Hyperopic Presbyopia: Weighing the Surgical Options
Surgeons share the advantages and drawbacks of six procedures.
Compiled by Christopher Kent, Senior Associate Editor

Until recently, myopic patients had more effective treatment options than hyperopes or presbyopes. Now, that appears to be changing. And not a moment too soon; with so many hyperopes reaching their 40s and 50s, the demand for efficacious alternatives has never been greater.

With that in mind, we've asked six surgeons to talk about the pros and cons of six options that you can consider offering to your hyperopic, presbyopic patients:

• surgical reversal of presbyopia (SRP)
• conductive keratoplasty (CK)
• PRELEX (presbyopic lens exchange)
• laser thermal keratoplasty (LTK)
• LASIK
• laser epithelial keratomileusis (LASEK).

Our contributors' comments also provide useful information about the unique characteristics of hyperopic accommodation, preventing induced astigmatism, resolving post-op problems, the advantages of combining procedures, mono-vision issues and patient selection.

I've been doing surgical reversal of presbyopia (SRP) using scleral expansion bands, in one form or another, since 1993. Initially, I thought that SRP would be a good treatment for low hyperopia in presbyopic patients, but I've learned from experience that patients presenting with what appears to be low hyperopia may not be low hyperopes at all. Needless to say, this can have a dramatic effect on your outcomes.

Why are these patients deceptive? Apparently, as a result of being hyperopic all their lives, they have very strong neurological and muscular accommodative mechanisms. These patients usually brag that all their lives they could see a bird in a tree two blocks away. This is true because they were able to accommodate to see the last fine details when their lenses were more supple.

In fact, their neurological and muscular accommodative mechanisms are so strong that when you examine these patients, simply using tropicamide (Mydriacyl) and/or cyclo-pentolate (Cyclogel) 2% -- alone or together -- won't show you the true degree of their latent hyperopia. This leads to the impression that you're expanding the accommodative range of a person whose vision is close to emmetropia. In reality, their accommodative muscles may be in temporary spasm, and the true refraction of many of these patients is far more hyperopic. This leads to "progressive hyperopia" during the months and years following the surgery.

Learning the hard way

This scenario occurred in 11 eyes of 6 patients we treated. The patients were between the ages of 45 and 64, and all 11 eyes initially presented with a history of great distance vision and symptomatic presbyopia. On mild cycloplegic measurements, none of the eyes displayed more than .50D of hyperopia.

We corrected the apparent low hyperopia using LASIK or PRK and then proceeded with SRP. None of the patients had great postoperative near reading results and all 6 patients were somewhat disappointed overall.

After we followed them for up to 3 years, all of them had a marked progression of their manifest hyperopia, eventually ranging from +1.25D to +2.00 SE. This moved their new accommodative range away from the excellent near vision they wanted. Most weren't satisfied with the explanation that "you're using much of your accommodation just so you can see well again at distance."

So far, I've surgically corrected the "progressive hyperopia" that occurred in nine of these eyes. (Initially, we had concerns about doing LASIK after SRP, but I've had no problem using a Hansatome keratome.) The results have been much better:

• Two patients were set to plano OU and are extremely happy. One of these patients is now 67; he sees 20/15 at distance and easily reads J1 at 10 to 12 inches.
• Three patients around the age of 50 were set at plano OD and -50D OS; they're very happy with the final outcome.

I recently operated on a 50-year-old patient with the lowest accommodation values following SRP (about +2.50 D). He works as a video editor and has a heavy near vision requirement. I gave him monovision, setting his OS to about -1.25D. It remains to be seen whether he'll want to be plano OS.

Avoiding hyperopic backlash

To prevent "progressive hyperopia" post-op, all patients seeking SRP who appear to be emmetropic, or only slightly hyperopic, must be cyclopleged for 3 days over the weekend with 5% homatropine and 2% cyclopentolate, both t.i.d. Following this protocol has produced far better results.

Another alternative is to perform SRP first and get the patient to agree to wait a few months before correcting the baseline refraction with LASIK or another technique. (This means getting the patient to agree to tolerate imperfect vision for a while to ensure a better long-term result.) If any additional hyperopic creep is going to occur, it should be measurable by that time. One recent surgical patient, a 48-year-old attorney, measured + 2.25D of hyperopia together with some astigmatism following the more intensive cycloplegia. I chose to do her SRP first; she's now waiting 3 months before undergoing LASIK.

