications. Tamsulosin therefore represents a significant risk factor for permanent secondary damage after cataract surgery. Even after discontinuing tamsulosin, IFIS was still observed after up to 3 years. Nevertheless, pausing of tamsulosin intake is recommended. An alternative preparation should therefore be preferred in patients who have not yet had cataract surgery. If patients are already pseudophakic, tamsulosin can be given without concern.

Dealing with floppy iris syndrome.

PURPOSE OF REVIEW: The aim of this study was to review and summarize recent findings and advancements regarding intraoperative floppy iris syndrome (IFIS). Although many improvements have been made for the management of IFIS, it remains a challenging condition for surgeons. An understanding of the syndrome as well as the multitude of tools to mitigate risk of complication is important for surgeons operating on high-risk patients. RECENT FINDINGS: A variety of management approaches have been modified and improved or further supported with new data, such as intracameral compounds, intraoperative devices and surgical techniques. SUMMARY: An understanding of risk factors is important for the identification of at-risk patients. A variety of approaches can greatly reduce incidence of IFIS complications. Multiple management strategies should be utilized to further reduce risk during these difficult surgeries.

Preoperative atropine and non-steroidal anti-inflammatory drugs for the prevention of intraoperative floppy iris syndrome.

PURPOSE: To examine the efficacy of preoperative administration of topical atropine 1% and non-steroidal anti-inflammatory drugs (NSAIDs) for prevention of intraoperative floppy iris syndrome (IFIS). METHODS: In this retrospective cohort study, patients who underwent cataract surgery by phacoemulsification between July 2019 and February 2020 in two hospitals were included. Both hospitals are located in central Israel, have similar patient demographics and employ similar surgical techniques. They, however, differ in policy of IFIS prevention. In Meir Medical Center no preventive medications are given pre-operatively, while in Shamir Medical Center patients at-risk for IFIS receive topical atropine 1% once daily and non-steroidal anti-inflammatory drugs (NSAIDs) thrice daily for 3 days preoperatively. RESULTS: Overall, 207 eyes of 207 patients with history of alpha-antagonist use were included. Mean age was 74.9 ± 7.8 years and 82.1% (n = 170) were male. Among patients from the pretreating center 86.8% (n = 92/106) were pre-treated with either NSAIDs or atropine preoperatively, while in the non-pretreating center no treatment was prescribed (n = 0/101). IFIS rate among the non-pretreating center was 29.7% (n = 30/101) compared to 15.1% (n = 16/106) in the pretreating center (p = 0.012). When strictly comparing treated to untreated patients, the treated group had an IFIS rate of 12.0% compared to 30.4% among untreated (p = 0.001). Adjusted for age and gender results remain consistent (odds ratio 0.329 for treated patients, 95% confidence interval: 0.150-0.720; p = 0.005). CONCLUSIONS: IFIS rates were significantly lower in the pretreating center compared to the non-pretreating center. When comparing strictly treated to untreated patients, differences were even more pronounced.

Silodosin as a predisposing factor of intraoperative floppy iris syndrome (IFIS): an observational propensity score-matching cohort study.

PURPOSE: To evaluate the correlation between silodosin and intraoperative floppy iris syndrome (IFIS) and compare it with other a1-adrenergic receptor antagonists (a1-ARAs) and other factors predisposing to IFIS. METHODS: From the patients who underwent phacoemulsification between 2014 and 2020, we identified all patients who, during their preoperative assessment, reported an a1-ARAs intake (exposed group). These patients were matched utilizing a propensity score matching analysis with an otherwise homogenous group of patients (control group) based on demographics and systemic/ocular comorbidities. RESULTS: A total of 350 patients were included in each group. In the exposed group, 177 (50.6%) patients were exposed to tamsulosin, 105 (30%) to alfuzosin, 43 (12.2%) to silodosin. Regarding IFIS, it was observed in 21.5% of patients on tamsulosin (38/177), 11.4% on alfuzosin (12/105), 37.2% on silodosin (16/43), and 3.4% in the controlled group (12/350). In a multiple regression model analysis, the only two factors significantly associated with IFIS development were silodosin and tamsulosin yielding an adjusted odds ratio of 8.471 (95%CI 4.005-17.920) and 3.803 (95%CI 2.231-6.485), respectively. CONCLUSION: Silodosin has been demonstrated as a predisposing factor, strongly correlated with IFIS development. These results should increase cataract surgeons' awareness to assess their patients preoperatively for exposure to silodosin carefully and employ the appropriate prophylactic measures to ameliorate the impact of silodosin intake on the surgical outcome.

