What Is Intraoperative Floppy Iris Syndrome?

Intraoperative floppy iris syndrome (IFIS) describes a floppiness of the iris (the colored part of the eye) and a smaller shape in the pupil (the black center of the eye) during cataract surgery. This weakening happens in some people using certain medications, including common medicines prescribed for benign prostate hyperplasia (an enlarged prostate). IFIS is not common but can cause complications, some of which can affect your vision after surgery.

A dilated eye, achieved through special drops, will help an eye healthcare professional (ophthalmologist) best perform cataract surgery. Floppy iris syndrome has the opposite effect and constricts the pupil (making it smaller) and weakens the shape of the iris.

This article will address the causes, symptoms, diagnosis, and treatment of intraoperative floppy iris syndrome.

Healthcare provider preparing patient for surgery.

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Intraoperative Floppy Iris Syndrome Causes

The cause of intraoperative floppy iris syndrome is related to the use of certain types of medications. The most common medication that causes IFIS is Flomax (tamsulosin). This may be prescribed to treat benign prostatic hyperplasia or an enlarged prostate. Drugs like Flomax help relax the prostate and improve the emptying of the bladder when urinating. It also can relax the iris muscles, which may lead to floppy iris syndrome.

Benign prostatic hyperplasia becomes more common with age, as does the need for cataract removal.

Other medications that may cause IFIS include:

Other medications also may be associated with intraoperative floppy iris syndrome, although tamsulosin is the medication reported most often. Medication categories associated with IFIS include:

  • Alpha-1 antagonists (also called alpha-1 blockers), particularly the alpha-1-A subtype. The alpha 1-antagonists include tamsulosin and other medications listed above that end in "sin." Although men are prescribed this type of medication for an enlarged prostate, they are sometimes prescribed to women for urinary problems or kidney stones.
  • Angiotensin II receptor inhibitors, such as Cozaar (losartan), are used for high blood pressure and heart failure.
  • Antipsychotic medications, such as Abilify (aripiprazole) and Thorazine (chlorpromazine), are used to help control psychotic symptoms.
  • Benzodiazepines help with mental health disorders such as anxiety.


The symptoms of IFIS occur during cataract surgery. With IFIS, the eye does not remain dilated well or as long as it usually would. This can lead to:

  • Iris billowing, meaning that the iris appears to move outward.
  • Pupil constriction is when the pupil, the black center of the eye, is constricted and becomes smaller.
  • Iris prolapse refers to tissue from the iris appearing in an injury within the cornea (the dome-shaped part of the eye).

These symptoms make cataract surgery more challenging and may lead to other complications.

Risk Factors for IFIS

  • Using alpha-1 antagonist medications, such as Flomax (tamsulosin)
  • Using other medications associated with IFIS, such as angiotensin II receptor inhibitors
  • Being older
  • Having high blood pressure. However, researchers debate whether high blood pressure is an actual risk factor for IFIS or if some medicines for high blood pressure raise the risk.
  • Having a smaller dilated pupil size. A dilated pupil of 6.5 millimeters (mm) or smaller, along with tamsulosin risk, is associated with the occurrence of IFIS.


IFIS is diagnosed if its associated symptoms appear during cataract surgery.

Since the first recognition of IFIS was reported in 2005, ophthalmologists who perform cataract surgery have become more aware of the risk for IFIS created by certain medications. They will work with individuals regarding their medication use to reduce the chance of IFIS.

Preoperative Evaluation and Preventive Measures

To help curb the risk for intraoperative floppy iris syndrome and other problems, optometrists or ophthalmologists will ask people to share a list of all medications they use before cataract surgery. They will discuss medication management as needed with healthcare providers prescribing medications that may increase the risk for IFIS. This may include primary care healthcare providers or urologists, for example.

Guidelines published in 2014 by the American Academy of Ophthalmology and the American Society for Cataract and Refractive Surgery note that people with cataracts causing visual symptoms may want to consider cataract surgery before they start alpha 1-antagonist drugs such as tamsulosin. They also note that those with cataracts with benign prostate hyperplasia may want to consider a non-selective alpha-1 antagonist as their initial treatment.

If a person is already using a drug such as tamsulosin, an ophthalmologist may advise stopping the drug for four to seven days before cataract surgery. This may prevent some cases of intraoperative floppy iris syndrome but not all.

Never stop using medications without first discussing them with your healthcare providers.

Some eye surgeons may try to use certain medications before surgery in at-risk people. These drugs may include:

  • Topical atropine with or without epinephrine. This combination appears to lower the occurrence of IFIS in higher-risk people.
  • Topical non-steroidal anti-inflammatory drugs like Toradol (ketorolac). This may help promote pupil dilation during surgery.

