Emerging modern technology in the areas of corneal ring sections, holmium laser thermokeratoplasty (LTK) and phakic IOLs is supplying brand-new alternatives for clients struggling with keratoconus, nearsightedness, hyperopia and presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) meeting in October 2000, Joseph Colin, MD, provided a research of options to passing through keratoplasty for patients with keratoconus. Of 23 eyes in 20 individuals, 60% achieved a best-corrected visual acuity of 20/40 or better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, commented on Dr. Colin’s paper, which recommends a choice that enhances the currently damaged cornea instead of additional thinning it with LASIK. The suggestion of using an additive treatment, such as Intacs (KeraVision, Fremont, Calif.), to strengthen the cornea makes a lot of feeling, Dr. Durrie informed Health care Optometry Information.
” For many years, we’ve looked at other choices to corneal transplants for these people, and some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have actually been tried in the past, but they get rid of part of the cornea in a client populace in which we understand the cornea is already slim and also weak,” Dr. Durrie claimed.
Since the keratoconic eye has a lump in the cornea, Dr. Durrie claimed, putting the Intacs place in the periphery of the cornea will certainly flatten the corneal center. This not only lowers the level of nearsightedness, however reinforces the center lump, he stated. The desired outcome is to postpone a corneal transplant for as long as possible.
While the information that Dr. Colin presented program that the treatment is fairly safe, said Dr. Durrie, the longest term information offered are just 2 years. “Checking out the fads in the 3-month, 6-month as well as 1-year data, it appears that all people took advantage of the treatment, but we can not state that it stopped the keratoconus for longer than that till additional data are collected,” he stated. “Although I remain to do this treatment on isolated situations, I inform people we don’t understand the long-term effects as well as we don’t recognize whether it will decrease, speed up or have no result on the normal course of keratoconus.
” The benefit of this procedure is, if it doesn’t work, you can take the Intacs out and also have not weakened the cornea,” he proceeded. “If the client does require to take place to a corneal transplant, the inserts can be secured and also not interfere with basic transplant therapy. Due to the change in shape of the keratoconic cornea, eventually, people become get in touch with lens intolerant, and also it is essential to recognize that there is an alternative to be investigated for these patients aside from just referring them for a corneal transplant.”
Specialists must make certain that people understand that the treatment is not refractive surgical procedure and will not necessarily correct their nearsightedness, claimed Dr. Durrie. “I have clients on whom I have actually done this procedure that have actually seen 20/40 without glasses, which would certainly be a superior result after a corneal transplant, but they’re still asking yourself why their buddies that have had Intacs dental implanted can see 20/20 when they can’t,” he claimed. “That’s why these clients need to be educated that this isn’t something that maintains them from using glasses. It maintains them from requiring a corneal transplant.”
Hyperopic adjustment with LTK
photograph– Post-LTK: The pulses are applied in eight areas, one at the 6-mm zone and the various other at the 7-mm zone.
Clinical researches have actually shown laser thermokeratoplasty (LTK) to be an effective technique of dealing with a client’s hyperopia, as well as it might also hold promise for treating presbyopia and also overcorrected myopia after LASIK or PRK, claimed David J. Conway, OD, supervisor of refractive surgery 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 (Sunup Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical procedure’s Summer season Globe Refractive Surgical Treatment Symposium 2000. Dr. Conway was not associated with any Food and Drug Administration (FDA) study; his ISRS presentation was based upon information from the Sunrise FDA examinations as well as lectures he participated in.
When dealing with a client for hyperopia, the practitioner requires to emphasize the impermanence of the procedure, he stated. “You need to communicate to the person that this is only a temporary adjustment in his/her hyperopic status,” he stated. “There suffices regression with this method that the FDA felt it essential to refer this.”
Any type of procedure for the correction of hyperopia may demand retreatment over time; this is not unique to LTK, stated Sandra Belmont, MD, director of the laser vision center at the Cornell Weill Medical Center in New York City. “Hyperopia enhances as you age,” she claimed. “We have patients 3 years out that are secure, so I’m extremely pleased with the outcomes.”
Dr. Belmont informs people of this opportunity, yet none of them have transformed their minds. She said that if retreatment were required, individuals did incline since the treatment is quick, and also producing a flap, which can result in complications, is not required.
The LTK procedure
picture– Stability: One scientist has people who are still secure 3 years post-LTK.
The procedure, Dr. Conway claimed, takes 3 seconds to execute. Seven pulses are used in 8 places, two times back to back, one at the 6-mm area as well as the other at the 7-mm area. The FDA research 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 best 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 as well as a bit of gain. We know that myopes and also hyperopes are extremely various. Fortunately, the resistance of hyperopes is really valuable in making their satisfaction degree really high.”
Before the treatment, patients receive three successive administrations of topical proparacaine at 3-minute intervals. Issues were minimal, Dr. Conway kept in mind.
