Arising technology in the locations of corneal ring sectors, holmium laser thermokeratoplasty (LTK) as well as phakic IOLs is offering new choices for people 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 study of choices to passing through keratoplasty for patients with keratoconus. Of 23 eyes in 20 people, 60% accomplished a best-corrected visual acuity of 20/40 or far better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, commented on Dr. Colin’s paper, which suggests an alternative that enhances the currently compromised cornea as opposed to more thinning it with LASIK. The suggestion of using an additive procedure, such as Intacs (KeraVision, Fremont, Calif.), to strengthen the cornea makes a lot of feeling, Dr. Durrie informed Health care Optometry News.
” For many years, we have actually checked out various other choices to corneal transplants for these patients, and some procedures such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been tried in the past, yet they remove part of the cornea in a client population in which we understand the cornea is already thin and also 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 flatten the corneal facility. This not just reduces the level of nearsightedness, but reinforces the facility lump, he claimed. The preferred result is to postpone a corneal transplant for as long as possible.
While the data that Dr. Colin offered program that the procedure is rather secure, claimed Dr. Durrie, the lengthiest term data offered are just 2 years. “Looking at the patterns in the 3-month, 6-month and 1-year data, it appears that all individuals benefited from the treatment, however we can not say that it stopped the keratoconus for longer than that until further information are gathered,” he claimed. “Although I remain to do this treatment on isolated instances, I tell patients we don’t know the long-term results and we don’t know whether it will decrease, accelerate or have no result on the normal course of keratoconus.
” The benefit of this treatment is, if it doesn’t work, you can take the Intacs out and also have actually not damaged the cornea,” he continued. “If the client does require to take place to a corneal transplant, the inserts can be secured and also not interfere with conventional transplant treatment. As a result of the adjustment in shape of the keratoconic cornea, ultimately, clients become get in touch with lens intolerant, and also it is essential to understand that there is an alternative to be examined for these individuals aside from simply referring them for a corneal transplant.”
Professionals ought to be sure that patients understand that the procedure is not refractive surgical procedure and also will not necessarily remedy their nearsightedness, said Dr. Durrie. “I have patients on whom I have actually performed this procedure who have seen 20/40 without glasses, which would be an exceptional result after a corneal transplant, yet they’re still asking yourself why their close friends who have had Intacs dental implanted can see 20/20 when they can’t,” he stated. “That’s why these people need to be educated that this isn’t something that keeps them from using glasses. It keeps them from needing a corneal transplant.”
Hyperopic change with LTK
photograph– Post-LTK: The pulses are applied in 8 areas, one at the 6-mm zone and the other at the 7-mm zone.
Professional researches have revealed laser thermokeratoplasty (LTK) to be an efficient technique of fixing a client’s hyperopia, and also it might likewise hold promise for treating presbyopia and overcorrected nearsightedness after LASIK or PRK, stated David J. Conway, OD, manager of refractive surgical treatment for Harvard Lead Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK strategy and also its outcomes with hyperopia using the Hyperion laser (Sunup Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgery’s Summer season World Refractive Surgical Procedure Symposium 2000. Dr. Conway was not associated with any kind of Food and Drug Administration (FDA) research; his ISRS discussion was based upon info from the Daybreak FDA investigations and also talks he went to.
When treating an individual for hyperopia, the specialist requires to stress the impermanence of the procedure, he claimed. “You require to convey to the individual that this is only a short-term modification in his/her hyperopic standing,” he said. “There suffices regression with this strategy that the FDA felt it essential to make mention of this.”
Any type of procedure for the correction of hyperopia might demand retreatment gradually; this is not one-of-a-kind 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 stated. “We have patients 3 years out that are stable, so I’m very happy with the results.”
Dr. Belmont notifies people of this possibility, however none of them have changed their minds. She claimed that if retreatment were needed, patients did not mind because the procedure is quick, and developing a flap, which can result in issues, is not necessary.
The LTK treatment
picture– Security: One scientist has people who are still steady 3 years post-LTK.
The procedure, Dr. Conway said, takes 3 secs to execute. Seven pulses are applied in eight areas, two times back to back, one at the 6-mm area and also the various other at the 7-mm area. The FDA 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 finest spectacle-corrected visual acuity (BSCVA) after 2 years, he noted.
” No loss of lines of skill were attributable to the LTK,” he said. “In contrasting preop to 24 months later on, there was no loss of BSCVA as well as a bit of gain. We understand that myopes and also hyperopes are very various. Fortunately, the resistance of hyperopes is very useful in making their satisfaction degree extremely high.”
Prior to the treatment, individuals receive three successive administrations of topical proparacaine at 3-minute periods. Complications were minimal, Dr. Conway kept in mind.
” Clients are generally taken care of from a comfort standpoint, purely with over-the-counter anesthetics to get them with the initial hrs of recovery,” he claimed. “Since you’re working on the corneal surface, FDA detectives reported a little bit of foreign-body feeling, which dissipates with time really perfectly.”
