⚡ Key Takeaways
- The McAhmed technique uses cautery to reshape the iris and narrow a dilated pupil
- Thermal energy causes iris tissue to contract and shorten, pulling the pupil smaller
- This is useful for traumatic mydriasis, iris defects, or persistent surgical mydriasis
- The technique is relatively simple and avoids the need for complex iris suturing
- Results may relax slightly over time — slight overcorrection is often desirable
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When Is Pupilloplasty Needed?
A permanently dilated or irregular pupil causes significant symptoms: glare, photophobia, halos, and cosmetic concerns. Causes include trauma, previous surgery (especially if the iris sphincter was damaged), or conditions like iridodialysis. Pupilloplasty aims to restore a more functional, round pupil.
The McAhmed Technique
Named after Ike Ahmed, this approach uses bipolar or monopolar cautery applied to the iris stroma. The thermal energy causes collagen contraction, shortening the iris tissue and pulling the pupil smaller — similar to how heat shrinks plastic.
Technique Steps
- Fill the anterior chamber with viscoelastic
- Introduce the cautery tip through a paracentesis
- Apply gentle cautery to the iris stroma at the area you want to contract
- Work circumferentially around the pupil as needed
- Assess pupil size and shape after each application
- Aim for slight overcorrection (the pupil will relax somewhat)
Tips and Pearls
- Start conservatively — you can always add more cautery, but you can't undo it
- Keep the AC filled with viscoelastic for protection and space
- The iris will swell initially — the true result is visible after inflammation resolves
- Combine with other procedures (IOL exchange, iris prosthesis) when needed
Frequently Asked Questions
Is the McAhmed technique permanent?
The cautery effect is permanent, but iris tissue can relax slightly over weeks to months. That's why slight overcorrection during the procedure is recommended. Major regression is uncommon.
Can this be combined with cataract surgery?
Yes. Pupilloplasty can be performed at the end of cataract surgery if the pupil remains excessively dilated. This is especially useful in cases where iris hooks or a Malyugin ring were needed.
What are the risks?
Risks include inflammation, iris atrophy, irregular pupil shape, and the need for repeat procedure. However, serious complications are rare when the technique is performed carefully.
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