Emerging innovation in the locations of corneal ring segments, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is providing new alternatives for clients struggling with keratoconus, myopia, hyperopia and also presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) conference in October 2000, Joseph Colin, MD, presented a study of options to penetrating keratoplasty for patients 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, commented on Dr. Colin’s paper, which recommends an option that strengthens the already compromised cornea instead of further thinning it with LASIK. The concept of using an additive procedure, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a great deal of feeling, Dr. Durrie told Health care Optometry News.
” For several years, we’ve considered various other choices to corneal transplants for these patients, and also some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been tried in the past, however they eliminate part of the cornea in an individual population in which we understand the cornea is already slim as well as weak,” Dr. Durrie claimed.
Because the keratoconic eye has a lump in the cornea, Dr. Durrie claimed, positioning the Intacs put in the perimeter of the cornea will certainly squash the corneal facility. This not just lowers the level of nearsightedness, but reinforces the center lump, he stated. The wanted end result is to postpone a corneal transplant for as long as possible.
While the information that Dr. Colin provided program that the treatment is rather secure, said Dr. Durrie, the lengthiest term information readily available are only 2 years. “Checking out the patterns in the 3-month, 6-month and 1-year information, it appears that all clients gained from the treatment, however we can’t say that it stopped the keratoconus for longer than that till additional information are collected,” he said. “Although I remain to do this procedure on isolated cases, I inform individuals we do not recognize the lasting effects and also we do not know whether it will certainly decrease, accelerate or have no impact on the normal course of keratoconus.
” The advantage of this treatment is, if it does not function, you can take the Intacs out and also have not weakened the cornea,” he proceeded. “If the client does need to take place to a corneal transplant, the inserts can be obtained and not interfere with typical transplant treatment. As a result of the modification in shape of the keratoconic cornea, ultimately, individuals come to be get in touch with lens intolerant, and also it is necessary to understand that there is an alternative to be checked out for these clients apart from just referring them for a corneal transplant.”
Specialists need to be sure that clients comprehend that the procedure is not refractive surgical procedure and will not always fix their nearsightedness, stated Dr. Durrie. “I have people on whom I have actually done this treatment that have actually seen 20/40 without glasses, which would certainly be an outstanding result after a corneal transplant, yet they’re still wondering why their pals who have actually had Intacs dental implanted can see 20/20 when they can’t,” he stated. “That’s why these people need to be enlightened that this isn’t something that keeps them from using glasses. It maintains them from requiring a corneal transplant.”
Hyperopic change with LTK
photograph– Post-LTK: The pulses are applied in eight areas, one at the 6-mm zone and the other at the 7-mm zone.
Medical researches have revealed laser thermokeratoplasty (LTK) to be an effective method of correcting a client’s hyperopia, and also it might likewise hold pledge for dealing with presbyopia as well as overcorrected nearsightedness after LASIK or PRK, said David J. Conway, OD, supervisor of refractive surgical procedure for Harvard Lead Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK strategy and its outcomes with hyperopia making use of the Hyperion laser (Dawn Technologies International, Fremont, Calif.) at the International Society of Refractive Surgical procedure’s Summer World Refractive Surgical Procedure Seminar 2000. Dr. Conway was not associated with any type of Food and Drug Administration (FDA) research; his ISRS presentation was based upon details from the Dawn FDA examinations and lectures he went to.
When treating an individual for hyperopia, the practitioner requires to stress the impermanence of the treatment, he said. “You need to share to the patient that this is just a short-lived modification in his/her hyperopic standing,” he claimed. “There is enough regression with this method that the FDA felt it needed to refer this.”
Any type of treatment for the improvement of hyperopia may demand retreatment in time; this is not one-of-a-kind to LTK, stated Sandra Belmont, MD, supervisor of the laser vision facility at the Cornell Weill Medical Facility in New York City City. “Hyperopia increases as you age,” she said. “We have people 3 years out who are stable, so I’m extremely happy with the results.”
Dr. Belmont notifies patients of this possibility, yet none of them have actually altered their minds. She said that if retreatment were required, clients did incline due to the fact that the treatment fasts, and also developing a flap, which can lead to issues, is not needed.
The LTK procedure
photograph– Stability: One scientist has clients that are still secure 3 years post-LTK.
The treatment, Dr. Conway said, takes 3 secs to carry out. 7 pulses are applied in eight areas, two times back to back, one at the 6-mm zone and the other at the 7-mm area. The FDA research 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 skill were attributable to the LTK,” he claimed. “In comparing preop to 24 months later on, there was no loss of BSCVA as well as a bit of gain. We understand that myopes as well as hyperopes are really various. Luckily, the tolerance 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 handled from a convenience viewpoint, purely with over-the-counter analgesics to obtain them with the very first hours of recovery,” he claimed. “Due to the fact that you’re servicing the corneal surface area, FDA investigators reported a bit of foreign-body sensation, which dissipates with time very well.”
