Arising innovation in the areas of corneal ring segments, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is offering brand-new options for people experiencing keratoconus, nearsightedness, hyperopia as well as presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) meeting in October 2000, Joseph Colin, MD, provided a research of choices to permeating keratoplasty for people with keratoconus. Of 23 eyes in 20 patients, 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 recommends an option that enhances the already compromised cornea rather than further thinning it with LASIK. The idea of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to enhance the cornea makes a great deal of sense, Dr. Durrie told Health care Optometry News.
” For many years, we’ve taken a look at other choices to corneal transplants for these people, and also some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been attempted in the past, however they remove part of the cornea in a patient population in which we know the cornea is already thin as well as weak,” Dr. Durrie claimed.
Because the keratoconic eye has a lump in the cornea, Dr. Durrie claimed, placing the Intacs insert in the periphery of the cornea will squash the corneal center. This not only reduces the degree of nearsightedness, however reinforces the center lump, he stated. The wanted end result is to delay a corneal transplant for as long as feasible.
While the data that Dr. Colin presented show that the procedure is quite risk-free, said Dr. Durrie, the longest term data readily available are only 2 years. “Taking a look at the trends in the 3-month, 6-month as well as 1-year information, it shows up that all patients gained from the procedure, yet we can’t claim that it stopped the keratoconus for longer than that till additional information are accumulated,” he claimed. “Although I continue to do this treatment on separated situations, I inform clients we do not know the lasting effects and we don’t know whether it will slow down, speed up or have no result on the normal course of keratoconus.
” The benefit of this procedure is, if it does not work, you can take the Intacs out as well as have not weakened the cornea,” he proceeded. “If the individual does require to take place to a corneal transplant, the inserts can be secured as well as not interfere with standard transplant treatment. Due to the modification in shape of the keratoconic cornea, eventually, individuals become get in touch with lens intolerant, and it is very important to recognize that there is a different to be checked out for these clients besides simply referring them for a corneal transplant.”
Experts need to make certain that individuals understand that the treatment is not refractive surgical procedure and also will not always correct their nearsightedness, said Dr. Durrie. “I have clients on whom I have actually done this procedure who have actually seen 20/40 without glasses, which would certainly be an outstanding outcome after a corneal transplant, yet they’re still wondering why their close friends that have had Intacs dental implanted can see 20/20 when they can’t,” he said. “That’s why these clients require to be enlightened that this isn’t something that keeps them from wearing glasses. It maintains them from needing a corneal transplant.”
Hyperopic change with LTK
picture– Post-LTK: The pulses are used in 8 spots, one at the 6-mm area and the other at the 7-mm area.
Medical researches have actually revealed laser thermokeratoplasty (LTK) to be a reliable technique of correcting a client’s hyperopia, and it may also hold assurance for treating presbyopia and also overcorrected myopia after LASIK or PRK, stated David J. Conway, OD, manager of refractive surgical procedure for Harvard Lead Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK technique as well as its outcomes with hyperopia making use of the Hyperion laser (Dawn Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical procedure’s Summertime Globe Refractive Surgical Procedure Seminar 2000. Dr. Conway was not associated with any kind of Fda (FDA) study; his ISRS presentation was based on info from the Sunrise FDA examinations and also talks he went to.
When dealing with a client for hyperopia, the expert needs to worry the impermanence of the procedure, he stated. “You need to communicate to the client that this is just a short-term adjustment in his/her hyperopic condition,” he stated. “There suffices regression with this technique that the FDA felt it needed to make mention of this.”
Any treatment for the correction of hyperopia may require retreatment over time; this is not unique to LTK, said Sandra Belmont, MD, director of the laser vision center at the Cornell Weill Medical Facility in New York City City. “Hyperopia enhances as you age,” she claimed. “We have clients 3 years out who are stable, so I’m really pleased with the outcomes.”
Dr. Belmont notifies patients of this possibility, but none of them have actually transformed their minds. She said that if retreatment were needed, patients did incline due to the fact that the treatment fasts, and also developing a flap, which can lead to difficulties, is not necessary.
The LTK procedure
photo– Security: One scientist has individuals that are still secure 3 years post-LTK.
The treatment, Dr. Conway claimed, takes 3 seconds to perform. Seven pulses are used in eight places, twice back to back, one at the 6-mm zone and also the various other at the 7-mm zone. The FDA research study reported that the 612 eyes in 379 people, 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 stated. “In comparing preop to 24 months later, there was no loss of BSCVA and also a bit of gain. We know that myopes and also hyperopes are really various. Luckily, the tolerance of hyperopes is really valuable in making their satisfaction level extremely high.”
Before the treatment, clients get 3 consecutive managements of topical proparacaine at 3-minute intervals. Issues were very little, Dr. Conway noted.
