⚡ Key Takeaways
- Never push iris back in directly — change the pressure gradient instead
- Iris prolapse during hydrodissection happens because fluid pushes the lens forward while viscoelastic leaks out
- Release BSS from behind the lens and reduce AC pressure to resolve prolapse
- Minimize side-to-side phaco probe movements — let the chopper feed pieces to you
- Reverse pupillary block can actually help by dilating the pupil during I/A
Watch the Full Video
The Challenge: Small Pupil + Floppy Iris
Floppy iris syndrome is one of the more nerve-wracking situations in cataract surgery. The pupil barely dilates, the iris billows and prolapses at every opportunity, and your margin for error is razor-thin. This annotated case walks through the entire procedure with practical tips for each critical moment.
Intracameral Mydriasis
When topical drops don't achieve adequate dilation, intracameral mydriasis is your next step. A mixture of tropicamide, phenylephrine, and lidocaine is injected directly into the anterior chamber from both sides. Even with this, you may only achieve modest dilation — but in floppy iris cases, the pupil often serves as a convenient stencil for your capsulorhexis size.
Iris Prolapse During Hydrodissection
This is the first major danger point. Here's why it happens:
- You inject BSS behind the lens → the lens moves forward
- The injection pressure simultaneously pushes viscoelastic out through the wound
- The pressure gradient now points outward → the floppy iris follows
How to Fix It (Without Making Holes)
The instinct is to push the iris back in. Don't. This will just poke holes in the iris. Instead:
- Push on the lens to release trapped BSS from behind it
- Release viscoelastic and aqueous from the anterior chamber to lower internal pressure
- The iris will retract on its own once the pressure gradient reverses
- Refill with viscoelastic in front of the wound before re-entering
Phaco Tips for Floppy Iris
During phacoemulsification, floppy irises love to migrate toward your phaco tip. The key principle: minimize lateral and anteroposterior movements of your phaco probe. Stay within the pupillary aperture and let your chopper do the work — feed nuclear pieces to the phaco tip rather than chasing them.
Iris Prolapse at the Paracentesis
You may notice the pupil becoming peaked — pointing toward a paracentesis. This isn't vitreous prolapse; it's iris prolapse into the side port. Again, don't push the iris back directly. Instead:
- Lower the AC pressure by releasing aqueous
- Approach the prolapsed iris at an angle, sliding past it
- Use the blunt side of your instrument to sweep it back in
Reverse Pupillary Block — Friend, Not Foe
During irrigation/aspiration, you may notice the pupil suddenly becomes much larger. This is reverse pupillary block: the irrigation pressure pushes the floppy iris against the capsule, trapping fluid in the anterior chamber and deepening it. The result? A paradoxically larger pupil.
In small pupil cases, this is actually beneficial — it gives you better visualization during cortex removal. In other scenarios (e.g., very deep AC), you can release it by lifting the iris with an instrument.
Managing Chemosis
As with many longer cases, chemosis (conjunctival ballooning) can develop. Use a chopper to hook and open the conjunctiva at the limbus, releasing the trapped fluid early. This prevents progressive obstruction of your surgical field.
Frequently Asked Questions
What causes floppy iris syndrome?
Intraoperative Floppy Iris Syndrome (IFIS) is most commonly associated with the use of alpha-1 adrenergic antagonists, particularly tamsulosin (Flomax). Even if the medication was stopped years ago, IFIS can still occur. Always ask about current and past alpha-blocker use.
When should you use iris hooks or a Malyugin ring?
If the pupil is extremely small (< 4mm) and intracameral mydriatics don't help, mechanical devices like iris hooks or a Malyugin ring are indicated. In this case, intracameral drops provided enough dilation to proceed without them.
How do you prevent iris prolapse during hydrodissection?
Inject slowly, keep the cannula tip visible, and avoid over-pressurizing the capsular bag. If ballooning occurs, immediately release BSS by decompressing the lens before the iris prolapses. Keeping the wound well-sealed with viscoelastic also helps.
Is reverse pupillary block dangerous?
Generally no. It's a transient intraoperative phenomenon. In floppy iris cases it can actually help by dilating the pupil. If problematic (very deep AC, difficulty seeing), simply lift the iris edge with an instrument to release the block.
Want to learn more surgical techniques?
Check out the Clinical Skills in Glaucoma course or subscribe to the YouTube channel for free annotated surgical cases.