Regression in time
Dr. Conway claimed that, while the person’s acuity level remains fairly steady, some regression is evident as the hyperopia boosts with time. “There will be a small but considerable regression in these patients; it’s just an issue of whether it’s at a reduced sufficient level to warrant the individual’s expense as well as experience of undertaking this technique,” he said. “By contrasting your cycloplegic to your reveal refraction, you can tell whether it’s latent hyperopia or not.”
An individual’s age consider to how long the effect of LTK might last, said Dr. Conway. “A 50-year-old patient will certainly experience a bit a lot more result than a 40-year-old person, perhaps because of a little extra dry skin or the collagen status of the cornea,” he said.
An off-label sign of LTK is the therapy of presbyopia, said Dr. Belmont. People that are plano as well as presbyopic may be treated with LTK to achieve monovision, she stated. “Today, their analysis vision comes into focus,” she said. “They get their outcomes quickly, and they’re actually delighted with that said.”
Individuals that have been treated for presbyopia normally will come across the exact same degree of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia enhances as you age, as does hyperopia,” she said. “People know that this procedure will have to be enhanced as their aging requires a boost in the power they’ll need to review. They more than happy as long as you tell them ahead of time. I expect this as being the treatment to deal with farsightedness as well as presbyopia.”
The size of time needed for presbyopic therapy coincides as for that of hyperopia, but the level of power that is related to the eye is differed, she claimed.
The treatment might additionally prove to be a legitimate option for enhancing myopic patients that have been overcorrected with LASIK or PRK, said Dr. Conway. “This qualities a great deal of consideration, due to the fact that you don’t need to get rid of any kind of tissue,” he claimed. “In addition, Daybreak is submitting for approval remediation of presbyopia, making people nearsighted in a monovision style. So, I believe this will become a relatively prominent and typical choice in this patient population, and we’ll see how many even more cosmetic surgeons decide to accept it.”
LTK is accepted for up to +2.5 D, stated Dr. Belmont, and also is currently going through trials for therapy as much as +5.6 D.
Refractec’s conductive keratoplasty
Preliminary professional tests suggest that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency technique is probably risk-free and also reliable for dealing with reduced to modest quantities of hyperopia, according to Penny A. Asbell, MD, who offered medical test information in Miami at the International Society of Refractive Surgical treatment conference. “Very early outcomes with our data out to twelve month recommend that we obtain terrific visual acuity, great security and really no unfavorable occasions, such as loss of vision,” claimed Dr. Asbell.
CK heats up the stromal tissue with an electric existing, reduces the collagen and steepens the central cornea, Dr. Asbell explained. A high-frequency existing is applied directly right into the outer corneal stroma with a delivery tip inserted at eight or more treatment factors. The release of radiofrequency energy heats the surrounding collagen to a homogenous temperature of 65 ° C and also produces a round footprint 500 µm deep vs. a shallower, cone-shaped impact made with the LTK method. A cycle of CK-treated spots cinches the cornea and raises its curvature to lower hyperopia.
” The adjustment appears to be long-term, as well as I believe one of the factors that holds true is that the therapy is supplied directly to the stroma,” claimed Dr. Asbell. “That’s where you desire the result– not on the endothelium, out the epithelium. It’s an extremely simple medical method. It’s a non-laser method, as well as it includes one more dimension to what we already can provide for refractive surgery– it is an affordable procedure,” she added.
CK is consistent
An additional crucial problem, Dr. Asbell explained, is that CK is a consistent treatment. “The treatment dimension and the area effect in the stroma are consistent from therapy area to therapy spot,” she said. “Among the essential problems to keep in mind is that the temperature we get with the CK procedure is always 65 ° as well as the imprint you make within the peripheral corneal stroma is always the exact same: 100 µm vast and also 500 µm deep within the corneal stroma.”
Dr. Asbell is an investigator in the FDA scientific trial of CK. Fellow investigators at various other sites include Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; as well as Edward E. Manche, MD
. Of the 54 clients on whom Dr. Asbell reported, the common age was 55, although, she stated, there is a rather variety of age among the trial’s individuals. To get approved for the trial, she explained, clients had to have uncorrected visual acuity of at the very least 20/40 or worse and poor near vision also– typical 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 speed and simpleness of the procedure. “This procedure takes 5 mins per eye. It is a very brief procedure; you’re in and also out very rapidly,” she said. “It is a surgery, yet an extremely straightforward one. It does not need a qualified technician [to help] It does not even call for an autoclave. The idea, which is about the width 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 [indicating the size of the therapy area] The level of hyperopia you are remedying determines the variety of treatment marks on the cornea. Every one coincides– the exact same amount of power and the very same deepness within the stroma in each area,” she said.
Results show up stable
Of the people on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or 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 far better, and 92% were 20/40 or far better. “Our outcomes look good and also steady. These are really delighted clients,” claimed Dr. Asbell. “They actually can go back to work quickly or definitely the next day if they so pick. No one takes discomfort medications.”
