Categories
Uncategorised

New modern technologies remain to increase choices for treating keratoconus, nearsightedness, hyperopia

Emerging innovation in the areas of corneal ring segments, holmium laser thermokeratoplasty (LTK) and also phakic IOLs is providing brand-new options for patients suffering from keratoconus, nearsightedness, hyperopia as well as presbyopia.

Intacs for keratoconus
At the American Academy of Ophthalmology (AAO) conference in October 2000, Joseph Colin, MD, provided a research study of choices to penetrating keratoplasty for clients 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, commented on Dr. Colin’s paper, which suggests an option that reinforces the currently compromised cornea instead of more thinning it with LASIK. The idea of using an additive procedure, such as Intacs (KeraVision, Fremont, Calif.), to reinforce the cornea makes a lot of feeling, Dr. Durrie informed Primary Care Optometry News.

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

Because the keratoconic eye has a lump in the cornea, Dr. Durrie claimed, positioning the Intacs put in the periphery of the cornea will certainly squash the corneal facility. This not only decreases the degree of myopia, but enhances the facility lump, he claimed. The desired outcome is to postpone a corneal transplant for as long as possible.

While the data that Dr. Colin presented program that the procedure is fairly safe, stated Dr. Durrie, the longest term data offered are just 2 years. “Checking out the patterns in the 3-month, 6-month and also 1-year data, it appears that all individuals benefited from the treatment, yet we can’t claim that it quit the keratoconus for longer than that till further information are collected,” he claimed. “Although I remain to do this treatment on separated cases, I tell patients we do not recognize the lasting impacts and we do not know whether it will reduce, speed up or have no effect on the normal course of keratoconus.

” The benefit of this procedure is, if it does not function, you can take the Intacs out as well as have not compromised the cornea,” he continued. “If the person does require to go on to a corneal transplant, the inserts can be gotten and also not interfere with conventional transplant therapy. As a result of the adjustment in shape of the keratoconic cornea, ultimately, individuals become contact lens intolerant, and also it is very important to know that there is an alternative to be checked out for these clients besides simply referring them for a corneal transplant.”

Specialists ought to make certain that people understand that the procedure is not refractive surgery as well as will certainly not necessarily remedy their nearsightedness, claimed Dr. Durrie. “I have people on whom I have actually done this treatment that have seen 20/40 without glasses, which would certainly be an exceptional outcome after a corneal transplant, yet they’re still asking yourself why their friends who have had Intacs implanted can see 20/20 when they can not,” he stated. “That’s why these individuals require to be educated that this isn’t something that maintains them from putting on glasses. It keeps them from needing a corneal transplant.”

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

Professional research studies have actually shown laser thermokeratoplasty (LTK) to be an efficient approach of fixing an individual’s hyperopia, as well as it might additionally hold promise for dealing with presbyopia and also overcorrected nearsightedness 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 technique and also its results with hyperopia utilizing the Hyperion laser (Sunup Technologies International, Fremont, Calif.) at the International Culture of Refractive Surgical procedure’s Summer season World Refractive Surgical Treatment Seminar 2000. Dr. Conway was not associated with any type of Food and Drug Administration (FDA) research; his ISRS presentation was based upon information from the Sunrise FDA examinations and lectures he went to.

When dealing with a person for hyperopia, the expert requires to stress the impermanence of the procedure, he claimed. “You require to communicate to the individual that this is just a momentary adjustment in his/her hyperopic condition,” he claimed. “There is enough regression with this method that the FDA felt it needed to refer this.”

Any treatment for the modification of hyperopia may require retreatment gradually; this is not unique to LTK, claimed Sandra Belmont, MD, supervisor of the laser vision facility at the Cornell Weill Medical Center in New York City. “Hyperopia increases as you age,” she said. “We have patients 3 years out that are steady, so I’m very delighted with the outcomes.”

Dr. Belmont informs people of this possibility, however none of them have altered their minds. She claimed that if retreatment were required, people did incline due to the fact that the treatment fasts, and creating a flap, which can cause complications, is not required.

The LTK procedure
picture– Security: One scientist has patients who are still stable 3 years post-LTK.

The procedure, Dr. Conway said, takes 3 seconds to carry out. Seven pulses are used in 8 places, twice back to back, one at the 6-mm area 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, ranging from +0.75 to +2.50 D, saw no loss in best spectacle-corrected visual acuity (BSCVA) after 2 years, he noted.

” No loss of lines of acuity were attributable to the LTK,” he said. “In contrasting preop to 24 months later on, there was no loss of BSCVA and a little bit of gain. We know that myopes and also hyperopes are very various. Fortunately, the resistance of hyperopes is extremely useful in making their complete satisfaction level really high.”

Prior to the treatment, individuals get three successive administrations of topical proparacaine at 3-minute intervals. Problems were marginal, Dr. Conway kept in mind.

” Patients are generally handled from a comfort viewpoint, purely with over-the-counter anesthetics to obtain them with the initial hours of recovery,” he said. “Since you’re working on the corneal surface area, FDA detectives reported a little of foreign-body sensation, which dissipates with time extremely perfectly.”

