The study of the innovative presbyopia correction surgery officially began April 6 when Stephen Slade, MD, of the Slade & Baker Vision Center (Houston, Texas) became the first U.S. surgeon to implant the device in the corneas of three patients.

The PresbyLens clinical study will evaluate 400 presbyopic subjects who undergo the procedure. The follow-up period after surgery will be three years.

The first two investigators chosen for the study were Dr. Slade and Jon Dishler, MD, of the Dishler Laser Institute (Greenwood Village, Colo.).

The PresbyLens corneal inlay has the potential to gently reshape the cornea to improve a person’s near or reading vision, while also allowing him or her to see clearly for distance vision tasks such as driving, according to the company.

The implantable lens is made of a proprietary, optically clear biocompatible material that is similar to materials used for soft contact lenses.

Though the PresbyLens has its CE mark and is approved for sale in Europe, it is considered an investigational device in the U.S. and is currently limited by federal law to investigational use only.

ReVision Optics says it is actively pursuing FDA regulatory approval of the device so U.S. refractive surgeons can begin offering the device to the 73 million Americans who are presbyopic.

SOURCE:  ReVision Optics begins U.S. clinical trial of the PresbyLens for restoration of near vision. (Press release issued by company on April 8, 2010.)

Since then, there have been many advances in IntraLase femtosecond lasers (now sold by Abbott Medical Optics) as well as the introduction of several competing femtosecond lasers that have gained FDA approval.

Refractive surgeons who prefer using a femtosecond laser rather than a microkeratome for creating the corneal flap in LASIK surgery say the laser is more predictable and reduces certain flap-related LASIK risks.

Proponents of the use of microkeratomes say the bladed instruments are safe and effective and that femtosecond lasers significantly increase LASIK eye surgery cost.

Recently, Review of Ophthalmology reviewed the latest femtosecond lasers currently used by refractive surgeons worldwide for all-laser LASIK. Some of these lasers may soon be approved for other refractive surgery procedures as well.

Here is a brief overview of the current offerings:

IntraLase FS-150

IntraLase femtosecond lasers (Abbott Medical Optics) are the most popular femtosecond lasers in use today for LASIK. The latest model, the FS-150, operates at a frequency of 150 kHz, which is ten times faster than the original IntraLase laser.

This makes the laser ablations much tighter for a smoother flap that is easier for the surgeon to lift prior to reshaping the eye with an excimer laser. It also enables the surgeon to make the flap much quicker for greater patient comfort and less risk of flap complications.

The FS-150 also gives the surgeon greater control over flap size and shape and enables him or her to vary the angle of the side-cut of the flap, which may enable the flap to heal faster after surgery.

Abbott Medical Optics (AMO) says it is planning to release a software module for the FS-150 in 2010 that will enable the laser to create intrastromal pockets in the cornea for corneal implant surgery to correct presbyopia.

Technolas Perfect Vision 520 FS

Previously called the Femtec laser, the name of this femtosecond laser for LASIK was changed to the 520 FS when its manufacturer, 20/10 Perfect Vision, entered into a joint venture with Bausch & Lomb in April 2009 to create a new company, Tecnolas Perfect Vision.

In addition to being designed to create the corneal flap in LASIK surgery, the 520 FS femtosecond laser also is able to perform the new IntraCor corneal refractive surgery for the correction of presbyopia.

Though the IntraCor procedure is not yet FDA-approved for use in the United States, it has received the CE Mark in Europe for use in correcting mild presbyopia.

The FS 520 laser also features a computer-controlled method for ensuring the LASIK flap is properly centered on the eye, and a curved interface that enables the laser to remain attached to the eye with less suction during flap creation.

Zeiss Visumax

The Zeiss Visumax femtosecond laser is extremely fast, operating at a frequency of 500 kHz. This enables surgeons to use lower energy settings while delivering more laser pulses. The result is very smooth flaps that the surgeon can more easily lift without trauma to the eye.

Like Technolas Perfect Vision’s 520 FS laser, the Zeiss Visumax laser features a curved corneal interface that requires less suction for greater patient comfort during creation of the LASIK flap.

The Visumax, like the IntraLase FS-150, features the ability to alter the angle of the side-cut of the flap to facilitate quick healing and to make the flap fit more securely after surgery.

In Europe, in addition to creating LASIK flaps, the Visumax laser is being used for a new refractive surgery procedure called femtosecond lenticule extraction (FLEx). In this procedure, the laser creates a small lens-shaped segment (lenticule) within the cornea, and then creates a flap so the surgeon can remove the lenticule.

The FLEx procedure has not been submitted for FDA approval for use in the United States, but early studies of the procedure in India are showing promising results for the correction of myopia.

