Cataract Surgery May Be Safer With Laser

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Posted on 2nd November 2011 by Pacific ClearVision Institute in Cataracts

Laser Pretreatment Softens Cataracts, Allows for Safer, Easier Removal, Researchers Say

(Orlando, Fla.) — Laser pretreatment to “soften” cataracts appears to be making cataract surgery safer, two new studies suggest.

“There certainly seems to be a benefit to using the laser,” says American Academy of Ophthalmology (AAO) spokesman James Salz, MD, clinical professor of ophthalmology at the University of Southern California in Los Angeles. He reviewed the findings for WebMD.

“If you have a technique to soften the cataract, there appears to be less chance of damage [to the eye],” Salz says.

The research was presented here at the AAO annual meeting.
Standard vs. Laser Cataract Surgery

More than 1.5 million cataract surgeries are performed annually in the U.S. One in three mostly older Americans will have the surgery at some point in their lives.

The surgery is performed to remove the natural lens of the eye after it has become clouded over time. A permanent artificial lens is then implanted to replace the natural lens and provide appropriate vision correction for each patient.

Currently, most aspects of cataract surgery, including the initial incision and the breakup and removal of the clouded lens from the lens capsule, are performed manually by the surgeon. An ultrasound instrument with a vibrating needle is used to break up the cataracts, and a vacuum sucks them out.

The new studies looked at using the so-called femtosecond laser to deliver near-infrared light to fragment the cataract into tiny segments prior to removal.

“The idea is that all the surgeon will have to do is remove the pieces with a vacuum,” says researcher Mark Packer, MD, of Oregon Health and Sciences University in Portland. “Ideally, you won’t need ultrasound, or at least you’ll need less ultrasound.”

That’s important because ultrasound can cause collateral damage to the eye, he says. It can hinder recovery and cause clouding of the cornea, which is the clear outer layer of the eye.

Although approved by the FDA, the femtosecond laser procedure is not widely used in the U.S., according to the American Academy of Ophthalmology.

Viral Vector Designed to Treat a Genetic Form of Blindness

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Posted on 2nd November 2011 by Pacific ClearVision Institute in General |Retina

Researchers at Ohio State University Medical Center and Nationwide Children’s Hospital have developed a viral vector designed to deliver a gene into the eyes of people born with an inherited, progressive form of blindness that affects mainly males.

The vector is part of a clinical trial investigating the use of gene therapy to cure choroideremia, a disease that affects an estimated 100,000 people worldwide. The trial is being conducted by researchers at the University of Oxford in England.

The vector was designed by Dr. Matthew During, professor of molecular virology, immunology and medical genetics and of neuroscience and neurological surgery at Ohio State, in collaboration with Robert MacLaren, professor of ophthalmology at the University of Oxford, who also leads the trial.

Researcher Dr. K. Reed Clark, director of the Clinical Manufacturing Facility at the Center for Gene Therapy, Nationwide Children’s Hospital, and his team produced the clinical-grade vector that is administered to patients in the trial.

During, who is also a visiting professor of translational neuroscience at Oxford, was in the operating room during the pioneering surgery. “I and my colleagues are excited about contributing to this significant medical breakthrough,” During says. “We have worked for many years to engineer and optimize viruses to safely deliver genes to humans, and the eye is an ideal target in many ways. The clinical vector manufacturing facility at Nationwide Children’s Hospital is outstanding, and Dr. Clark and his team deserve congratulations for providing a clinical vector that for the first time offers these patients the possibility of an effective therapy.”

During and his colleagues designed the viral vector to infect the light-sensitive photoreceptor cells that line the back of the eye and make up the retina. Choroideremia causes a degeneration of these photosensitive retinal cells and progressive blindness. The diagnosis is usually made in childhood and leads to blindness by around age 45.

“This trial represents the first attempt to treat this disease and the first time that gene therapy has been directed towards the photoreceptor cells of the human retina,” During says. “We believe it holds great promise for the treatment of other genetic causes of blindness such as retinitis pigmentosa.”