Regression with time
Dr. Conway said that, while the client’s acuity level stays relatively steady, some regression appears as the hyperopia enhances with time. “There will certainly be a small but considerable regression in these individuals; it’s just an issue of whether it’s at a reduced enough level to validate the person’s cost and experience of undergoing this strategy,” he stated. “By comparing your cycloplegic to your show refraction, you can tell whether it’s latent hyperopia or otherwise.”
An individual’s age factors in to the length of time the effect of LTK may last, said Dr. Conway. “A 50-year-old patient will experience a little much more result than a 40-year-old client, perhaps because of a little bit much more dry skin or the collagen standing of the cornea,” he stated.
An off-label sign of LTK is the therapy of presbyopia, stated Dr. Belmont. Individuals that are plano as well as presbyopic may be treated with LTK to accomplish monovision, she said. “Right away, their reading vision enters into focus,” she claimed. “They obtain their outcomes quickly, as well as they’re really pleased with that.”
Individuals who have actually been dealt with for presbyopia generally will experience the exact same degree of regression as hyperopes, Dr. Belmont noted. “Presbyopia boosts as you age, as does hyperopia,” she said. “Clients understand that this treatment will have to be boosted as their aging necessitates a boost in the power they’ll need to read. They more than happy as long as you tell them beforehand. I anticipate this as being the treatment to deal with farsightedness and also presbyopia.”
The length of time required 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 procedure might likewise show to be a valid option for improving nearsighted patients who have been overcorrected with LASIK or PRK, claimed Dr. Conway. “This values a great deal of factor to consider, since you do not have to eliminate any type of cells,” he stated. “Additionally, Sunup is submitting for authorization removal of presbyopia, making individuals myopic in a monovision style. So, I believe this will become a relatively prominent and also common option in this client populace, and we’ll see the amount of even more cosmetic surgeons decide to embrace it.”
LTK is accepted for as much as +2.5 D, said Dr. Belmont, and is currently undergoing trials for therapy approximately +5.6 D.
Refractec’s conductive keratoplasty
Initial medical trials recommend that conductive keratoplasty (CK) using Refractec’s (Irvine, Calif.) radiofrequency method is probably risk-free and also efficient for correcting reduced to modest quantities of hyperopia, according to Cent A. Asbell, MD, that provided clinical test data in Miami at the International Society of Refractive Surgical treatment meeting. “Early results with our data bent on one year suggest that we obtain fantastic visual acuity, excellent security and actually no damaging events, such as loss of vision,” said Dr. Asbell.
CK warms the stromal tissue with an electrical current, shrinks the collagen and also steepens the central cornea, Dr. Asbell discussed. A high-frequency current is applied directly into the peripheral corneal stroma with a shipment idea put at eight or even more therapy factors. The launch of radiofrequency energy warms the surrounding collagen to an uniform temperature level of 65 ° C as well as generates a round impact 500 µm deep vs. a shallower, conical footprint made with the LTK strategy. A full circle of CK-treated areas cinches the cornea and raises its curvature to lower hyperopia.
” The adjustment seems to be irreversible, and I believe one of the reasons that’s true is that the treatment is supplied straight to the stroma,” claimed Dr. Asbell. “That’s where you desire the impact– not on the endothelium, not on the epithelium. It’s a very simple surgical technique. It’s a non-laser method, and it includes one more dimension to what we already can supply for refractive surgery– it is an affordable procedure,” she included.
An additional essential issue, Dr. Asbell mentioned, is that CK is a constant therapy. “The treatment size and also the zone impact in the stroma are consistent from treatment area to treatment spot,” she said. “One of the key issues to keep in mind is that the temperature we get with the CK treatment is always 65 ° and the imprint you make within the peripheral corneal stroma is always the very same: 100 µm large and also 500 µm deep within the corneal stroma.”
Dr. Asbell is a private investigator in the FDA clinical test of CK. Fellow investigators at various other sites 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 individuals on whom Dr. Asbell reported, the typical age was 55, although, she said, there is a rather variety of age among the trial’s individuals. To get approved for the test, she explained, patients needed to have uncorrected visual acuity of at least 20/40 or worse and bad near vision as well– conventional 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 minutes per eye. It is a very short treatment; you’re in and out really promptly,” she claimed. “It is a surgical procedure, yet a very basic one. It does not require a qualified technician [to help] It doesn’t also need 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 size of the therapy area] The level of hyperopia you are fixing figures out the variety of therapy marks on the cornea. Each one coincides– the very same amount of energy as well as the same depth within the stroma in each place,” she said.
