The Verisyse phakic IOL (Advanced Medical Optics, Inc., Santa Ana, CA), which was approved by the FDA in September 2004, offers refractive surgeons a very effective lens implant to treat patients who are not candidates for LASIK. The Verisyse phakic lens implant is approved to correct -5.00 to -20.00D of myopia. During the FDA clinical trial, the average prescription treated was between -12.00 and -13.00D.1 Ideal candidates for the Verisyse lens are those whose myopia is greater than -5.00D or whose corneal thickness with respect to their refractive error is insufficient for LASIK treatment. Patients with irregular astigmatism may also benefit from the Verisyse lens.

Studies from large LASIK practices have shown that, even though the prevalence of high myopia (>-6.00D) is only 2% in the general population, it accounted for 17% to 55% of myopic patients presenting for refractive surgery.2,3 In one study, 30% of patients who came in for laser vision correction (LASIK or PRK) did not undergo the procedure because their myopia was too high (>-12.00D) or their corneas were too thin to correct for the amount of myopia.4 A significant percentage of these types of patients wanting LASIK or PRK could benefit from the Verisyse lens.

THE VERISYSE'S
ADVANTAGES

There are several advantages to the Verisyse lens that make it appealing to patients who are candidates for LASIK but who are reluctant to undergo a permanent procedure. The surgery is appealing to these patients because the implant can be removed at any time should serious complications develop.

One of the biggest concerns patients have with LASIK regards the possibility of a bad outcome and the permanent loss of vision in an otherwise healthy eye. Patients are also concerned about the quality of their vision after receiving LASIK as well as post-LASIK glare and halos at night. There is a subset of LASIK candidates who have held off undergoing the procedure because of this fear. I have had many patients express their willingness to undergo phakic IOL implantation, which requires an incision into the eye, because it does not induce permanent changes like LASIK.

CASE STUDY

A 47-year-old female underwent standard LASIK with the Ladarvision system (Alcon Laboratories, Inc., Fort Worth, TX) in her left eye in 2001. She had decided on uniocular surgery, because she was very concerned about not having a good outcome and did not want to risk both eyes at the same time. Postoperatively, she remained undercorrected in that eye and wore a soft contact lens for her residual refractive error. However, she still complained of glares and halos at night as well as ghosting of images with that eye. Due to her dissatisfaction with her primary LASIK treatment (and her reluctance to undergo an enhancement), she decided to research alternatives for her second eye. She presented to me in November 2004 for a Verisyse consultation with a very long list of questions (a sign that she might not be a candidate for any refractive procedure).

Upon examination, the UCVA in her LASIK-treated eye was 20/60, which corrected to 20/20 with a manifest refraction of -1.50D of sphere. In her untreated eye, her BCVA was 20/20 with a manifest refraction of -8.50 -0.75 X 10º. After detailed informed consent, she received a Verisyse (6-mm optic) phakic lens implant

(-10.00D) in that eye (Figure 1). At the 1-month postoperative period, her UCVA measured 20/20 with a plano -0.25 X 169º refraction. Subjectively, she had no glare, halos, or ghosting with the Verisyse eye, and she was extremely pleased with her outcome.

DISCUSSION

The Verisyse lens' 6-mm optic offers an effective 7-mm optical zone when referenced to the corneal plane compared with the standard 6-mm LASIK treatment.5 Consistent with this patient's subjective results, a larger optical zone is more likely to reduce the chances of glare and halos in mesopic conditions. After LASIK surgery, glare and halos along with decreased contrast sensitivity have been shown to be significantly more common with higher amounts of myopic correction.6 This complication is related to the change in the configuration of the cornea from its natural prolate form to an oblate shape after LASIK.7

The patient's wavefront error as measured by the Nidek OPD Scan (Nidek Inc., Fremont, CA) was 0.133µm in her LASIK-treated eye and 0.076µm in her Verisyse-treated eye. Preoperatively, the patient's non-LASIK eye had a wavefront error of 0.073µm (Figure 2). These results parallel the contrast sensitivity results in the FDA clinical trial, which showed no significant difference in contrast sensitivity tested under mesopic conditions with glare between preoperative and postoperative values (cycles/degree).1

International investigators have compared the results of LASIK in one eye and a Verisyse lens in the other in a group of patients whose myopia averaged -13.50D (mean spherical equivalent).8 Although the mean postoperative spherical equivalent was very similar between the Verisyse and LASIK eyes, the UCVA results, number of Snellen lines gained, contrast sensitivity results, and patient preference all favored the Verisyse eyes. More data are required to compare the results with the phakic implant versus wavefront-guided LASIK treatment to determine the best procedure for those patients who are candidates for both modalities.

Gregory Pamel, MD, is Attending Surgeon at the Manhattan Eye Ear & Throat Hospital in New York and is Medical Director of Pamel Vision and Laser Group in Manhattan. He was the principle investigator for the phase 3 FDA clinical trials for the Verisyse lens implant for myopia. Dr. Pamel states that he holds no financial interest in any company or product mentioned herein. He may be reached at (212) 355-2215; gjpmd@aol.com.

1. Stulting D. Artisan Phakic IOL for the correction of myopia. Paper presented at: The FDA Ophthalmic Devices Advisory Panel Meeting; February 5, 2004; Washington, DC.
2. Uckahan OO, Sokol J, Brodie SE, Asbell PA. Characteristics of the myopic patient population applying for refractive surgery. CLAO
J. 2000;26:102-105.
3. McCarty CA, Livingston PM, Taylor HR. Prevalence of myopia in adults: implications for refractive surgeons. J Refract Surg.
1997;12:229-234.
4. Hori-Komai Y, Ikuko T, Asano-Kato N, Tsubota K. Reasons for not performing refractive surgery. J Cataract Refract Surg.
2002;28:795-797.
5. Holladay JT. Optics and intraocular lens power calculations for phakic intraocular lenses. In: Phakic Intraocular Lenses: Principles and Practices. Thorofare, NJ: Slack Inc.; 2004: 39.
6. Halliday BL. Refractive and visual results and patient satisfaction after excimer laser photorefractive keratectomy for myopia. Br J Ophthalmol.
1995;79:881-887.
7. Holladay JT, Dudeja DR, Chang J. Functional vision and corneal changes after laser in situ keratomileusis determined by contrast sensitivity, glare testing, and corneal topography. J Cataract Refract Surg.
1999;25;663-669.
8. El Danasoury MA, El Maghraby A, Gamali TO. Comparison of iris-fixed Artisan lens implantation with excimer laser in situ keratomileusis in correcting myopia between -9.00 and -19.50 diopters: a randomized study. Ophthalmology.
2002;109:955-964.