Emerging innovation in the areas of corneal ring sectors, holmium laser thermokeratoplasty (LTK) as well as phakic IOLs is giving brand-new choices for individuals dealing with keratoconus, nearsightedness, hyperopia and presbyopia.
Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) meeting in October 2000, Joseph Colin, MD, presented a research study of options to passing through keratoplasty for clients with keratoconus. Of 23 eyes in 20 individuals, 60% achieved a best-corrected visual acuity of 20/40 or far better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, discussed Dr. Colin’s paper, which recommends an option that reinforces the currently deteriorated cornea instead of further 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 Medical care Optometry Information.
” For several years, we have actually taken a look at other options to corneal transplants for these clients, and also some procedures such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been attempted in the past, yet they remove part of the cornea in an individual population in which we know the cornea is already thin as well as weak,” Dr. Durrie said.
Since the keratoconic eye has a lump in the cornea, Dr. Durrie claimed, putting the Intacs put in the perimeter of the cornea will certainly flatten the corneal facility. This not only decreases the level of myopia, however enhances the facility bulge, he said. The desired outcome is to delay a corneal transplant for as long as feasible.
While the information that Dr. Colin presented show that the procedure is fairly secure, claimed Dr. Durrie, the longest term information available are just 2 years. “Taking a look at the trends in the 3-month, 6-month and also 1-year data, it shows up that all people took advantage of the treatment, but we can’t state that it stopped the keratoconus for longer than that up until additional information are gathered,” he stated. “Although I continue to do this procedure on separated cases, I tell individuals we do not know the lasting effects as well as we don’t know whether it will certainly slow down, accelerate or have no impact on the normal course of keratoconus.
” The benefit of this treatment is, if it does not work, you can take the Intacs out and have not weakened the cornea,” he continued. “If the individual does need to take place to a corneal transplant, the inserts can be secured as well as not interfere with typical transplant treatment. Because of the adjustment in shape of the keratoconic cornea, ultimately, patients become get in touch with lens intolerant, as well as it is essential to understand that there is an alternative to be investigated for these individuals besides simply referring them for a corneal transplant.”
Specialists need to be sure that individuals recognize that the treatment is not refractive surgery as well as will certainly not necessarily fix their nearsightedness, stated Dr. Durrie. “I have clients on whom I have actually performed this treatment who have seen 20/40 without glasses, which would certainly be an outstanding result after a corneal transplant, yet they’re still asking yourself why their buddies that have had Intacs dental implanted can see 20/20 when they can’t,” he stated. “That’s why these people need to be informed that this isn’t something that keeps them from wearing glasses. It keeps them from requiring a corneal transplant.”
Hyperopic modification with LTK
photograph– Post-LTK: The pulses are applied in eight spots, one at the 6-mm area and also the other at the 7-mm area.
Clinical researches have actually revealed laser thermokeratoplasty (LTK) to be an efficient method of dealing with a person’s hyperopia, and it might also hold pledge for treating presbyopia and also overcorrected myopia after LASIK or PRK, stated David J. Conway, OD, supervisor of refractive surgical treatment for Harvard Lead Medical Associates in Somerville, Mass
. Dr. Conway reported on the LTK strategy as well as its outcomes with hyperopia making use of the Hyperion laser (Sunup Technologies International, Fremont, Calif.) at the International Society of Refractive Surgical treatment’s Summertime World Refractive Surgical Procedure Symposium 2000. Dr. Conway was not involved in any type of Food and Drug Administration (FDA) research; his ISRS presentation was based on info from the Sunrise FDA examinations and also talks he went to.
When dealing with a patient for hyperopia, the practitioner requires to stress the brevity of the treatment, he said. “You require to communicate to the individual that this is just a momentary adjustment in his or her hyperopic condition,” he stated. “There suffices regression with this strategy that the FDA felt it essential to refer this.”
Any type of procedure for the correction of hyperopia may demand retreatment with time; this is not unique to LTK, said Sandra Belmont, MD, supervisor of the laser vision center at the Cornell Weill Medical Center in New York City. “Hyperopia boosts as you age,” she said. “We have patients 3 years out who are secure, so I’m very happy with the results.”
Dr. Belmont notifies patients of this opportunity, yet none have actually transformed their minds. She claimed that if retreatment were needed, individuals did not mind because the treatment fasts, and producing a flap, which can result in complications, is not essential.
The LTK treatment
photograph– Security: One scientist has clients who are still secure 3 years post-LTK.
The procedure, Dr. Conway said, takes 3 secs to perform. 7 pulses are applied in eight spots, two times consecutively, one at the 6-mm area and also the other at the 7-mm zone. The FDA research study reported that the 612 eyes in 379 individuals, 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 contrasting preop to 24 months later, there was no loss of BSCVA and also a bit of gain. We understand that myopes and hyperopes are extremely different. Fortunately, the tolerance of hyperopes is very useful in making their satisfaction degree extremely high.”
