July 2007

 

CATARACT/ IOL

 

Glistenings affect ophthalmologists more than patients


by David Laber EyeWorld Staff Writer

 

 

 

Despite their threatening appearance, most patients with glistenings do not complain about any loss of visual acuity

Penetrating keratoplasty, pictured here, is still a commonly performed transplant procedure but Francis W. Price Jr. makes a strong case for endothelial keratoplasty.

Source: Edward J. Holland, M.D.

Recently more ophthalmologists have been reporting an increase in the number of patients who have glistenings on their intraocular lenses (IOLs), but for the most part, other than the physician noticing the glistenings, the patients remain asymptomatic.

It also remains to be determined if glistenings are being seen more frequently or if physicians are just recognizing them more now than before, said Nick Mamalis, M.D., John A. Moran Eye Center, University of Utah, Salt Lake City.

At this point, however, an increase in the number of patients with glistenings has not resulted in an increase in glistening-related lens exchanges.

“These are phenomenon that when the surgeon sees them at the slit lamp, it affects the surgeon more than it affects the patient,” Dr. Mamalis said. “This can look alarming with a slit lamp, but the patient does not perceive a problem.”

Hydrophobic acrylic lenses and glistenings

Dr. Mamalis described the glistening phenomenon as water vacuoles within a hydrophobic acrylic lens visible through a slit lamp.

Sonia H. Yoo, M.D., Bascom Palmer Eye Institute, University of Miami, added that the change in temperature combined with water absorption causes the vacuoles to form. Glistenings have been reported in other lens material, but it is most common in hydrophobic acrylic lenses. Several companies market a hydrophobic acrylic IOL including Advanced Medical Optics (AMO, Santa Ana, Calif., Sensar), Alcon (Fort Worth, Texas, AcrySof), Eyekon Medical (Clearwater, Fla., NaturaLens) and Medennium (Irvine, Calif., Matrix).

However Dr. Mamalis notes that when Alcon introduced the three-piece AcrySof in the United States in the early 1990s, significant glistenings were noticed. This was attributed to the AcryPack packaging in which the lens was placed on a folding device within a plastic box, which was then sterilized. Alcon worked with the Moran Eye Center and repackaged the IOL in the current Wagon Wheel packaging, which has reduced instances of glistenings and prolonged their appearance. But Dr. Mamalis said that now that the three-piece IOLs have been in the eyes for years, more and more glistenings are appearing.

He added that the one-piece AcrySof did not have reports of glistenings early on, but now that they have been out for several years, the glistenings have been seen in these IOLs as well.

Tending to patients with glistenings

“This is one of those things that as you see a significant amount of glistenings, it will alarm the ophthalmologist, but it doesn’t necessarily alarm the patient because it is very uncommon for the patient to have any symptoms from these glistenings,” Dr. Mamalis said.

Dr. Yoo said that when glistenings occur, they are not visually significant. In the more extreme cases, they can have some reduction in contrast sensitivity, but in general, visual acuity is not affected except for in the most severe cases.

Contrast sensitivity can be subtly affected by glistenings, Dr. Mamalis agreed. But he said there has not been a significant decrease in visual acuity that the lens needed to be explanted.

When ophthalmologists see patients with significant amount of glistenings, the patients are not complaining about loss of visual acuity or any other symptoms that can be attributed to glistenings, he said.

Ophthalmologists should watch glistening patients closely because the glistenings increase with time, Dr. Yoo said, but she added that physicians do not need to be quick to react to the glistenings because most cases are mild and the patient is asymptomatic.

When the glistenings are present in a patient’s eye, they cannot be removed, Dr. Mamalis said. Instead, the lens would have to be explanted, and then the glistenings will evaporate.

“It is OK to wait and watch,” Dr. Yoo said about treating patients with glistenings noting that glistenings tend to increase over time. “And an indication for a lens exchange would be if the patient complains about loss of visual function.”

Dr. Mamalis said, however, that he is not aware of an IOL being removed because of symptoms caused by glistenings. There have been some lenses removed, but in those cases, there have been some questions about whether or not it was a result of glistening symptoms.

Should glistenings affect IOL selection?

Hydrophobic acrylic IOLs are Dr. Yoo’s lens of choice because they tend to be well tolerated by patients while providing good optical qualities, she said.

Dr. Mamalis said the hydrophobic acrylic has excellent biocompatibility and is well tolerated by the patients. Hydrophobic acrylic lenses also have the advantage of the square-edge design, which is useful for reducing posterior capsular opacification (PCO).

On the flip side of the coin, silicone lenses have problems with oil adherence unlike the acrylic lenses, he said, and the silicone lens is not preferable for patients who will also have retinal surgery. However, patients who have a breakdown of their blood-aqueous barrier, such as diabetics, and patients with inflammations such as uveitis are more prone to get glistenings,” Dr. Mamalis said.

“There have been reports that patients with more post-op inflammation or have a history of uveitis have a higher incidence of glistenings,” Dr. Yoo said.

While admitting that even in these patient groups with the increased risk, it still is rare for them to have symptoms, she said. Yet Dr. Yoo said even though these are her lens of choice, they might not be for the at-risk patients.

Dr. Mamalis, on the other hand, said he has not found there to be enough evidence to cause him to be hesitant about using a hydrophobic acrylic IOL.

“I think the bottom line with glistenings is that I am not aware of a lens where the glistenings were so bad that they actually caused the lens itself to be explanted,” Dr. Mamalis said.

Editors’ note: Editors’ note: Dr. Yoo has financial interests with Alcon (Fort Worth, Texas). Dr. Mamalis has financial interests with Alcon and Advanced Medical Optics (Santa Ana, Calif.).

Contact Information

Mamalis: 801-581-6586, nick.mamalis@hsc.utah.edu

Yoo: 305-326-6322, syoo@med.miami.edu

Glistenings affect ophthalmologists more than patients Glistenings affect ophthalmologists more than patients
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