” Individuals are usually taken care of from a convenience viewpoint, purely with over the counter analgesics to obtain them via the initial hours of healing,” he stated. “Due to the fact that you’re servicing the corneal surface area, FDA private investigators reported a little of foreign-body feeling, which dissipates with time extremely nicely.”
Dr. Conway said that, while the person’s skill level remains rather secure, some regression is evident as the hyperopia raises in time. “There will certainly be a tiny however considerable regression in these individuals; it’s simply a matter of whether it’s at a low enough level to validate the individual’s cost as well as experience of undergoing this method,” he stated. “By contrasting your cycloplegic to your show refraction, you can inform whether it’s latent hyperopia or not.”
A person’s age consider to how much time the result of LTK might last, stated Dr. Conway. “A 50-year-old person will experience a little much more result than a 40-year-old client, probably because of a bit more dryness or the collagen condition of the cornea,” he claimed.
An off-label indicator of LTK is the treatment of presbyopia, stated Dr. Belmont. Clients that are plano and also presbyopic may be treated with LTK to attain monovision, she claimed. “Right away, their analysis vision comes into emphasis,” she claimed. “They obtain their outcomes right away, and they’re really happy with that.”
Clients who have actually been dealt with for presbyopia usually will encounter the exact same degree 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 certainly need to be improved as their aging necessitates a boost 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 deal with farsightedness and also presbyopia.”
The length of time needed for presbyopic therapy is the same as for that of hyperopia, however the level of energy that is applied to the eye is differed, she stated.
The treatment might also show to be a valid choice for enhancing myopic clients who have been overcorrected with LASIK or PRK, claimed Dr. Conway. “This benefits a great deal of factor to consider, since you do not need to eliminate any type of cells,” he claimed. “Furthermore, Dawn is submitting for approval removal of presbyopia, making clients nearsighted in a monovision fashion. So, I think this will certainly come to be a relatively preferred as well as usual option in this individual population, and also we’ll see the amount of more doctors make a decision to accept it.”
LTK is accepted for up to +2.5 D, stated Dr. Belmont, and is presently undergoing trials for therapy approximately +5.6 D.
Refractec’s conductive keratoplasty
Initial scientific trials suggest that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency approach is most likely risk-free and also reliable for correcting low to moderate quantities of hyperopia, according to Dime A. Asbell, MD, that presented clinical trial data in Miami at the International Society of Refractive Surgical procedure conference. “Very early results with our information out to twelve month recommend that we obtain wonderful visual acuity, great stability and truly no adverse events, such as loss of vision,” said Dr. Asbell.
CK heats up the stromal cells with an electrical existing, shrinks the collagen as well as steepens the main cornea, Dr. Asbell discussed. A high-frequency existing is applied straight into the peripheral corneal stroma with a distribution tip inserted at eight or even more therapy points. The launch of radiofrequency power heats up the surrounding collagen to an uniform temperature level of 65 ° C as well as produces a round impact 500 µm deep vs. a shallower, conical impact made with the LTK technique. A full circle of CK-treated places cinches the cornea as well as raises its curvature to lower hyperopia.
” The change seems to be irreversible, and also I think one of the factors that holds true is that the treatment is provided straight to the stroma,” said Dr. Asbell. “That’s where you want the result– out the endothelium, not on the epithelium. It’s an extremely simple medical strategy. It’s a non-laser technique, as well as it adds an additional measurement to what we currently can provide for refractive surgical procedure– it is an affordable procedure,” she added.
CK is consistent
One more key issue, Dr. Asbell pointed out, is that CK is a regular therapy. “The therapy size as well as the area effect in the stroma are consistent from therapy area to treatment spot,” she said. “Among the key problems to keep in mind is that the temperature level we get with the CK procedure is constantly 65 ° and the imprint you make within the peripheral corneal stroma is constantly the exact same: 100 µm large as well as 500 µm deep within the corneal stroma.”
Dr. Asbell is a detective in the FDA professional trial of CK. Fellow investigators at other sites include Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; and also Edward E. Manche, MD
. Of the 54 people on whom Dr. Asbell reported, the typical age was 55, although, she claimed, there is a fairly wide variety old amongst the test’s individuals. To get approved for the test, she explained, individuals needed to have uncorrected visual acuity of a minimum of 20/40 or worse and bad near vision too– basic for a hyperope. “We are correcting from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She stressed the rate and also simplicity of the treatment. “This treatment takes 5 minutes per eye. It is a very short procedure; you remain in and out extremely quickly,” she claimed. “It is a procedure, yet a really straightforward one. It does not require an experienced technician [to help] It doesn’t even need an autoclave. The tip, which has to do with the width of a hair, is disposable.”
Dr. Asbell described the CK nomogram thus: “The treatment is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [indicating the dimension of the treatment zone] The level of hyperopia you are fixing identifies the variety of therapy marks on the cornea. Each one coincides– the same amount of energy and also the same deepness within the stroma in each place,” she stated.