Ziemer Femto LDV

The Ziemer Femto LDV is the fastest FDA-approved femtosecond laser, with a pulse rate in the megahertz (mHz) range.

The faster pulse rate (as with the Zeiss Visumax laser) enables the laser to deliver more treatment spots using lower energy settings for the creation of very smooth flaps. This reduces the risk of trauma to the eye when the surgeon lifts the flap.

The Femto LDV laser is more portable than other femtosecond lasers, making it more convenient for use in conjunction with an excimer laser in all-laser LASIK, especially in small surgical rooms.

Zeimer says that in addition to being used for LASIK surgery, the Femto LDV laser soon will be able to create intrastromal pockets for corneal implant procedures and create channels in the cornea for intrastromal corneal ring segment surgery used in the treatment myopia and keratoconus.

SOURCE:  The evolution of the femtosecond laser. Review of Ophthalmology. February, 2010.

The CE mark certifies that the implantable micro-lens meets European Union consumer safety, health and environmental requirements.

The approval was announced in a press release issued last month by Presbia, the Amsterdam-based ophthalmic device company that makes the Flexivue lens.

“Today’s CE certification of the Flexivue lens validates our technology and will enable us to move forward with commercialization of our solution for the huge presbyopic market by mid-2010,” Presbia’s CEO Zohar Loshitzer said in the press release.

The Flexivue implant is just 3 millimeters in diameter and less than 20 microns thick at its edge and is made of a hydrophilic (“water-loving”) plastic polymer similar to materials used for intraocular lenses used in cataract surgery for the past 20 years, according to Presbia.

The Flexivue lens is implanted in a small pocket in the center of the cornea that is created with a femtosecond laser. The refractive surgeon inserts the lens into the corneal pocket with a proprietary device developed by Presbia.

Once the lens is properly positioned within the cornea, the pocket seals itself to keep the lens in place.

The Flexivue lens can be left in the eye indefinitely, or it can be removed and replaced if the patient’s visual needs change.

The lens is implanted only in the patient’s non-dominant eye, and the entire procedure generally takes less than 10 minutes.

[Ed. note: The Flexivue corneal implant has not yet been evaluated or approved by the U.S. Food and Drug Administration for use by eye surgeons in the United States.]

SOURCE:  Presbia’s Flexivue micro-lens receives European market approval. Press release issued December 3, 2009 by Presbia. (Viewable at presbia.com.)

The Flexivue intracorneal inlay is designed to restore near vision lost to normal age-related changes in the lens inside the eye by increasing the curvature of a small central zone of the clear front surface of the eye.

The added curvature increases magnification to improve near vision and reduce the need for reading glasses in people over age 40 with clear distance vision.

Flexivue corneal inlay design

The tiny and ultra-thin Flexivue corneal inlay is 3 millimeters (mm) in diameter and has an edge thickness of less than 0.02 mm. The clear micro-lens is made of a hydrophilic (water-absorbing) plastic similar to a soft contact lens material.

The device is implanted in the center of the cornea and can stay in place permanently or can be removed and replaced with a stronger corneal implant if greater magnification for reading is needed.

Implantation of the Flexivue inlay creates a variable curvature to the cornea, similar to the curves on certain multifocal contact lenses.

When successfully implanted, the device should provide improved near and intermediate vision with minimal loss of distance clarity.

The corneal implant procedure

The implantation procedure for the Flexivue corneal inlay typically takes less than 10 minutes and, like LASIK and PresbyLASIK, is performed on an outpatient basis.

Usually, the corneal inlay is implanted in the patient’s non-dominant eye to reduce the risk of any decrease in distance vision.

The steps of the procedure are:

1. Numbing eye drops are applied to the eye to prevent discomfort.
2. A femtosecond laser is used to create a small pocket in the center of the cornea.
3. The Flexivue inlay is implanted in the corneal pocket.

The corneal pocket soon seals itself, securing the inlay in proper position in front of the pupil. Due to its small size, the inlay is virtually invisible, even in blue eyes.

Flexivue clinical trials to begin soon

Clinical trials of the Flexivue System will begin prior to the end of the year under the direction of Ioannis Pallikaris, MD, PhD, according to the company.

Dr. Pallikaris, director of the Institute of Vision and Optics at the University of Crete, Greece, leads Presbia’s medical advisory board and will train surgeons to perform the Flexivue System at his clinical facilities.

Note: At the time of this posting, the Flexivue System and Flexivue corneal inlay for the treatment of presbyopia have not received FDA approval for use by refractive surgeons in the United States.

SOURCE:  Presbia unveils implantable micro-lens. Ophthalmology Times. October 2, 2009.

