Lenses an alternative for hyperopia treatment

Some surgeons are concluding that refractive IOLs, whether phakic or aphakic, are a better solution than laser for hyperopia.

Surgical treatment of hyperopia has historically been more problematic than treatment of myopia. Surgeons have found that flattening the cornea is easier – and more stable – than steepening it. Some surgeons are concluding that an intraocular approach, whether with phakic or aphakic IOLs, is more reliable than a corneal approach.

Some reports have said that excimer laser refractive surgery for hyperopia is unstable and subject to regression. Other laser and nonlaser cornea-based modalities have been labeled “temporary” because of their tendency to regress.

Refractive IOLs, on the other hand, do not fluctuate or change power with time. They require intraocular surgery.

What is the best treatment for hyperopes currently available? The answer varies from surgeon to surgeon.

A variety of strategies

Each type of hyperopic surgery has its own niche, according to Daniel Durrie, MD. He said he has several techniques in his armamentarium, including conductive keratoplasty (CK), hyperopic LASIK and surface ablation, as well as the possibility of clear lens extraction. He chooses the best surgical option based on the patient’s needs.

“When it comes down to which procedure for which patient, I try to keep it very simple,” he said. “There’s a different kind of patient for each surgery. It’s a good thing we have so many options for this often difficult group of patients.”

He noted that hyperopia correction is quite different from myopia correction, which is why this group of patients is discussed separately at refractive surgery meetings.

“At the Refractive Surgery Interest Group meeting before this year’s Academy meeting we have a session on these patients alone because they are so different from the myopic patients,” he said.

Dr. Durrie outlined some of the characteristics that make hyperopic patients better candidates for one procedure than another.

For CK, his ideal candidates have had good, stable distance vision all their lives and need only reading glasses; they are typically age 55 or over, not interested in lasers or techniques that remove tissue, and they are very protective of their sight.

“They understand that CK is much like plastic surgery, sort of a longer-lasting Botox. It works for a while and then the wrinkles come back. CK works for several years, but it does not stop changes that occur due to aging,” Dr. Durrie said.

For a patient who has hyperopia and astigmatism, he recommends hyperopic LASIK; or surface ablation if the patient has a history of dry eye. If he thinks the patient is likely to be problematic, he prefers LASIK with the idea he may have to do enhancements in the future.

Dr. Durrie does not do cataract surgery. However, in older hyperopic patients who have a family history of early cataract or the very early stages of cataracts in their own eyes, he may recommend clear lens extraction. He said he is not a proponent of any particular type of IOL in this situation, but he does like the fact clear lens extraction fixes two problems at one time – hyperopia and the incipient cataract.

CLE, other options?

I. Howard Fine, MD, said he believes in the future the best answer for hyperopic patients will lie in clear lens extraction, also called refractive lens exchange, with implantation of an accommodating or multifocal IOL.

“While the spherical aberration of the cornea will remain fairly constant over a lifetime, the lens will change as time goes on,” said Dr. Fine.

He said that only removing the crystalline lens and replacing it with an accommodating or multifocal IOL lens will allow patients permanent relief from hyperopia and presbyopia as well.

Philippe Sourdille, MD, said that only “reasonably reversible” treatments are suitable for surgical correction of hyperopia.

“‘Reasonably reversible’ means something that will not permanently modify the anatomical status of the eye,” Dr. Sourdille said. “Another point to be considered is the association of hyperopia to astigmatism, and the need for two separate treatments in these patients.”

In general, phakic IOLs are his preference, especially in younger hyperopic patients. He uses both iris-supported and soft angle-supported lenses. He said no angle-supported IOL with rigid or semi-rigid haptics should be considered as a possible hyperopia treatment, and corneal procedures should be considered only when the patient has associated astigmatism.

Dr. Sourdille said a multifocal IOL could be implanted in certain patients after clear lens removal.

“Clear lens extraction would be an alternative only in older patients, or in case of high hyperopes with shallow anterior chambers, making phakic IOL implantation risky in the long term,” Dr. Sourdille said.

“We have no experience with CK, and do not intend to develop any,” he said.

Dry eye, regression after LASIK

One factor to consider when choosing IOL implantation over LASIK for hyperopes is the incidence of dry eye after LASIK that has been reported. Regression of effect has also historically been a concern after hyperopic surgery.

In a recent study, Julie M. Albietz, BAppSc(Optom), PhD, and colleagues in Brisbane, Australia, found that dry eye and regression were experienced by about one-third of patients after hyperopic LASIK.