Prior to the procedure, clients receive three successive administrations of topical proparacaine at 3-minute periods. Issues were minimal, Dr. Conway kept in mind.
” Patients are typically taken care of from a comfort point ofview, strictly with non-prescription analgesics to get them through the very first hours of recovery,” he claimed. “Because you’re working on the corneal surface area, FDA investigators reported a bit of foreign-body experience, which dissipates with time really well.”
Regression over time
Dr. Conway stated that, while the individual’s skill level remains relatively stable, some regression is evident as the hyperopia raises in time. “There will be a tiny however substantial regression in these people; it’s just a matter of whether it’s at a reduced sufficient degree to validate the client’s cost as well as experience of undergoing this method,” he claimed. “By contrasting your cycloplegic to your manifest refraction, you can tell whether it exists hyperopia or not.”
A patient’s age consider to the length of time the result of LTK may last, stated Dr. Conway. “A 50-year-old patient will experience a bit a lot more effect than a 40-year-old individual, perhaps because of a little more dry skin or the collagen condition of the cornea,” he said.
An off-label indicator of LTK is the therapy of presbyopia, said Dr. Belmont. Clients that are plano and presbyopic may be treated with LTK to attain monovision, she claimed. “Right now, their reading vision comes into focus,” she claimed. “They get their results right away, as well as they’re truly happy with that said.”
Individuals that have actually been treated for presbyopia commonly will come across the very same degree of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia enhances as you age, as does hyperopia,” she stated. “People understand that this procedure will need to be boosted as their aging demands a boost in the power they’ll require to check out. They more than happy as long as you tell them ahead of time. I expect this as being the procedure to treat farsightedness and also presbyopia.”
The length of time needed for presbyopic therapy coincides as for that of hyperopia, but the degree of power that is applied to the eye is varied, she said.
The treatment might additionally confirm to be a valid alternative for improving nearsighted patients that have been overcorrected with LASIK or PRK, claimed Dr. Conway. “This qualities a great deal of consideration, because you do not need to eliminate any type of tissue,” he claimed. “Additionally, Daybreak is sending for approval remediation of presbyopia, making clients myopic in a monovision style. So, I think this will certainly end up being a relatively preferred and also usual choice in this client population, and we’ll see how many even more specialists make a decision to accept it.”
LTK is accepted for as much as +2.5 D, claimed Dr. Belmont, and is presently undergoing trials for therapy up to +5.6 D.
Refractec’s conductive keratoplasty
Initial clinical tests suggest that conductive keratoplasty (CK) using Refractec’s (Irvine, Calif.) radiofrequency method is probably safe as well as reliable for fixing reduced to modest amounts of hyperopia, according to Dime A. Asbell, MD, that presented clinical test information in Miami at the International Culture of Refractive Surgical procedure conference. “Very early outcomes with our information out to year recommend that we get terrific visual acuity, excellent stability and also actually no damaging events, such as loss of vision,” said Dr. Asbell.
CK warms the stromal tissue with an electric present, reduces the collagen and steepens the central cornea, Dr. Asbell discussed. A high-frequency existing is applied straight right into the outer corneal stroma through a distribution suggestion inserted at 8 or more treatment points. The release of radiofrequency power warms the surrounding collagen to an identical temperature level of 65 ° C and produces a cylindrical impact 500 µm deep vs. a shallower, conelike impact made with the LTK strategy. A full circle of CK-treated areas cinches the cornea and raises its curvature to decrease hyperopia.
” The modification seems to be permanent, as well as I think among the factors that holds true is that the therapy is provided directly to the stroma,” stated Dr. Asbell. “That’s where you want the effect– out the endothelium, not on the epithelium. It’s an extremely easy surgical strategy. It’s a non-laser strategy, as well as it adds another dimension to what we already can provide for refractive surgical procedure– it is a cost-effective treatment,” she included.
One more crucial problem, Dr. Asbell pointed out, is that CK is a consistent therapy. “The therapy dimension and also the zone effect in the stroma correspond from therapy place to treatment area,” she stated. “Among the vital issues to keep in mind is that the temperature we get with the CK procedure is constantly 65 ° as well as the imprint you make within the outer corneal stroma is always the same: 100 µm wide and 500 µm deep within the corneal stroma.”
Dr. Asbell is an investigator in the FDA professional trial of CK. Fellow private investigators at various other websites 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 regular age was 55, although, she stated, there is a relatively vast array of age amongst the test’s participants. To receive the test, she discussed, patients needed to have uncorrected visual acuity of at least 20/40 or worse and also poor near vision also– common for a hyperope. “We are correcting from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.
She emphasized the rate and simpleness of the procedure. “This procedure takes 5 mins per eye. It is an extremely brief procedure; you’re in and out extremely rapidly,” she stated. “It is an operation, however a very easy one. It does not need a qualified service technician [to aid] It does not even require an autoclave. The suggestion, which has to do with the width of a hair, is non reusable.”
