Phaco Principles | Nov/Dec '17

Power Modulation in Complex Cases

Who Needs Zonules … Or Vitreous?

By Brandon D. Ayres, MD

A 68-year-old man presented with severe zonular deficiency secondary to Marfan syndrome. He had a history of progressive vision loss in both eyes. He was well educated about the problems that could be encountered during cataract surgery in patients with his medical condition. This knowledge had prevented him from opting for surgery up to this point. However, he began having difficulty driving and wanted to explore options for cataract surgery.

On exam, the patient’s BCVA was 20/60 in the right eye and 20/100 in the left. No afferent pupillary defect was noted, and motility was full. The slit-lamp exam was significant for 3+ nuclear sclerotic lens changes and significant phacodonesis. Retinal exam was normal in both eyes.

A very detailed risk-benefit analysis was discussed with the patient. The increased risk of surgical complication was well explained, and he fully understood his unusual ophthalmic condition. After careful consideration, the patient decided to move forward with cataract surgery on his left eye.

SURGICAL CASE

Preparation was key for this case, and additional equipment was made easily accessible in the OR. On standby were pupil expanders, capsular hooks, capsular tension rings, a vitrector, and plenty of ophthalmic viscosurgical device (OVD). I also used a retrobulbar block in anticipation of a long case, as opposed to my standard topical anesthesia.

The first surgical challenge was in dilating the pupil. Visualization is key in difficult cases and was essential in this case. A 6.25-mm Malyugin Ring (MicroSurgical Technology) was used to achieve adequate dilation. Using a ring allows the anterior chamber to remain deep, which is helpful when additional support systems may be needed later in the case (such as capsular support hooks).

Once the anterior capsule was accessible, a continuous curvilinear capsulorhexis (CCC) was created. The severe laxity made tearing the CCC very challenging. The initial puncture into the lens had to be performed using a sharp blade. An atraumatic intraocular forcep were then used to fixate the anterior capsule, while the remainder of the rhexis was torn using Utrata forceps. Once the CCC was completed, capsular retractors were placed to hold the lens in place and allow removal of the nuclear material. In this case, a double-loop flexible capsular retractor was selected for use.

Extreme care must be taken during phacoemulsification. Capsular hooks were crucial in keeping the capsule in place during lens removal. In cases with zonular laxity, I perform hydrodelineation but not hydrodissection. This leaves an epinuclear layer acting as a buffer against unintentional trauma to the posterior capsule by the phaco needle. Slow and controlled phaco was used to remove the nuclear lens, and bimanual irrigation/aspiration was used to remove the cortex. After lens removal, the capsular support hooks were removed, leaving a very unstable capsule. I typically try to fixate the capsule, but, in this case, the capsule was not worth using and was removed.

A vitrectomy was performed until vitreous stopped prolapsing into the anterior chamber. Visualization was enhanced using triamcinolone. My plan was to use a double-needle technique to haptic-fixate a three-piece IOL into the sclera. For safety reasons, the vitrectomy had to be complete and is one of the most important steps in this surgery.

Once clear of vitreous, a three-piece acrylic IOL was placed in the anterior chamber. Using a thin-walled 30-gauge needle, two sclerotomies were placed 180° apart. The location of the sclerotomy was 2 mm to 3 mm posterior to the limbus, with a 2-mm circumlimbal tunnel. After tunneling for 2 mm, the needle was introduced into the posterior segment and then visualized in the center of the pupil. Using microforceps, each haptic was carefully introduced into the lumen of the needle.

Once both haptics were incarcerated into the 30-gauge needles, they were externalized by removal of the needles, exposing the haptics on the conjunctival surface. The haptics were then grasped with tying forceps, and low-temperature cautery was used to melt the terminal 2 mm or so of the haptic, forming a ball or stopper. The stopper prevents the haptic from prolapsing through the scleral tunnel, fixating the IOL in the posterior chamber. This technique was first described by Yamane in 2014 (Editor’s note: For more on the Yamane technique, see Peer Review).

After IOL placement, all that was left to do was remove the Malyugin Ring and remove any residual OVD from the anterior segment. The vitrector was used in irrigation/aspiration mode for removal of OVD, and all incisions were hydrated or sutured to ensure a watertight closure. I always add a miotic agent at the end of cases in which vitrectomy has been performed. The miotic agent serves two purposes: It will show if any vitreous is incarcerated into a limbal incision by “peaking” the pupil, and it will help keep the pressure down if any OVD is left in the anterior chamber.

CONCLUSION

The challenges in this case included a small pupil and severe loss of zonular sufficiency. With some creative thinking, specialized tools, and fantastic surgical equipment, the patient did exceedingly well. On postoperative day 1, his vision had improved to 20/30 without correction, and he is eager to get the second eye on the schedule.

author
Brandon D. Ayres, MD
  • Surgeon in the Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania
  • bayres@willseye.org
  • Financial disclosure: Consultant (Alcon, MicroSurgical Technology)

Posterior Polar Cataract

By Zaina Al-Mohtaseb, MD

This video demonstrates a case of a posterior polar cataract. To begin, I created two paracentesis incisions and injected trypan blue to highlight the anterior capsule. I then injected Viscoat into the eye, taking care not to overfill the anterior chamber, as that could result in a posterior capsular blowout. A 2.4-mm temporal incision was made. I created a smaller capsulorhexis than typical in case I needed to optic-capture a sulcus IOL.

I then carefully performed hydrodelineation without hydrodissection to prevent hydrostatic pressure from creating or extending a posterior capsular tear. I used a Chang cannula on a syringe filled with balanced salt solution to perform hydrodelineation. Hydrodelineation provides an epinucleus bowl that acts as a mechanical cushion, protecting the posterior capsule during subsequent maneuvers. I placed the Chang cannula in the lens substance and injected fluid slowly while looking for a golden ring sign. 

The nucleus was aspirated within the epinucleus shell using low vacuum settings and infusion pressure and minimal ultrasound power. My epinuclear setting using the Stellaris Elite (Bausch + Lomb) utilizes dual-linear control with linear vacuum; while pushing down on the foot pedal, I increase vacuum, and, as I slide my foot to the right, I can add ultrasound power. My epinuclear setting utilizes low ultrasound power (0-8) with a low pulse and duty cycle (20 pps, 27 duty cycle). This allows me to remove epinuclear material and cortex in these complex cases by being close to the bag with low vacuum and minimal to no ultrasound, both of which I can control with my foot pedal. 

I injected OVD to maintain the anterior chamber prior to removing any instrument to prevent collapse of the anterior chamber and movement of the lens-iris diaphragm. I used a dispersive OVD to viscodissect the epinucleus and cortex (especially in the area of concern to tamponade the vitreous) and then used phaco with the same settings to remove the epinuclear shell. I started in the periphery and moved toward the area of concern.

Next, I used bimanual I/A to remove the remaining cortex. Bimanual I/A ensures anterior chamber stability and aids in complete cortex removal. Even if the capsule is intact, I avoid capsular polish because the posterior capsule is not normal in that area. I again filled the chamber with OVD prior to removing the I/A, and the IOL was placed with care not to push centrally in the area of abnormality of the capsule. Residual OVD was removed with bimanual I/A, and the incision and paracentesis were sealed with stromal hydration. 

author
Zaina Al-Mohtaseb, MD
  • Assistant Professor of Ophthalmology and Associate Residency Program Director, Baylor College of Medicine, Houston, Texas
  • zaina@bcm.edu
  • Financial disclosure: Consultant (Bausch + Lomb)

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