” Clients are normally handled from a comfort standpoint, strictly with over-the-counter analgesics to obtain them through the first hours of healing,” he claimed. “Since you’re working on the corneal surface, FDA detectives reported a little of foreign-body feeling, which dissipates with time really perfectly.”
Dr. Conway claimed that, while the individual’s skill level stays fairly stable, some regression is evident as the hyperopia raises over time. “There will be a small yet substantial regression in these individuals; it’s simply a matter of whether it goes to a reduced sufficient degree to justify the person’s cost as well as experience of undertaking this method,” he said. “By comparing your cycloplegic to your reveal refraction, you can tell whether it’s latent hyperopia or otherwise.”
A patient’s age consider to how long the effect of LTK might last, claimed Dr. Conway. “A 50-year-old patient will certainly experience a little a lot more impact than a 40-year-old individual, probably because of a little bit extra dryness or the collagen status of the cornea,” he said.
An off-label sign of LTK is the therapy of presbyopia, stated Dr. Belmont. Clients that are plano as well as presbyopic may be treated with LTK to accomplish monovision, she claimed. “Right now, their analysis vision comes into focus,” she said. “They obtain their results immediately, as well as they’re actually happy with that.”
Patients that have actually been dealt with for presbyopia usually will encounter the very same degree of regression as hyperopes, Dr. Belmont noted. “Presbyopia raises as you age, as does hyperopia,” she claimed. “Individuals recognize that this procedure will have to be improved as their aging demands a boost in the power they’ll require to review. They more than happy as long as you tell them in advance. I anticipate this as being the procedure to deal with farsightedness and also presbyopia.”
The length of time required for presbyopic therapy coincides as for that of hyperopia, yet the level of energy that is related to the eye is differed, she said.
The procedure might also prove to be a legitimate choice for enhancing myopic patients who have actually been overcorrected with LASIK or PRK, claimed Dr. Conway. “This merits a great deal of factor to consider, because you do not have to remove any type of tissue,” he stated. “In addition, Daybreak is submitting for approval remediation of presbyopia, making clients short-sighted in a monovision fashion. So, I assume this will end up being a fairly prominent and also usual choice in this client populace, and also we’ll see how many more doctors decide to welcome it.”
LTK is accepted for approximately +2.5 D, said Dr. Belmont, and also is presently undertaking trials for therapy approximately +5.6 D.
Refractec’s conductive keratoplasty
Initial clinical tests recommend that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency method is possibly secure as well as efficient for fixing low to modest amounts of hyperopia, according to Cent A. Asbell, MD, who presented professional trial data in Miami at the International Society of Refractive Surgical treatment meeting. “Early results with our information bent on 12 months recommend that we get fantastic visual acuity, excellent security and also really no adverse occasions, such as loss of vision,” stated Dr. Asbell.
CK heats up the stromal cells with an electric current, reduces the collagen and also steepens the main cornea, Dr. Asbell described. A high-frequency current is used straight right into the peripheral corneal stroma via a delivery idea inserted at eight or more treatment points. The launch of radiofrequency power heats the surrounding collagen to a homogenous temperature of 65 ° C and also creates a round impact 500 µm deep vs. a shallower, cone-shaped impact made with the LTK strategy. A full circle of CK-treated places cinches the cornea as well as enhances its curvature to lower hyperopia.
” The adjustment seems to be permanent, and I think among the factors that holds true is that the treatment is provided straight to the stroma,” stated Dr. Asbell. “That’s where you desire the effect– not on the endothelium, not on the epithelium. It’s an extremely simple medical method. It’s a non-laser strategy, and it includes another dimension to what we already can supply for refractive surgical treatment– it is an economical procedure,” she added.
An additional crucial concern, Dr. Asbell explained, is that CK is a constant treatment. “The treatment dimension as well as the area effect in the stroma are consistent from treatment area to therapy area,” she said. “Among the vital concerns to bear in mind is that the temperature we get with the CK treatment is always 65 ° as well as the imprint you make within the outer corneal stroma is always the exact same: 100 µm broad and also 500 µm deep within the corneal stroma.”
Dr. Asbell is an investigator in the FDA clinical 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 people on whom Dr. Asbell reported, the normal age was 55, although, she stated, there is a rather wide range old amongst the trial’s individuals. To get approved for the test, she discussed, individuals had to have uncorrected visual acuity of at the very least 20/40 or even worse and inadequate near vision too– standard for a hyperope. “We are remedying from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She stressed the rate as well as simpleness of the procedure. “This treatment takes 5 minutes per eye. It is an extremely brief procedure; you remain in and out extremely quickly,” she stated. “It is a surgery, however an extremely easy one. It does not require a qualified technician [to help] It does not even need an autoclave. The idea, which is about the size of a hair, is non reusable.”
Dr. Asbell defined the CK nomogram thus: “The therapy is either at 6 mm, 7 mm or 8 mm. You make a mark on the cornea [suggesting the size of the treatment area] The degree of hyperopia you are correcting figures out the variety of treatment marks on the cornea. Every one coincides– the exact same amount of energy as well as the very same depth within the stroma in each spot,” she said.
