Emerging innovation in the locations of corneal ring sections, holmium laser thermokeratoplasty (LTK) and phakic IOLs is offering new alternatives for clients suffering from keratoconus, myopia, hyperopia as well as presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) meeting in October 2000, Joseph Colin, MD, presented a research study of choices to penetrating keratoplasty for clients with keratoconus. Of 23 eyes in 20 people, 60% achieved a best-corrected visual acuity of 20/40 or much better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, talked about Dr. Colin’s paper, which suggests an option that strengthens the already compromised cornea instead of additional 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 sense, Dr. Durrie told Health care Optometry News.
” For many years, we have actually taken a look at various other alternatives to corneal transplants for these patients, and some procedures such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been attempted in the past, but they remove part of the cornea in a person population in which we know the cornea is currently thin and also weak,” Dr. Durrie stated.
Since the keratoconic eye has a lump in the cornea, Dr. Durrie stated, putting the Intacs put in the periphery of the cornea will squash the corneal facility. This not only reduces the level of myopia, yet reinforces the facility lump, he said. The preferred result is to postpone a corneal transplant for as long as possible.
While the information that Dr. Colin presented show that the treatment is rather safe, stated Dr. Durrie, the longest term data available are just 2 years. “Checking out the fads in the 3-month, 6-month as well as 1-year data, it appears that all individuals benefited from the treatment, however we can’t claim that it quit the keratoconus for longer than that till further information are built up,” he stated. “Although I remain to do this treatment on separated situations, I tell people we don’t know the long-lasting effects and also we do not recognize whether it will certainly decrease, speed up or have no result on the normal course of keratoconus.
” The advantage of this treatment is, if it does not function, you can take the Intacs out and have actually not weakened the cornea,” he proceeded. “If the patient does need to go on to a corneal transplant, the inserts can be gotten and not interfere with common transplant therapy. Due to the modification fit of the keratoconic cornea, at some point, clients become contact lens intolerant, as well as it’s important to understand that there is a different to be examined for these patients besides simply referring them for a corneal transplant.”
Specialists need to make certain that individuals recognize that the procedure is not refractive surgery and will not always remedy their nearsightedness, stated Dr. Durrie. “I have clients on whom I have actually executed this procedure that have seen 20/40 without glasses, which would certainly be an outstanding result after a corneal transplant, however they’re still asking yourself why their close friends that have had Intacs implanted can see 20/20 when they can not,” he stated. “That’s why these patients need to be educated that this isn’t something that keeps them from putting on glasses. It keeps them from needing a corneal transplant.”
Hyperopic modification with LTK
photograph– Post-LTK: The pulses are used in 8 spots, one at the 6-mm area and the various other at the 7-mm area.
Scientific studies have shown laser thermokeratoplasty (LTK) to be an effective technique of remedying a client’s hyperopia, and it may likewise hold guarantee for dealing with presbyopia and overcorrected myopia after LASIK or PRK, said David J. Conway, OD, supervisor of refractive surgical treatment for Harvard Vanguard Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK method and also its outcomes with hyperopia using the Hyperion laser (Sunrise Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical procedure’s Summer season World Refractive Surgical Treatment Seminar 2000. Dr. Conway was not involved in any Food and Drug Administration (FDA) research; his ISRS discussion was based upon details from the Dawn FDA investigations and lectures he participated in.
When dealing with a client for hyperopia, the practitioner needs to stress the brevity of the treatment, he stated. “You need to convey to the patient that this is just a short-lived adjustment in his or her hyperopic standing,” he stated. “There is enough regression with this strategy that the FDA felt it needed to refer this.”
Any kind of treatment for the adjustment of hyperopia might require retreatment over time; this is not unique to LTK, claimed Sandra Belmont, MD, supervisor of the laser vision facility at the Cornell Weill Medical Center in New York City City. “Hyperopia boosts as you age,” she said. “We have people 3 years out who are stable, so I’m very happy with the outcomes.”