Managing hyperopic exophoria

Another issue that may compound the problem of undercorrecting latent hyperopia is the presence of exophoria. Two of our patients had a 5D exophoria, about the same at distance and near, and they complained more than any other patients about their inability to read at near. However, this was intimately connected to the way they used their eyes.

On evaluation they were about J3 to J5 at near with both eyes open, but their near vision improved dramatically when each eye was measured separately. One patient, age 45, could read J1 at near using each eye separately, but only J5 -- with many complaints -- when reading using both eyes together. The other patient's workup was almost identical.

In both cases, wearing a distance correction before surgery actually made their near vision worse and their complaints more severe. However, correcting their latent hyperopia greatly decreased the complaints, making this a potentially useful treatment for patients with similar symptoms.

Dr. Cross is an internationally known surgeon who specializes in LASIK, SRP, glaucoma treatment and cataract surgery; he founded and practices at the Bellaire Eye and Laser Center in Houston, Texas. Dr. Cross has performed more than 15,000 refractive keratectomies and has been involved in photorefractive keratectomy (PRK) since its inception. He lectures on these topics frequently.

A few months ago, the FDA finally approved the use of the ViewPoint conductive keratoplasty (CK) System for the treatment of mild to moderate (+0.75D to +3.00D), previously untreated, spherical hyperopia. This provides us with another significant treatment option to offer these patients. (Other potential applications, including treatment of astigmatism, correction of hyperopia induced by previous refractive procedures, and the treatment of presbyopia through monovision surgery, are being explored internationally and in the United States.)

CK, pioneered by Refractec, Inc., in Irvine, Calif., is a recent innovation in refractive surgery that allows reshaping of the cornea using laserless, nonablative, nonincisional, collagen shrinkage. The fine CK Keratoplast tip is inserted directly into the peripheral corneal stroma (see illustration, right). The tip produces radiofrequency energy, causing collagen in the area sur- rounding the tip to shrink and form a column of denatured collagen.

	During CK treatment, radiofrequency energy is delivered deep into the stroma through a probe inserted at previously marked spots on the mid-peripheral cornea.

Treatment for hyperopia is applied in a symmetrical ring pattern outside of the visual axis; it produces a flattening of the peripheral cornea and steepening of the central cornea. The number of CK spots applied to treat hyperopia ranges from eight to 32, with an increasing number of spots applied for increasing levels of hyperopia. Because the zone of collagen shrinkage is deep (see image, page 82), the resulting shrinkage and corresponding change in vision is long-lasting, with minimal regression.

Compared with excimer laser treatments, CK has numerous advantages:

• It doesn't invade the central cornea or compromise the integrity or structure of the cornea.
• It's technically easier to perform, with a shorter surgical learning curve.
• It doesn't produce flap complications.
• The procedure takes less than 5 minutes.
• It can be performed in an office setting.
• It requires only topical anesthesia.
• The small portable CK unit is much less expensive than other collagen shrinkage technologies.

CK and monovision

Monovision is perhaps the safest and least controversial of all the options available for presbyopic patients seeking refractive surgical correction. To induce mild myopia in one eye for monovision, an overcorrection can be designed by the surgeon.

Histology of a pig cornea 1 week after CK. The footprint is cylindrical and approximately 80% of corneal depth. Such deep treatment penetration is likely to contribute to permanence of effect.

In a multicenter clinical trial of CK monovision as a treatment for presbyopia, surgeons induced myopia of up to 2D. A total of 74% of eyes had binocular UCVA of 20/20 or better together with J2 or better, 6 months postoperatively, and a total of 91% had binocular UCVA of 20/25 or better together with J3 or better.

CK trials for treating presbyopia (with and without monovision) are ongoing, and I look forward to seeing results beyond the 6-month data that's available now.

[Editor's note: For more information about conductive keratoplasty, see the cover story in the July issue of Ophthalmology Management.] 

Dr. Hardten is director of refractive surgery for Minnesota Eye Consultants and Regions Hospital, clinical associate professor of ophthalmology at the University of Minnesota, and a member of the board of directors for the International Society of Refractive Surgery.

PRELEX (Presbyopic Lens Exchange)
By R. Bruce Wallace, III, M.D., F.A.C.S.