The AcuFocus corneal inlay restores near vision lost to normal age-related changes in the lens inside the eye by creating a pinhole camera effect in the cornea to expand depth of focus.

AcuFocus corneal inlay design

The ultra-thin AcuFocus corneal inlay is a small circular device that measures only 3 millimeters (mm) in diameter. By comparison, most soft contact lenses are 14 mm in diameter or larger.

The center of the implant has a very small (1.6 mm) round opening. The inlay is implanted in the center of the cornea, directly in front of the pupil. In this position, the central opening of the inlay acts like the aperture of a camera to increase depth of focus and improve near vision.

The opaque body of the inlay is made of a lightweight biocompatible material called polyvinylidene fluoride. Tiny holes are randomly dispersed throughout the inlay to allow nutrients to pass through the device to keep the underlying cornea healthy.

The corneal implant procedure

The implant procedure for the AcuFocus corneal inlay takes only a few minutes and, like laser eye surgery, is performed on an outpatient basis.

The steps of the procedure are:

1. Numbing eye drops are applied to the eye to prevent discomfort.
2. A femtosecond laser is used to create a small pocket in the center of the cornea.
3. The AcuFocus inlay is implanted in the corneal pocket.

Because there is little tissue disruption, the corneal pocket heals within a few days with no need for stitches. Due to its small size, the implanted corneal inlay is virtually invisible, even in blue eyes.

AcuFocus corneal inlay: Study results

Jason E. Stahl, MD, reported the results of an ongoing European study of the AcuFocus inlay at OSN New York 2009, an educational conference for ophthalmologists held this week in New York.

So far in the study, 70 patients have undergone the AcuFocus corneal implant procedure and 57 patients have been evaluated after a follow-up period of one year.

The mean uncorrected visual acuity of patients receiving the corneal inlay is 20/20 in the distance and 20/20 at a normal reading distance up close, Dr. Stahl said.

There has been no significant loss of distance vision among people receiving the corneal implant, and early results of other studies are mirroring the results of the European study, according to Dr. Stahl.

Note: At the time of this posting, the AcuFocus corneal inlay has not received FDA approval for use by refractive surgeons in the United States.

SOURCE:  Intracorneal inlay improves near vision in presbyopic patients. Ocular Surgery News website (OSNSuperSite.com). September 28, 2009.

Dr. Tan reported the outcomes of presbyopia correction surgery he performed on 15 patients using the corneal implant at the annual meeting of the European Society of Cataract and Refractive Surgeons (ESCRS) held this week in Barcelona, Spain.

The AcuFocus KAMRA corneal implant procedure

The AcuFocus KAMRA intracorneal inlay corrects presbyopia by creating a pinhole camera effect in the central zone of the cornea.

The small (3.8 mm diameter) opaque circular device has a 1.6 mm opening in the center. This small aperture increases depth of focus to improve near vision without significantly affecting distance vision.

The corneal inlay is typically implanted in only one eye of a person with good uncorrected distance vision, producing a modified monovision effect: one eye is left untreated for optimal distance vision and the other eye receives the AcuFocus KAMRA inlay to improve near vision.

The distance vision of the eye receiving the implant may be slightly blurred after the procedure, but usually this is not noticed with both eyes open.

The implantation procedure involves creating a corneal flap (as in LASIK) or a small pocket in the central cornea with a femtosecond laser. The device is then positioned in the center of the cornea. After implantation, the corneal wound self-seals without stitches.

Visual outcomes with the AcuFocus KAMRA corneal inlay

Prior to the procedure, the 15 patients receiving the corneal implant had near uncorrected visual acuity (UCVA) worse than 20/60. One week after surgery, mean near UCVA was 20/30, and one month after surgery it was 20/25, Dr. Tan said.

Binocular distance visual acuity remained the same after the monocular surgery, he said.

In addition to performing the monocular inlay procedure on presbyopes with good distance vision, Dr. Tan has also implanted the AcuFocus KAMRA device as part of a combined surgical procedure for people with nearsightedness, astigmatism and presbyopia.

In the combination procedure, all-laser LASIK is performed on both eyes to correct distance vision, and then the inlay is implanted in one eye to improve near vision.

Dr Tan said the AcuFocus KAMRA corneal inlay is easy to implant and typically has little or no negative affect on the distance vision of the implanted eye and patients retain good depth perception.

The KAMRA device is not yet approved for use in the United States, but clinical trials are underway to fulfill requirements for FDA approval in the near future.

SOURCE:  Intracorneal inlay for presbyopia achieves success in early commercial implantation. Ocular Surgery News website (OSNsupersite.com). September 16, 2009.