New technologies remain to expand options for treating keratoconus, myopia, hyperopia

Arising innovation in the areas of corneal ring sectors, holmium laser thermokeratoplasty (LTK) and phakic IOLs is providing brand-new choices for clients struggling with keratoconus, myopia, hyperopia as well as presbyopia.

Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) meeting in October 2000, Joseph Colin, MD, offered a study of alternatives to permeating keratoplasty for clients with keratoconus. Of 23 eyes in 20 patients, 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 a choice that enhances the currently damaged cornea as opposed to more thinning it with LASIK. The idea of using an additive procedure, such as Intacs (KeraVision, Fremont, Calif.), to strengthen the cornea makes a great deal of feeling, Dr. Durrie told Primary Care Optometry Information.

” For several years, we’ve looked at various other choices to corneal transplants for these people, as well as some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been tried in the past, yet they eliminate part of the cornea in a patient population in which we understand the cornea is already thin and also weak,” Dr. Durrie stated.

Since the keratoconic eye has a bulge in the cornea, Dr. Durrie claimed, positioning the Intacs put in the perimeter of the cornea will flatten the corneal center. This not only reduces the level of myopia, but enhances the center lump, he claimed. The wanted result is to postpone a corneal transplant for as long as feasible.

While the information that Dr. Colin offered show that the treatment is quite safe, claimed Dr. Durrie, the longest term data offered are just 2 years. “Considering the patterns in the 3-month, 6-month and 1-year data, it shows up that all people took advantage of the procedure, but we can not claim that it quit the keratoconus for longer than that until more information are built up,” he said. “Although I continue to do this treatment on isolated cases, I inform individuals we don’t know the long-lasting results and we do not understand whether it will reduce, quicken or have no result on the normal course of keratoconus.

” The advantage of this procedure is, if it doesn’t function, you can take the Intacs out and also have not damaged the cornea,” he proceeded. “If the person does require to go on to a corneal transplant, the inserts can be secured as well as not interfere with typical transplant therapy. Because of the change in shape of the keratoconic cornea, eventually, people come to be contact lens intolerant, as well as it is necessary to know that there is an alternative to be examined for these clients aside from simply referring them for a corneal transplant.”

Practitioners must make certain that clients understand that the treatment is not refractive surgery as well as will certainly not always remedy their nearsightedness, stated Dr. Durrie. “I have individuals on whom I have executed this procedure that have seen 20/40 without glasses, which would be an outstanding outcome after a corneal transplant, yet they’re still wondering why their good friends that have actually had Intacs dental implanted can see 20/20 when they can’t,” 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 needing a corneal transplant.”

Hyperopic change with LTK
photo– Post-LTK: The pulses are applied in eight spots, one at the 6-mm zone and also the various other at the 7-mm area.

Clinical researches have shown laser thermokeratoplasty (LTK) to be an effective method of dealing with a client’s hyperopia, and also it may additionally hold promise for treating presbyopia as well as overcorrected nearsightedness after LASIK or PRK, said David J. Conway, OD, supervisor of refractive surgery for Harvard Lead Medical Associates in Somerville, Mass

. Dr. Conway reported on the LTK strategy as well as its results with hyperopia making use of the Hyperion laser (Daybreak Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical procedure’s Summer World Refractive Surgical Procedure Seminar 2000. Dr. Conway was not associated with any kind of Food and Drug Administration (FDA) research; his ISRS discussion was based on details from the Daybreak FDA examinations and lectures he attended.

When dealing with a person for hyperopia, the expert needs to stress the brevity of the procedure, he stated. “You require to communicate to the client that this is only a temporary modification in his/her hyperopic status,” he said. “There suffices regression with this technique that the FDA felt it necessary to make mention of this.”

Any kind of procedure for the modification of hyperopia might require retreatment over time; this is not distinct to LTK, stated Sandra Belmont, MD, supervisor of the laser vision facility at the Cornell Weill Medical Facility in New York City City. “Hyperopia enhances as you age,” she claimed. “We have individuals 3 years out that are stable, so I’m really pleased with the results.”

Dr. Belmont educates individuals of this possibility, yet none of them have transformed their minds. She stated that if retreatment were needed, patients did incline since the procedure fasts, as well as creating a flap, which can result in problems, is not needed.

The LTK treatment
photo– Stability: One researcher has individuals who are still stable 3 years post-LTK.

The treatment, Dr. Conway said, takes 3 secs to do. 7 pulses are applied in 8 areas, 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 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 kept in mind.

” No loss of lines of acuity were attributable to the LTK,” he said. “In comparing preop to 24 months later on, there was no loss of BSCVA and a little of gain. We know that myopes as well as hyperopes are really different. The good news is, the tolerance of hyperopes is very practical in making their complete satisfaction degree extremely high.”

