In our cover story, Dick Lindstrom, MD, does an excellent job of listing all the intracorneal inlays that are available today. He summarizes their physical properties, their progress in clinical trials and their regulatory status. As always, your comments and questions are most welcome! Also, please don’t forget to register for the 2007 ISRS/AAO annual regional meeting in Beijing, Expanding Horizons in Refractive and Cataract Surgery. Advance registration closes on April 11, 2007. -- Marguerite McDonald, MD, FACS
- What’s New With Intracorneal Inlays
- CATz ablation appears useful in treating corneal irregularities induced by refractive surgery or corneal injury
- LASEK may be preferable to LASIK for low myopia
- Femtosecond laser achieves better contrast sensitivity results at high spatial frequencies under mesopic conditions
- Corneal ectasia can occur after hyperopic LASIK in patients with or without recognized preoperative risk factors
- Contact lens tolerance is restored in most keratoconus patients treated with intacs
- Aspherical IOL results in better optical quality compared to spherical IOL
- LASIK eleven years on
- Registration for the 2007 ISRS/AAO meeting is now open
- Help us tell the story of ISRS/AAO, send us your photos
- FDA approves Alcon's aspheric multi-focal IOL
- Bausch & Lomb plans to purchase a company developing corneal inlay technology
- AMO acquires WaveFront Sciences Inc.
- Upcoming meetings
CATz ablation appears useful in treating corneal irregularities induced by refractive surgery or corneal injury
This evaluation of 32 eyes shows that topography-guided CATz ablation effectively improves UCVA, BSCVA, SRI, SAI, higher order aberrations, as well as subjective symptoms in most patients. However, residual or induced refractive errors may need to be corrected with a second operation after CATz. American Journal of Refractive Surgery, February 2007
LASEK may be preferable to LASIK for low myopia
This prospective, nonrandomized study of 79 eyes finds that visual recovery is slower after LASEK, but BSCVA and the safety index are slightly better. Postoperative UCVA was significantly better after LASIK on day one and day seven postop, but this difference was insignificant by one and three months postop. At three months, BSCVA was slightly but significantly better in LASEK eyes. Journal of Refractive Surgery, February 2007
Femtosecond laser achieves better contrast sensitivity results at high spatial frequencies under mesopic conditions
The IntraLase femtosecond laser and a mechanical microkeratome were used to create flaps in 100 LASIK patients. Compared to mechanical LASIK, IntraLASIK surgery demonstrated better contrast sensitivity under mesopic conditions at 12 cpd and photopic and mesopic conditions at 18 cpd. Journal Refractive Surgery, February 2007
Corneal ectasia can occur after hyperopic LASIK in patients with or without recognized preoperative risk factors
Researchers describe two case reports: a 47-year-old man who developed ectasia at six months postop, whose preoperative topography was suggestive of early pellucid marginal corneal degeneration. A 35-year-old patient with normal preoperative topography developed ectasia in one eye more than three years after bi-lateral surgery. Journal of Refractive Surgery , January 2007
Contact lens tolerance is restored in most keratoconus patients treated with intacs
This two-year, prospective study of 100 eyes with moderate to severe keratoconus shows contact lens tolerance was restored in more than 80 percent of cases. Both BSCVA and UCVA showed a marked and stable improvement. Intacs were removed from four eyes without complications or sequelae. Journal of Cataract & Refractive Surgery, January 2007
Aspherical IOL results in better optical quality compared to spherical IOL
An evaluation of optical aberrations in eyes having uneventful cataract surgery finds the aspherical IOL yielded better ocular aberration and optical quality. Induced coma was somewhat higher in the aspherical group, but overall results were unaffected. Physiologic IOL decentration after correct in-the-bag implantation did not negate the advantages of asphericity. Journal of Cataract & Refractive Surgery, February 2007
LASIK eleven years on
Eleven years of follow-up on seven patients who had myopic LASIK shows the procedure is moderately predictable in the correction of high degrees of myopia. Refractive and topographic stability were obtained at six months postop. No sight-threatening complications occurred. Journal of Cataract & Refractive Surgery, February 2007
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Registration for the 2007 ISRS/AAO meeting is now open
Advance registration is from Jan. 24 to April 11, 2007. ISRS/AAO presents this regional meeting in partnership with the Chinese Ophthalmological Society and the Asia-Pacific Association of Cataract and Refractive Surgeons. It will be held May 26 - 27, 2007.
