Arising technology in the locations of corneal ring sections, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is providing brand-new alternatives for clients dealing with keratoconus, nearsightedness, hyperopia and also presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) conference in October 2000, Joseph Colin, MD, offered a research of choices to permeating keratoplasty for clients with keratoconus. Of 23 eyes in 20 patients, 60% attained 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 recommends a choice that reinforces the currently damaged cornea rather than additional thinning it with LASIK. The concept of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a great deal of sense, Dr. Durrie told Health care Optometry Information.
” For many years, we have actually looked at various other choices to corneal transplants for these people, and some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been attempted in the past, yet they get rid of part of the cornea in a client populace in which we understand the cornea is currently thin and also weak,” Dr. Durrie stated.
Because the keratoconic eye has a bulge in the cornea, Dr. Durrie claimed, positioning the Intacs put in the periphery of the cornea will flatten the corneal facility. This not just decreases the level of nearsightedness, however reinforces the center bulge, he stated. The preferred result is to delay a corneal transplant for as long as feasible.
While the data that Dr. Colin offered show that the treatment is rather secure, stated Dr. Durrie, the lengthiest term data available are only 2 years. “Checking out the patterns in the 3-month, 6-month and also 1-year data, it appears that all clients gained from the treatment, yet we can not claim that it quit the keratoconus for longer than that till further data are collected,” he claimed. “Although I remain to do this procedure on isolated situations, I inform patients we don’t know the lasting impacts and we do not understand whether it will slow down, speed up or have no impact on the normal course of keratoconus.
” The benefit of this treatment is, if it does not work, you can take the Intacs out and have not damaged the cornea,” he continued. “If the person does require to take place to a corneal transplant, the inserts can be taken out as well as not interfere with conventional transplant treatment. As a result of the modification fit of the keratoconic cornea, at some point, individuals come to be get in touch with lens intolerant, and also it is very important to understand that there is a different to be explored for these clients aside from just referring them for a corneal transplant.”
Experts must be sure that individuals recognize that the treatment is not refractive surgery and will not necessarily fix their nearsightedness, said Dr. Durrie. “I have people on whom I have done this procedure that have seen 20/40 without glasses, which would be an impressive outcome after a corneal transplant, but they’re still questioning why their close friends who have actually had Intacs implanted can see 20/20 when they can not,” he said. “That’s why these people need to be educated that this isn’t something that maintains them from using glasses. It maintains them from needing a corneal transplant.”
Hyperopic change with LTK
picture– Post-LTK: The pulses are applied in eight spots, one at the 6-mm area and also the various other at the 7-mm area.
Professional studies have actually shown laser thermokeratoplasty (LTK) to be an efficient approach of fixing a person’s hyperopia, and it might also hold pledge for dealing with presbyopia and overcorrected myopia after LASIK or PRK, stated David J. Conway, OD, manager of refractive surgical procedure for Harvard Vanguard Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK technique as well as its outcomes with hyperopia utilizing the Hyperion laser (Sunup Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical treatment’s Summertime World Refractive Surgery Symposium 2000. Dr. Conway was not involved in any kind of Food and Drug Administration (FDA) research; his ISRS discussion was based on details from the Dawn FDA investigations and talks he went to.
When treating an individual for hyperopia, the specialist requires to emphasize the brevity of the treatment, he stated. “You require to communicate to the client that this is only a short-term modification in his or her hyperopic standing,” he stated. “There is enough regression with this method that the FDA felt it needed to refer this.”
Any type of procedure for the improvement of hyperopia might demand retreatment gradually; this is not one-of-a-kind to LTK, claimed Sandra Belmont, MD, supervisor of the laser vision center at the Cornell Weill Medical Facility in New York City City. “Hyperopia increases as you age,” she stated. “We have patients 3 years out who are stable, so I’m extremely satisfied with the outcomes.”
Dr. Belmont educates individuals of this opportunity, however none have transformed their minds. She claimed that if retreatment were required, people did incline due to the fact that the procedure is quick, and developing a flap, which can cause complications, is not necessary.
The LTK treatment
photograph– Stability: One scientist has clients who are still stable 3 years post-LTK.
The procedure, Dr. Conway claimed, takes 3 seconds to execute. Seven pulses are used in eight spots, twice back to back, one at the 6-mm zone as well as the other at the 7-mm area. 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 finest 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 and also a little of gain. We know that myopes as well as hyperopes are extremely different. The good news is, the resistance of hyperopes is really handy in making their complete satisfaction degree very high.”
Before the procedure, patients obtain 3 consecutive administrations of topical proparacaine at 3-minute intervals. Problems were minimal, Dr. Conway kept in mind.
