Arising innovation in the areas of corneal ring segments, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is supplying brand-new alternatives for patients struggling with keratoconus, nearsightedness, hyperopia as well as presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) conference in October 2000, Joseph Colin, MD, presented a research study of options to permeating keratoplasty for people with keratoconus. Of 23 eyes in 20 clients, 60% accomplished 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 alternative that reinforces the already compromised cornea as opposed to more thinning it with LASIK. The suggestion of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a great deal of feeling, Dr. Durrie informed Health care Optometry Information.
” For several years, we have actually considered various other alternatives to corneal transplants for these individuals, and also some procedures such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been attempted in the past, yet they eliminate part of the cornea in a client population in which we understand the cornea is already slim and also weak,” Dr. Durrie stated.
Due to the fact that the keratoconic eye has a bulge in the cornea, Dr. Durrie stated, positioning the Intacs place in the perimeter of the cornea will squash the corneal center. This not only decreases the degree of nearsightedness, but enhances the center bulge, he stated. The preferred result is to postpone a corneal transplant for as long as feasible.
While the information that Dr. Colin presented program that the treatment is quite risk-free, claimed Dr. Durrie, the lengthiest term information readily available are just 2 years. “Looking at the patterns in the 3-month, 6-month and also 1-year data, it appears that all people gained from the procedure, but we can not state that it stopped the keratoconus for longer than that till further data are collected,” he claimed. “Although I continue to do this treatment on isolated situations, I tell people we don’t understand the long-term effects and we don’t recognize whether it will certainly slow down, speed up or have no result on the normal course of keratoconus.
” The benefit of this treatment is, if it doesn’t function, you can take the Intacs out and have not compromised the cornea,” he continued. “If the patient does require to go on to a corneal transplant, the inserts can be gotten and not interfere with typical transplant treatment. Because of the modification in shape of the keratoconic cornea, at some point, clients become call lens intolerant, and also it is very important to understand that there is a different to be investigated for these patients apart from just referring them for a corneal transplant.”
Practitioners need to make certain that people recognize that the procedure is not refractive surgical procedure and also will not always remedy their nearsightedness, said Dr. Durrie. “I have people on whom I have actually executed this procedure that have seen 20/40 without glasses, which would be an impressive result after a corneal transplant, but they’re still asking yourself why their pals that have actually had Intacs implanted can see 20/20 when they can not,” he claimed. “That’s why these clients require to be educated that this isn’t something that keeps them from putting on glasses. It maintains them from requiring a corneal transplant.”
Hyperopic change with LTK
picture– Post-LTK: The pulses are used in eight areas, one at the 6-mm area and also the other at the 7-mm area.
Clinical researches have actually shown laser thermokeratoplasty (LTK) to be a reliable approach of correcting an individual’s hyperopia, and also it might likewise hold assurance for treating presbyopia and overcorrected nearsightedness after LASIK or PRK, claimed David J. Conway, OD, supervisor of refractive surgical treatment for Harvard Vanguard Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK technique as well as its results with hyperopia utilizing the Hyperion laser (Sunrise Technologies International, Fremont, Calif.) at the International Society of Refractive Surgical procedure’s Summer season Globe Refractive Surgical Procedure Seminar 2000. Dr. Conway was not involved in any type of Fda (FDA) research; his ISRS discussion was based on details from the Daybreak FDA investigations and lectures he participated in.
When treating an individual for hyperopia, the practitioner requires to emphasize the impermanence of the procedure, he claimed. “You need to convey to the client that this is just a temporary change in his/her hyperopic standing,” he said. “There suffices regression with this strategy that the FDA felt it needed to make mention of this.”
Any procedure for the correction of hyperopia might demand retreatment with time; this is not one-of-a-kind to LTK, said Sandra Belmont, MD, supervisor of the laser vision center at the Cornell Weill Medical Facility in New York City City. “Hyperopia boosts as you age,” she said. “We have patients 3 years out that are stable, so I’m extremely satisfied with the results.”
Dr. Belmont educates clients of this possibility, however none have altered their minds. She said that if retreatment were needed, individuals did not mind since the treatment fasts, and also developing a flap, which can result in complications, is not required.
The LTK procedure
photo– Security: One scientist has people that are still steady 3 years post-LTK.
The procedure, Dr. Conway said, takes 3 seconds to execute. 7 pulses are applied in eight spots, two times back to back, one at the 6-mm area and the various other at the 7-mm area. The FDA study reported that the 612 eyes in 379 patients, 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 noted.
” 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 bit of gain. We know that myopes as well as hyperopes are extremely different. Fortunately, the resistance of hyperopes is extremely helpful in making their fulfillment level extremely high.”
Prior to the procedure, people obtain three consecutive administrations of topical proparacaine at 3-minute intervals. Difficulties were minimal, Dr. Conway kept in mind.