Dr. Belmont notifies clients of this opportunity, yet none have altered their minds. She said that if retreatment were required, individuals did incline because the procedure is quick, and creating a flap, which can result in problems, is not essential.
The LTK treatment
photo– Stability: One scientist has clients who are still steady 3 years post-LTK.
The treatment, Dr. Conway said, takes 3 seconds to do. 7 pulses are applied in eight areas, twice consecutively, one at the 6-mm zone as well as the other at the 7-mm zone. The FDA study reported that the 612 eyes in 379 clients, all older than 40, varying from +0.75 to +2.50 D, saw no loss in ideal spectacle-corrected visual acuity (BSCVA) after 2 years, he kept in mind.
” No loss of lines of acuity were attributable to the LTK,” he claimed. “In comparing preop to 24 months later, there was no loss of BSCVA as well as a little bit of gain. We understand that myopes and hyperopes are very various. Luckily, the tolerance of hyperopes is extremely helpful in making their satisfaction degree very high.”
Before the treatment, individuals obtain three successive administrations of topical proparacaine at 3-minute periods. Difficulties were very little, Dr. Conway noted.
” Clients are generally taken care of from a convenience standpoint, purely with over-the-counter anesthetics to get them through the very first hours of recovery,” he stated. “Since you’re dealing with the corneal surface area, FDA detectives reported a little of foreign-body sensation, which dissipates with time really well.”
Regression with time
Dr. Conway claimed that, while the individual’s skill degree remains rather stable, some regression appears as the hyperopia raises gradually. “There will certainly be a small however substantial regression in these people; it’s simply a matter of whether it’s at a reduced adequate degree to warrant the person’s price and experience of undertaking this strategy,” he claimed. “By comparing your cycloplegic to your manifest refraction, you can tell whether it exists hyperopia or otherwise.”
An individual’s age factors in to how long the impact of LTK may last, said Dr. Conway. “A 50-year-old patient will experience a little bit more effect than a 40-year-old individual, probably due to a bit much more dryness or the collagen status of the cornea,” he stated.
An off-label sign of LTK is the treatment of presbyopia, stated Dr. Belmont. People who are plano and presbyopic might be treated with LTK to achieve monovision, she stated. “As soon as possible, their reading vision enters focus,” she said. “They get their outcomes promptly, and they’re truly happy with that said.”
People that have actually been dealt with for presbyopia normally will come across the exact same level of regression as hyperopes, Dr. Belmont noted. “Presbyopia enhances as you age, as does hyperopia,” she said. “Individuals understand that this procedure will certainly have to be improved as their aging requires an increase in the power they’ll need to read. They enjoy as long as you tell them ahead of time. I anticipate this as being the treatment to treat farsightedness and also presbyopia.”
The size of time needed for presbyopic therapy is the same when it comes to that of hyperopia, however the degree of power that is applied to the eye is varied, she stated.
The treatment might also prove to be a valid alternative for boosting short-sighted clients who have actually been overcorrected with LASIK or PRK, said Dr. Conway. “This benefits a lot of factor to consider, because you do not need to get rid of any type of cells,” he stated. “In addition, Dawn is sending for approval removal of presbyopia, making patients short-sighted in a monovision fashion. So, I believe this will become a fairly preferred and also common option in this patient population, and also we’ll see how many even more doctors decide to welcome it.”
LTK is authorized for as much as +2.5 D, claimed Dr. Belmont, as well as is currently going through tests for treatment as much as +5.6 D.
Refractec’s conductive keratoplasty
Preliminary scientific trials recommend that conductive keratoplasty (CK) making use of Refractec’s (Irvine, Calif.) radiofrequency approach is most likely secure and reliable for dealing with low to modest amounts of hyperopia, according to Dime A. Asbell, MD, who presented scientific test data in Miami at the International Culture of Refractive Surgical treatment conference. “Very early outcomes with our information out to year suggest that we obtain terrific visual acuity, excellent stability as well as really no unfavorable events, such as loss of vision,” said Dr. Asbell.