Severe sequelae in bilateral acute iris transillumination syndrome secondary to the use of oral moxifloxacin: a case report.

BACKGROUND: Moxifloxacin is a fourth-generation fluoroquinolone used as a second-line treatment for multiple bacterial infections. Uveitis has been described as an adverse effect related to this medication. Although several case reports have been published describing uveitis and bilateral acute iris transillumination syndrome related to moxifloxacin, we present a unique case of a patient with severe sequelae associated with bilateral acute iris transillumination syndrome secondary to the use of oral moxifloxacin. CASE PRESENTATION: A 45-year-old Colombian hispanic female presented bilateral conjunctival hyperemia, decreased visual acuity, blurred vision, photophobia, and ocular pain after 15 days of treatment with systemic moxifloxacin for an upper tract respiratory infection. The patient presented unilateral anterior chamber pigment dispersion, mydriatic and nonreactive pupils, extensive iris transillumination defects, and secondary glaucoma. Blood and aqueous humor tests were negative for infectious and autoimmune diseases. Moxifloxacin-induced bilateral acute iris transillumination syndrome was diagnosed. Permanent sequelae such as ocular pain, photophobia, and focus difficulty secondary to severe bilateral iridian atrophy and inability of synkinetic reflex were left. Additionally, glaucoma was diagnosed, and Ahmed valve implantation was required. CONCLUSIONS: We should be aware of the possible association between moxifloxacin and bilateral acute iris transillumination syndrome. A detailed anamnesis, adequate examination, and laboratory tests are necessary to reach an early diagnosis and treatment to avoid unnecessary therapies. Larger studies should be carried out to understand the pathophysiology, diagnosis, management, and sequelae of the disease.

Intraoperative Floppy Iris Syndrome Induced by Tamsulosin: The Risk and Preventive Strategies.

Tamsulosin is an antagonist of a subtype-specific alpha-1A- and alpha-1D-adrenoceptor (AR) that is expressed in the prostate gland, urethra, and bladder. Several reports have shown a possible relationship between ophthalmologic adverse effects and the use of alpha-1-receptor medicines, including tamsulosin. This descriptive review evaluates the intraoperative floppy iris syndrome (IFIS) associated with tamsulosin. A search of the Medline and PubMed databases was conducted to identify control trials, case reports, and observational examinations published in English. The publication dates were restricted (January 1, 2000, to January 1, 2020). Keywords (tamsulosin, alpha-blocker, ocular, eye, adverse reaction, and IFIS) were used in the searches. The searches identified 66 studies including in vitro or in vivo studies, trials, and observational studies. Twenty-two (33.33%) studies were articles citing tamsulosin and IFIS as having confirmed potential risk to ocular safety. The results of this review, including a comprehensive summary of published research on tamsulosin use in different populations, have identified several articles showing associations between tamsulosin and IFIS that merit further investigation. Suspending of potential causative pharmacological treatment of IFIS before ocular surgery including tamsulosin, proper identification of at-risk patients, preoperative prophylaxis treatments, and surgical technique modifications clearly can mitigate the anticipated risk of IFIS induced by tamsulosin.

Intraoperative floppy iris syndrome: an updated review of literature.