” Individuals are typically taken care of from a convenience point ofview, purely with non-prescription anesthetics to get them through the initial hrs of recuperation,” he said. “Due to the fact that you’re working on the corneal surface, FDA private investigators reported a little of foreign-body feeling, which dissipates with time really well.”
Regression with time
Dr. Conway claimed that, while the client’s skill level stays fairly steady, some regression appears as the hyperopia enhances with time. “There will certainly be a tiny however substantial regression in these clients; it’s simply an issue of whether it goes to a low sufficient degree to warrant the person’s expense and experience of undertaking this technique,” he said. “By comparing your cycloplegic to your show refraction, you can tell whether it’s latent hyperopia or not.”
A client’s age factors in to how much time the impact of LTK may last, stated Dr. Conway. “A 50-year-old patient will experience a little more effect than a 40-year-old person, perhaps due to a little bit more dryness or the collagen status of the cornea,” he stated.
An off-label indicator of LTK is the therapy of presbyopia, said Dr. Belmont. People that are plano and presbyopic may be treated with LTK to attain monovision, she said. “As soon as possible, their reading vision enters focus,” she stated. “They obtain their results right away, as well as they’re actually delighted with that said.”
Patients that have been treated for presbyopia generally will come across the same level of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia boosts as you age, as does hyperopia,” she stated. “Individuals understand that this procedure will certainly need to be boosted as their aging necessitates a boost in the power they’ll require to read. They’re happy as long as you tell them ahead of time. I expect this as being the treatment to deal with farsightedness and also presbyopia.”
The length of time needed for presbyopic treatment coincides as for that of hyperopia, but the level of energy that is related to the eye is differed, she claimed.
The treatment might likewise show to be a valid alternative for improving myopic people that have actually been overcorrected with LASIK or PRK, stated Dr. Conway. “This advantages a great deal of consideration, since you don’t need to eliminate any kind of tissue,” he stated. “In addition, Daybreak is sending for approval remediation of presbyopia, making clients myopic in a monovision style. So, I think this will certainly end up being a relatively preferred and also usual option in this client populace, as well as we’ll see the amount of even more surgeons determine to welcome it.”
LTK is authorized for approximately +2.5 D, stated Dr. Belmont, as well as is currently undertaking trials for treatment up to +5.6 D.
Refractec’s conductive keratoplasty
Initial clinical trials suggest that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency method is most likely secure as well as reliable for remedying reduced to modest quantities of hyperopia, according to Penny A. Asbell, MD, who provided medical trial information in Miami at the International Society of Refractive Surgical procedure meeting. “Very early outcomes with our information bent on 12 months recommend that we obtain excellent visual acuity, great security as well as actually no unfavorable events, such as loss of vision,” claimed Dr. Asbell.
CK warms the stromal cells with an electrical present, reduces the collagen as well as steepens the central cornea, Dr. Asbell clarified. A high-frequency current is used straight into the outer corneal stroma with a shipment pointer put at 8 or even more therapy factors. The launch of radiofrequency power heats up the surrounding collagen to an identical temperature level of 65 ° C and also creates 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 raises its curvature to decrease hyperopia.
” The modification appears to be long-term, and I assume among the factors that holds true is that the treatment is supplied straight to the stroma,” stated Dr. Asbell. “That’s where you desire the effect– not on the endothelium, not on the epithelium. It’s an extremely simple medical technique. It’s a non-laser strategy, as well as it adds another measurement to what we currently can use for refractive surgical treatment– it is a cost-effective treatment,” she included.
CK is consistent
Another vital problem, Dr. Asbell mentioned, is that CK is a consistent therapy. “The therapy dimension and also the area effect in the stroma correspond from therapy spot to therapy area,” she claimed. “One of the key concerns to remember is that the temperature level we get with the CK treatment is constantly 65 ° as well as the imprint you make within the outer corneal stroma is constantly the same: 100 µm broad and also 500 µm deep within the corneal stroma.”
Dr. Asbell is an investigator in the FDA medical test of CK. Other investigators at various other websites consist of Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; as well as Edward E. Manche, MD
. Of the 54 patients on whom Dr. Asbell reported, the typical age was 55, although, she claimed, there is a relatively wide range of age amongst the test’s participants. To get the trial, she clarified, people had to have uncorrected visual acuity of a minimum of 20/40 or even worse and bad near vision also– standard for a hyperope. “We are dealing with from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She worried the rate as well as simplicity of the procedure. “This treatment takes 5 mins per eye. It is a really brief treatment; you’re in and out very quickly,” she stated. “It is a surgical procedure, but an extremely simple one. It does not need a qualified service technician [to aid] It does not even call for an autoclave. The tip, which is about the size of a hair, is disposable.”
