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Pitfalls and pearls in managing dense nuclear cataracts
Removing dense nuclear cataracts presents certain challenges for the surgeon. The capsule of the lens is thin and fragile, and is in tight contact with the nucleus because there is little cortex and the zonular fiber is weak. Removing the dense nucleus without damaging other eye structures is key to successful and safe management of these cases.
 Danying Zheng |
Cataract surgery is different for patients with dense, hard nuclear cataracts than for patients with thinner, softer ones. It is difficult to hold the nucleus tightly and divide it into small pieces. When the pieces are broken, the fragments may be jagged and hard, making the adjacent structures vulnerable to endothelial trauma.
Pitfalls
When using any ultrasound modality, greater phaco energy and prolonged ultrasound time are needed to remove dense nuclear cataracts, making the eye more vulnerable to endothelial trauma, capsular rupture, incision burns and lens dislocation. For this reason, I find efficient lens removal essential. When I remove a dense nucleus, I use higher phaco power, usually at 60%, but sometimes as high as 70%, and prolong the ultrasound time. Both methods increase the energy delivery in the eyes, putting the patient at risk for these pitfalls.
"Cataract surgery is different for patients with dense, hard nuclear cataracts than for patients with thinner, softer ones."
— Danying Zheng, MD
During this period, the phaco tip is easily obstructed and, without caution, the endothelium at the incision site may be damaged. Safety is a great consideration in the phacoemulsification of dense nuclear cataracts.
Furthermore, patients with dense nuclear cataracts are likely to have other health issues, such as age-related cataract combined with high myopia, diabetes or glaucoma surgical history.
Technique and experience
In my experience, for standard cataract removal using a traditional, longitudinal modality, I like to use a burst and pulse method. I use the burst mode when sculpting and chopping, but then I change to pulse mode when removing the epinucleus to prevent damage to the capsule.
The modality I prefer for removing all cataracts is to use the OZil torsional handpiece (Alcon Laboratories, Inc.) in continuous mode. In my view, torsional modality can decrease incision burn.
I find that using the OZil torsional handpiece achieves safe and better patient outcomes. There is less repulsion, better followability, high energy efficiency, less chamber turbulence and less time needed to complete the procedure. I use the following settings:
- Bottle height: 110 mm
- Vacuum power: 400 mm Hg to 450 mm Hg
- Amplitude: 100%, torsional (70% to 100%)
- Aspiration rate: 36 to 40 mL/min.
When I use the Infiniti system (Alcon Laboratories, Inc.) for patients with dense nuclear cataracts, the efficient delivery of energy makes it easy to remove the dense nucleus. The system lessens the risk of thermal injury and lessens turbulent flow of fluid through the eye to maintain a stable anterior chamber. I only use the chopper to divide the nucleus.
In my microcoaxial approach, I use a 45-degree mini-flared tip and ultrasleeve through a 2.2-mm incision and then use fixed aspiration and the Intrepid Fluidic Management System (FMS) (Alcon Laboratories, Inc.). When using the 45-degree microtip plus High Infusion Sleeve, I make a 3-mm incision and use fixed aspiration and Infiniti FMS. The Intrepid FMS has more rigid tubing to prevent turbulence in the anterior chamber. The 45-degree mini-flared tip has a wider opening to hold the pieces more tightly and cut more efficiently.
After creating the incision and capsulorrhexis (Figures 1, 2), I use phaco chop technique to divide the nucleus into small pieces. I usually use high vacuum (400 mm Hg to 450 mm Hg) to hold the nucleus tightly and chop it. When the nucleus is broken into many small pieces, I lower the vacuum (250 mm Hg), especially for the last pieces. This is especially important in dense nuclear cataracts because the weak zonules are susceptible to final vacuum surge.
 Figure 1. A 2.2-mm incision for cataract surgery in a patient with a dense, nuclear cataract. |
 Figure 2. Creating the capsulorrhexis in a patient with a dense, nuclear cataract. |
To insert the IOL, I use the Monarch III injector with D cartridge (Alcon Laboratories, Inc.), and I prefer an aspherical lens, such as an AcrySof IQ ReSTOR IOL (Alcon Laboratories, Inc.).
Pearls
To lessen the loss of endothelial cells during cataract surgery in patients with dense nuclear cataracts, I use a soft-shell technique, which incorporates a dispersive viscoelastic to protect the endothelium and a cohesive viscoelastic to create space.
Other clinical pearls for achieving success when performing surgery in patients with dense cataracts include the following:
- Use a good phaco system at a suitable setting (torsional handpiece with 70% to 100% amplitude setting).
- Use a combination of mechanical chopping and phaco power that complement each other.
- Use two viscoelastics, such as the DuoVisc Viscoelastic System (ProVisc [1% sodium hyaluronate] and Viscoat [3% sodium hyaluronate, 4% chondroitin sulfate]; Alcon Laboratories, Inc.) in a soft-shell technique to protect the endothelium and create space.
- Use careful skill and have patience.
Dr. Zheng is from Zhongshan Ophthalmic Center, Sun-Yat-Sen University, in Guangzhou, China.
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