April 2008

 

CATARACT/ IOL

 

Less cell loss with AquaLase


by Matt Young EyeWorld Contributing Editor

 

What you should know about AquaLase now

• At one month post-op, it caused less endothelial cell loss than traditional ultrasound in one study. Only central endothelial cell density was analyzed (peripheral density was not). • This is a change from the past, when previous studies found no significant difference in endothelial cell loss between AquaLase and traditional ultrasound. • At other time points, there was reportedly no significant difference in endothelial cell loss. • The results are valid only for the divide-and-conquer technique. • This study performed phacoemulsification with AquaLase in a range of dense nuclei. Analysis was performed on nuclei that were harder than in previous studies.

Source: Louis Hoffart, M.D.

 

Study compares AquaLase with tradiional ultrasound phaco

Dense congenital cataract: in a recent study, higher grade nuclei were emulsified with AquaLase with relatively less endothelial cell loss than with traditional ultrasound Source: Charlotta Zetterstrom, M.D., Ph.D.

New research is casting AquaLase (Alcon, Fort Worth, Texas) in a compelling new light. While previous studies have found endothelial cell loss has not been significantly different between AquaLase and ultrasound methods of phacoemulsification, new research finds differently. The new study, published in the January 2008 issue of Cornea, found that not only is a certain type of endothelial cell loss more minimal with AquaLase, but that it’s more minimal across a range of cataract densities. That is to say, in this study, cataracts had an opalescence of up to 4.9 in the LOCS III classification system. The LOCS III system grades nuclear opalescence on a scale of 1–6.

Previous research focused on less dense cataracts in relation to AquaLase phacoemulsification. Phacoemulsification clearly is a safe and effective procedure, but these data also suggest taking a fresh look at AquaLase might not be a bad idea. A detailed look Two groups, each of 21 patients, underwent phacoemulsification via traditional ultrasound or with AquaLase. Both methods were performed using the same Infiniti lens removal system (Alcon, Fort Worth, Texas), which allows surgeons to choose either technique. A divide-and-conquer technique to address the cataract was performed. Average nuclear opalescence was identical for both groups. In the ultrasound group, mean endothelial cell loss (ECL) was 589 +/– 342 and 254 +/– 214 in the AquaLase group at one month post-op. The cell loss in the AquaLase group was significantly lower. “To our knowledge, this prospective study is the first to report a statistically significant difference in ECL [endothelial cell loss] after in vivo ultrasound phacoemulsification versus a fluid-based system phacoextraction,” wrote study co-author Louis Hoffart, M.D., Service d’Ophtalmologie, Hospital d’Adultes de la Timone, France. Previous research with one-year follow-up found no significant difference in endothelial cell count between such methods. “An important difference with our study is that all types of nuclear opalescence and lens density were included,” Dr. Hoffart reported. Dr. Hoffart also noted some limitations of the study, including that results only are valid for the divide-and-conquer technique—not other techniques like phaco chop and prechop, which also can reduce ECL. Interestingly, the rate of ECL for the ultrasound group was “relatively high,” Dr. Hoffart noted. The fact that the nuclear opalescence was relatively higher than in previous studies could, however, explain the higher amount of ECL loss, Dr. Hoffart concluded.

However, Dr. Hoffart did directly note, “The fluid-based method was safer than conventional ultrasound in soft cataract surgery.” Logically, this makes sense. “The fluid-based system can improve both the safety and efficacy of cataract surgery by means of maintaining the integrity of the posterior capsule and eliminating the risk of thermal incisional injury,” Dr. Hoffart reported. “However, questions have arisen in relation to endothelial toxicity associated with water jet technology.” In this study, only central endothelial measures were taken. “These measures do not account for a peripheral difference in ECD [endothelial cell density] that might be significant,” Dr. Hoffart noted. Some have criticized AquaLase for not being as effective as ultrasound because in subjects with dense nuclei, it requires more surgery time and applied energy. John D. Sheppard, M.D., professor of ophthalmology, microbiology and immunology, Eastern Virginia Medical School, Norfolk, said it is understandable that AquaLase causes relatively less endothelial cell loss. But traditional ultrasound still is an excellent phacoemulsification system, he said. Torsional phacoemulsficiation has further improved on traditional ultrasound in some ways, he said. “Everybody always is looking for new technologies, but phaco has been very successful,” he said. “The existing cataract technology is so good that we’re able to preserve the endothelium very well in the vast majority of cases.”

Editors’ note: Dr. Hoffart has no financial interests related to this study. Dr. Sheppard has financial interests with Alcon (Fort Worth, Texas).

Contact Information

Hoffart: l.hoffart@wanadoo.fr

Sheppard: 757-622-2200, docshep@hotmail.com

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