Eye research targets scar tissue that forms after surgery

November 5, 2018 by Ann Manser, University of Delaware
Melinda Duncan (seated) and research team members (from left) Mahbubul Shihan, Yan Wang and Samuel Novo look at a section through an eye showing a cataractous lens. Credit: University of Delaware

Today's cataract surgery is often described as a marvel of modern medicine, a one-hour outpatient procedure that has spared millions from blindness, especially in developed countries.

But nothing is perfect.

"Modern cataract is one of the most miraculous human health innovations," said Melinda Duncan, professor of biological sciences at the University of Delaware. "It has completely revolutionized eye care and has greatly reduced the incidence of blindness around the world.

"As with any surgery, there are side effects."

Duncan conducts research into those side effects—both short term and long term—and is seeking ways to prevent what is called "secondary cataract" that can occur years after a successful surgery. Her research also explores the makeup of cells in the of the eye and the way surgery affects them.

Cataracts occur when the lens of the eye becomes cloudy, a process that develops over time and is commonly related to aging. Eventually, individuals with a cataract in one or both eyes feel as if they are looking at the world through a dirty window.

The surgical procedure removes that clouded natural lens through a tiny incision and replaces it with a clear, flexible plastic lens. The surgery and the artificial lenses have been steadily improving, Duncan said, leading to better and better vision for patients.

Eye research targets scar tissue that forms after surgery
These images from Melinda Duncan’s lab show the clear lens of a healthy eye and one clouded by a cataract. Credit: University of Delaware
"But some lens cells always remain behind after surgery," she said. "And that can form scar tissue, which isn't transparent."

Some 40-to-70 percent of patients will develop this scarring in the eye, which will often interfere with their vision. Occurring as long as 10 years after the original surgery, the condition is known as posterior capsular opacification (PCO), sometimes termed "secondary cataract."

"Most people who develop PCO are fine with a further treatment, but others are at risk for additional problems," including damage to their retinas, Duncan said. "It's much better to prevent PCO in the first place."

Her research on this issue has been continuously funded by the National Eye Institute (NEI), a division of the National Institutes of Health (NIH), since 2004, and the institute recently awarded her a four-year grant renewal for the project of $1.37 million. Duncan said her research team has already discovered several molecules that are critical for the formation of PCO scar tissue.

"We hope to identify clinical interventions to block this potentially blinding condition," she said. "That's what we're working on now—a drug that would shut this process down."

In another active research project, initiated with support from both a Shovel-Ready Pilot Grant from the Delaware Center for Translational Research and a dual core access award from Delaware INBRE (the IDeA Network for Biomedical Research Excellence), Duncan is investigating the mechanisms that operate immediately after surgery to trigger PCO.

Eye research targets scar tissue that forms after surgery
Melinda Duncan looks at a section through an eye showing a cataractous lens in her lab, where she conducts research on some of the short-term and long-term side effects that can occur with cataract surgery. Credit: University of Delaware

In researching that process, Duncan made a novel discovery, finding that the lens cells left behind after surgery produce molecules that may be the primary triggers for post-surgical eye inflammation.

This was important because doctors prescribe general anti-inflammatory eye drops to be used in the days after to prevent pain and damage to the retina. The finding also relates to PCO, as inflammation is known to drive formation in other organs. This work opens up the possibility that the exact cause of inflammation could be determined, allowing for a more targeted therapy to be used in the future, Duncan said.

"Normally in the eye, are completely walled off from the immune system and have no resemblance to immune cells," she said. "But it turns out that an injury to the lens, such as surgery, changes that. The data really surprised us because this was completely unknown before."

These findings are the focus of a recent paper published by Duncan's group in the journal Investigative Ophthalmology and Visual Sciences.

Explore further: Preventing secondary cataract

More information: Jian Jiang et al. Lens Epithelial Cells Initiate an Inflammatory Response Following Cataract Surgery, Investigative Opthalmology & Visual Science (2018). DOI: 10.1167/iovs.18-25067

Related Stories

Preventing secondary cataract

April 28, 2016
Scientists may have found a way to prevent complications from surgery to treat cataract, the world's leading cause of blindness. The study was part-funded by eye research charity Fight for Sight and is published by a research ...

Cataracts linked to higher risks of osteoporosis and fracture

October 3, 2018
A new Journal of the American Geriatrics Society study has evaluated the potential impacts of cataracts and cataract surgery on the risks of osteoporosis and bone fractures.

Cellular 'tuning mechanism' builds elegant eyes

October 16, 2018
How different cells in a multicellular organism acquire their identities remains a fundamental mystery of development. In the eye, for example, the lens contains two cell types—lens epithelial cells and lens fiber cells—the ...

Cataract surgery tied to fewer car crashes for seniors

June 28, 2018
(HealthDay)—Data on more than half a million Canadian seniors shows that traffic accident rates fall after drivers undergo a needed cataract surgery.

Sealant gel approved for eye surgery

January 10, 2014
(HealthDay)—A sealant gel to prevent fluid leakage after cataract surgery has been approved by the U.S. Food and Drug Administration.

Stem cells regenerate human lens after cataract surgery, restoring vision

March 9, 2016
Researchers at University of California, San Diego School of Medicine and Shiley Eye Institute, with colleagues in China, have developed a new, regenerative medicine approach to remove congenital cataracts in infants, permitting ...

Recommended for you

Scientists combine technologies to view the retina in unprecedented detail

November 14, 2018
By combining two imaging modalities—adaptive optics and angiography—investigators at the National Eye Institute (NEI) can see live neurons, epithelial cells, and blood vessels deep in the eye's light-sensing retina. Resolving ...

Eyepatch with dissolvable needles used to treat eye disease

November 12, 2018
A team of researchers affiliated with several institutions in Singapore has developed an eyepatch with dissolvable needles for use in treating eye diseases. In their paper published in the journal Nature Communications, the ...

Calcifications in the eye increase risk for progression to advanced AMD by more than six times

November 8, 2018
Calcified nodules in the retina are associated with progression to late stages of age-related macular degeneration (AMD). Experts from Queen's University Belfast, working in partnership with the University of Alabama of Birmingham ...

Traditional glaucoma test can miss severity of disease

November 8, 2018
The most common tests for glaucoma can underestimate the severity of the condition by not detecting the presence of central vision loss, according to a new Columbia University study.

New contact lens to treat eye injuries

November 5, 2018
A new therapeutic contact lens that acts as a bandage for eye surface injuries being developed by QUT researchers could soon fast track the healing of previously difficult to treat corneal wounds.

New study offers hope for patients suffering from a rare form of blindness

November 1, 2018
A new form of therapy may halt or even reverse a form of progressive vision loss that, until now, has inevitably led to blindness. This hyper-targeted approach offers hope to individuals living with spinocerebellar ataxia ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.