Surgical options with narrow pupil and floppy iris syndrome

The main reasons for encountering small pupils during cataract surgery are well established. They include cases with pseudoexfoliation syndrome, uveitis, posterior synechiae. Campbell have described the intraoperative floppy-iris syndrome (IFIS) associated with systemic administration of the α-1A antagonist tamsulosin (Flomax). The intraoperative diagnostic triad of this symptom is fluttering and billowing of the iris stroma, a tendency to iris prolapse through the main and/or sideport incisions, and progressive constriction of the pupil during surgery. Unfortunately, current pharmacological approaches for managing a small pupil during cataract surgery have limitations. Patients whose pupils respond poorly to the pharmacological protocols present significant challenges. The most significant problems for the surgeon are decreased visualization, iris trauma due to incarceration into the wound, iris chafing, pupillary margin damage by the phaco needle and others. All of these problems compromise the surgery and increase the risk for complications. There is no general recommendation or solution to the small pupil problem because the strategies for pupil enlargement greatly depend on surgeon skill and preferences, as well as on intraoperative situation. Most surgeons decide to dilate the pupil mechanically at the time of the surgery if pharmacological agents fail. There are four main mechanical dilation methods: synechiolysis, mechanical stretching, cutting of the iris tissue and iris retraction. Most of the surgical maneuvers for enlarging the pupil and preventing its intraoperative constriction are not safe enough. They can lead to an increased risk of iris sphincter tear, bleeding, iris damage, posterior capsule tears and loss of the vitreous body. But not all patients require pupil dilation protocols with the mechanical devices. If the iris tissue is rigid and the diameter of the pupil is about 4.0mm to 4.5mm, an experienced surgeon, especially when using different modifications of phaco-chop technique, can effectively remove cataract and avoid significant trauma of the anterior segment tissues. Conversely, if the iris tissue is flaccid and atonic, even if the pupil is reasonably wide, such as with IFIS, there is a significant risk of complications. The postoperative complications can include an atonic pupil of irregular shape with poor cosmetic result and photophobia. One of the newest devices to enlarge the small pupil during phacoemulsification is the Malyugin Ring utilizing the scroll principle of catching the papillary margin (Figure 1).

Fig.1 The malyugin Ring.

Malyugin Ring System consisting of a sterile single-use inserter and holder. The dark blue Ring is located inside the holder and can be visualized through its upper portion. It can be used with conventional SICS (Small Incision Cataract Surgery) as well as MICS (Microincision Cataract Surgery). The newest version – the 7.0-mm Malyugin Ring produced by MST provides a larger pupil diameter compared to the conventional 6.25-mm ring. 7.0 Ring handles IFIS cases more easily. When the iris is very flaccid but the pupil is wide, the 6.25mm Ring can be dislocated at one or two scrolls and would need to be repositioned. This does not happen with the larger-size Ring. Advantages of the Malyugin Ring: Adequate transpupillary access to the lens is essential for the success of phaco procedures. We believe that our irisretraction technique with the Malyugin Ring System has at least six distinct advantages:

• The single-use ring is as effective as other conventional iris hooks; however, compared with other commonly used iris retractors, it is friendlier to the eye due to its well distributed stretching, gentle holding of delicate iris tissue and the easier and less traumatic implantation. It has no sharp or pointed endings that can damage the eye.

• An equidistant positioning of the loops holds the iris tissue, ensuring correct position of the iris and preventing the effects of an overstretched pupil that are often observed in the incorrect positioning of iris hooks.

• The device applies pressure to the sphincter muscle over an area that is wider than with iris hooks. It is particularly useful in patients for whom cutting or tearing of the iris tissue should be avoided, especially in the presence of rubeosis, chronic anterior uveitis or systemic coagulopathy. The iris rim is safely fixed in the Ring's loops and there is no risk of iris aspiration during phacoemulsification.

• Additional incisions are not required. This instrument is inserted through the one main incision, thus reducing surgical trauma and minimizing the risk of contamination and postoperative inflammatory reaction. In the technique, when the square pupil is formed by the conventional iris retractors, the iris can prolapse through the wound. This is particularly true in patients with relatively wide paracenteses and atonic and atrophic irises that seem particularly floppy.

• Sufficient room is available for nucleus fragmentation and removal. The device configuration allows a surgeon to work in the deep lens layers below the iris plane and the squareshaped pupil formed by the ring. This provides enough space for grooving and cutting the nucleus and increases peripheral visualization during the chopping phase.

• The ring is inserted and removed from the eye with an inserter, reducing the risks of contamination and disturbance of the incision's architecture and wound integrity.

Summary: Different techniques of nucleus disassembly in small-incision cataract surgery require a wide and unobstructed view of the anterior portion of the lens, as well as of the instruments inserted into the anterior chamber. The other important factor is sufficient manipulability of the instruments, which is critical for the successful completion of surgery. A pupil that fails to dilate makes cataract removal more difficult. The Malyugin Ring adequately dilates the pupil and prevents iris sphincter damage. The ease of inserting and removing the device expands the pupil, protects the iris sphincter during surgery, and allows the pupil to return to its normal shape, size and function after the operation. Careful intraoperative manipulation and insertion of the Ring, with liberal use of an ophthalmic viscoelastic device, helps to prevent complications. Most of our postop patients had pupils almost indistinguishable in appearance than before surgery and functional activity was preserved. This is among the most effective methods to increase the size of even very rigid small pupils during phacoemulsification abnormalities in pupil size and function.