New innovations continue to broaden choices for dealing with keratoconus, myopia, hyperopia

Arising modern technology in the areas of corneal ring segments, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is giving new options for individuals suffering from 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 penetrating keratoplasty for people with keratoconus. Of 23 eyes in 20 individuals, 60% attained 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 option that strengthens the currently deteriorated cornea rather than further thinning it with LASIK. The suggestion of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a lot of feeling, Dr. Durrie told Medical care Optometry News.

” For many years, we have actually checked out other options to corneal transplants for these patients, and also some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been attempted in the past, however they remove part of the cornea in a patient population in which we understand the cornea is already slim and also weak,” Dr. Durrie claimed.

Because the keratoconic eye has a bulge in the cornea, Dr. Durrie stated, placing the Intacs insert in the perimeter of the cornea will squash the corneal center. This not just lowers the level of myopia, but reinforces the facility lump, he claimed. The preferred outcome is to postpone a corneal transplant for as long as possible.

While the information that Dr. Colin offered show that the treatment is rather secure, said Dr. Durrie, the lengthiest term information offered are just 2 years. “Checking out the patterns in the 3-month, 6-month and 1-year data, it appears that all people benefited from the procedure, but we can’t state that it stopped the keratoconus for longer than that until additional data are built up,” he stated. “Although I remain to do this procedure on isolated cases, I inform patients we don’t understand the long-term results and also we don’t understand whether it will decrease, accelerate or have no result 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 damaged the cornea,” he continued. “If the individual does need to go on to a corneal transplant, the inserts can be taken out and not interfere with basic transplant therapy. As a result of the change fit of the keratoconic cornea, ultimately, patients end up being contact lens intolerant, and also it is necessary to understand that there is an alternative to be investigated for these clients aside from just referring them for a corneal transplant.”

Professionals should make sure that individuals comprehend that the treatment is not refractive surgical procedure as well as will not always remedy their nearsightedness, claimed Dr. Durrie. “I have people on whom I have actually performed this procedure that have seen 20/40 without glasses, which would certainly be a superior result after a corneal transplant, but they’re still questioning why their good friends who have had Intacs dental implanted can see 20/20 when they can not,” he claimed. “That’s why these patients need to be informed that this isn’t something that maintains them from wearing glasses. It keeps them from requiring a corneal transplant.”

Hyperopic change with LTK
photo– Post-LTK: The pulses are applied in 8 places, one at the 6-mm area and also the other at the 7-mm zone.

Scientific studies have actually revealed laser thermokeratoplasty (LTK) to be a reliable method of dealing with a person’s hyperopia, and also it might also hold promise for treating presbyopia and overcorrected myopia after LASIK or PRK, claimed David J. Conway, OD, manager of refractive surgical treatment for Harvard Vanguard Medical Associates in Somerville, Mass

. Dr. Conway reported on the LTK technique and also its outcomes with hyperopia utilizing the Hyperion laser (Sunrise Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgery’s Summer season Globe Refractive Surgical Procedure Seminar 2000. Dr. Conway was not involved in any kind of Food and Drug Administration (FDA) research study; his ISRS presentation was based on information from the Daybreak FDA investigations and talks he went to.

When treating a client for hyperopia, the expert requires to emphasize the brevity of the procedure, he stated. “You need to communicate to the patient that this is only a short-term modification in his/her hyperopic condition,” he claimed. “There suffices regression with this method that the FDA felt it needed to refer this.”

Any kind of treatment for the improvement of hyperopia may demand retreatment over 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 raises as you age,” she claimed. “We have clients 3 years out who are secure, so I’m really pleased with the results.”

Dr. Belmont educates individuals of this opportunity, but none of them have altered their minds. She stated that if retreatment were required, clients did not mind because the treatment is quick, as well as creating a flap, which can lead to problems, is not required.

The LTK treatment
photograph– Stability: One scientist has patients that are still stable 3 years post-LTK.

The procedure, Dr. Conway claimed, takes 3 seconds to perform. 7 pulses are applied in eight areas, twice consecutively, one at the 6-mm area and the various other at the 7-mm area. The FDA research reported that the 612 eyes in 379 clients, all older than 40, ranging 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 said. “In contrasting preop to 24 months later, there was no loss of BSCVA as well as a bit of gain. We understand that myopes and also hyperopes are extremely different. Thankfully, the resistance of hyperopes is extremely valuable in making their contentment degree really high.”

Before the procedure, patients obtain three successive administrations of topical proparacaine at 3-minute intervals. Issues were very little, Dr. Conway kept in mind.

