Arising innovation in the areas of corneal ring segments, holmium laser thermokeratoplasty (LTK) as well as phakic IOLs is giving new alternatives for patients experiencing keratoconus, myopia, hyperopia and presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) conference in October 2000, Joseph Colin, MD, provided a research of alternatives to passing through keratoplasty for people with keratoconus. Of 23 eyes in 20 individuals, 60% achieved a best-corrected visual acuity of 20/40 or better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, discussed Dr. Colin’s paper, which suggests an option that strengthens the currently compromised cornea rather than further thinning it with LASIK. The suggestion of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a lot of feeling, Dr. Durrie informed Medical care Optometry Information.
” For years, we have actually looked at various other options to corneal transplants for these individuals, as well as some procedures such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been attempted in the past, however they eliminate part of the cornea in a patient populace in which we understand the cornea is currently slim and weak,” Dr. Durrie said.
Due to the fact that the keratoconic eye has a lump in the cornea, Dr. Durrie said, positioning the Intacs insert in the perimeter of the cornea will certainly flatten the corneal facility. This not just lowers the level of nearsightedness, but reinforces the center lump, he claimed. The preferred end result is to delay a corneal transplant for as long as possible.
While the data that Dr. Colin presented show that the procedure is fairly safe, said Dr. Durrie, the longest term data available are just 2 years. “Taking a look at the fads in the 3-month, 6-month and also 1-year information, it shows up that all patients took advantage of the procedure, yet we can’t state that it stopped the keratoconus for longer than that up until more data are accumulated,” he stated. “Although I continue to do this procedure on separated cases, I inform patients we do not recognize the long-lasting impacts as well as we do not understand whether it will slow down, accelerate or have no impact on the normal course of keratoconus.
” The advantage of this procedure is, if it doesn’t function, you can take the Intacs out and also have actually not weakened the cornea,” he continued. “If the individual does require to go on to a corneal transplant, the inserts can be gotten and not interfere with conventional transplant therapy. Due to the change fit of the keratoconic cornea, at some point, people end up being contact lens intolerant, and also it is necessary to understand that there is an alternative to be explored for these individuals aside from simply referring them for a corneal transplant.”
Specialists should make sure that people recognize that the treatment is not refractive surgical procedure as well as will certainly not always fix their nearsightedness, said Dr. Durrie. “I have clients on whom I have actually performed this procedure who have seen 20/40 without glasses, which would be an outstanding outcome after a corneal transplant, but they’re still questioning why their good friends that have actually had Intacs implanted can see 20/20 when they can’t,” he stated. “That’s why these patients require to be educated that this isn’t something that maintains them from wearing glasses. It maintains them from requiring a corneal transplant.”
Hyperopic adjustment with LTK
picture– Post-LTK: The pulses are used in eight spots, one at the 6-mm area and also the various other at the 7-mm area.
Professional research studies have actually shown laser thermokeratoplasty (LTK) to be a reliable approach of correcting a patient’s hyperopia, and also it might also hold promise for treating presbyopia as well as overcorrected myopia after LASIK or PRK, said David J. Conway, OD, supervisor of refractive surgical treatment for Harvard Lead Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK technique and also its results with hyperopia making use of the Hyperion laser (Daybreak Technologies International, Fremont, Calif.) at the International Society of Refractive Surgical procedure’s Summer Globe Refractive Surgical Treatment Symposium 2000. Dr. Conway was not associated with any type of Fda (FDA) research study; his ISRS presentation was based on details from the Daybreak FDA investigations and lectures he attended.
When treating a person for hyperopia, the expert requires to stress the impermanence of the procedure, he claimed. “You need to communicate to the person that this is just a short-term modification in his or her hyperopic condition,” he stated. “There is enough regression with this method that the FDA felt it required to make mention of this.”
Any type of procedure for the correction of hyperopia might demand retreatment gradually; this is not distinct to LTK, said Sandra Belmont, MD, supervisor of the laser vision facility at the Cornell Weill Medical Facility in New York City. “Hyperopia raises as you age,” she said. “We have clients 3 years out who are steady, so I’m very satisfied with the results.”