CK heats the stromal tissue with an electric present, diminishes the collagen as well as steepens the main cornea, Dr. Asbell discussed. A high-frequency existing is applied straight into the outer corneal stroma with a delivery tip put at 8 or more therapy points. The launch of radiofrequency power heats up the bordering collagen to an identical temperature level of 65 ° C as well as creates a round footprint 500 µm deep vs. a shallower, cone-shaped footprint made with the LTK method. A cycle of CK-treated spots cinches the cornea and also boosts its curvature to lower hyperopia.
” The adjustment seems to be permanent, and also I believe among the reasons that’s true is that the therapy is supplied straight to the stroma,” claimed Dr. Asbell. “That’s where you want the result– out the endothelium, out the epithelium. It’s a very simple surgical technique. It’s a non-laser strategy, as well as it includes one more measurement to what we already can use for refractive surgical treatment– it is a cost-effective procedure,” she included.
CK is consistent
Another key concern, Dr. Asbell explained, is that CK is a constant therapy. “The treatment size as well as the zone impact in the stroma correspond from treatment spot to therapy area,” she claimed. “One of the crucial problems to remember is that the temperature level we get with the CK procedure is constantly 65 ° and also the imprint you make within the outer corneal stroma is constantly the same: 100 µm wide and also 500 µm deep within the corneal stroma.”
Dr. Asbell is a detective in the FDA clinical test of CK. Other detectives at various other websites consist of Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; and Edward E. Manche, MD
. Of the 54 clients on whom Dr. Asbell reported, the common age was 55, although, she claimed, there is a relatively large range of age among the trial’s participants. To receive the trial, she described, clients had to have uncorrected visual acuity of at least 20/40 or even worse as well as inadequate near vision as well– common for a hyperope. “We are fixing from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She emphasized the rate and simpleness of the procedure. “This procedure takes 5 mins per eye. It is an extremely short treatment; you’re in and out really rapidly,” she claimed. “It is an operation, yet an extremely basic one. It does not call for a skilled technician [to assist] It does not even call for an autoclave. The idea, which has to do with the width of a hair, is disposable.”
Dr. Asbell described the CK nomogram as such: “The treatment is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [showing the dimension of the therapy zone] The degree of hyperopia you are fixing identifies the number of treatment marks on the cornea. Every one is the same– the exact same amount of power and the exact same deepness within the stroma in each area,” she stated.
Outcomes appear stable
Of the patients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or much better 6 months postoperatively and also 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 far better. “Our results look excellent and also secure. These are extremely pleased patients,” said Dr. Asbell. “They really can return to work right away or absolutely the following day if they so pick. No person takes pain medicines.”
Safety and security variables were “basically zero,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she said. “I believe this is mosting likely to be a treatment and also a machine that’s mosting likely to be simple for us to have and to use as well as an exceptional method to deal with hyperopia postop LASIK or to retouch a postop cataract or corneal transplant,” she said. “I assume it’s mosting likely to have a great deal of versatility in regards to its usages for dealing with hyperopia and also perhaps astigmatism.”
Increased clinical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually increased its medical trial research studies of laser presbyopia reversal (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas as well as Japan. Likewise, the company has set up installation of the IR-laser in some European countries.
SurgiLight has submitted 4 papers to the American Society of Cataract as well as Refractive Surgery for the May 2001 conference, where greater than 500 situations of LAPR will exist by ophthalmologists from various countries using the company’s IR laser.
The firm remains in the process of obtaining CE-Mark qualification and selecting various international suppliers. It plans to submit added 510K applications based on particular clearances obtained from Premier Laser Solutions. SurgiLight expects to charge an aristocracy fee of $500 per individual to cosmetic surgeons that utilize the company’s IR-3000 system in the United States and also Europe.