Help us tell the story of ISRS/AAO, send us your photos
To honor ISRS’ 20th anniversary Jorge Alio, MD, has arranged to have published a history of our organization, from its formation and growth to its current status as the world’s largest and strongest eye care organization dedicated solely to refractive surgery. If you have photos that would help tell our story, please forward them to Annamarie Hastings at firstname.lastname@example.org. The book will be presented during the ISRS/AAO Gala Dinner & Dance during the Academy’s 2007 Annual Meeting in New Orleans. Photos need to be at least 300 dpi and no smaller than 4 X 4 inches. If you have many images or very large images, you may post them on our FTP site at ftp://ftp.aao.org (Username: isrsaao Password: isrsaao). To import your images, create a new folder labeled with your full name, and then drag and drop the images from your computer into the folder on the FTP site. Lastly, please e-mail email@example.com to let us know of your contribution. If you need assistance, call Annamarie at +1-415-447-0398.
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INDUSTRY NEWSFDA approves Alcon’s aspheric multi-focal IOL
A company press release states the new version of the ReSTOR IOL is now the only FDA-approved, presbyopia-correcting IOL with an aspheric optic design.
Bausch & Lomb plans to purchase a company developing corneal inlay technology
The company reports that it has made an equity investment in AcuFocus, Inc. The AcuFocus ACI 7000(TM) is designed to treat presbyopia in all patients, including those who have had cataract surgery.
AMO acquires WaveFront Sciences Inc.
In its second acquisition in as many weeks, AMO reports that it purchased the privately-held Albuquerque company for $20 million. Last week, AMO announced that it would buy IntraLase Corp.
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|UPCOMING MEETINGS || |
|March 8 - 10, 2007 |
Alicante Refractiva Internacional 2007
|May 26-27, 2007|
2007 ISRS/AAO Meeting:
Expanding Horizons in Refractive and Cataract Surgery
|March 29-April 1, 2007 |
International IX Congress of the Middle East African Council of Ophthalmology
Dubai, United Arab Emirates
|May 31 - June 3, 2007 |
XXVII Pan-American Association of Ophthalmology
November 9 -10, 2007
American Academy of Ophthalmology's Refractive Surgery Subspecialty Day
New Orleans, Lousiana
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What's New With Intracorneal Inlays
Richard L. Lindstrom, MD
There are about 62 million emmetropic presbyopes in the United States today, which includes approximately 44 million who are naturally occurring; 6 million post-LASIK emmetropic presbyopes, and 12 million post-cataract emmetropic presbyopes. It goes without saying that, as the population ages, with longer life expectancies, the ranks of emmetropic presbyopes will grow.
Effective treatment for presbyopia
There is a new class of treatment in development for presbyopes: small diameter intracorneal inlays, implants designed to correct presbyopia without intraocular surgery. This treatment has been shown to improve reading vision without significant detriment to distance vision, making it an exciting treatment option for emmetropic presbyopes. Emerging results from clinical trials at both international and US sites are promising.
There are four products currently in development: AcuFocus/Bausch & Lomb ACI 7000®, AcuFocus/Bausch & Lomb Hydrogel lens®, ReVision Optics PresbyLens® and Biovision's Invue Intracorneal Microlens system.
Intracorneal inlays are good news for both surgeons and patients. These implants offer new opportunities to expand the LASIK market because inlays are appropriate for both presbyopic patients undergoing LASIK, and also existing LASIK patients who may be experiencing recent onset presbyopia.
Many surgeons believe this may be an optimal solution for correcting the emmetropic presbyope. Procedures for all four implants are fast, without a steep learning curve and offer relatively easy explantation for those patients who might wish to exchange the implant to compensate for presbyopic progression that may occur later.
Bausch & Lomb/AcuFocus Hydrogel Lens
This meniscus lens is constructed of 45 percent Hydrogel: Hefilcon–A, with a diopter range of +1.50 to +3.50. The lens thickness ranges from 0.03 to 0.006mm, and its diameter is 1.80 to 2.20mm, with a resolution of =3/4 AFTR. Near vision improvement is achieved when a multi-focal cornea is created by utilizing the different refractive indices of the hydrogel lens and the cornea.
In one study, eight patients were implanted monocularly with the lens in a modified monovision approach, and examined five years later. Their typical vision was 20/25 at distance and near, with reading distance ranges from 7”-16”, averaging about 14” comfortably. The loss of distance with best corrected vision, versus the other eye, is one letter to one line. This lens also works in phakic and pseudophakic patients.
