Emerging technology in the locations of corneal ring sections, holmium laser thermokeratoplasty (LTK) as well as phakic IOLs is supplying 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, offered a study of options to permeating keratoplasty for patients with keratoconus. Of 23 eyes in 20 individuals, 60% attained a best-corrected visual acuity of 20/40 or far better. The mean postoperative keratometry was decreased by 3 D.
Daniel S. Durrie, MD, talked about Dr. Colin’s paper, which recommends an option that enhances the currently damaged cornea instead of further thinning it with LASIK. The concept of using an additive procedure, such as Intacs (KeraVision, Fremont, Calif.), to enhance the cornea makes a lot of feeling, Dr. Durrie informed Primary Care Optometry News.
” For years, we’ve checked out other options to corneal transplants for these clients, and also some treatments such as radial keratotomy (RK), photorefractive keratectomy (PRK) or LASIK have been tried in the past, however they get rid of part of the cornea in a person population in which we understand the cornea is currently thin as well as weak,” Dr. Durrie stated.
Since the keratoconic eye has a lump in the cornea, Dr. Durrie stated, positioning the Intacs place in the periphery of the cornea will certainly squash the corneal facility. This not only reduces the level of nearsightedness, however reinforces the facility bulge, he claimed. The preferred result is to delay a corneal transplant for as long as feasible.
While the information that Dr. Colin provided program that the procedure is fairly risk-free, said Dr. Durrie, the longest term data readily available are only 2 years. “Considering the fads in the 3-month, 6-month and 1-year data, it shows up that all people gained from the treatment, however we can’t claim that it quit the keratoconus for longer than that until further information are collected,” he stated. “Although I remain to do this procedure on isolated situations, I inform people we don’t understand the lasting results and also we do not know whether it will certainly decrease, speed up or have no result on the normal course of keratoconus.
” The advantage of this procedure is, if it does not function, you can take the Intacs out and also have not compromised the cornea,” he continued. “If the person does need to take place to a corneal transplant, the inserts can be obtained and not interfere with standard transplant treatment. Because of the modification fit of the keratoconic cornea, ultimately, individuals become get in touch with lens intolerant, and also it’s important to know that there is an alternate to be explored for these people apart from simply referring them for a corneal transplant.”
Professionals must make certain that clients recognize that the procedure is not refractive surgery as well as will certainly not always remedy their nearsightedness, claimed Dr. Durrie. “I have individuals on whom I have actually performed this treatment who have actually seen 20/40 without glasses, which would certainly be an exceptional result after a corneal transplant, yet they’re still asking yourself why their good friends who have actually had Intacs implanted can see 20/20 when they can not,” he said. “That’s why these individuals need to be informed that this isn’t something that maintains them from putting on glasses. It maintains them from needing a corneal transplant.”
Hyperopic adjustment with LTK
photo– Post-LTK: The pulses are applied in eight spots, one at the 6-mm area and also the other at the 7-mm zone.
Scientific research studies have actually revealed laser thermokeratoplasty (LTK) to be a reliable approach of remedying an individual’s hyperopia, as well as it may likewise hold assurance for treating presbyopia and also 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 method and its results with hyperopia using the Hyperion laser (Sunup Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical treatment’s Summer World Refractive Surgical Treatment Symposium 2000. Dr. Conway was not involved in any type of Fda (FDA) research study; his ISRS presentation was based on information from the Dawn FDA examinations as well as lectures he attended.
When treating a person for hyperopia, the specialist requires to stress the impermanence of the procedure, he said. “You require to communicate to the client that this is just a short-term change in his or her hyperopic standing,” he said. “There suffices regression with this technique that the FDA felt it needed to refer this.”
Any procedure for the improvement of hyperopia might demand retreatment with time; this is not distinct to LTK, claimed Sandra Belmont, MD, supervisor of the laser vision center at the Cornell Weill Medical Center in New York City City. “Hyperopia enhances as you age,” she stated. “We have patients 3 years out that are stable, so I’m really happy with the results.”
Dr. Belmont educates patients of this possibility, yet none of them have actually transformed their minds. She said that if retreatment were required, clients did not mind due to the fact that the procedure is quick, as well as developing a flap, which can cause issues, is not needed.
The LTK treatment
photograph– Security: One researcher has patients who are still stable 3 years post-LTK.
The procedure, Dr. Conway said, takes 3 seconds to perform. 7 pulses are applied in eight areas, twice back to back, one at the 6-mm area and also the other at the 7-mm area. The FDA research study reported that the 612 eyes in 379 people, all older than 40, ranging 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 stated. “In comparing preop to 24 months later, there was no loss of BSCVA and a bit of gain. We know that myopes as well as hyperopes are really various. The good news is, the tolerance of hyperopes is extremely valuable in making their satisfaction level very high.”
Before the treatment, people get 3 consecutive managements of topical proparacaine at 3-minute intervals. Difficulties were very little, Dr. Conway kept in mind.