Safety and security variables were “basically absolutely no,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she stated. “I believe this is going to be a treatment and also a device that’s mosting likely to be simple for us to own as well as to utilize and an excellent means to deal with hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she claimed. “I believe it’s going to have a great deal of flexibility in terms of its usages for correcting hyperopia and potentially astigmatism.”
Increased scientific trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually broadened its clinical test researches of laser presbyopia turnaround (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and Japan. Additionally, the company has actually scheduled installment of the IR-laser in some European nations.
SurgiLight has submitted four papers to the American Culture of Cataract as well as Refractive Surgery for the May 2001 meeting, where greater than 500 situations of LAPR will certainly exist by ophthalmologists from different nations using the business’s IR laser.
The firm remains in the procedure of getting CE-Mark certification as well as picking numerous international representatives. It prepares to submit added 510K applications based on particular clearances acquired from Premier Laser Systems. SurgiLight anticipates to bill a nobility fee of $500 per patient to cosmetic surgeons that utilize the firm’s IR-3000 system in the USA as well as Europe.
B&L NuVita phakic IOL
The 3rd generation of George Baikoff, MD’s, anterior chamber phakic IOL is stood for with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is readily available for myopes varying from 7 D to 20 D. The design is an angle-fixated, single-piece lens, with a lens optical form and a PMMA surface. The overall optical diameter is 5 mm as well as the general size of the NuVita varies from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loop and also footplate were all revamped from the previous version to minimize refracted glare, pressure in the angle as well as far better clearance of the iris and natural lens. Likewise, the haptics were revamped to get rid of iris retraction. The haptics were made a lot more flexible as well as, as a result, caused much less student ovalization.
In its 2nd generation, the fluorine plasma treatment was contributed to the production process to produce covalent bonds of fluorocarbon radicals with the PMMA surface, which produced lower surface area energy as well as remarkably smooth surface. The fluorine therapy considerably enhanced biocompatibility.
In research studies performed by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted showed a precision rate of ± 0.5 D while 97% revealed a precision rate of ± 2 D. In regards to security, the BSCVA prices had 47 gaining at the very least two lines, as well as no eyes shed lines. The total glare report showed that many patients had few issues.
According to Mike Landreville, international director for refractive modern technologies at Bausch & Lomb, the firm has no intention of introducing the NuVita lens into the USA for FDA approval or for medical usage. Instead, the firm is establishing an entire brand-new phakic innovation for a foldable former chamber phakic lens. The brand-new phakic lens will certainly not only exist as a new lens, however as part of an entirely brand-new system, totally different from the NuVita line. The brand-new, unrevealed lens system will be of a new material, include a new collapsible delivery system and provide a brand-new analysis tool for implantation.
According to Mr. Landreville, the company intends to have the brand-new system all set for medical use in the USA by this year.
Alcon phakic IOL
A brand-new former chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO meeting. The lens has an Acrysof-based (Alcon, Ft. Well Worth, Texas) product as well as has several advantages over various other phakic IOLs such as its foldability, which enables the lens to be inserted through a cut smaller sized than 3 mm, in addition to an angle-fixated, single-piece layout and high biocompatibility. The distance between the cornea as well as the implant additionally drops in between 2.96 mm and 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 carried out to date, more than 90% of the clients have 20/40 or much better uncorrected vision at their postoperative sees. The mean spherical equivalent in people implanted thus far was– 11.5 D, he said, with a result of– 0.39 D at 1 month and– 0.8 D at 6 months of residual myopia.
” We see substantial enhancement in best-corrected visual acuity, as well as in all yet one individual the postoperative ideal dealt with vision is far better than the most effective preoperative vision; oftentimes, there are 2-, 3- or 4-line boosts in best-corrected visual acuity,” Dr. Maxwell said. “In the one instance where it had not been much better, it coincided as the preoperative acuity.”
CIBA gets licenses for IOL
CIBA Vision announced at the AAO conference that it has acquired three patents from Dr. Baikoff for collapsible phakic anterior chamber IOL makes to correct not only myopia and also hyperopia however also presbyopia.
” We are really thrilled about this new innovation,” David Bailey, surgical organization unit head of state for CIBA, said. “We assume that the MemoryLens material integrated with these anterior chamber styles will be a very successful mix.”
That anterior chamber lens campaign complements an additional refractive dental implant that was the subject of several discussions in the CIBA Vision booth– the PRL. This posterior-chamber phakic implant is being created by Medennium Inc. CIBA Vision took a 10% equity stake in Medennium in July and now holds special around the world advertising and also distribution legal rights to the lens, which is currently in phase 2 scientific trials.
” We are taking a strong placement in phakic IOLs,” Mr. Bailey said, “and also we’ll be strengthening that setting with more new modern technology.”
This is the method to treat myopia, ypermetropia as well as astigmatism (υπερμετρωπια ).