Dr. Belmont notifies patients of this opportunity, however none have transformed their minds. She stated that if retreatment were needed, individuals did incline due to the fact that the treatment fasts, and also producing a flap, which can lead to complications, is not required.
The LTK treatment
photo– Security: One scientist has patients that are still stable 3 years post-LTK.
The treatment, Dr. Conway claimed, takes 3 secs to perform. 7 pulses are used in 8 places, two times back to back, one at the 6-mm area and also the other at the 7-mm zone. The FDA study reported that the 612 eyes in 379 patients, all older than 40, ranging from +0.75 to +2.50 D, saw no loss in best spectacle-corrected visual acuity (BSCVA) after 2 years, he kept in mind.
” No loss of lines of skill were attributable to the LTK,” he said. “In contrasting preop to 24 months later, there was no loss of BSCVA and a little of gain. We understand that myopes as well as hyperopes are extremely various. Fortunately, the tolerance of hyperopes is really valuable in making their satisfaction level really high.”
Before the treatment, patients obtain 3 successive managements of topical proparacaine at 3-minute intervals. Problems were very little, Dr. Conway noted.
” Individuals are normally managed from a comfort perspective, purely with over-the-counter anesthetics to obtain them through the initial hours of recuperation,” he claimed. “Due to the fact that you’re working with the corneal surface area, FDA detectives reported a bit of foreign-body experience, which dissipates with time extremely well.”
Regression over time
Dr. Conway stated that, while the individual’s skill degree stays fairly stable, some regression appears as the hyperopia enhances gradually. “There will certainly be a little yet significant regression in these individuals; it’s just a matter of whether it goes to a low sufficient degree to warrant the individual’s price as well as experience of undergoing this method,” he stated. “By contrasting your cycloplegic to your reveal refraction, you can tell whether it’s latent hyperopia or not.”
A person’s age consider to the length of time the effect of LTK may last, claimed Dr. Conway. “A 50-year-old person will experience a bit more impact than a 40-year-old person, maybe due to a little bit a lot more dryness or the collagen status of the cornea,” he said.
An off-label indication of LTK is the therapy of presbyopia, claimed Dr. Belmont. Patients that are plano as well as presbyopic might be treated with LTK to attain monovision, she said. “Today, their analysis vision comes into focus,” she claimed. “They obtain their outcomes quickly, and also they’re really delighted with that.”
Clients that have been dealt with for presbyopia commonly will come across the exact same level of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia increases as you age, as does hyperopia,” she claimed. “Individuals know that this treatment will need to be enhanced as their aging demands a rise in the power they’ll need to read. They’re happy as long as you tell them ahead of time. I anticipate this as being the procedure to treat farsightedness as well as presbyopia.”
The size of time needed for presbyopic therapy coincides as for that of hyperopia, yet the degree of power that is applied to the eye is varied, she said.
The procedure might additionally verify to be a valid option for boosting nearsighted clients who have been overcorrected with LASIK or PRK, said Dr. Conway. “This merits a lot of factor to consider, since you do not need to remove any kind of tissue,” he claimed. “In addition, Sunup is submitting for authorization remediation of presbyopia, making people myopic in a monovision fashion. So, I assume this will end up being a fairly preferred and common alternative in this individual population, and we’ll see the amount of more cosmetic surgeons choose to accept it.”
LTK is authorized for as much as +2.5 D, stated Dr. Belmont, as well as is presently going through tests for therapy as much as +5.6 D.
Refractec’s conductive keratoplasty
Preliminary medical tests recommend that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency technique is possibly safe as well as reliable for dealing with low to modest quantities of hyperopia, according to Dime A. Asbell, MD, who offered scientific trial information in Miami at the International Society of Refractive Surgical treatment conference. “Very early outcomes with our information bent on year suggest that we get fantastic visual acuity, excellent stability as well as actually no damaging events, such as loss of vision,” stated Dr. Asbell.