” Individuals are normally handled from a convenience point ofview, strictly with over-the-counter analgesics to obtain them via the initial hours of recovery,” he said. “Because you’re dealing with the corneal surface area, FDA detectives reported a little of foreign-body experience, which dissipates with time extremely perfectly.”
Regression over time
Dr. Conway said that, while the individual’s acuity degree remains rather stable, some regression appears as the hyperopia increases with time. “There will certainly be a small but considerable regression in these people; it’s just an issue of whether it’s at a reduced sufficient degree to justify the individual’s cost and also experience of undertaking this strategy,” he stated. “By comparing your cycloplegic to your reveal refraction, you can inform whether it’s latent hyperopia or otherwise.”
A client’s age consider to for how long the result of LTK may last, said Dr. Conway. “A 50-year-old individual will certainly experience a little bit extra effect than a 40-year-old client, possibly because of a bit extra dryness or the collagen standing of the cornea,” he claimed.
An off-label indicator of LTK is the therapy of presbyopia, stated Dr. Belmont. Individuals that are plano as well as presbyopic might be treated with LTK to accomplish monovision, she said. “As soon as possible, their reading vision enters focus,” she said. “They obtain their results promptly, and they’re actually delighted keeping that.”
Clients that have been treated for presbyopia commonly will run into the exact same degree of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia raises as you age, as does hyperopia,” she said. “Clients recognize that this procedure will certainly have to be improved as their aging necessitates a boost in the power they’ll need to read. They enjoy as long as you tell them in advance. I expect this as being the treatment to treat farsightedness as well as presbyopia.”
The length of time required for presbyopic therapy is the same when it comes to that of hyperopia, yet the degree of power that is applied to the eye is varied, she said.
The procedure may additionally prove to be a valid option for improving myopic individuals that have actually been overcorrected with LASIK or PRK, claimed Dr. Conway. “This benefits a great deal of factor to consider, because you don’t need to remove any tissue,” he stated. “Furthermore, Daybreak is submitting for approval removal of presbyopia, making people myopic in a monovision fashion. So, I think this will end up being a relatively prominent and typical choice in this person population, as well as we’ll see the number of even more doctors make a decision to welcome it.”
LTK is authorized for up to +2.5 D, said Dr. Belmont, and also is presently undergoing trials for treatment up to +5.6 D.
Refractec’s conductive keratoplasty
Initial clinical tests recommend that conductive keratoplasty (CK) utilizing Refractec’s (Irvine, Calif.) radiofrequency technique is most likely risk-free and effective for fixing reduced to modest quantities of hyperopia, according to Penny A. Asbell, MD, that presented clinical trial data in Miami at the International Society of Refractive Surgical procedure conference. “Early outcomes with our information bent on 12 months suggest that we obtain excellent visual acuity, excellent stability as well as truly no unfavorable events, such as loss of vision,” said Dr. Asbell.
CK warms the stromal tissue with an electric present, reduces the collagen as well as steepens the central cornea, Dr. Asbell described. A high-frequency present is used straight into the peripheral corneal stroma via a delivery suggestion inserted at 8 or more treatment points. The release of radiofrequency energy warms the bordering collagen to an identical temperature level of 65 ° C and creates a round impact 500 µm deep vs. a shallower, cone-shaped footprint made with the LTK strategy. A cycle of CK-treated places cinches the cornea and boosts its curvature to decrease hyperopia.
” The change appears to be long-term, as well as I assume one of the reasons that holds true is that the therapy is delivered straight to the stroma,” claimed Dr. Asbell. “That’s where you desire the result– not on the endothelium, not on the epithelium. It’s a really simple medical method. It’s a non-laser method, and also it adds an additional dimension to what we already can use for refractive surgical treatment– it is a cost-efficient treatment,” she added.
An additional essential problem, Dr. Asbell explained, is that CK is a consistent treatment. “The treatment dimension and the zone result in the stroma correspond from therapy area to therapy place,” she said. “One of the essential issues to remember is that the temperature we get with the CK treatment is constantly 65 ° and the imprint you make within the peripheral corneal stroma is constantly the same: 100 µm vast and also 500 µm deep within the corneal stroma.”
Dr. Asbell is a detective in the FDA medical test of CK. Fellow investigators at 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 patients on whom Dr. Asbell reported, the normal age was 55, although, she said, there is a fairly large range old amongst the trial’s participants. To get the trial, she described, individuals had to have uncorrected visual acuity of a minimum of 20/40 or even worse as well as inadequate near vision as well– basic 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 rate and simplicity of the treatment. “This procedure takes 5 mins per eye. It is a very short treatment; you’re in and also out extremely quickly,” she stated. “It is a surgical procedure, but a really easy one. It does not require a qualified specialist [to aid] It does not also need an autoclave. The suggestion, which is about the width of a hair, is disposable.”
Dr. Asbell described the CK nomogram therefore: “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 zone] The level of hyperopia you are remedying determines the number of treatment marks on the cornea. Each one is the same– the same amount of power and the very same depth within the stroma in each area,” she said.