Intraoperative Preventive Measures

If cataract surgery must be performed on an individual with a higher risk for IFIS, there are a few preventive measures that optometrists and ophthalmologists can make:

  1. Assign the surgery to the most experienced eye surgeon on the surgical team.
  2. Slightly change some steps associated with the cataract surgery technique. For instance, the most common surgical technique used for cataract surgery in the United States is called phacoemulsification. This involves the use of fluid provided by a special machine to facilitate cataract removal. For high-risk people, the eye surgeon can use lower-flow, smaller amounts of fluid to help control how the iris behaves.
  3. Using anterior elongated cornea incisions. This may lower the severity of IFIS in dilated pupils that are no less than 4.5 millimeters.


If floppy iris syndrome occurs during cataract surgery, the eye surgeon will take specific actions to try and avoid further problems. These may include:

  • The use of a device called a pupil expansion ring. This helps to maintain a larger pupil size during surgery.
  • The use of an iris retractor. This helps to gently stretch the iris during surgery.
  • Certain types of ophthalmic viscosurgical devices are solutions used in the eye during surgery. For example, the right ophthalmic viscosurgical device may help to keep the pupil dilated. Another option to maintain pupil dilation is using epinephrine and phenylephrine injected into the eye.
  • To help prevent iris prolapse, the eye surgeon may try to release fluid from behind the iris during surgery, use a more ophthalmic viscosurgical device solution in the front of the iris, or inject certain drugs that help to dilate the eye.


Intraoperative floppy iris syndrome may cause several complications. Some of these can be resolved during cataract surgery. Others require longer-term management. This is why ophthalmologists will ask questions about medication use to lower the risk for IFIS before surgery.

Complications associated with IFIS include:

  • Bleeding inside the eye is also called hyphema.
  • Cystoid macular edema or swelling of the macula, located in the center of the light-sensitive tissue in the back of the eye called the retina. This may cause some decreased vision.
  • Endophthalmitis, which is a serious infection in the eye that may lead to vision loss
  • Injury to the iris
  • Iridodialysis, or a separation of the iris from the ciliary body
  • Permanent distortion of the pupil with glare
  • Photophobia, or sensitivity to bright light
  • Posterior capsule rupture, which affects the thin membrane around the natural lens of the eye
  • Retina detachment, which is when the retina detaches from its placement in the back of the eye


Intraoperative floppy iris syndrome describes a weakening in the shape of the iris during cataract surgery. This weakening happens in some people using certain medications, including common ones prescribed for benign prostate hyperplasia. In addition, symptoms of IFIS occur during cataract surgery, including the pupil becoming smaller and the iris appearing to move outward.

Before cataract surgery, optometrists or ophthalmologists will ask about medications used to determine if they may increase the risk for IFIS. Sometimes, they will coordinate medication use with other prescribing healthcare providers to lower the chance of floppy iris syndrome occurring. Eye surgeons also may make preventive moves to cut down IFIS risk. If IFIS occurs, the ophthalmologist can manage it, but there is still a risk of further complications.

A Word From Verywell

Medications that you use for problems elsewhere in the body still have the potential to affect your eyes. If your optometrist or ophthalmologist has said that you need cataract surgery, provide them with a complete list of any medications you use, including herbal supplements. Discuss medication use as needed to reduce the risk for IFIS, and follow any guidance to stop medications that may increase the chance of intraoperative floppy iris syndrome occurring. However, do not stop any medications without getting approval from your healthcare providers.

Frequently Asked Questions

  • How can intraoperative floppy iris be prevented?

    Intraoperative floppy iris cannot always be prevented, but the risk can be reduced by not using medications that may cause it. This includes certain alpha-1 antagonist medications commonly prescribed for benign prostate hyperplasia, or enlarged prostate. Sharing your medications with your ophthalmologist or optometrist before cataract surgery can help them decide which medications may raise your risk.

  • What drugs cause floppy iris syndrome?

    Tamsulosin is the drug most commonly associated with floppy iris syndrome, along with alfuzosin, doxazosin, and some other drugs considered alpha-1 antagonists that also may increase the risk. Donepezil and duloxetine also may cause floppy iris syndrome. Drugs considered benzodiazepines, angiotensin II receptor inhibitors, and antipsychotic medications are also associated with floppy iris syndrome. In addition, saw palmetto, an herbal treatment for benign prostate hyperplasia, may raise the risk for IFIS.

  • Does floppy iris syndrome affect vision?

    Floppy iris syndrome can affect vision if certain complications occur. Complications that may result from floppy iris syndrome that affects vision include cystoid macular edema, retina detachment, and an infection called endophthalmitis. These will require management after cataract surgery.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Vanessa Caceres
Vanessa Caceres is a nationally published health journalist with over 15 years of experience covering medical topics including eye health, cardiology, and more.