Before the procedure, individuals obtain three successive managements of topical proparacaine at 3-minute periods. Complications were marginal, Dr. Conway kept in mind.

” Individuals are generally taken care of from a convenience viewpoint, purely with non-prescription analgesics to obtain them with the first hours of recuperation,” he stated. “Because you’re working with the corneal surface area, FDA investigators reported a little of foreign-body feeling, which dissipates with time extremely well.”

Regression with time
Dr. Conway said that, while the person’s acuity level remains relatively stable, some regression is evident as the hyperopia increases gradually. “There will be a tiny however substantial regression in these patients; it’s simply an issue of whether it goes to a reduced adequate level to justify the patient’s cost and also experience of undergoing this technique,” he stated. “By comparing 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 impact of LTK might last, claimed Dr. Conway. “A 50-year-old individual will experience a little extra effect than a 40-year-old client, maybe because of a bit a lot more dryness or the collagen status of the cornea,” he claimed.

An off-label indicator of LTK is the therapy of presbyopia, said Dr. Belmont. People that are plano and also presbyopic might be treated with LTK to achieve monovision, she said. “Right away, their reading vision enters into emphasis,” she claimed. “They obtain their outcomes right away, and they’re truly delighted with that.”

Clients who have actually been dealt with for presbyopia normally will run into the exact same level of regression as hyperopes, Dr. Belmont noted. “Presbyopia boosts as you age, as does hyperopia,” she stated. “Individuals recognize that this treatment will have to be enhanced as their aging necessitates a boost in the power they’ll require to review. They more than happy as long as you tell them ahead of time. I anticipate this as being the treatment to deal with farsightedness and also presbyopia.”

The size of time needed for presbyopic therapy coincides when it comes to that of hyperopia, however the degree of power that is put on the eye is varied, she claimed.

Overcorrected myopia
The treatment may also prove to be a valid choice for boosting myopic clients who have been overcorrected with LASIK or PRK, claimed Dr. Conway. “This merits a lot of factor to consider, because you don’t have to get rid of any cells,” he said. “In addition, Dawn is submitting for authorization remediation of presbyopia, making individuals myopic in a monovision style. So, I think this will become a rather popular and also common alternative in this patient population, as well as we’ll see how many even more cosmetic surgeons determine to embrace it.”

LTK is accepted for approximately +2.5 D, stated Dr. Belmont, and also is presently going through trials for therapy up to +5.6 D.

Refractec’s conductive keratoplasty
Preliminary medical trials suggest that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency approach is most likely safe and also effective for fixing low to moderate quantities of hyperopia, according to Dime A. Asbell, MD, that presented medical trial data in Miami at the International Society of Refractive Surgical treatment conference. “Early results with our information bent on one year recommend that we obtain fantastic visual acuity, very good stability and also really no damaging events, such as loss of vision,” stated Dr. Asbell.

CK heats up the stromal tissue with an electrical present, diminishes the collagen and steepens the main cornea, Dr. Asbell discussed. A high-frequency current is applied directly into the outer corneal stroma with a delivery pointer put at 8 or even more therapy points. The launch of radiofrequency energy warms the bordering collagen to an uniform temperature level of 65 ° C and generates a cylindrical impact 500 µm deep vs. a shallower, cone-shaped impact made with the LTK technique. A cycle of CK-treated places cinches the cornea and also raises its curvature to lower hyperopia.

” The adjustment seems to be long-term, and I believe among the factors that holds true is that the treatment is delivered directly to the stroma,” claimed Dr. Asbell. “That’s where you want the impact– out the endothelium, out the epithelium. It’s a very easy surgical method. It’s a non-laser technique, and it adds an additional dimension to what we already can offer for refractive surgical procedure– it is an affordable procedure,” she added.

CK corresponds
An additional vital issue, Dr. Asbell pointed out, is that CK is a regular therapy. “The treatment dimension and also the area impact in the stroma correspond from therapy area to treatment spot,” she said. “Among the key concerns to bear in mind is that the temperature we get with the CK procedure is always 65 ° and the imprint you make within the peripheral 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 scientific trial of CK. Other private investigators at various 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 patients on whom Dr. Asbell reported, the typical age was 55, although, she stated, there is a relatively large range old amongst the test’s individuals. To qualify for the trial, she described, patients had to have uncorrected visual acuity of at the very least 20/40 or worse and poor near vision too– conventional 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 also simplicity of the procedure. “This procedure takes 5 mins per eye. It is an extremely brief procedure; you’re in and out very quickly,” she said. “It is a surgical procedure, yet a really easy one. It does not call for a trained technician [to help] It does not also call for an autoclave. The suggestion, which is about the size of a hair, is disposable.”

Dr. Asbell explained the CK nomogram because of this: “The treatment is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [indicating the dimension of the therapy zone] The level of hyperopia you are dealing with determines the variety of therapy marks on the cornea. Each one coincides– the very same amount of energy and the same depth within the stroma in each place,” she claimed.