” Individuals are generally taken care of from a convenience perspective, purely with non-prescription analgesics to obtain them via the first hrs of recovery,” he stated. “Because you’re working on the corneal surface, FDA private investigators reported a bit of foreign-body experience, which dissipates with time really well.”

Regression with time
Dr. Conway stated that, while the patient’s skill level remains rather secure, some regression appears as the hyperopia raises over time. “There will be a tiny but considerable regression in these individuals; it’s just an issue of whether it goes to a reduced adequate degree to justify the client’s cost and also experience of undertaking this strategy,” he said. “By contrasting your cycloplegic to your reveal refraction, you can tell whether it exists hyperopia or otherwise.”

A person’s age factors in to how much time the result of LTK may last, said Dr. Conway. “A 50-year-old client will certainly experience a little more result than a 40-year-old client, probably due to a little bit a lot more dryness or the collagen condition of the cornea,” he claimed.

An off-label sign of LTK is the therapy of presbyopia, stated Dr. Belmont. Individuals who are plano and also presbyopic might be treated with LTK to attain monovision, she said. “Right now, their analysis vision enters focus,” she claimed. “They get their results instantly, and they’re really delighted keeping that.”

Patients who have been dealt with for presbyopia commonly will run into the exact same degree of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia enhances as you age, as does hyperopia,” she claimed. “Individuals recognize that this procedure will have to be improved as their aging necessitates a boost in the power they’ll require to read. They’re happy as long as you tell them in advance. I expect this as being the procedure to treat farsightedness as well as presbyopia.”

The size of time required for presbyopic therapy coincides when it comes to that of hyperopia, yet the degree of power that is applied to the eye is varied, she claimed.

Overcorrected myopia
The procedure may additionally show to be a valid option for boosting nearsighted clients that have been overcorrected with LASIK or PRK, stated Dr. Conway. “This values a lot of factor to consider, since you do not have to get rid of any tissue,” he stated. “In addition, Sunup is submitting for authorization removal of presbyopia, making individuals myopic in a monovision style. So, I assume this will certainly become a relatively preferred and typical option in this patient population, and also we’ll see the number of more surgeons determine to embrace it.”

LTK is approved for as much as +2.5 D, stated Dr. Belmont, as well as is presently undertaking tests for therapy approximately +5.6 D.

Refractec’s conductive keratoplasty
Initial scientific tests recommend that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency approach is most likely secure and also reliable for dealing with reduced to moderate amounts of hyperopia, according to Cent A. Asbell, MD, that provided medical trial information in Miami at the International Culture of Refractive Surgical treatment meeting. “Very early results with our information bent on year recommend that we get great visual acuity, great security as well as actually no unfavorable events, such as loss of vision,” claimed Dr. Asbell.

CK heats up the stromal cells with an electric current, reduces the collagen and steepens the central cornea, Dr. Asbell clarified. A high-frequency present is applied directly right into the peripheral corneal stroma via a shipment idea inserted at eight or more treatment factors. The launch of radiofrequency energy warms the bordering collagen to an identical temperature of 65 ° C and generates a cylindrical footprint 500 µm deep vs. a shallower, conical impact made with the LTK strategy. A full circle of CK-treated spots cinches the cornea and also boosts its curvature to decrease hyperopia.

” The adjustment seems to be long-term, as well as I think one of the reasons that holds true is that the treatment is delivered straight to the stroma,” claimed Dr. Asbell. “That’s where you desire the impact– not on the endothelium, out the epithelium. It’s a really easy medical method. It’s a non-laser technique, as well as it includes another dimension to what we currently can use for refractive surgical procedure– it is an economical treatment,” she included.

CK is consistent
An additional crucial concern, Dr. Asbell mentioned, is that CK is a regular treatment. “The therapy size as well as the area result in the stroma correspond from treatment spot to therapy area,” she claimed. “Among the essential problems to remember is that the temperature level we get with the CK procedure is constantly 65 ° as well as the imprint you make within the outer corneal stroma is constantly the exact same: 100 µm vast as well as 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 clients on whom Dr. Asbell reported, the regular age was 55, although, she said, there is a rather wide range of age amongst the test’s individuals. To qualify for the trial, she clarified, individuals needed to have uncorrected visual acuity of at least 20/40 or worse and bad near vision too– basic 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 and also simplicity of the procedure. “This procedure takes 5 mins per eye. It is a very brief treatment; you remain in and also out really rapidly,” she claimed. “It is a surgical procedure, however a very easy one. It does not require a qualified technician [to help] It doesn’t even require an autoclave. The suggestion, 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 [suggesting the size of the therapy area] The degree of hyperopia you are remedying identifies the number of therapy marks on the cornea. Every one is the same– the same quantity of power as well as the exact same depth within the stroma in each area,” she claimed.

