October 2014

 

COVER FEATURE

 

Complex cataract cases

Cataract surgery and the small pupil


by Michelle Dalton EyeWorld Contributing Writer

 
 

Couple small pupils with patients who want toric lenses and its important to have a low threshold to use a pupillary expansion device, especially where you need to see the marks for alignment.

Preeya K. Gupta, MD

 
Small pupils

Patient with pseudoexfoliation syndrome and small pupils

Late subluxation of IOL Late subluxation of IOL in an eye with pseudoexfoliation syndrome Source (all): Bonnie An Henderson, MD

Small pupil article summary

Regardless of the cause, performing cataract surgery on patients with small pupils is no easy task

One of the more complicated variables when planning for cataract surgery is small pupils in a patient. The causes are widespread, and often they require the use of hooks or rings to prevent the pupil from coming down intraoperatively, and lens fragments may be more difficult to see. But by understanding the causes and how to manipulate the iris, surgeons can be confident of successful postoperative outcomes, experts say.

For example, if the small pupil is a result of pseudoexfoliation, once it is stretched the iris usually will not rebound back to its original small state, said Laura K. Green, MD, residency program director, Krieger Eye Institute, Baltimore, and in private practice at Sinai Physician Partners, Baltimore. If the cause is uveitis, after pupil stretching the pupil may not be perfectly round and regular ever again, she said.

Michael Summerfield, MD, founder, Washington Eye Institute, Washington, D.C., and residency program director, Georgetown University/Washington Hospital Center, recommends using pupil expanders in all small pupil cases.

Over time, Ive become a little more liberal with the use of the Malyugin ring [MicroSurgical Technology, Redmond, Wash.] because it doesnt add a lot of case time, he said, but in cases of potential intraoperative floppy iris syndrome (IFIS) or in rare cases when the iris prolapses to the main phaco incision, he will opt for iris hooks instead.

Dr. Green is comfortable operating through a 5 mm pupil if that enables me to perform the surgery without the need for any hooks. She noted hooks could be used without permanently stretching the pupil.

Toric IOLs and small pupils

Couple small pupils with patients who want toric lenses and its important to have a low threshold to use a pupillary expansion device, especially where you need to see the marks for alignment, said Preeya K. Gupta, MD, assistant professor of ophthalmology, Duke University School of Medicine, and clinical director, Duke Eye Center at Page Road, Durham, N.C.

Visualization and alignment are by far the most difficult issues when placing a toric lens in a patient with small pupils, Dr. Summerfield said.

One potential problem is when youre removing the viscosurgical device (OVD) from the bag, he said. Sometimes the lens needs to be pushed aside and that may result in the lens spinning. My advice is to check lens position, remove the OVD, and then recheck once youve finished. While Dr. Green will use toric lenses in patients with IFIS or diabetes, I do not feel comfortable using them in patients with scarring conditions of the pupil. Centration is not a considerable factor as long as the capsule is intact, she said. The IOL itself will still work from an optic perspective whether the pupil is widely opened, whether its fixed at a particular diameter, or whether its completely normal, she said, but cautioned that managing patient expectations is essential.

After implanting a toric lens in these patients, Dr. Gupta removes the OVD from behind the lens and rotates it to within about 2030 degrees of where my final axis of placement is going to be, removes more OVD, and rotates the lens a bit closer to the final axis. When the lens is within 5 degrees, I will take out the Malyugin ring and fine-tune the IOL placement, she said. The pupil will often stay a little bit stretched after you take the Malyugin ring out. She advised retaining some of the OVD in the chamber when removing the ring so theres less damage to the endothelium. But if the pupil does come down or if visualization is difficult, she takes a Kuglen hook (Katena, Denville, N.J.) and essentially tents the iris far enough into the periphery so that I can see the exact alignment of the lens. She puts some gentle downward pressure on the lens so it doesnt rotate as she removes the remaining OVD.

Alpha-blockers and cataract surgery

Alpha-blockersand tamsulosin in particularare well-known causes of IFIS. None of the physicians recommended that patients stop their medication use before cataract surgery simply because the patient can run into bladder issues during the case if theyre on tamsulosin for benign prostatic hyperplasia, Dr. Summerfield said. Discontinuing the medication could make the condition worse, and its not going to help with the floppy iris. Because there are numerous drugs that can treat prostate disorders, Dr. Summerfield has broadened his questioning to ask if patients have any prostate hypertrophy or if they have any bladder issues at all, for women. Dr. Gupta cited a case recently where a woman on finasteride and doxazosin developed IFIS; although these drugs are often used as prostate medications, the patient was using it to treat alopecia and hypertension. Some blood pressure medications are in the same alpha-blocker family as tamsulosin, and Dr. Gupta expects more women will develop IFIS than may be expected.

By asking open-ended questions about any drug use for prostate issues, youre able to discover that patients may have a history of using tamsulosin or related medications in the past. Even saw palmetto, with enough chronic use, can cause significant IFIS, Dr. Green said. Tamsulosin is the worst offender, but alfuzosin can wreak havoc as well. Dr. Gupta is particularly wary when patients have light-colored irises and use alpha-blockers. In these cases, I always use Shugarcaine (lidocaine/epinephrine solution) to manage the potential complications better, she said.

Dr. Green has been using intracameral epinephrine for all known cases with a history of tamsulosin use, even if that use was several years prior to the cataract surgery. I think its very important to identify these cases. If epinephrine is insufficient, shell move to using iris retractors.

Hidden lens fragments

Retained lens fragments can be very easily overlooked. Surgeons can be distracted by the small pupil and lens removal; our train of thought concentrates on what we perceive to be the most difficult aspect of the surgery, Dr. Gupta said. Spend extra time vacuuming with a push/pull technique and have a high suspicion for hiding fragments, she recommended.

The key, Dr. Green said, is observing the anterior chamber with the final irrigation and aspiration (I/A) after implantation of the IOL. Carefully irrigate around the anterior chamber; I certainly take more time and more effort than I normally would in a standard case. Dr. Summerfield advised surgeons to clean up as you go along, even if surgeons are using a femtosecond laser for some aspects of the surgery. Check the wound, hydrate through the wound at the end of the case, and double check retained fragments arent there, he said. If hes concerned about lens fragments, hell take a cannula with just balanced salt solution and flush through the main incision, let it all circulate through the eye, and whirlpool in there to flush out anything that may be stuck. Dr. Green will intentionally use Miochol-E [acetylcholine, Novartis, Basel, Switzerland] to gently irrigate small fragments around into the angle to aid me in flushing out any additional nuclear fragments. Look at the actual configuration of the iris, Dr. Gupta said. If you use a chop technique where youre fractionating the lens into a lot of small pieces or if the cataract is dense, sometimes the phaco machine will shatter the small-to-medium-sized pieces. I have a low threshold to look under the iris, while my irrigation handpiece is in the eye, to make sure nothings trapped. By tenting the iris with the irrigation handpiece, while you have the irrigation on but not the aspiration, you can use the I/A tip to lift up the iris enough to clear a fragment. That will swirl the fluid around in the anterior chamber to flush that space where a lens fragment could potentially be retained. Shes particularly careful with any cataract grade 3 or higher.

Irrigating a little longer than normal will help you discover those hiding places, Dr. Green said.

Editors note: The physicians have no financial interests related to their comments.

Contact information

Green
: largreen@lifebridgehealth.org
Gupta: preeya.gupta@duke.edu
Summerfield: michaelsummerfield@gmail.com


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