May 2020

CATARACT

Skill Focus
Placing hooks, rings, and things


by Maxine Lipner Senior Contributing Writer


A capsular tension ring is inserted with three clock hours of traumatic zonular loss. Because the remaining zonules were intact, the ring provided sufficient support for the capsule and IOL.

In this case of nasal traumatic zonular loss, three Mackool hooks were inserted to support the lens during phacoemulsification. After all lens material was removed, a CTR was inserted, and an Ahmed segment was sutured to the sclera to provide good long-term capsular support.
Source (all): Douglas Koch, MD

 

Hooks and expansion rings can be an ophthalmologist’s partner when performing phacoemulsification.
Douglas Koch, MD, relies on pupillary expansion devices when there’s a risk of inadequate visualization or the potential for iris trauma (via accidental engagement with the phaco tip or through some other manipulation). “When I’m doing phacoemulsification, if the iris is not particularly floppy, I’m comfortable working through pupils as small as 4 mm,” Dr. Koch said. “When I’m doing an IOL exchange, I may need to visualize the haptics and their location in the capsular fornix. That requires a pupil size that’s 8 mm or larger, so I may need to use iris hooks in the area of the haptics in order to get visualization for that.”
In the case of a subluxated lens and capsule, Dr. Koch usually performs scleral fixation of the IOL and capsule. With this procedure, it’s important to see where the haptics are, which may mean enlarging the pupil to 7 mm.
Thomas Oetting, MD, relies on pupil expansion devices when a patient is on an alpha blocker or has a past history of uveitis. If the pupil is small because drops weren’t given in time, he said he may proceed with the aid of some epinephrine and insert a device later, if needed.

Considering pupil devices

When deciding between pupil expansion devices or iris hooks, Dr. Oetting considers other
hardware he might need inside the eye, such
as a capsular tension segment or an especially big lens. “I think iris hooks are good if you want to be 100% sure there’s no prolapse,” Dr. Oetting said, adding that for most patients with a reasonable chamber depth, he finds it quicker to use a Malyugin ring.
Dr. Koch uses a pupil expansion ring if the iris is not fibrotic. “Whenever I see the pupil is too small and I need to enlarge it to 6 mm and I don’t see a lot of fibrosis, I use the Malyugin ring,” Dr. Koch said. However, he avoids these rings in cases where there is a lot of iris fibrosis because he’s concerned it could lead to asymmetrical tears. He’ll instead rely on iris hooks so he can titrate the amount that he opens. Dr. Koch said he’ll also use iris hooks when he wants to better visualize one section of the eye.
If the iris is floppy due to IFIS, however, he injects 1:5,000 epinephrine at the beginning of the case. This gives him enough stability and adequate pupil size to complete the case, sometimes in conjunction with reinjecting dispersive OVD.
Dr. Oetting uses intracameral epinephrine on every patient. “The truth of the matter with IFIS is patients aren’t sure if they are on an alpha blocker,” he said, adding you have to assume they’re taking tamsulosin.
Because of his “paranoia” about this, Dr. Oetting also avoids mechanically stretching the pupil because it can make IFIS worse. Dr. Koch finds that mechanical stretching tends to create asymmetric tears and, likewise, he has stopped doing this.
For patients with small pupils, Dr. Oetting tends to use the Malyugin ring, which doesn’t require any additional incisions that can affect the fluid dynamics of the chamber. He reserves iris hooks for cases with narrow angles with posterior synechiae. “In that situation, I’ll simultaneously lyse the synechiae and place the iris hooks,” Dr. Oetting said.

Stabilizing possibilities

All hooks are not the same. For stabilizing the bag, Dr. Oetting finds capsular tension hooks, sometimes known as capsule retractors, are useful when zonules are weak and there is concern that they may not hold up to nuclear fracture. “The idea is you’re stabilizing the bag while you’re doing nucleus removal,” Dr. Oetting said. Typically, he likes to place these retractors before nuclear fracture. Once the bag is empty, he places a capsule tension ring and assesses whether he needs another device, such as a sutured capsular tension segment.
Whenever Dr. Koch thinks the capsule is so weak that the lens will subluxate posteriorly, he relies on either Mackool hooks (FCI Ophthalmics) or MicroSurgical Technology (MST) capsular hooks. With the MST hooks, he prefers the newer model that has a smaller opening that prevents it from getting entangled with the capsular tension ring. He also finds the Mackool hooks are easy to use. “They’re placed as early as I need to assure good stability,” he said. “The other ‘device’ that I use when I’m removing the nucleus is a lot of dispersive OVD, Healon EndoCoat [3% sodium hyaluronate, Johnson & Johnson Vision]. Injecting this into the bag provides a great cushion and prevents the bag from collapsing into the phaco tip.” If needed, he may also insert a capsule tension ring for additional support during phacoemulsification. In these instances, a scleral-fixated Ahmed segment (or two) is almost always used to assume long-term capsular stability.
Capsule tension rings can make cortex removal more challenging, so Dr. Koch recommends viscodissecting away from the capsule before trying to aspirate it in order to minimize traction on the capsule.

About the doctors

Douglas Koch, MD
Professor and Allen, Mosbacher, and Law Chair in Ophthalmology
Cullen Eye Institute
Baylor College of Medicine
Houston, Texas

Thomas Oetting, MD
Professor of ophthalmology
University of Iowa
Iowa City, Iowa


Relevant disclosures

Koch
: Alcon, Johnson & Johnson Vision
Oetting: None

Contact

Koch
: dkoch@bcm.edu
Oetting: thomas-oetting@uiowa.edu
Placing hooks, rings, and things Placing hooks, rings, and things
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