B&L NuVita phakic IOL
The 3rd generation of George Baikoff, MD’s, former chamber phakic IOL is represented with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is readily available for myopes varying from 7 D to 20 D. The layout is an angle-fixated, single-piece lens, with a crescent optical form and also a PMMA surface area. The total optical size is 5 mm and also the overall size of the NuVita varies from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loophole as well as footplate were all revamped from the previous variation to minimize refracted glow, pressure in the angle and also far better clearance of the iris as well as all-natural lens. Likewise, the haptics were redesigned to get rid of iris retraction. The haptics were made a lot more flexible as well as, consequently, caused much less pupil ovalization.
In its 2nd generation, the fluorine plasma therapy was included in the production process to develop covalent bonds of fluorocarbon radicals with the PMMA surface area, which produced lower surface area power and also exceptionally smooth surface. The fluorine treatment greatly enhanced biocompatibility.
In researches performed by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted revealed a precision rate of ± 0.5 D while 97% showed an accuracy rate of ± 2 D. In terms of safety and security, the BSCVA rates had 47 obtaining a minimum of 2 lines, as well as no eyes shed lines. The overall glow report revealed that a lot of people had couple of issues.
According to Mike Landreville, worldwide supervisor for refractive modern technologies at Bausch & Lomb, the business has no intention of presenting the NuVita lens right into the USA for FDA approval or for medical use. Rather, the firm is creating a whole brand-new phakic modern technology for a collapsible anterior chamber phakic lens. The brand-new phakic lens will certainly not only exist as a new lens, but as part of an entirely brand-new system, totally different from the NuVita line. The new, unrevealed lens system will certainly be of a new product, include a brand-new collapsible delivery system and supply a new diagnostic device for implantation.
According to Mr. Landreville, the firm intends to have the brand-new system ready for clinical use in the United States by this year.
Alcon phakic IOL
A brand-new former chamber phakic IOL was presented by Andrew Maxwell, MD, PhD, at the AAO meeting. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) product and also has a number of advantages over other phakic IOLs such as its foldability, which allows the lens to be inserted through a cut smaller than 3 mm, as well as an angle-fixated, single-piece style and high biocompatibility. The range between the cornea as well as the dental implant likewise drops between 2.96 mm as well as 3.35 mm, a larger range than with some other lenses, he claimed.
Dr. Maxwell reported that of the 10 implants that have actually been done to day, more than 90% of the people have 20/40 or far better uncorrected vision at their postoperative visits. The mean round matching in people dental implanted thus far was– 11.5 D, he claimed, with an outcome of– 0.39 D at 1 month and also– 0.8 D at 6 months of residual nearsightedness.
” We see considerable enhancement in best-corrected visual acuity, and in all yet one individual the postoperative ideal remedied vision is far better than the best preoperative vision; in many cases, there are 2-, 3- or 4-line increases in best-corrected visual acuity,” Dr. Maxwell stated. “In the one situation where it wasn’t much better, it was the same as the preoperative acuity.”
CIBA obtains licenses for IOL
CIBA Vision announced at the AAO conference that it has actually obtained three patents from Dr. Baikoff for collapsible phakic former chamber IOL creates to deal with not just myopia and also hyperopia however also presbyopia.
” We are extremely excited regarding this brand-new innovation,” David Bailey, medical service unit head of state for CIBA, stated. “We assume that the MemoryLens material integrated with these anterior chamber layouts will be a very successful mix.”
That anterior chamber lens campaign enhances one more refractive dental implant that was the topic of a number of discussions in the CIBA Vision booth– the PRL. This posterior-chamber phakic dental implant is being created by Medennium Inc. CIBA Vision took a 10% equity risk in Medennium in July and currently holds exclusive around the world marketing as well as distribution rights to the lens, which is currently in phase 2 clinical trials.
” We are taking a strong position in phakic IOLs,” Mr. Bailey said, “and we’ll be strengthening that position with more new technology.”
This is the way to treat myopia, ypermetropia and astigmatism (αστιγματισμος ).