Intraoperative Floppy iris syndrome(IFIS) remains a challenge for surgeons during phacoemulsification. Initially, it was related to the use of tamsulosin, an alpha adrenergic receptor blocker used in benign prostatic hyperplasia. Subsequently, other alpha adrenergic receptor such as alfuzosin, terazosin and doxazosin alongwith different other class of medications and systemic risk factors were identified. Other class of medications includes 5-alpha reductase inhibitor, angiotensin receptor antagonist, benzodiazepines, antipsychotics and antidepressants. Other risk factors include increasing age, male gender, diabetes, hypertension and decreased preoperative pupil diameter. It is very important for surgeons to identify these risk factors preoperatively and take appropriate preoperative and intraoperative measures to tackle the dreaded complications of IFIS. Sometimes, it is important for an ophthalmologist to work in cooperation with physician and urologist to minimize the complications. In conclusion, awareness of the risk factors associated with IFIS, their detailed preoperative assessment and intraoperative measures and surgical intervention is crucial in addressing IFIS. Lack of awareness can turn a routine, uneventful surgery into one with significant visual morbidity.

Preoperative ocular characteristics predicting the development of intraoperative floppy iris syndrome regardless of alpha-antagonist exposure status.

PURPOSE: To assess structural risk factors for intraoperative floppy iris syndrome (IFIS) available on preoperative examination before cataract surgery. METHODS: In this retrospective study, medical records of patients who underwent cataract surgery in Shamir Medical Center, between July and September 2019, were reviewed. Patients younger than 50 years, with preexisting ocular conditions affecting the pupillary size or anterior chamber depth (ACD), and combined procedures were excluded. Association of IFIS with preoperative ocular parameters was tested using uni- and multivariant analyses. RESULTS: Overall, 394 eyes of 394 patients were included. The mean age was 72.48 ± 8.63 years, and 58.4% were female. IFIS occurred in 18 eyes (4.6%), seven (38.89%) of which had been previously treated with alpha-antagonists. Patients in the IFIS group were significantly older compared with those in the non-IFIS group (78.1 ± 6.7 vs. 72.2 ± 8.6 years, P = 0.005), with no significant gender difference. The mydriatic pupil diameter was significantly smaller in the IFIS group (5.73 ± 1.16 vs. 6.97 ± 1.03 mm, P < 0.001), and the lens thickness (LT) was larger (4.93 ± 0.42 vs. 4.49 ± 0.42 mm, P = 0.001). ACD was inversely correlated with LT (r = - 0.613, P < 0.001) and positively correlated with pupil diameter (r = 0.252, P < 0.001). On univariate analysis, ACD was significantly shallower in the IFIS group (2.88 ± 0.49 vs. 3.14 ± 0.39 mm, P = 0.008). In multivariant analysis controlling for alpha-antagonist use, both LT and mydriatic pupil diameter remained significantly predictive of IFIS (LT: OR 9.9, 95%CI 1.9-49, P = 0.005; pupil diameter OR 0.427, 95%CI 0.26-0.69, P < 0.001). CONCLUSIONS: Increased LT and decreased mydriatic pupil diameter were associated with increased IFIS risk regardless of alpha-antagonist treatment status.

[Unusual anisocoria]. / Anisokorie mal anders.