The trial’s 12 patients will be treated in one eye. It will take 24 months to know whether the gene-therapy treatment has stopped the degeneration. The trial builds on gene-therapy research performed in collaboration with Professor Miguel Seabra at Imperial College London, along with During and Clark at Ohio State.

“This disease has been recognized as an incurable form of blindness for over a hundred years,” MacLaren says. “I cannot describe the excitement in thinking that we have designed a genetic treatment that could potentially stop it in its tracks with one single injection.”

Fast High Precision Eye-Surgery Robot Developed

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Posted on 2nd November 2011 by Pacific ClearVision Institute in General

Researcher Thijs Meenink at Eindhoven University of Technology (TU/e) has developed a smart eye-surgery robot that allows eye surgeons to operate with increased ease and greater precision on the retina and the vitreous humor of the eye. The system also extends the effective period during which ophthalmologists can carry out these intricate procedures.

Meenink will defend his PhD thesis on Oct. 31 for his work on the robot, and intends later to commercialize his system.

Filters-out tremors

Eye operations such as retina repairs or treating a detached retina demands high precision. In most cases surgeons can only carry out these operations for a limited part of their career. “When ophthalmologists start operating they are usually already at an advanced stage in their careers,” says Thijs Meenink. “But at a later age it becomes increasingly difficult to perform these intricate procedures.” The new system can simply filter-out hand tremors, which significantly increases the effective working period of the ophthalmologist.

Same location every time

The robot consists of a ‘master’ and a ‘slave’. The ophthalmologist remains fully in control, and operates from the master using two joysticks. This master was developed in an earlier PhD project at TU/e by dr.ir. Ron Hendrix. Two robot arms (the ‘slave’ developed by Meenink) copy the movements of the master and carry out the actual operation. The tiny needle-like instruments on the robot arms have a diameter of only 0.5 millimeter, and include forceps, surgical scissors and drains. The robot is designed such that the point at which the needle enters the eye is always at the same location, to prevent damage to the delicate eye structures.

Quick instrument change

Meenink has also designed a unique ‘instrument changer’ for the slave allowing the robot arms to change instruments, for example from forceps to scissors, within only a few seconds. This is an important factor in reducing the time taken by the procedure. Some eye operations can require as many as 40 instrument changes, which are normally a time consuming part of the overall procedure.

High precision movements

The surgeon’s movements are scaled-down, for example so that each centimeter of motion on the joystick is translated into a movement of only one millimeter at the tip of the instrument. “This greatly increases the precision of the movements,” says Meenink.

Haptic feedback

The master also provides haptic feedback. Ophthalmologists currently work entirely by sight — the forces used in the operation are usually too small to be felt. However Meenink’s robot can ‘measure’ these tiny forces, which are then amplified and transmitted to the joysticks. This allows surgeons to feel the effects of their actions, which also contributes to the precision of the procedure.

Comfort

The system developed by Meenink and Hendrix also offers ergonomic benefits. While surgeons currently are bent statically over the patient, they will soon be able to operate the robot from a comfortable seated position. In addition, the slave is so compact and lightweight that operating room staff can easily carry it and attach it to the operating table.

New procedures

Ophthalmologist prof.dr. Marc de Smet (AMC Amsterdam), one of Meenink’s PhD supervisors, is enthusiastic about the system — not only because of the time savings it offers, but also because in his view the limits of manual procedures have now been reached. “Robotic eye surgery is the next step in the evolution of microsurgery in ophthalmology, and will lead to the development of new and more precise procedures,” de Smet explains.

Market opportunities

Both slave and master are ready for use, and Meenink intends to optimize them in the near future. The first surgery on humans is expected within five years. He also plans to investigate the market opportunities for the robot system. Robotic eye surgery is a new development; eye surgery robots are not yet available on the market.