Regression over time
Dr. Conway stated that, while the patient’s skill level stays fairly stable, some regression appears as the hyperopia increases with time. “There will certainly be a little yet considerable regression in these clients; it’s just an issue of whether it goes to a low enough degree to justify the patient’s cost and also experience of undertaking this method,” he claimed. “By comparing your cycloplegic to your show refraction, you can tell whether it exists hyperopia or not.”

A person’s age consider to for how long the impact of LTK might last, stated Dr. Conway. “A 50-year-old person will certainly experience a little bit much more result than a 40-year-old person, possibly as a result of a bit a lot more dryness or the collagen standing of the cornea,” he claimed.

An off-label indicator of LTK is the therapy of presbyopia, claimed Dr. Belmont. People that are plano and also presbyopic may be treated with LTK to accomplish monovision, she stated. “Today, their reading vision comes into emphasis,” she said. “They get their results immediately, as well as they’re truly delighted with that.”

Patients that have actually been treated for presbyopia generally will encounter the very same level of regression as hyperopes, Dr. Belmont kept in mind. “Presbyopia raises as you age, as does hyperopia,” she said. “Patients understand that this treatment will need to be boosted as their aging necessitates a boost in the power they’ll require to check out. They more than happy as long as you tell them beforehand. I expect this as being the treatment to treat farsightedness as well as presbyopia.”

The size of time needed for presbyopic treatment is the same when it comes to that of hyperopia, but the level of energy that is put on the eye is differed, she claimed.

Overcorrected myopia
The treatment might additionally verify to be a valid choice for boosting myopic clients that have been overcorrected with LASIK or PRK, claimed Dr. Conway. “This qualities a great deal of factor to consider, since you don’t need to remove any type of cells,” he claimed. “Additionally, Sunup is sending for authorization remediation of presbyopia, making individuals short-sighted in a monovision fashion. So, I think this will certainly come to be a rather popular and also usual choice in this person populace, and also we’ll see how many more cosmetic surgeons choose to embrace it.”

LTK is accepted for approximately +2.5 D, claimed Dr. Belmont, and is currently going through tests for treatment as much as +5.6 D.

Refractec’s conductive keratoplasty
Initial scientific trials suggest that conductive keratoplasty (CK) using Refractec’s (Irvine, Calif.) radiofrequency method is most likely risk-free as well as efficient for correcting reduced to moderate amounts of hyperopia, according to Cent A. Asbell, MD, that provided clinical test data in Miami at the International Society of Refractive Surgical treatment meeting. “Early results with our information bent on twelve month suggest that we obtain wonderful visual acuity, very good security and also actually no damaging occasions, such as loss of vision,” stated Dr. Asbell.

CK heats up the stromal cells with an electric existing, reduces the collagen and steepens the central cornea, Dr. Asbell described. A high-frequency current is used directly right into the outer corneal stroma with a distribution pointer put at 8 or more treatment factors. The launch of radiofrequency energy warms the bordering collagen to an uniform temperature level of 65 ° C as well as generates a cylindrical footprint 500 µm deep vs. a shallower, cone-shaped footprint made with the LTK method. A full circle of CK-treated places cinches the cornea and boosts its curvature to lower hyperopia.

” The adjustment appears to be permanent, as well as I believe among the factors that holds true is that the therapy is delivered straight to the stroma,” stated Dr. Asbell. “That’s where you desire the impact– out the endothelium, not on the epithelium. It’s a really simple surgical method. It’s a non-laser technique, and it includes one more measurement to what we already can provide for refractive surgical treatment– it is an affordable procedure,” she included.

CK corresponds
An additional vital issue, Dr. Asbell mentioned, is that CK is a consistent treatment. “The treatment dimension and the zone result in the stroma are consistent from treatment spot to treatment place,” she claimed. “Among the crucial problems to remember is that the temperature level we get with the CK treatment is constantly 65 ° and also the imprint you make within the outer corneal stroma is always the exact same: 100 µm wide and 500 µm deep within the corneal stroma.”

Dr. Asbell is a detective in the FDA clinical test of CK. Other investigators at other sites include Marguerite McDonald, MD; Robert K. Maloney, MD; Jonathan Davidorf, MD; Peter Hersh, MD; and Edward E. Manche, MD

. Of the 54 clients on whom Dr. Asbell reported, the typical age was 55, although, she stated, there is a relatively vast array old among the trial’s individuals. To get the test, she clarified, clients had to have uncorrected visual acuity of a minimum of 20/40 or worse as well as bad near vision as well– conventional for a hyperope. “We are correcting from 1 D to 4 D of hyperopia, with little or no astigmatism,” Dr. Asbell reported.

She stressed the speed and also simplicity of the treatment. “This procedure takes 5 mins per eye. It is a really brief procedure; you’re in and out extremely rapidly,” she claimed. “It is an operation, yet an extremely easy one. It does not call for a trained professional [to help] It doesn’t also require an autoclave. The pointer, which has to do with the width of a hair, is non reusable.”