Dr. Asbell defined 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 correcting figures out the number of treatment marks on the cornea. Every one coincides– the exact same quantity of power as well as the exact same deepness within the stroma in each place,” she stated.
Outcomes appear steady
Of the clients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or much better 6 months postoperatively and 96% were 20/40 or much better at the 6-month mark. One year postoperatively, 62% were 20/20 or much better, as well as 92% were 20/40 or far better. “Our results look good and also secure. These are very delighted people,” claimed Dr. Asbell. “They in fact can go back to function immediately or definitely the following day if they so select. Nobody takes pain medications.”
Safety variables were “generally absolutely no,” Dr. Asbell reported. “There was no loss of vision and also no corneal edema,” she said. “I think this is going to be a procedure as well as a maker that’s going to be simple for us to possess and to use and also a superb means to fix hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she said. “I believe it’s mosting likely to have a lot of flexibility in terms of its uses for dealing with hyperopia as well as potentially astigmatism.”
Broadened clinical trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has broadened its professional trial research studies of laser presbyopia turnaround (LAPR) utilizing its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and Japan. Additionally, the company has actually arranged installment of the IR-laser in some European nations.
SurgiLight has submitted 4 papers to the American Society of Cataract and also Refractive Surgery for the May 2001 meeting, where more than 500 situations of LAPR will certainly be presented by eye doctors from different countries making use of the firm’s IR laser.
The firm remains in the process of getting CE-Mark accreditation as well as picking numerous worldwide representatives. It prepares to send additional 510K applications based upon certain clearances obtained from Premier Laser Equipments. SurgiLight expects to charge a royalty charge of $500 per individual to surgeons that use the business’s IR-3000 system in the USA and 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 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 overall optical size is 5 mm and the general length of the NuVita ranges from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loop as well as footplate were all upgraded from the previous version to lower refracted glare, stress in the angle and also far better clearance of the iris and natural lens. Additionally, the haptics were upgraded to get rid of iris retraction. The haptics were made more flexible as well as, therefore, led to much less pupil ovalization.
In its second generation, the fluorine plasma therapy was added to the production procedure to develop covalent bonds of fluorocarbon radicals with the PMMA surface area, which produced reduced surface power as well as remarkably smooth surface. The fluorine treatment significantly enhanced biocompatibility.
In researches conducted by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes dental implanted revealed a precision rate of ± 0.5 D while 97% showed a precision rate of ± 2 D. In regards to security, the BSCVA rates had 47 acquiring at the very least 2 lines, and no eyes lost lines. The total glow report showed that most people had few issues.
According to Mike Landreville, global director for refractive innovations at Bausch & Lomb, the firm has no objective of presenting the NuVita lens right into the USA for FDA authorization or for professional use. Rather, the firm is developing a whole brand-new phakic innovation for a collapsible former chamber phakic lens. The new phakic lens will certainly not only exist as a brand-new lens, however as part of a completely brand-new system, completely different from the NuVita line. The new, unrevealed lens system will be of a brand-new material, integrate a new collapsible delivery system and also supply a new diagnostic tool for implantation.
According to Mr. Landreville, the business intends to have the new system ready for clinical use in the USA 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 also has a number of benefits over other phakic IOLs such as its foldability, which allows the lens to be inserted via an incision smaller than 3 mm, in addition to an angle-fixated, single-piece layout and high biocompatibility. The range between the cornea and the dental implant likewise drops between 2.96 mm and also 3.35 mm, a larger range than with some other lenses, he stated.
Dr. Maxwell reported that of the 10 implants that have actually been carried out to date, more than 90% of the clients have 20/40 or better uncorrected vision at their postoperative sees. The mean round matching in people implanted thus far was– 11.5 D, he stated, with an outcome of– 0.39 D at 1 month and– 0.8 D at 6 months of recurring myopia.
” We see considerable improvement in best-corrected visual acuity, and also in all however one person the postoperative best fixed vision is far better than the very best preoperative vision; in most cases, there are 2-, 3- or 4-line boosts in best-corrected visual acuity,” Dr. Maxwell said. “In the one case where it had not been much better, it was the same as the preoperative skill.”
CIBA obtains licenses for IOL
CIBA Vision revealed at the AAO meeting that it has actually obtained 3 patents from Dr. Baikoff for foldable phakic former chamber IOL makes to fix not just nearsightedness and also hyperopia however additionally presbyopia.
” We are really excited about this brand-new modern technology,” David Bailey, medical business device president for CIBA, claimed. “We think that the MemoryLens product combined with these former chamber layouts will certainly be a very successful combination.”
That anterior chamber lens effort complements one more refractive dental 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 unique globally advertising and circulation rights to the lens, which is presently in stage 2 scientific tests.
” We are taking a solid setting in phakic IOLs,” Mr. Bailey stated, “as well as we’ll be strengthening that placement with more new innovation.”
This is the way to treat nearsightedness, ypermetropia and also astigmatism (υπερμετρωπια ).