Results show up secure
Of the clients on whom Dr. Asbell reported, 61% attained uncorrected visual acuity of 20/20 or 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 great as well as secure. These are really pleased individuals,” said Dr. Asbell. “They actually can return to work instantly or definitely the next day if they so pick. Nobody takes discomfort medicines.”
Security 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 device that’s going to be very easy for us to possess and also to use and an excellent method to fix hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she claimed. “I think it’s going to have a great deal of adaptability in terms of its uses for fixing hyperopia and also perhaps astigmatism.”
Increased professional trials of LAPR
SurgiLight Inc. (Orlando, Fla.) has actually broadened its professional test researches of laser presbyopia reversal (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas as well as Japan. Additionally, the business has scheduled installment of the IR-laser in some European countries.
SurgiLight has sent four documents to the American Culture of Cataract and Refractive Surgical Treatment for the May 2001 meeting, where greater than 500 cases of LAPR will certainly be presented by eye doctors from different nations making use of the business’s IR laser.
The firm is in the procedure of acquiring CE-Mark qualification as well as choosing various worldwide representatives. It prepares to submit added 510K applications based upon certain clearances obtained from Premier Laser Solutions. SurgiLight anticipates to bill a royalty fee of $500 per individual to specialists that use the business’s IR-3000 system in the United States 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 offered for myopes varying from 7 D to 20 D. The style is an angle-fixated, single-piece lens, with a meniscus optical shape and a PMMA surface. The general optical diameter is 5 mm and also the total length of the NuVita varies from 12 mm to 13.5 mm in 0.5-mm increments.
The optic, loop and footplate were all upgraded from the previous variation to decrease refracted glow, stress in the angle as well as much better clearance of the iris and also natural lens. Also, the haptics were upgraded to eliminate iris retraction. The haptics were made more adaptable and, for that reason, resulted in less student ovalization.
In its second generation, the fluorine plasma therapy was contributed to the production procedure to develop covalent bonds of fluorocarbon radicals with the PMMA surface, which produced lower surface energy and incredibly smooth coating. The fluorine therapy substantially enhanced biocompatibility.
In researches carried out by Antonio Marinho, MD, with 30-month follow-up, 64% of the 88 eyes dental implanted revealed 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 least two lines, and no eyes shed lines. The overall glow record revealed that a lot of patients had couple of issues.
According to Mike Landreville, worldwide supervisor for refractive innovations at Bausch & Lomb, the company has no intention of presenting the NuVita lens right into the United States for FDA approval or for medical usage. Rather, the business is establishing a whole brand-new phakic technology for a collapsible anterior chamber phakic lens. The new phakic lens will not just exist as a brand-new lens, yet as part of a totally brand-new system, totally separate from the NuVita line. The brand-new, unnamed lens system will certainly be of a brand-new product, include a brand-new collapsible distribution system and also offer a new analysis device for implantation.
According to Mr. Landreville, the firm prepares to have the brand-new system ready for medical usage in the United States by this year.
Alcon phakic IOL
A brand-new former chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO meeting. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) material and has numerous benefits over other phakic IOLs such as its foldability, which enables the lens to be put through a laceration smaller than 3 mm, in addition to an angle-fixated, single-piece style as well as high biocompatibility. The range between the cornea and the implant also falls in between 2.96 mm as well as 3.35 mm, a bigger range than with some other lenses, he said.
Dr. Maxwell reported that of the 10 implants that have been performed to date, greater than 90% of the individuals have 20/40 or far better uncorrected vision at their postoperative check outs. The mean spherical matching in people implanted thus far was– 11.5 D, he said, with an outcome of– 0.39 D at 1 month and– 0.8 D at 6 months of residual nearsightedness.
” We see considerable improvement in best-corrected visual acuity, and also in all yet one individual the postoperative ideal remedied vision is better than the very best preoperative vision; in a lot of cases, there are 2-, 3- or 4-line rises in best-corrected visual acuity,” Dr. Maxwell claimed. “In the one instance where it had not been better, it coincided as the preoperative skill.”
CIBA acquires patents for IOL
CIBA Vision introduced at the AAO conference that it has obtained 3 licenses from Dr. Baikoff for collapsible phakic former chamber IOL makes to correct not just nearsightedness as well as hyperopia yet also presbyopia.
” We are really delighted about this brand-new innovation,” David Bailey, medical business system head of state for CIBA, said. “We believe that the MemoryLens material incorporated with these anterior chamber styles will certainly be a very successful mix.”
That former chamber lens initiative enhances one more refractive implant that was the subject of numerous 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 stake in Medennium in July and also now holds special around the world advertising and circulation civil liberties to the lens, which is presently in phase 2 scientific tests.
” We are taking a solid placement in phakic IOLs,” Mr. Bailey said, “and also we’ll be strengthening that position with even more new modern technology.”
This is the means to treat nearsightedness, ypermetropia and also astigmatism (υπερμετρωπια ).