Outcomes appear steady
Of the clients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or better 6 months postoperatively and 96% were 20/40 or better at the 6-month mark. One year postoperatively, 62% were 20/20 or better, as well as 92% were 20/40 or better. “Our outcomes look excellent as well as stable. These are extremely satisfied clients,” stated Dr. Asbell. “They actually can return to work quickly or definitely the next day if they so choose. Nobody takes pain medications.”
Security variables were “essentially absolutely no,” Dr. Asbell reported. “There was no loss of vision and also no corneal edema,” she stated. “I believe this is mosting likely to be a procedure and a maker that’s mosting likely to be very easy for us to possess as well as to make use of and an outstanding method to deal with hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she said. “I assume it’s going to have a lot of adaptability in regards to its usages for remedying hyperopia and potentially astigmatism.”
Expanded clinical trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has broadened its clinical trial research studies of laser presbyopia turnaround (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas as well as Japan. Additionally, the company has actually scheduled installation of the IR-laser in some European countries.
SurgiLight has actually submitted four papers to the American Society of Cataract as well as Refractive Surgical Treatment for the May 2001 conference, where greater than 500 instances of LAPR will certainly exist by ophthalmologists from various nations utilizing the firm’s IR laser.
The firm is in the process of obtaining CE-Mark certification and also choosing numerous global representatives. It plans to send added 510K applications based upon certain clearances gotten from Premier Laser Solutions. SurgiLight anticipates to charge a nobility charge of $500 per individual to doctors that use the business’s IR-3000 system in the United States as well as Europe.
B&L NuVita phakic IOL
The third generation of George Baikoff, MD’s, anterior chamber phakic IOL is represented with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is offered for myopes varying from 7 D to 20 D. The layout is an angle-fixated, single-piece lens, with a curve optical form as well as a PMMA surface area. The overall optical size is 5 mm as well as the overall 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 upgraded from the previous variation to reduce refracted glare, stress in the angle and much better clearance of the iris and all-natural lens. Likewise, the haptics were redesigned to eliminate iris retraction. The haptics were made more versatile and also, as a result, caused much less pupil ovalization.
In its 2nd generation, the fluorine plasma therapy was contributed to the production procedure to develop covalent bonds of fluorocarbon radicals with the PMMA surface area, which produced lower surface area power and also remarkably smooth surface. The fluorine therapy greatly enhanced biocompatibility.
In research studies conducted by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted showed a precision price of ± 0.5 D while 97% showed a precision price of ± 2 D. In terms of security, the BSCVA rates had 47 gaining at the very least 2 lines, as well as no eyes lost lines. The total glow record showed that a lot of patients had few problems.
According to Mike Landreville, global director for refractive modern technologies at Bausch & Lomb, the business has no objective of introducing the NuVita lens right into the United States for FDA authorization or for professional use. Rather, the company is developing a whole new phakic innovation for a foldable former chamber phakic lens. The brand-new phakic lens will not just exist as a new lens, but as part of a totally new system, completely different from the NuVita line. The brand-new, unnamed lens system will certainly be of a brand-new product, incorporate a new foldable distribution system and also provide a brand-new diagnostic device for implantation.
According to Mr. Landreville, the firm prepares to have the new system prepared for clinical usage in the United States by this year.
Alcon phakic IOL
A new former chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO conference. The lens has an Acrysof-based (Alcon, Ft. Well Worth, Texas) product and also has numerous advantages over other phakic IOLs such as its foldability, which allows the lens to be inserted via an incision smaller sized than 3 mm, in addition to an angle-fixated, single-piece style as well as high biocompatibility. The distance in between the cornea as well as the implant likewise falls between 2.96 mm and 3.35 mm, a bigger distance than with a few other lenses, he claimed.
Dr. Maxwell reported that of the 10 implants that have been carried out to date, greater than 90% of the patients have 20/40 or far better uncorrected vision at their postoperative visits. The mean spherical equivalent in people implanted so far was– 11.5 D, he said, with a result of– 0.39 D at 1 month as well as– 0.8 D at 6 months of recurring myopia.
” We see considerable improvement in best-corrected visual acuity, and in all yet one client the postoperative finest corrected vision is much better than the most effective preoperative vision; oftentimes, there are 2-, 3- or 4-line increases in best-corrected visual acuity,” Dr. Maxwell claimed. “In the one situation where it wasn’t better, it coincided as the preoperative acuity.”
CIBA obtains patents for IOL
CIBA Vision introduced at the AAO meeting that it has actually obtained three licenses from Dr. Baikoff for collapsible phakic former chamber IOL develops to remedy not just nearsightedness and also hyperopia but likewise presbyopia.
” We are really thrilled concerning this new innovation,” David Bailey, surgical organization system head of state for CIBA, claimed. “We think that the MemoryLens material integrated with these anterior chamber styles will be a very successful combination.”
That former chamber lens campaign enhances an additional refractive implant that was the topic of several presentations in the CIBA Vision cubicle– 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 currently holds special around the world marketing and 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 (μυωπια ).