PRELEX (PREsbyopic Lens EXchange) is a proven surgical procedure that restores quality distance and near vision without glasses for hyperopic presbyopes. The centerpiece of the PRELEX procedure is the implantation of an ARRAY multifocal IOL in place of the patient's own lens.

However, PRELEX requires more than just the implantation of the ARRAY IOL; it requires careful attention to biometry, effective astigmatism control, proper attention to postoperative conditions (such as dry eye syndrome) and helping the patient adjust to a new visual system that requires adaptation at the level of the visual cortex. (Using the term PRELEX focuses the patient on the concept of a surgical procedure rather than a single element of the procedure such as the use of the ARRAY multifocal lens.)

We can offer this kind of lens exchange as a refractive procedure because of significant advancements in lens surgery, such as topical anesthesia, clear corneal temporal incisions, and refinements in phaco fluidics and astigmatism control (with procedures such as limbal relaxing incisions). Also, improvements in biometry, such as the introduction of the Zeiss Humphrey IOLMaster, which some surgeons have found to be as much as 10 times more accurate than standard ultrasonic A-scans, have helped to make this possible.

Patient selection and education

Hyperopes are better candidates for refractive lensectomy than myopes because of a smaller risk of retinal detachment after surgery. Hyperopes also tend to be less attractive candidates for LASIK and PRK because of the need for corneal tissue removal, particularly if monovision is being considered.

An important element in the ultimate success of PRELEX is the patient's adjustment to the new visual system. For that reason, before performing PRELEX on a hyperopic presbyope, it's important to have a careful discussion with the patient. We ask the following questions, as proposed by Dr. Howard Fine:

• How important is it to you to reduce your need for bifocals?
• Would you be willing to accept some visual changes in the first weeks or months after surgery, such as halos around lights -- changes that will likely become less noticeable over time -- if this will provide you with quality distance and near vision without the need for glasses?

We explain that the patient is unlikely to have any loss of best corrected vision, although he may have some difficulty with near vision until he learns to ignore the distant image superimposed on the near image. For pre-cataract patients, we explain to the patient that PRELEX involves the off-label use of an FDA-approved device.

If the patient seems interested after this conversation, then PRELEX may be an appropriate option.

Giving patients what they want

PRELEX represents an important opportunity for lens surgeons to provide excellent uncorrected distance and near vision for hyperopic presbyopes. With careful attention to biometry, low impact phaco and effective astigmatism control, patient satisfaction with PRELEX is usually very high. OM

Dr. Wallace is founder and medical director of Wallace Eye Surgery in Alexandria, La., and is assistant clinical professor of ophthalmology at Tulane School of Medicine in New Orleans.

I've found that presbyopic hyperopes between +1.00 and +2.50, including undercorrected pseudophakes, are good candidates for laser thermal keratoplasty (LTK). The LTK procedure, developed by Sunrise Technologies, uses heat applied by a laser onto a symmetrical series of spots around the periphery of the cornea, causing collagen tissue to contract, resulting in steepening of the central cornea. The postoperative routine is simple: an overnight bandage contact lens, followed by antibiotic and nonsteroidal eye drops for 4 days. We usually treat the second eye the following week.

The downside with using LTK to treat hyperopic presbyopes is that the enhancement rate is about 20%. However, the patient is not disadvantaged and the procedure is a very benign one with little risk. To date, none of my patients has experienced any loss of BCVA.

When selecting patients for LTK, I follow the approved limits for pre-existing astigmatism. At least half of the time, I use a single ring of laser applications at 6 mm.

Other helpful strategies include:

Avoid overcorrecting. To correct +2.00D or more, I use two rings set at 75% of the company's nomograms to avoid significant overcorrections. Overcorrections are usually difficult to manage. I find it much easier to deal with undercorrections, and I'd rather enhance a result than wait out an overcorrection.

Astigmatism. We've tried to minimize induced against-the-rule astigmatism by modulating the pretreatment protocol. However, we still can't use LTK to treat existing astigmatism, induced or otherwise.

Monovision. Some doctors have used LTK to create monovision, but I've stopped offering this alternative to my patients. Before I would allow patients to choose monovision, I required them to do a monovision trial using contact lenses. I found that most of them hadn't worn contact lenses before and weren't willing to go to the trouble of doing a trial run. Response was so lukewarm that I eventually stopped mentioning this alternative.