Outcomes appear steady
Of the clients on whom Dr. Asbell reported, 61% accomplished uncorrected visual acuity of 20/20 or 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 better. “Our results look great and also secure. These are very delighted people,” claimed Dr. Asbell. “They actually can return to function quickly or absolutely the following day if they so pick. No one takes discomfort medicines.”

Security variables were “essentially absolutely no,” Dr. Asbell reported. “There was no loss of vision and also no corneal edema,” she claimed. “I assume this is mosting likely to be a procedure as well as an equipment that’s going to be very easy for us to have and also to use as well as an exceptional method to correct hyperopia postop LASIK or to touch up a postop cataract or corneal transplant,” she said. “I think it’s mosting likely to have a lot of flexibility in terms of its uses for dealing with hyperopia and also potentially astigmatism.”

Increased medical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually increased its professional trial studies of laser presbyopia turnaround (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Also, the firm has actually scheduled setup of the IR-laser in some European nations.

SurgiLight has actually sent four papers to the American Society of Cataract as well as Refractive Surgical Procedure for the May 2001 meeting, where more than 500 cases of LAPR will certainly exist by ophthalmologists from different countries using the company’s IR laser.

The firm is in the process of obtaining CE-Mark qualification and picking different worldwide suppliers. It prepares to send added 510K applications based on certain clearances acquired from Premier Laser Systems. SurgiLight anticipates to charge a royalty cost of $500 per person to cosmetic surgeons who make use of the firm’s IR-3000 system in the United States and also 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 available for myopes ranging 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. The general optical size is 5 mm and also the overall length 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 revamped from the previous version to reduce refracted glare, stress in the angle and also better clearance of the iris and all-natural lens. Additionally, the haptics were upgraded to get rid of iris retraction. The haptics were made a lot more versatile and, for that reason, caused much less student ovalization.

In its 2nd generation, the fluorine plasma therapy was added to the manufacturing process to develop covalent bonds of fluorocarbon radicals with the PMMA surface area, which produced lower surface area power as well as extremely smooth coating. The fluorine therapy significantly enhanced biocompatibility.

In researches 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% revealed an accuracy rate of ± 2 D. In regards to safety, the BSCVA prices had 47 gaining at the very least two lines, and no eyes lost lines. The total glow report showed that many people had few problems.

According to Mike Landreville, global director for refractive innovations at Bausch & Lomb, the firm has no objective of introducing the NuVita lens right into the USA for FDA authorization or for clinical use. Rather, the firm is creating an entire new phakic innovation for a collapsible anterior chamber phakic lens. The brand-new phakic lens will certainly not just exist as a brand-new lens, however as part of a completely brand-new system, completely separate from the NuVita line. The brand-new, unnamed lens system will be of a brand-new material, integrate a brand-new collapsible delivery system and supply a brand-new diagnostic tool for implantation.

According to Mr. Landreville, the firm intends to have the new system all set for clinical usage 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 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 enables the lens to be inserted via a laceration smaller than 3 mm, along with an angle-fixated, single-piece design and high biocompatibility. The distance between the cornea as well as the implant likewise drops between 2.96 mm and 3.35 mm, a larger range than with some other lenses, he said.

Dr. Maxwell reported that of the 10 implants that have actually been carried out to day, greater than 90% of the patients have 20/40 or much better uncorrected vision at their postoperative sees. The mean round equivalent in clients dental implanted thus far was– 11.5 D, he claimed, with a result of– 0.39 D at 1 month and also– 0.8 D at 6 months of residual myopia.

” We see substantial renovation in best-corrected visual acuity, and in all however one patient the postoperative ideal fixed 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 said. “In the one case where it wasn’t better, it coincided as the preoperative acuity.”

CIBA acquires patents for IOL
CIBA Vision announced at the AAO conference that it has actually gotten 3 patents from Dr. Baikoff for foldable phakic anterior chamber IOL makes to deal with not just nearsightedness and hyperopia but additionally presbyopia.

” We are very excited about this brand-new technology,” David Bailey, medical business device head of state for CIBA, claimed. “We assume that the MemoryLens material incorporated with these former chamber designs will be a very successful combination.”

That former chamber lens campaign matches an additional refractive dental implant that was the subject of a number of presentations in the CIBA Vision cubicle– 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 marketing and also 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 ).