Outcomes show up stable
Of the clients on whom Dr. Asbell reported, 61% accomplished uncorrected visual acuity of 20/20 or far better 6 months postoperatively and also 96% were 20/40 or far better at the 6-month mark. One year postoperatively, 62% were 20/20 or better, and also 92% were 20/40 or much better. “Our results look excellent and stable. These are extremely happy individuals,” stated Dr. Asbell. “They really can return to work right away or absolutely the following day if they so select. Nobody takes pain medications.”
Security variables were “essentially no,” Dr. Asbell reported. “There was no loss of vision and also no corneal edema,” she said. “I believe this is mosting likely to be a procedure as well as a machine that’s going to be very easy for us to own as well as to make use of as well as an excellent means to fix hyperopia postop LASIK or to retouch a postop cataract or corneal transplant,” she stated. “I believe it’s going to have a lot of flexibility in terms of its uses for remedying hyperopia and possibly astigmatism.”
Increased clinical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has expanded its scientific test researches of laser presbyopia reversal (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Likewise, the firm has arranged setup of the IR-laser in some European countries.
SurgiLight has actually sent four papers to the American Society of Cataract as well as Refractive Surgical Treatment for the May 2001 meeting, where greater than 500 instances of LAPR will certainly be presented by ophthalmologists from various countries utilizing the company’s IR laser.
The business remains in the procedure of obtaining CE-Mark certification and also selecting various worldwide distributors. It plans to submit extra 510K applications based on certain clearances obtained from Premier Laser Equipments. SurgiLight anticipates to charge a nobility charge of $500 per patient to cosmetic surgeons that make use of the business’s IR-3000 system in the United States and Europe.
B&L NuVita phakic IOL
The 3rd generation of George Baikoff, MD’s, anterior chamber phakic IOL is represented 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 crescent optical shape as well as 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, loophole as well as footplate were all revamped from the previous version to lower refracted glare, pressure in the angle as well as far better clearance of the iris and natural lens. Additionally, the haptics were revamped to eliminate iris retraction. The haptics were made more versatile as well as, consequently, led to much less student ovalization.
In its second generation, the fluorine plasma treatment was contributed to the manufacturing process to produce covalent bonds of fluorocarbon radicals with the PMMA surface area, which yielded lower surface energy and extremely smooth surface. The fluorine treatment significantly enhanced biocompatibility.
In researches conducted 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 a precision price of ± 2 D. In terms of safety, the BSCVA prices had 47 getting a minimum of 2 lines, and also no eyes lost lines. The overall glare record showed that a lot of clients had few problems.
According to Mike Landreville, worldwide supervisor for refractive innovations at Bausch & Lomb, the firm has no intent of introducing the NuVita lens right into the USA for FDA approval or for medical use. Rather, the company is developing an entire new phakic technology for a foldable former chamber phakic lens. The new phakic lens will certainly not just exist as a brand-new lens, however as part of an entirely new system, entirely different from the NuVita line. The new, unnamed lens system will be of a new material, include a new foldable distribution system and also provide a new diagnostic tool for implantation.
According to Mr. Landreville, the firm prepares to have the brand-new system all set for clinical use in the United States by this year.
Alcon phakic IOL
A new anterior 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 also has numerous benefits 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 distance between the cornea and also the implant likewise drops between 2.96 mm as well as 3.35 mm, a larger distance than with a few other lenses, he claimed.
Dr. Maxwell reported that of the 10 implants that have been carried out to date, more than 90% of the clients have 20/40 or far better uncorrected vision at their postoperative sees. The mean spherical equivalent in clients dental implanted so far was– 11.5 D, he said, with an outcome of– 0.39 D at 1 month and– 0.8 D at 6 months of recurring nearsightedness.
” We see substantial renovation in best-corrected visual acuity, as well as in all however one individual the postoperative ideal fixed vision is much better than the most effective preoperative vision; in many cases, there are 2-, 3- or 4-line boosts in best-corrected visual acuity,” Dr. Maxwell stated. “In the one instance where it had not been much better, it was the same as the preoperative skill.”
CIBA gets licenses for IOL
CIBA Vision revealed at the AAO meeting that it has actually gotten three patents from Dr. Baikoff for collapsible phakic former chamber IOL develops to deal with not just nearsightedness as well as hyperopia however additionally presbyopia.
” We are extremely delighted about this new technology,” David Bailey, medical business system president for CIBA, claimed. “We think that the MemoryLens product incorporated with these former chamber layouts will certainly be a very successful combination.”
That anterior chamber lens campaign complements one more refractive implant that was the subject of several discussions in the CIBA Vision booth– 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 currently holds exclusive worldwide advertising and also 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 ).