Dr. Asbell explained the CK nomogram as such: “The treatment 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 dealing with figures out the variety of therapy marks on the cornea. Each one coincides– the exact same quantity of energy as well as the very same deepness within the stroma in each area,” she said.

Results show up steady
Of the patients 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 results look great as well as stable. These are very delighted patients,” claimed Dr. Asbell. “They really can return to work right away or absolutely the following day if they so choose. No one takes discomfort medications.”

Safety and security variables were “essentially zero,” Dr. Asbell reported. “There was no loss of vision as well as no corneal edema,” she stated. “I believe this is mosting likely to be a procedure and a device that’s mosting likely to be simple for us to own and to use and also an excellent means to deal with hyperopia postop LASIK or to repair a postop cataract or corneal transplant,” she said. “I think it’s going to have a great deal of adaptability in regards to its usages for remedying hyperopia and possibly astigmatism.”

Increased medical tests of LAPR
SurgiLight Inc. (Orlando, Fla.) has broadened its medical trial researches of laser presbyopia reversal (LAPR) using its IR-laser in Venezuela, Argentina, Brazil, the Bahamas and also Japan. Additionally, the business has arranged installment of the IR-laser in some European nations.

SurgiLight has actually submitted four papers to the American Culture of Cataract and Refractive Surgery for the May 2001 meeting, where greater than 500 situations of LAPR will be presented by ophthalmologists from numerous nations using the firm’s IR laser.

The company is in the procedure of obtaining CE-Mark certification and also choosing numerous worldwide suppliers. It intends to submit added 510K applications based on certain clearances gotten from Premier Laser Equipments. SurgiLight expects to charge a nobility charge of $500 per patient to surgeons who utilize the company’s IR-3000 system in the United States as well as Europe.

B&L NuVita phakic IOL
The 3rd generation of George Baikoff, MD’s, anterior 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 layout is an angle-fixated, single-piece lens, with a lens optical form and also a PMMA surface. The total optical size is 5 mm as well as the general length of the NuVita varies from 12 mm to 13.5 mm in 0.5-mm increments.

The optic, loop as well as footplate were all redesigned from the previous variation to minimize refracted glow, pressure in the angle and also better clearance of the iris and also all-natural lens. Likewise, the haptics were revamped to eliminate iris retraction. The haptics were made more versatile and, for that reason, led to much less student ovalization.

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

In researches performed 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% showed a precision price of ± 2 D. In terms of safety and security, the BSCVA rates had 47 gaining at least two lines, and also no eyes lost lines. The general glow record showed that many clients had few problems.

According to Mike Landreville, global director for refractive innovations at Bausch & Lomb, the company has no intention of presenting the NuVita lens into the USA for FDA approval or for medical usage. Rather, the firm is establishing an entire brand-new phakic modern technology for a foldable anterior chamber phakic lens. The new phakic lens will certainly not only exist as a new lens, but as part of a completely brand-new system, totally different from the NuVita line. The brand-new, unnamed lens system will be of a brand-new product, incorporate a new collapsible shipment system and offer a brand-new analysis tool for implantation.

According to Mr. Landreville, the business intends to have the new system ready for professional usage in the USA by this year.

Alcon phakic IOL
A new former chamber phakic IOL existed by Andrew Maxwell, MD, PhD, at the AAO conference. The lens has an Acrysof-based (Alcon, Ft. Worth, Texas) material as well as has a number of advantages over other phakic IOLs such as its foldability, which enables the lens to be inserted via an incision smaller than 3 mm, in addition to an angle-fixated, single-piece style as well as high biocompatibility. The range in between the cornea and also the dental implant also falls in between 2.96 mm as well as 3.35 mm, a larger distance than with a few other lenses, he claimed.

Dr. Maxwell reported that of the 10 implants that have been executed to day, more than 90% of the patients have 20/40 or much better uncorrected vision at their postoperative check outs. The mean round matching in clients dental implanted thus far was– 11.5 D, he stated, with a result of– 0.39 D at 1 month and– 0.8 D at 6 months of residual myopia.

” We see considerable improvement in best-corrected visual acuity, and in all but one patient the postoperative ideal corrected vision is far better than the very best preoperative vision; oftentimes, there are 2-, 3- or 4-line rises in best-corrected visual acuity,” Dr. Maxwell said. “In the one situation where it had not been much better, it was the same as the preoperative acuity.”

CIBA acquires patents for IOL
CIBA Vision announced at the AAO conference that it has actually obtained 3 licenses from Dr. Baikoff for collapsible phakic anterior chamber IOL creates to fix not only myopia as well as hyperopia however also presbyopia.

” We are extremely thrilled regarding this brand-new modern technology,” David Bailey, surgical service device president for CIBA, claimed. “We think that the MemoryLens material integrated with these former chamber styles will be a very successful mix.”

That former chamber lens initiative complements another refractive implant that was the topic of a number of 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 risk in Medennium in July as well as now holds unique globally advertising and marketing as well as 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 ).