A Closer Look at Premium Lenses
The annual ASCRS meeting yielded valuable new data on how they perform in practice.
BY RENÉ LUTHE, SENIOR ASSOCIATE EDITOR
The economy may have slowed, but research in presbyopia-correcting IOLs continues apace. Read on for a sampling of the latest from last month's American Society of Cataract and Refractive Surgeons meeting in San Francisco. If any of these pique your interest and you'd like more information, the titles and authors of the studies appear at the end of each summary.
Of course, bear in mind that while each may be illluminating, rarely is any single study definitive, so be mindful not to overestimate the impact of individual findings. It's also prudent to note that some of these studies may have used older lens designs than those currently being marketed.
■ A 3-year retrospective study compared visual outcomes of Crystalens, ReZoom and ReSTOR at distance, near and intermediate. Sixty-three eyes of 32 patients were implanted with the Crystalens 5.0, 473 eyes of 240 patients received the ReZoom, and 62 eyes of 31 patients received the ReSTOR. For the Crystalens patients, uncorrected distance visual acuity (UCDVA) was 20/25; uncorrected intermediate visual acuity (UCIVA) was J 3; uncorrected near visual acuity (UCNVA) was J 2.5.
The ReZoom achieved 20/20 for UCDVA, J 4 for UCIVA and J 2 for UCNVA. The ReSTOR achieved 20/30 for UCDVA, J4 for UCIVA and J 1.5 for UCNVA.
"The process of choosing candidates became more complex, but also more rewarding, with the development of more types of multifocal IOLs," says lead researcher Francis A. D'Ambrosio, M.D. "All the lenses perform well. Surgeons need to look at their strengths and weaknesses and apply that to meet patients' needs."
Retrospective Analysis of More Than 500+ Eyes Implanted with Crystalens, ReSTOR, and ReZoom IOLs. D'Ambrosio FA, Wilson LM.
■ In one study, 50 eyes are to be implanted with the Crystalens HD IOL to assess predictability, range of visual acuity and refractive error. In this interim report, 18 eyes have been implanted, with a mean follow up of 2 months. All eyes were 20/30 or better with best correction for distance and 76% were 20/20 or better. Sixty-five percent of eyes achieved UCIVA of 20/40 or better, while 18% were J2 or better. UCNVA was 20/40 or better for all eyes and J2 or better for 65% of eyes. Without correction, 94% of eyes were 20/40 or better (distance) and J3 or better (near), with 53% 20/25 and J2 or better.
Patient Outcomes After Implantation of the Crystalens HD Accommodating IOL. Davies JA.
Intermediate Vision with the ReSTOR +3.0 Aspheric Multifocal IOL. Nuijts RM, Levy P, de Vries NE.
■ A comparison of functional vision outcomes for the AcrySof ReSTOR +3 Aspheric Multifocal IOL and the ReSTOR +4 Multifocal showed that the +3 achieved an improvement of >1 line compared to the +4. The results come from 3-month visit outcomes for 117 ReSTOR +3 subjects and 114 ReSTOR +4 subjects. Binocular defocus testing was performed using a phoropter or trial frames and a 100% contrast ETDRS chart at 4 m from the subject under photopic lighting conditions. Binocular defocus curves demonstrated the same level of near visual acuity for both IOLs; however, the ReSTOR +3 demonstrated a mean of 20/32 or better in the intermediate vision range.
Functional Outcomes of +3.0 D Add Aspheric Multifocal IOL and +4.0 D Add Aspheric Multifocal IOL. Solomon KD, Sandoval HP, Guenena MA.
■ The investigator compared the visual outcomes and patient satisfaction in refractive lens exchange patients with bilateral Crystalens HD (HD/HD), bilateral ReSTOR +4 (RS/RS), and ReSTOR/ReZoom (RS/RZ) or Crystalens 5-0/ReSTOR (CL/RS) combinations, as well as pseudophakic monovision. Ten patients were evaluated. Manifest refraction, BCVA, UCVA (distance, intermediate and near), contrast sensitivity and patient questionnaire were among the factors evaluated in patients greater than 3 months postop. All groups reported satisfaction with surgery and spectacle independence at distance and near.