Outcomes appear stable
Of the clients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or far 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 much better, and also 92% were 20/40 or much better. “Our outcomes look excellent as well as stable. These are extremely pleased clients,” stated Dr. Asbell. “They really can go back to function right away or absolutely the following day if they so pick. No one takes pain medications.”

Safety variables were “primarily no,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she stated. “I think this is going to be a treatment as well as a maker that’s mosting likely to be simple for us to possess and also to use as well as an exceptional way to correct hyperopia postop LASIK or to touch up a postop cataract or corneal transplant,” she claimed. “I assume it’s mosting likely to have a great deal of adaptability in terms of its uses for fixing hyperopia and also potentially astigmatism.”

Broadened clinical trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has increased its professional test research studies of laser presbyopia reversal (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Also, the firm has actually arranged setup of the IR-laser in some European nations.

SurgiLight has submitted four papers to the American Society of Cataract as well as Refractive Surgical Procedure for the May 2001 conference, where greater than 500 situations of LAPR will certainly be presented by ophthalmologists from different countries utilizing the firm’s IR laser.

The business remains in the process of obtaining CE-Mark accreditation and also picking different international suppliers. It intends to send additional 510K applications based on specific clearances gotten from Premier Laser Solutions. SurgiLight anticipates to charge a royalty charge of $500 per client to surgeons who make use of 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, former 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 design is an angle-fixated, single-piece lens, with a meniscus optical shape as well as a PMMA surface area. The total optical size is 5 mm as well as the general size of the NuVita ranges from 12 mm to 13.5 mm in 0.5-mm increments.

The optic, loophole and footplate were all upgraded from the previous variation to lower refracted glow, stress in the angle and better clearance of the iris as well as all-natural lens. Also, the haptics were redesigned to eliminate iris retraction. The haptics were made a lot more versatile and, for that reason, resulted in much less student ovalization.

In its 2nd generation, the fluorine plasma therapy was included in the manufacturing procedure to develop covalent bonds of fluorocarbon radicals with the PMMA surface, which yielded reduced surface area power as well as remarkably smooth finish. The fluorine therapy significantly enhanced biocompatibility.

In researches carried out by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes dental implanted showed an accuracy rate of ± 0.5 D while 97% showed an accuracy price of ± 2 D. In regards to security, the BSCVA rates had 47 getting at the very least 2 lines, and also no eyes shed lines. The overall glow record revealed that many clients had few issues.

According to Mike Landreville, global director for refractive technologies at Bausch & Lomb, the firm has no intent of presenting the NuVita lens into the United States for FDA approval or for scientific use. Instead, the firm is developing an entire new phakic modern technology for a foldable former chamber phakic lens. The brand-new phakic lens will certainly not just exist as a new lens, however as part of an entirely brand-new system, entirely separate from the NuVita line. The brand-new, unrevealed lens system will be of a new material, incorporate a new collapsible delivery system and also supply a brand-new analysis tool for implantation.

According to Mr. Landreville, the company plans to have the new system all set for clinical usage in the United States by this year.

Alcon phakic IOL
A brand-new former chamber phakic IOL was presented by Andrew Maxwell, MD, PhD, at the AAO meeting. The lens has an Acrysof-based (Alcon, Ft. Well Worth, Texas) product and also has a number of benefits over various other phakic IOLs such as its foldability, which allows the lens to be put with a cut smaller sized than 3 mm, along with an angle-fixated, single-piece style and high biocompatibility. The distance between the cornea as well as the implant additionally 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 actually been executed to day, greater than 90% of the clients have 20/40 or better uncorrected vision at their postoperative gos to. The mean round equivalent in clients dental implanted thus far was– 11.5 D, he stated, with an outcome of– 0.39 D at 1 month as well as– 0.8 D at 6 months of residual nearsightedness.

” We see substantial enhancement in best-corrected visual acuity, and in all yet one patient the postoperative finest remedied vision is much 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 situation where it wasn’t much better, it was the same as the preoperative skill.”

CIBA obtains licenses for IOL
CIBA Vision announced at the AAO conference that it has acquired three licenses from Dr. Baikoff for collapsible phakic anterior chamber IOL creates to remedy not just nearsightedness and hyperopia yet likewise presbyopia.

” We are very excited about this brand-new modern technology,” David Bailey, medical company device president for CIBA, claimed. “We assume that the MemoryLens product incorporated with these former chamber styles will be a very successful mix.”

That anterior chamber lens initiative enhances an additional refractive dental implant that was the subject of a number of presentations in the CIBA Vision booth– the PRL. This posterior-chamber phakic implant is being developed by Medennium Inc. CIBA Vision took a 10% equity risk in Medennium in July and also currently holds unique worldwide advertising 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 ).