” People are usually managed from a convenience standpoint, purely with over the counter analgesics to get them with the first hours of healing,” he claimed. “Due to the fact that you’re working on the corneal surface area, FDA detectives reported a bit of foreign-body experience, which dissipates with time extremely well.”
Dr. Conway said that, while the individual’s acuity level stays rather stable, some regression appears as the hyperopia enhances with time. “There will certainly be a tiny yet significant regression in these individuals; it’s just an issue of whether it goes to a reduced adequate degree to validate the patient’s price as well as experience of undergoing this technique,” he said. “By comparing your cycloplegic to your manifest refraction, you can tell whether it exists hyperopia or not.”
A patient’s age factors in to how long the effect of LTK may last, said Dr. Conway. “A 50-year-old person will certainly experience a little bit much more effect than a 40-year-old client, possibly because of a bit more dry skin or the collagen standing of the cornea,” he stated.
An off-label indication of LTK is the treatment of presbyopia, said Dr. Belmont. Clients who are plano and also presbyopic may be treated with LTK to attain monovision, she claimed. “Right now, their reading vision enters focus,” she said. “They obtain their outcomes promptly, and they’re really satisfied with that said.”
Patients who have been treated for presbyopia typically will experience the very same level of regression as hyperopes, Dr. Belmont noted. “Presbyopia enhances as you age, as does hyperopia,” she stated. “Patients recognize that this procedure will need to be improved as their aging requires a boost in the power they’ll need to check out. They’re happy as long as you tell them ahead of time. I expect this as being the procedure to deal with farsightedness as well as presbyopia.”
The length of time needed for presbyopic therapy is the same as for that of hyperopia, however the degree of power that is put on the eye is differed, she claimed.
The procedure may likewise confirm to be a valid choice for enhancing nearsighted clients who have been overcorrected with LASIK or PRK, said Dr. Conway. “This values a lot of consideration, since you do not need to eliminate any type of cells,” he stated. “Furthermore, Dawn is sending for approval remediation of presbyopia, making patients myopic in a monovision fashion. So, I believe this will certainly become a relatively prominent and usual alternative in this individual populace, and also we’ll see how many more specialists determine to welcome it.”
LTK is approved for up to +2.5 D, stated Dr. Belmont, and is presently going through trials for therapy as much as +5.6 D.
Refractec’s conductive keratoplasty
Initial clinical tests recommend that conductive keratoplasty (CK) making use of Refractec’s (Irvine, Calif.) radiofrequency technique is possibly risk-free and also efficient for dealing with low to modest amounts of hyperopia, according to Cent A. Asbell, MD, that offered scientific test data in Miami at the International Society of Refractive Surgery meeting. “Very early results with our data out to year suggest that we obtain terrific visual acuity, great security as well as actually no negative events, such as loss of vision,” claimed Dr. Asbell.
CK warms the stromal cells with an electrical present, reduces the collagen and steepens the main cornea, Dr. Asbell discussed. A high-frequency current is used directly into the peripheral corneal stroma via a shipment pointer placed at 8 or even more therapy points. The launch of radiofrequency power heats up the surrounding collagen to an uniform temperature level of 65 ° C and generates a round footprint 500 µm deep vs. a shallower, conelike footprint made with the LTK strategy. A cycle of CK-treated spots cinches the cornea as well as increases its curvature to lower hyperopia.
” The adjustment seems to be permanent, as well as I believe one of the reasons that’s true is that the treatment is delivered straight to the stroma,” stated Dr. Asbell. “That’s where you want the result– out the endothelium, out the epithelium. It’s a very easy medical method. It’s a non-laser technique, as well as it adds one more dimension to what we already can provide for refractive surgical treatment– it is an economical treatment,” she added.
Another crucial concern, Dr. Asbell mentioned, is that CK is a constant therapy. “The therapy dimension as well as the area impact in the stroma are consistent from therapy spot to therapy area,” she claimed. “Among the vital concerns to bear in mind is that the temperature we get with the CK treatment is constantly 65 ° and the imprint you make within the outer corneal stroma is always the very same: 100 µm vast and 500 µm deep within the corneal stroma.”
Dr. Asbell is a private investigator in the FDA professional trial of CK. Other private investigators at other sites consist of 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 common age was 55, although, she stated, there is a fairly large range old among the trial’s individuals. To get the trial, she discussed, individuals needed to have uncorrected visual acuity of a minimum of 20/40 or even worse as well as inadequate near vision also– common for a hyperope. “We are fixing from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She worried the speed and simplicity of the procedure. “This procedure takes 5 mins per eye. It is an extremely short treatment; you remain in and out extremely promptly,” she claimed. “It is an operation, however a very easy one. It does not call for a qualified professional [to assist] It doesn’t also call for an autoclave. The tip, which has to do with the size of a hair, is disposable.”
Dr. Asbell explained 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 zone] The level of hyperopia you are dealing with determines the number of treatment marks on the cornea. Every one is the same– the exact same quantity of energy as well as the very same deepness within the stroma in each spot,” she claimed.