Comparison of Bilateral Crystalens HD and Other Presbyopia-Correcting IOL Combinations and Pseudophakic Monovision in RLE. Stahl JE.
| Next-Generation IOLs: A Glimpse of the Future? |
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The Light Adjustable Lens (LAL), from San Francisco's Calhoun Vision, Inc., contains photosensitive silicone molecules that enable precise and noninvasive postoperative adjustment of refractive power using ultraviolet light, the company says. The LAL formulation consists of four basic components: silicone matrix polymer, photoreactive macromer, photoinitiator and UV absorber.1 The AT.LISA multifocal and toric lenses from Carl Zeiss Meditec, available internationally but not in the US, are implanted through incisions of 1.5 mm. The AT.LISA toric power is calculated individually for every patient to provide optimal postop refractive results. According to CZM, AT.LISA multifocal is the only microincision multifocal IOL on the market with a proven pseudo-accommodation range of 5 D. An international multi-center study is currently underway at approximately 20 centers throughout the UK, Europe and Asia.2 The Tetraflex (Lenstec, St. Petersburg, Fla.) acrylic foldable microincision presbyopic accommodating IOL is placed in the eye in a "flat" position, designed to give patients clear distance vision. When focusing on a near object, the Tetraflex is designed to move subtly forward, like the natural lens once did, giving clear near vision. The Tetraflex is designed to move subtly back and forth, as the patient focuses on distant, mid or near objects, allowing users to once again "accommodate."3 The NuLens, from a company of the same name based in Herzliya-Pituach, Israel, is composed of a flexible polymer between two rigid plates, one of which has an opening. When the plates are compressed, the flexible polymer bulges through the opening in the front surface, creating a much more plus-powered lens. The NuLens is designed to be placed on top of the collapsed capsular bag after cataract removal.4 The Synchrony from Visiogen is a 3-dimensional, single-piece, accommodating lens with two separate optics connected by a spring system that are designed to work together in providing patients a full range of vision. When the two lenses are close together, the focal point of the eye is targeted for distance. When the ciliary body contracts, reducing capsular bag and zonular tension, the anterior lens moves forward, changing the eye's focus to intermediate or near vision. The lens features a +32 D anterior optic and a minus-powered posterior optic that varies based on the biometry of the patient. Visiogen recently completed it FDA trials and is preparing submission of the data for FDA review, the company says. The Vision Membrane lens from Vision Membrane Technologies, Inc. of Carlsbad, Calif. is a silicone, anterior-chamber phakic IOL that employs a combination of refractive and diffractive optics to maintain a constant thinness in the range of 200 μm to 300 μm for all refractive powers. It's the first IOL to possess a vaulted optic, which provides enough clearance from the corneal endothelium to accommodate an optic of greater than 6 mm in diameter. This larger optic is critical to eliminating the halos that have been inherent in phakic IOLs with optic diameters of 4.5 mm, the company says, and the vaulted optic precludes the need for a peripheral iridectomy to prevent pupillary block and angle-closure glaucoma.6 References
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Predictability of IOL Calculations in Clinical Practice for Presbyopic IOLs: ReSTOR Aspheric and Crystalens HD IOLs. Davidorf JM.
■ To assess visual acuity for near and distance vision for both the AcrySof ReSTOR aspheric IOL and the Tecnis ZM900 multifocal, researchers implanted one in each eye of 22 patients in the randomized prospective study. Patients were followed for 3 months. Uncorrected visual acuity for near, intermediate and distance, best-corrected visual acuity, contrast sensitivity and spherical equivalent were measured. While both the ReSTOR and Tecnis ZM900 provided high-quality visual acuity for near and distance vision, the Tecnis provided better distance-corrected intermediate visual acuity. However, contrast sensitivity revealed better values with the ReSTOR, particularly under mesopic conditions.
Ocular Aberrations and Contrast Sensitivity After AcrySof ReSTOR Aspheric IOL Implantation in 1 Eye and Tecnis Multifocal in the Other Eye. Vaz RQ, Akaishi L, Tzelikis PF, Gondim JD, Donato BG.
■ The study evaluated the efficacy, safety, quality of vision for far and near, and depth of field in presbyopic patients with bilateral ReSTOR IOLs, CustomVue Monovision and wavefront-guided correction with a Spotscanning Platform. Twenty patients were placed in each group and follow-up was performed at 1, 3, 6 and 12 months. Researchers evaluated depth-of-field, UCVA, BCVA, stability, predictability, contrast sensitivity, mesopic and glare vision. The ReSTOR group achieved J1-2 mean 20/25 distance vision; intermediate vision was 40~50 cm. The group ranked second in patient satisfaction.
Presbyopia Correction with AcrySof ReSTOR, CustomVue Monovision and Wavefront-Guided Monofocal Ablation: Comparative Analysis. Kim M, Lee S, Lee H, Lee S, Schroeder E.
■ Visual outcomes and patient satisfaction with the Tecnis ZM900 multifocal were analyzed in this retrospective analysis of 1,426 eyes (847 patients) implanted with the lens (Jan. 2006 to Jul. 2008). After 3 months follow-up, patients were assessed for uncorrected near visual acuity (UCNVA) at a fixed distance of 33 cm and uncorrected distance visual acuity (UCDVA). Patients were questioned about photic phenomena and spectacle independence. At 2 months postop, 76% of patients had UCDVA of 20/25 or better. At 3 months, 98% of patients had J2 or better for UCNVA. Thirty-nine percent reported halos, with 3% rated severe.