A 53-year-old female patient presented with increased light sensitivity 3 weeks after oral intake of moxifloxacin tablets for an upper respiratory tract infection. The symptoms were anisocoria and the pupils did not react to light or accommodation. The examination of the anterior segment of the eye revealed extensive bilateral iris transillumination defects (ITD). We diagnosed a bilateral acute iris transillumination (BAIT) syndrome. The BAIT syndrome is a rare disorder associated with massive depigmentation of the iris and atrophy of the iris musculature. A risk factor for BAIT syndrome seems to be the oral intake of antibiotics, in particular moxifloxacin after an upper respiratory tract infection but cases of spontaneous occurrence have also been described. Middle-aged women are particularly affected. The exact cause of BAIT syndrome is so far unknown but a potential mechanism involves the concentration of the antibiotic in the vitreous body. Differential diagnoses include other causes for ITD, such as albinism, intraocular inflammation, pseudoexfoliation syndrome and pigment dispersion syndrome. To date there is no specific treatment for BAIT syndrome. Possible complications include increased light sensitivity and post-BAIT glaucoma. Knowledge of the rare BAIT syndrome can be useful in the clinical routine for the differential diagnostic classification of an anisocoria and can possibly contribute to avoidance of unnecessary diagnostic steps.

Bilateral acute depigmentation of the iris in a child following exposure to insecticide spray.

Bilateral acute depigmentation of the iris (BADI) is a rare disease of unkown etiology. We report a case of BADI in a 10-year-old child after accidental exposure to a herbal insecticide. Spontaneous iris repigmentation was observed during the follow-up period.

The Eye Color Experiment: From Berlin to Auschwitz and Back.

BACKGROUND: In an effort to alter eye color during World War II, devout Nazi researcher Karin Magnussen had adrenaline eye drops administered to inmates at the concentration camp Auschwitz-Birkenau. A Sinti family, with a high prevalence of heterochromia iridis, was forced to participate in this study. Members of this family, as well as other victims, were later killed and had their eyes enucleated and sent to Magnussen for examination. Magnussen articulated the findings of these events in a manuscript that has never been published. The author is the first ophthalmologist to review this manuscript. The generation who experienced the atrocities of World War II will soon be gone and awareness of what happened during this tragic chapter of world history is fading. OBJECTIVES: To describe these events to raise awareness among future generations. METHODS: A literature review and archival search was conducted. RESULTS: Magnussen's research was based on an animal study published in 1937. For Magnussen's study, adrenaline drops were administered to inmates, including a 12-year-old girl from the Sinti family. As there was a reported case of deaf-mutism within the family, Waardenburg syndrome seems to be the most plausible explanation for this family's heritable heterochromia. CONCLUSIONS: The effort to change eye color was doomed to fail from the beginning because there was a probable diagnosis of Waardenburg syndrome. Extinction of humans for ophthalmological research is an insane act beyond imagination. For the sake of these victims, and for the generations who still feel their pain, it is imperative to tell their stories.

Modelling floppy iris syndrome and the impact of pupil size and ring devices on iris displacement.

INTRODUCTION: The aim of this paper was to further develop a previously described finite element model which equates clinical iris billowing movements with mechanical buckling behaviour, simulating floppy iris syndrome. We wished to evaluate the impact of pupil dilation and mechanical devices on normal iris and floppy iris models. METHODS: Theoretical mathematical modelling and computer simulations were used to assess billowing/buckling patterns of the iris under loading pressures for the undilated and dilated normal iris, the undilated and dilated floppy iris, and additionally with a mechanical ring device. RESULTS: For the normal iris, billowing/buckling occurred at a critical pressure of 19.92 mmHg for 5 mm pupil size, which increased to 28.00 mmHg (40.56%) with a 7 mm pupil. The Malyugin ring device significantly increased critical initiating buckling pressures in the normal iris scenario, to 34.58 mmHg (73.59%) for 7 mm ring with boundary conditions I (BC I) and 34.51 mmHg (73.24%) with BC II. For the most floppy iris modelling (40% degradation), initiating buckling value was 18.04 mmHg (-9.44%), which increased to 28.39 mmHg (42.52%) with the 7 mm ring. These results were much greater than for normal undilated iris without restrictive mechanical expansion (19.92 mmHg). CONCLUSION: This simulation demonstrates that pupil expansion devices inhibit iris billowing even in the setting of floppy iris syndrome. Our work also provides a model to further investigate the impact of pupil size or pharmacological interventions on anterior segment conditions affected by iris position.