Study: Acrylic, thermoplastic IOLs are comparable

A recent retrospective study comparing the lenses over a 3-year period found that they yielded similar results.

ByMichelle Stephenson

MONZA, Italy — In a recent study comparing an acrylic IOL with a thermoplastic IOL, the two appeared to be comparable in endothelial cell counts, visual acuity, induced astigmatism and occurrence of posterior capsule opacity. However, the thermoplastic lens did not require folding, making IOL insertion faster and easier.

This study retrospectively evaluated the long-term results of acrylic and thermoplastic IOL implantation. The MemoryLens (CIBA Vision/Novartis; Duluth, U.S.A.), a thermoplastic lens, was compared with AcrySof (Alcon; Fort Worth, U.S.A.), an acrylic lens. “I chose AcrySof because it is one of the best-known lenses in the world. It is worn by more than 50% of the U.S. market,” said Matteo Piovella, MD, an ophthalmologist at the Centro Microchirurgia Ambulatoriale, located here.

No unfolding complications

“I have 10 years of experience with the MemoryLens, and I would like to stress that it is not necessary to run from the refrigerator to the patient because you have a lot of time before the lens comes back to its previous, normal shape. Additionally, it is not necessary to wait for lens unfolding. No one in the study experienced an unfolding-related complication,” he added.

After phacoemulsification with topical anesthesia and a 4.1-mm temporal clear corneal incision, an AcrySof lens was implanted in 142 eyes, and a MemoryLens was implanted in more than 600 eyes.

“Both of these lenses were really effective,” Dr. Piovella said.

Surgical time

The study found that surgical time was slightly increased with the AcrySof lens, because it takes time to fold the lens. Mean surgical time with the MemoryLens was 11 minutes and 33 seconds, while the mean surgical time with the AcrySof lens was 13 minutes and 41 seconds. “Naturally, you lose time folding the lens. Three years after implantation, there was not a significant difference in visual acuity or in induced manifest astigmatism. Endothelial cell counts were also comparable. However, a different implantation technique could achieve a different result,” he explained.

“My current choice is to use the AcrySof lens, because I want to be sure that the lens opens immediately. This ensures that the opening of the posterior capsule is well managed immediately, and you don’t have to await the opening of the lens. Additionally, the posterior capsule opacity is similar, but, naturally, we need more numbers and more time to achieve the final result,” he added.

Importantly, the intraocular pressure immediately after surgery was similar and in the normal range.

MemoryLens implantation.	MemoryLens development with shorter haptic.
MemoryLens implantation. Look at the forceps always outside the corneal tunnel (to decrease the necessary size of the incision).	MemoryLens inside the eye.
MemoryLens opening.	MemoryLens 30 minutes after implantation, perfectly flat and normal.

For Your Information:

Matteo Piovella, MD, can be reached at Centro Microchirurgia Ambulatoriale, Via Donizetti 24, 20052 Monza, Italy; +(39) 039-389-498; fax: +(39) 039-230-0964; e-mail: piovella@galactica.it. Dr. Piovella does not have a direct financial interest in any product mentioned in this article, nor is he a paid consultant for any company mentioned.