In a retrospective 12-month analysis of 88 eyes of 88 participants who had LASIK for hyperopia, the investigators concluded that dry eye, particularly in females, was problematic after LASIK for hyperopia and was associated with refractive regression. The investigators said current methods for managing the tear film and ocular surface may not control LASIK-induced dry eye, particularly in some females during the first 6 months after surgery.

Participants were evaluated before and after surgery up to 12 months for dry eye symptoms, tear film stability, tear volume, ocular surface staining and conjunctival goblet cell density.

Chronic dry eye was experienced by 32% of participants postoperatively. Postop dry eye symptoms were significantly associated with female sex, preoperative dry eye symptoms, lower tear film stability after surgery, greater ocular surface staining after surgery, lower tear volume before and after surgery and lower goblet cell density after surgery.

Perhaps even more important, the regression rate 12 months after surgery was 32%. Regression was significantly associated with female sex, chronic dry eye symptoms, lower tear film stability after surgery, greater ocular surface staining before and after surgery and lower tear volume before and after surgery.

Phakic IOLs

There have been few published studies of phakic IOLs for hyperopia. In one published several years ago, Jonathan M. Davidorf, MD, Roberto Zaldivar, MD, and Susana Oscherow, MD, reported on posterior chamber phakic IOLs for hyperopia of +4 D to +11 D.

Dr. Davidorf and colleagues found that posterior chamber phakic IOL implantation with a plate-haptic IOL was an effective method for correcting high hyperopia. They made sure to point out that large, patent iridotomies are important in hyperopic eyes to lower the risk of postoperative pupillary block.

The investigators analyzed the results of 24 eyes that received a posterior chamber hydrogel-collagen plate phakic IOL for the correction of hyperopia with the goal of emmetropia. The mean follow-up was 8.4 months.

The mean preoperative spherical equivalent refraction was +6.5 D. Mean postoperative spherical equivalent refraction at last examination was –0.4 D, with 79% (19 eyes) within ± 1 D and 58% (14 eyes) within ±0.5 D of emmetropia. Postoperative uncorrected visual acuity at last examination was 20/20 or better in 8% (two eyes) and 20/40 or better in 63% (15 eyes). A gain of two or more lines of spectacle-corrected visual acuity was seen in two eyes (8%) at last examination. One eye (4%) lost two or more lines of spectacle-corrected visual acuity due to progressive neovascular glaucoma initiated by early postoperative pupillary block.

For Your Information:

• I. Howard Fine, MD, can be reached at 1550 Oak St., Suite 5, Eugene, OR 97401 U.S.A.; +(1) 541-687-2110; fax: +(1) 541-484-3883; e-mail: hfine@finemd.com. Dr. Fine has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Daniel Durrie, MD, can be reached at Hunkeler Eye Centers, 5520 College Blvd., Overland Park, KS 66211 U.S.A.; +(1) 913-491-3737; fax: +(1) 913-491-9650; e-mail: ddurrie@novamed.com. Dr. Durrie has no direct financial interest in any of the products mentioned in this article. He is a paid consultant for Refractec, Alcon and Bausch & Lomb.
• Philippe Sourdille, MD, can be reached at Clinique Sourdille, 3, Place Anatole France, 44000 Nantes, France: fax: +(33) 251-83-87-19; e-mail: philippe.sourdille@wanadoo.fr. Dr. Sourdille has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Jonathan M. Davidorf, MD, can be reached at 7230 Medical Center Drive, Suite 201, West Hills, CA 91307 U.S.A.; +(1) 818-883-0112; fax: +(1) 818-883-2767; e-mail: jdavidorf@pol.net.
• Roberto Zaldivar, MD, can be reached at the Instituto Zaldivar, Av. Emilio Civit 685, 5500 Mendoza, Argentina; +(54) 61 293 222; fax: +(54) 61-380-350.
• Julie Albietz, BAppSc(Optom), PhD, can be reached at Queensland University of Technology, Centre for Eye Research, Victoria Park Rd., Kelvin Grove, 4059 Australia; +(61)73832-2100; fax: +(61) 73832-2130 e-mail: julie@darkoptics.com.au.

References:

• JM Albietz, LM Lenton, SG McLennan. Effect of laser in situ keratomileusis for hyperopia on tear film and ocular surface. J Refract Surg. 2002;18:113-123.
• JM Davidorf, R Zaldivar, S Oscherow. Posterior chamber phakic IOL for hyperopia of +4 to +11 diopters. J Refract Surg. 1998;14:306-311.