Results show up secure
Of the patients on whom Dr. Asbell reported, 61% attained 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 much better, and 92% were 20/40 or much better. “Our outcomes look good and also stable. These are really satisfied individuals,” claimed Dr. Asbell. “They actually can return to function right away or certainly the next day if they so select. No one takes pain medications.”
Safety and security variables were “primarily absolutely no,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she said. “I believe this is mosting likely to be a procedure and also an equipment that’s going to be easy for us to own as well as to utilize and also an exceptional method to remedy hyperopia postop LASIK or to touch up a postop cataract or corneal transplant,” she stated. “I assume it’s mosting likely to have a lot of adaptability in regards to its uses for dealing with hyperopia and perhaps astigmatism.”
Expanded clinical 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 Japan. Also, the business has actually set up setup of the IR-laser in some European nations.
SurgiLight has sent four papers to the American Culture of Cataract and also Refractive Surgical Treatment for the May 2001 conference, where greater than 500 situations of LAPR will exist by eye doctors from different nations making use of the firm’s IR laser.
The company remains in the process of acquiring CE-Mark qualification and also selecting various international distributors. It plans to submit extra 510K applications based on certain clearances acquired from Premier Laser Solutions. SurgiLight anticipates to bill a royalty fee of $500 per individual to doctors who utilize the company’s IR-3000 system in the USA and also Europe.
B&L NuVita phakic IOL
The 3rd generation of George Baikoff, MD’s, former chamber phakic IOL is stood for with Bausch & Lomb’s (St. Louis) NuVita MA20. The lens is available for myopes ranging from 7 D to 20 D. The style is an angle-fixated, single-piece lens, with a lens optical form as well as a PMMA surface area. The total optical size is 5 mm and the total length of the NuVita ranges from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loophole and footplate were all revamped from the previous variation to reduce refracted glow, stress in the angle and much better clearance of the iris and also all-natural lens. Also, the haptics were revamped to eliminate iris retraction. The haptics were made extra versatile and also, for that reason, caused much less student ovalization.
In its second generation, the fluorine plasma treatment was included in the manufacturing process to produce covalent bonds of fluorocarbon radicals with the PMMA surface area, which produced reduced surface area power and remarkably smooth coating. The fluorine therapy greatly enhanced biocompatibility.
In research studies carried out by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes implanted revealed a precision rate of ± 0.5 D while 97% revealed a precision rate of ± 2 D. In regards to safety, the BSCVA rates had 47 acquiring at least 2 lines, and also no eyes lost lines. The overall glare report showed that many individuals had couple of troubles.
According to Mike Landreville, global director for refractive modern technologies at Bausch & Lomb, the company has no intent of presenting the NuVita lens into the United States for FDA authorization or for medical usage. Instead, the business is developing a whole new phakic innovation for a foldable anterior chamber phakic lens. The brand-new phakic lens will not just exist as a new lens, however as part of a completely new system, entirely separate from the NuVita line. The brand-new, unnamed lens system will certainly be of a new product, include a brand-new collapsible distribution system as well as give a brand-new diagnostic device for implantation.
According to Mr. Landreville, the business plans to have the new system prepared for professional usage in the United States by this year.
Alcon phakic IOL
A brand-new anterior chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO conference. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) product and has numerous benefits over various other phakic IOLs such as its foldability, which permits the lens to be inserted via a laceration smaller sized than 3 mm, in addition to an angle-fixated, single-piece style and also high biocompatibility. The distance between the cornea and also the dental implant also drops between 2.96 mm and also 3.35 mm, a bigger range than with some other lenses, he said.
Dr. Maxwell reported that of the 10 implants that have actually been done to day, greater than 90% of the individuals have 20/40 or much better uncorrected vision at their postoperative visits. The mean spherical matching in clients implanted so far was– 11.5 D, he said, with an outcome of– 0.39 D at 1 month and also– 0.8 D at 6 months of recurring myopia.
” We see substantial enhancement in best-corrected visual acuity, and in all however one client the postoperative best corrected vision is better than the best preoperative vision; in a lot of cases, there are 2-, 3- or 4-line boosts in best-corrected visual acuity,” Dr. Maxwell said. “In the one instance where it wasn’t much better, it coincided as the preoperative skill.”
CIBA acquires licenses for IOL
CIBA Vision introduced at the AAO conference that it has obtained three licenses from Dr. Baikoff for foldable phakic former chamber IOL makes to remedy not just nearsightedness and also hyperopia yet also presbyopia.
” We are really delighted about this new innovation,” David Bailey, medical service system head of state for CIBA, claimed. “We assume that the MemoryLens material incorporated with these former chamber styles will certainly be a very successful combination.”
That anterior chamber lens effort matches one more refractive implant that was the topic of numerous 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 currently holds exclusive globally 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 (υπερμετρωπια ).