Outcomes show up secure
Of the people on whom Dr. Asbell reported, 61% achieved uncorrected visual acuity of 20/20 or far 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 better, and 92% were 20/40 or much better. “Our outcomes look excellent and secure. These are really pleased clients,” claimed Dr. Asbell. “They actually can return to work promptly or certainly the following day if they so choose. Nobody takes discomfort medications.”
Safety variables were “generally absolutely no,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she stated. “I assume this is going to be a treatment as well as a device that’s going to be simple for us to possess and to use and an exceptional way to remedy hyperopia postop LASIK or to touch up a postop cataract or corneal transplant,” she said. “I assume it’s going to have a lot of versatility in regards to its uses for correcting hyperopia and potentially astigmatism.”
Increased medical trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually increased its medical test studies of laser presbyopia turnaround (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas as well as Japan. Additionally, the firm has arranged setup of the IR-laser in some European countries.
SurgiLight has actually sent four documents to the American Culture of Cataract as well as Refractive Surgery for the May 2001 meeting, where greater than 500 cases of LAPR will certainly be presented by ophthalmologists from various countries using the company’s IR laser.
The firm is in the procedure of obtaining CE-Mark qualification and also choosing different worldwide suppliers. It intends to submit added 510K applications based upon particular clearances acquired from Premier Laser Systems. SurgiLight expects to bill a royalty cost of $500 per client to surgeons who utilize the company’s IR-3000 system in the USA and also Europe.
B&L NuVita phakic IOL
The third generation of George Baikoff, MD’s, former chamber phakic IOL is stood for with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is offered for myopes varying 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 area. The overall 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, loop and also footplate were all upgraded from the previous version to minimize refracted glow, stress in the angle as well as better clearance of the iris and also natural lens. Additionally, the haptics were redesigned to eliminate iris retraction. The haptics were made extra adaptable as well as, therefore, led to much less student ovalization.
In its second generation, the fluorine plasma therapy was added to the manufacturing process to develop covalent bonds of fluorocarbon radicals with the PMMA surface, which yielded reduced surface energy and also extremely smooth coating. The fluorine treatment substantially improved biocompatibility.
In research studies conducted by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted revealed a precision price of ± 0.5 D while 97% showed an accuracy price of ± 2 D. In terms of security, the BSCVA rates had 47 obtaining at the very least two lines, as well as no eyes lost lines. The overall glow record revealed that a lot of patients had few issues.
According to Mike Landreville, international director for refractive technologies at Bausch & Lomb, the business has no objective of introducing the NuVita lens into the USA for FDA approval or for clinical usage. Instead, the firm is establishing an entire brand-new phakic technology for a foldable anterior chamber phakic lens. The new phakic lens will certainly not just exist as a brand-new lens, yet as part of a completely new system, completely separate from the NuVita line. The brand-new, unrevealed lens system will certainly be of a brand-new material, include a new foldable distribution system and also provide a new analysis tool for implantation.
According to Mr. Landreville, the business prepares to have the brand-new system all set for professional usage in the USA by this year.
Alcon phakic IOL
A 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) material as well as has numerous advantages over various other phakic IOLs such as its foldability, which allows the lens to be put with a cut smaller than 3 mm, along with an angle-fixated, single-piece layout and high biocompatibility. The distance in between the cornea and the implant likewise drops in between 2.96 mm and 3.35 mm, a bigger range than with some other lenses, he claimed.
Dr. Maxwell reported that of the 10 implants that have actually been executed to day, greater than 90% of the patients have 20/40 or much better uncorrected vision at their postoperative sees. The mean spherical equivalent in clients 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 substantial enhancement in best-corrected visual acuity, and also in all however one patient the postoperative finest fixed vision is far better than the very best preoperative vision; in many cases, there are 2-, 3- or 4-line boosts in best-corrected visual acuity,” Dr. Maxwell stated. “In the one situation where it had not been much better, it was the same as the preoperative skill.”
CIBA obtains patents for IOL
CIBA Vision revealed at the AAO conference that it has obtained 3 licenses from Dr. Baikoff for foldable phakic former chamber IOL makes to correct not just nearsightedness and hyperopia yet also presbyopia.
” We are very thrilled concerning this brand-new technology,” David Bailey, surgical company system president for CIBA, claimed. “We believe that the MemoryLens material combined with these former chamber designs will certainly be a very successful combination.”
That former chamber lens initiative complements another refractive implant that was the topic of a number of discussions in the CIBA Vision cubicle– the PRL. This posterior-chamber phakic implant is being created by Medennium Inc. CIBA Vision took a 10% equity risk in Medennium in July as well as currently holds special globally advertising and marketing and also circulation rights to the lens, which is presently in phase 2 medical tests.
” We are taking a strong placement in phakic IOLs,” Mr. Bailey said, “and we’ll be strengthening that position with more new modern technology.”
This is the means to treat myopia, ypermetropia and astigmatism (αστιγματισμος ).