CK heats the stromal cells with an electrical present, reduces the collagen and also steepens the main cornea, Dr. Asbell clarified. A high-frequency present is applied directly right into the outer corneal stroma with a delivery suggestion put at eight or even more therapy points. The release of radiofrequency power warms the surrounding collagen to an identical temperature level of 65 ° C as well as produces a cylindrical footprint 500 µm deep vs. a shallower, conical impact made with the LTK technique. A cycle of CK-treated areas cinches the cornea and also boosts its curvature to lower hyperopia.
” The modification seems to be long-term, and also I believe among the reasons that holds true is that the treatment is delivered directly to the stroma,” said Dr. Asbell. “That’s where you desire the impact– not on the endothelium, not on the epithelium. It’s an extremely simple medical strategy. It’s a non-laser strategy, as well as it adds another dimension to what we already can supply for refractive surgical treatment– it is an economical procedure,” she included.
An additional key problem, Dr. Asbell pointed out, is that CK is a consistent therapy. “The treatment dimension as well as the zone result in the stroma are consistent from treatment area to treatment place,” she said. “Among the crucial issues to remember is that the temperature we get with the CK procedure is constantly 65 ° as well as the imprint you make within the outer corneal stroma is always the exact same: 100 µm broad and 500 µm deep within the corneal stroma.”
Dr. Asbell is a private investigator in the FDA professional trial of CK. Fellow detectives at various other websites consist of Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; and also Edward E. Manche, MD
. Of the 54 patients on whom Dr. Asbell reported, the typical age was 55, although, she said, there is a rather wide variety of age amongst the trial’s participants. To qualify for the trial, she explained, patients had to have uncorrected visual acuity of at the very least 20/40 or worse and poor near vision too– standard for a hyperope. “We are remedying from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She worried the rate and also simpleness of the procedure. “This procedure takes 5 mins per eye. It is a very short treatment; you remain in and also out very promptly,” she said. “It is a procedure, but a very straightforward one. It does not require a skilled technician [to help] It doesn’t also need an autoclave. The suggestion, which is about the width of a hair, is disposable.”
Dr. Asbell defined the CK nomogram therefore: “The treatment is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [indicating the size of the therapy area] The level of hyperopia you are fixing determines the number of therapy marks on the cornea. Each one coincides– the very same amount of power and also the very same deepness within the stroma in each place,” she said.
Results appear secure
Of the clients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or far better 6 months postoperatively and 96% were 20/40 or better at the 6-month mark. One year postoperatively, 62% were 20/20 or much better, and also 92% were 20/40 or much better. “Our outcomes look excellent and also secure. These are very delighted clients,” said Dr. Asbell. “They really can go back to work promptly or certainly the next day if they so choose. No person takes discomfort medications.”
Safety variables were “generally zero,” Dr. Asbell reported. “There was no loss of vision and also no corneal edema,” she claimed. “I think this is mosting likely to be a procedure as well as a device that’s mosting likely to be easy for us to possess and also to use as well as a superb way to remedy hyperopia postop LASIK or to retouch a postop cataract or corneal transplant,” she claimed. “I think it’s mosting likely to have a lot of adaptability in terms of its uses for remedying hyperopia and possibly astigmatism.”
Increased medical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually expanded its scientific trial studies of laser presbyopia reversal (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Additionally, the firm has actually arranged installment of the IR-laser in some European nations.
SurgiLight has submitted four documents to the American Society of Cataract and also Refractive Surgical Procedure for the May 2001 conference, where more than 500 situations of LAPR will certainly exist by ophthalmologists from numerous countries using the company’s IR laser.
The business is in the process of acquiring CE-Mark accreditation as well as choosing numerous international representatives. It plans to submit additional 510K applications based upon specific clearances gotten from Premier Laser Solutions. SurgiLight anticipates to bill a royalty cost of $500 per client to cosmetic surgeons that make use of the company’s IR-3000 system in the United States as well as Europe.