Presbyopia Correction with Tecnis ZM900 Diffractive Multifocal IOL. Akaishi L, Tzelikis PF, Vaz RQ.
■ To evaluate the accommodative potential of the Opal-A IOL, which is designed to function via the focus shift principle, the lens was implanted in 22 eyes of 22 patients. Outcome measures included logMAR best distance corrected acuity at distance, intermediate and near, defocus curves and subjective and objective accommodation. Excellent distance corrected acuity was achieved, but acuity degraded with decreasing target distance. "Subjective accommodative tests indicate better accommodation than objective tests of accommodation (dioptric change, IOL movement), indicating that these accommodating IOLs work by increased depth of focus rather than true accommodation," David J. Spalton, M.D., says.
Accommodative Performance of the Opal-A IOL: Pilot Study. Cleary G, Spalton DJ, Marshall J.
Visiogen's accommodating IOL, the Synchrony, expected to be launched in the United States in 2010, had several studies presented at the ASCRS meeting. Here is a roundup of the findings:
■ Visual outcomes, functional range of vision and quality-of-life measurements for the Synchrony and ReSTOR aspheric IOLs were compared in a randomized, double-masked evaluation. One hundred twenty eyes in 60 patients were implanted. The results of the first 30 eyes (15 in each group) did not show a significant difference in distance-corrected visual acuity at either distance or near. However, a statistically significant difference was found at distance-corrected intermediate visual acuity in which eyes implanted with the Synchrony performed better (p = 0.003).
Prospective Randomized Clinical Study Comparing Synchrony Dual-Optic Accommodating IOL and ReSTOR Aspheric Multifocal IOL. Marques EF, Casares A.
■ This evaluation of the long-term visual outcomes and safety of the Synchrony examined 48 eyes in 24 patients implanted with the IOL since 2004. Uncorrected and distance-corrected visual acuity for far, intermediate (80 cm) and near (40 cm) was evaluated at 12, 24 and 36 months using ETDRS charts. Average UCVA at 12 months for distance was 20/20, 20/20 for intermediate vision and 20/25 for distance vision. At 36 months, mean UCVA remains stable: 20/20 for distance vision, 20/16 for intermediate vision and 20/23 logMAR for near vision. After 36 months, more than 90% of patients can read 20/40.
3-Year Results with Synchrony Dual-Optic Accommodating IOL. Alarcon R, Bohorquez VM.
■ An evaluation of the long-term clinical results of the first-generation Synchrony showed no obvious malposition, posterior capsule opacification or interlenticular opacification. Six patients were enrolled in the study and one eye implanted with the Synchrony and the fellow eye implanted with another IOL. Postoperative measurements included UCVA, BCVA, centration, posterior capsule opacification and interlenticular opacification. At 5 years, UCDVA in LogMAR was 0.14 ± 0.15 and BCDVA in LogMAR was 0.05 ± 0.06; UCNVA in LogMAR was 0.53 ± 0.09; BCNVA in LogMAR was 0.15 ± 0.13.
5-Year Clinical Results of First-Generation Dual-Optic Accommodating IOL. Limberger I, Heggemann Y, Auffarth GU.
■ Researchers assessed reading speed at 1 and 2 years in patients implanted binocularly with the Synchrony, using a high-contrast reading speed chart to test patients at 40 cm at a constant luminance. Distance-corrected near visual acuity and reading speeds without near add were evaluated in 19 bilateral Synchrony patients. Reading acuity was significantly better at 2 years than at 1 year.
Long-Term Functional Vision with Synchrony Dual-Optic Accommodating IOL. Bohorquez VM, Alarcon R.
■ A retrospective analysis demonstrated evidence for the proposed mechanism of action of the Synchrony lens, an IOL designed for forward axial movement of the anterior optic with an accommodative effort that translates into dynamic optical power change and improved near vision. Subjective and objective measures of accommodation were compared in five Synchrony patients who had demonstrated good amplitude of accommodation. Accommodative changes in the anterior optic position were measured with UBM and sphero-cylindrical refractive change with wavefront aberrometry. While subjective methods showed slightly different values, mechanism of action of the IOL was confirmed by objective techniques.
Objective Evidence for Mechanism of Accommodation of the Synchrony Dual-Optic IOL. Koch DD, Alarcon R, Bohorquez VM, Kasturirangan S, Evans S, Vargas LG.
■ This study evaluated long-term binocular visual function in 17 patients implanted with the Synchrony. Patients were followed for 41 months to ascertain visual outcomes and stability of near vision effect. All subjects had UCVA of 20/40 or better for distance and intermediate vision, and 88% achieved that same level of uncorrected vision for near. UBM analysis for distance and near showed evidence of movement of the anterior optic of the IOL after stimulation of accommodation.
Long-Term Functional Performance After Dual-Optic Accommodating IOL Implantation. Galvis A, Galvis V.
More research on all of the above will no doubt be forthcoming. Stay tuned! OM
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