In my experience, LTK has been a valuable option for my hyperopic, presbyopic patients. Hopefully the technology will survive Sunrise Technologies' current economic problems and be further refined over time. OM

Dr. Kansas is the founder and director of both Kansas Eye Surgery and Laser Associates in Albany, N.Y. He's clinical professor of ophthalmology at Albany Medical College and is certified by the American Academy of Ophthalmology and the American Board of Eye Surgery.

When deciding whether a hyperopic presbyope is a good candidate for LASIK, my primary concern is how much corneal steepening would be involved -- first, to treat the hyperopia, and second, to induce myopia in order to create monovision (assuming this option has been approved by the patient after experiencing it with contact lenses.)

When deciding whether I can correct the hyperopia, I consider two issues: the amount of refractive error I'll have to correct and the resulting corneal curvature. I prefer not to cause a refractive shift of more than 3D. I've found that going beyond this causes my accuracy and patient satisfaction results to drop. However, I will correct up to 4D if the patient understands the risks and still wants the procedure, or if the patient has a flat cornea (e.g., 40D).

In terms of corneal curvature, I don't want to make the cornea steeper than 48D. If I steepen a cornea more than this, best corrected visual acuity begins to diminish and the cornea begins to look as if the patient suffers from keratoconus.

When considering whether treating the presbyopia by creating monovision is an acceptable option, I factor in the correction for the patient's hyperopia plus the amount of myopia I'd need to induce. If the amount of correction involved is within the aforementioned limits, I'd consider performing hyperopic LASIK.

For example, if a 55-year-old patient has 2D of hyperopia and after contact lens trials has decided to have his nondominant eye surgically altered to a -2.0D reading eye, I'd need to create a total of 4D of refractive change, a borderline amount by my standards. If preoperative keratometry was 46D, then surgery would take the patient above 48D, which I wouldn't recommend.

In this situation, I'd suggest a phakic IOL or refractive lensectomy. If the patient's preoperative Ks were 40D, I'd feel better about hyperopic LASIK, but I'd still suggest the alternative of lens surgery. Of course, if I found any evidence of a beginning cataract, I'd recommend either lens surgery or no surgery at all.

Dr. Thompson practices at Ophthalmology, Ltd. in Sioux Falls, South Dakota and is assistant professor of ophthalmology at the University of South Dakota School of Medicine. He's been a principle investigator in numerous clinical trials involving refractive surgery and technology, and he lectures on these topics around the world.

Perhaps because many myopes have already had refractive surgery -- or perhaps becasue of word-of-mouth from successful post-ops -- hyperopic candidates for refractive surgery are becoming an increasing part of my practice. For these patients I perform LASEK exclusively, as I do for myopic patients.

For the hyperope who is already demonstrating symptoms of presbyopia, I usually discuss a few options. I generally recommend correcting both eyes fully for distance. I attempt to achieve a slightly myopic final refraction (-0.25D to -0.50D), giving a little extra reading power while still achieving excellent distance acuity. I explain that within a few years there will probably be some excellent procedures that will reduce the need for reading glasses. In the meantime, we will already have corrected their distance vision.

In a few cases, I attempt monovision correction. However, I generally reserve this option for patients who have tried monovision already using contact lenses and are happy with both distance and near vision achieved monocularly.

Although I don't perform clear lens extraction with implantation of multifocal intraocular lenses such as the ARRAY, this is also an option for the hyperopic presbyope. I've referred three patients who were interested in this procedure to other surgeons. However, the outcomes were mixed; the results of the surgeries were technically excellent, but all three patients were somewhat disappointed with the end results. They state that although their distance and near vision are both "good," there's no point at which their vision is completely clear. Two of the patients also complain of nighttime glare, even though they were fully aware of the possibility of this problem.

Because of these patients' experience, I'm strongly cautioning patients about clear lens exchange.

Dr. Claringbold is chief ophthalmologist at the MidMichigan Physicians Group in Clare, Mich., and clinical assistant professor, Department of Neurology and Ophthalmology, Michigan State University. He's been performing LASEK exclusively since 1999 and has been co-instructor of LASEK symposia at the ASCRS and AAO annual meetings. His article "LASEK for the Correction of Myopia" was recently published in the Journal of Cataract and Refractive Surgery. You can contact him at 989-802-8811, via fax at 989-802-8809, or via e-mail at eyeboy@tm.net.