B&L NuVita phakic IOL
The third generation of George Baikoff, MD’s, anterior chamber phakic IOL is stood for with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is available for myopes varying from 7 D to 20 D. The design is an angle-fixated, single-piece lens, with a meniscus optical shape and a PMMA surface area. The overall optical size is 5 mm and the total size of the NuVita ranges from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loop and footplate were all revamped from the previous version to minimize refracted glow, stress in the angle and much better clearance of the iris as well as natural lens. Likewise, the haptics were redesigned to remove iris retraction. The haptics were made a lot more flexible as well as, for that reason, caused less student ovalization.
In its 2nd generation, the fluorine plasma therapy was included in the production procedure to develop covalent bonds of fluorocarbon radicals with the PMMA surface, which yielded reduced surface energy and extremely smooth coating. The fluorine treatment greatly improved biocompatibility.
In researches conducted by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes dental implanted revealed an accuracy price of ± 0.5 D while 97% revealed a precision rate of ± 2 D. In terms of safety and security, the BSCVA rates had 47 acquiring at least 2 lines, and also no eyes shed lines. The total glare report revealed that many people had couple of issues.
According to Mike Landreville, international supervisor for refractive modern technologies at Bausch & Lomb, the company has no intention of presenting the NuVita lens into the USA for FDA approval or for scientific use. Rather, the firm is establishing an entire new phakic technology for a foldable former chamber phakic lens. The brand-new phakic lens will certainly not just exist as a new lens, yet as part of an entirely new system, totally different from the NuVita line. The new, unnamed lens system will be of a new product, integrate a brand-new collapsible delivery system and offer a new diagnostic tool for implantation.
According to Mr. Landreville, the company plans to have the new system prepared for professional usage in the USA by this year.
Alcon phakic IOL
A brand-new former chamber phakic IOL was presented by Andrew Maxwell, MD, PhD, at the AAO conference. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) product and has a number of benefits over various other phakic IOLs such as its foldability, which permits the lens to be put via a cut smaller than 3 mm, in addition to an angle-fixated, single-piece design and high biocompatibility. The distance between the cornea and the implant also drops in between 2.96 mm as well as 3.35 mm, a bigger distance than with some other lenses, he said.
Dr. Maxwell reported that of the 10 implants that have actually been performed to day, greater than 90% of the patients have 20/40 or much better uncorrected vision at their postoperative check outs. The mean round equivalent in individuals dental implanted so far was– 11.5 D, he said, with a result of– 0.39 D at 1 month as well as– 0.8 D at 6 months of recurring myopia.
” We see significant improvement in best-corrected visual acuity, and also in all but one person the postoperative ideal dealt with vision is far better than the best preoperative vision; in a lot of cases, there are 2-, 3- or 4-line increases in best-corrected visual acuity,” Dr. Maxwell said. “In the one case where it wasn’t better, it coincided as the preoperative acuity.”
CIBA gets licenses for IOL
CIBA Vision introduced at the AAO meeting that it has actually obtained three licenses from Dr. Baikoff for foldable phakic anterior chamber IOL makes to fix not just myopia as well as hyperopia however additionally presbyopia.
” We are really thrilled concerning this new innovation,” David Bailey, medical organization device president for CIBA, claimed. “We believe that the MemoryLens product incorporated with these anterior chamber styles will certainly be a very successful mix.”
That former chamber lens campaign complements one more refractive dental implant that was the topic of numerous presentations in the CIBA Vision cubicle– the PRL. This posterior-chamber phakic implant is being established by Medennium Inc. CIBA Vision took a 10% equity risk in Medennium in July and also now holds exclusive worldwide advertising and marketing as well as circulation legal rights to the lens, which is currently in phase 2 medical trials.
” We are taking a strong placement in phakic IOLs,” Mr. Bailey stated, “as well as we’ll be strengthening that position with even more new technology.”
This is the way to deal with nearsightedness, ypermetropia as well as astigmatism (μυωπια ).