Dr. Asbell defined the CK nomogram as such: “The therapy is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [showing the dimension of the therapy area] The level of hyperopia you are correcting identifies the variety of treatment marks on the cornea. Every one is the same– the exact same amount of energy as well as the very same deepness within the stroma in each area,” she stated.
Results appear secure
Of the clients on whom Dr. Asbell reported, 61% accomplished uncorrected visual acuity of 20/20 or much better 6 months postoperatively as well as 96% were 20/40 or better at the 6-month mark. One year postoperatively, 62% were 20/20 or far better, and also 92% were 20/40 or much better. “Our results look good as well as stable. These are extremely pleased patients,” stated Dr. Asbell. “They in fact can go back to work promptly or definitely the following day if they so pick. No one takes pain medicines.”
Security variables were “basically zero,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she said. “I think this is mosting likely to be a procedure and also a maker that’s mosting likely to be very easy for us to have as well as to utilize and also an excellent way to deal with hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she said. “I believe it’s mosting likely to have a lot of adaptability in terms of its usages for dealing with hyperopia as well as perhaps astigmatism.”
Broadened medical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has broadened its professional trial studies of laser presbyopia turnaround (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Additionally, the business has actually set up installation of the IR-laser in some European nations.
SurgiLight has actually sent 4 documents to the American Society of Cataract as well as Refractive Surgery for the May 2001 conference, where more than 500 situations of LAPR will be presented by ophthalmologists from different nations using the firm’s IR laser.
The company is in the procedure of obtaining CE-Mark qualification and also selecting numerous international distributors. It prepares to send added 510K applications based on certain clearances gotten from Premier Laser Solutions. SurgiLight expects to bill a nobility charge of $500 per patient to specialists who utilize the company’s IR-3000 system in the USA and 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 ranging from 7 D to 20 D. The design is an angle-fixated, single-piece lens, with a crescent optical shape and also a PMMA surface. The total optical size is 5 mm as well as 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 redesigned from the previous version to minimize refracted glare, pressure in the angle and also far better clearance of the iris as well as all-natural lens. Likewise, the haptics were redesigned to eliminate iris retraction. The haptics were made extra versatile and also, as a result, caused much less pupil ovalization.
In its second generation, the fluorine plasma treatment was included in the manufacturing procedure to create covalent bonds of fluorocarbon radicals with the PMMA surface, which produced reduced surface area energy and extremely smooth surface. The fluorine therapy greatly boosted biocompatibility.
In researches performed by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted revealed an accuracy rate of ± 0.5 D while 97% showed an accuracy rate of ± 2 D. In regards to safety and security, the BSCVA prices had 47 getting at least 2 lines, and no eyes lost lines. The total glare report revealed that a lot of patients had few troubles.
According to Mike Landreville, international director for refractive modern technologies at Bausch & Lomb, the company has no purpose of introducing the NuVita lens right into the United States for FDA authorization or for clinical usage. Instead, the business is developing an entire brand-new phakic modern technology for a foldable anterior chamber phakic lens. The brand-new phakic lens will not only exist as a new lens, but as part of a totally new system, entirely separate from the NuVita line. The new, unnamed lens system will be of a new product, integrate a brand-new foldable shipment system and also offer a new diagnostic device for implantation.
According to Mr. Landreville, the firm prepares to have the new system ready for clinical usage in the USA by this year.
Alcon phakic IOL
A brand-new anterior chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO meeting. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) product and has several benefits over other phakic IOLs such as its foldability, which allows the lens to be inserted with a laceration smaller than 3 mm, as well as an angle-fixated, single-piece style as well as high biocompatibility. The range in between the cornea and the dental implant also falls in between 2.96 mm and 3.35 mm, a bigger distance than with some other lenses, he stated.
Dr. Maxwell reported that of the 10 implants that have been carried out to date, more than 90% of the people have 20/40 or better uncorrected vision at their postoperative brows through. The mean spherical matching in patients dental implanted thus 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 myopia.
” We see substantial improvement in best-corrected visual acuity, and also in all but one patient the postoperative ideal dealt with vision is better than the very best preoperative vision; oftentimes, there are 2-, 3- or 4-line increases in best-corrected visual acuity,” Dr. Maxwell claimed. “In the one case where it had not been better, it was the same as the preoperative skill.”
CIBA acquires licenses for IOL
CIBA Vision revealed at the AAO conference that it has actually obtained three licenses from Dr. Baikoff for collapsible phakic anterior chamber IOL creates to correct not just nearsightedness as well as hyperopia however additionally presbyopia.
” We are extremely excited regarding this new technology,” David Bailey, surgical service device head of state for CIBA, said. “We assume that the MemoryLens material combined with these former chamber styles will be a very successful mix.”
That former chamber lens initiative complements another refractive dental 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 stake in Medennium in July and also now holds unique 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 ).