At five years the pocket incision was still visible. The surgical technique is straightforward. Explantation is possible with no permanent loss of vision or adverse reaction. The lens material was well-tolerated by patients with few pigment deposits detected. Every patient was satisfied with their results, and 75 percent were spectacle-free. Only one patient noticed “ghosts” and no one complained of halos.
Biovision Invue™ Intracorneal Microlens System
Biovision’s intracorneal microlens is a made of water-permeable, biocompatible hydrogel, 20 µm thick and 3 mm in diameter. This Invue system positions the lens in a tunnel, 200 µm to 400 µm deep, in the center of the cornea in a patient’s non-dominant eye.
The system offers implantation within minutes and stable centration of the lens, giving steady and permanent near visual acuity/improvement. If required, lens removal is easily accomplished without loss of tissue.
Biovision’s Visitome 20-10 microkeratome and blade cartridges are used to cut a precise corneal tunnel, and an inserter is used to position the lens precisely in the center of the eye.
This lens is for the emmetropic presbyope whose cornea is the proper power for distance with no astigmatism. By adding plus power to the cornea with a hydrogel material that has a higher refractive index than the cornea, an emmetropic cornea is transformed into a multifocal cornea. The lens is also appropriate for patients who are emmetropic as a result of refractive or cataract surgery.
A multifocal cornea significantly improves a patient’s ability to read. Potential drawbacks include a small loss of contrast sensitivity and an induction of mild night-vision symptoms; primarily halo, as occurs with other multifocal optics. However, the lens is monocularly implanted, and it is the extremely rare patient who is bothered significantly by optical aberration problems. In clinical trials presbyopia was corrected in nearly all cases that received an implant. The material was well-tolerated and, after surgery, patients rapidly gained their near vision, resulting in a high degree of patient satisfaction.
In a preliminary clinical evaluation 13 patients had a mean vision of 20/40 at distance without correction. Preoperatively, four patients had 20/100 uncorrected near vision. At one month postop, two patients were at 20/25; the other two were at 20/20. Side effects have included loss of distance acuity, halo, decentration and mild interface haze.
Bausch & Lomb/AcuFocus ACI 7000™ Inlay
The ACI is an ultra-thin, 10 µm disc made of Kynar®, an opaque biocompatible polymer with a small aperture in the center, like a camera’s pinhole, where the peripheral rays are obscured and the central rays pass unaffected.
Both preoperative preparation and postoperative care are handled in the same way as a standard LASIK procedure. A corneal flap is cut using a mechanical microkeratome or IntraLase. The ACI 7000 is then placed on the stromal bed over the pupil of the non-dominant eye, increasing the eye’s depth of focus by reducing the circle of blur. The flap is then replaced. Appropriate post-surgical care is consistent with that for standard LASIK.
The ACI 7000 has been used to treat up to 2 D of presbyopia, and significantly improves near visual acuity with minimal loss of distance visual acuity. Patients also have good intermediate visual acuity.
Clinical results for mean visual acuity indicate that 59 pre-operative patients had 20/20 UCDVA, with UCNVA at J-9. Three months later, 51 patients maintained a MVA of 20/20. UCDVA, UCIVA and UCNVA was J-2.
ReVision Optics PresbyLens®
The PresbyLens, developed by ReVision Optics (formerly IntraLens), is a promising new treatment for presbyopia that has also been extensively studied for hyperopia correction.
Made from a proprietary micro-porous hydrogel material called Nutrapore®, the PresbyLens is composed of 78 percent water, with the same refractive index as the human cornea. It is also the first bio-engineered intracorneal implant to be used for keratophakia. This lens is used to change the anterior curvature of the cornea when placed under a LASIK flap.
One and one-half millimeters in diameter, the PresbyLens is an intracorneal implant designed to provide a central near add zone and a paracentral intermediate zone, which allows the remaining cornea to be used for distance vision.
The lens is placed in the patient's nondominant eye, and can be combined with LASIK, with bilateral plano vision as the objective.
Currently ReVision Optics is operating clinical trials at several international sites to evaluate PresbyLens for presbyopia correction. Clinical trials are also underway in the US to determine this lens’ efficacy in hyperopia up to +6 D.
Intracorneal inlays are potentially safe, simple and minimally invasive procedures that present a new solution for presbyopes in all ranges – including the emmetropic patient. Research data continues to suggest that inlay technology offers promising results and high patient satisfaction, by preserving distance vision and enhancing near vision.
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