Premium IOL Update
Cataract surgeons bring their insights to the 2010 ASCRS meeting
By René Luthe, Senior Associate Editor
At last month's ASCRS meeting, researchers continued in their quest to make premium IOLs work better for both physicians and their patients. Here is a sampling of their insights on how to meet the clinical challenges these lenses pose. Of course, rarely is any one study definitive on the finer points of IOL performance, so it's prudent to be conservative when interpreting their impact on clinical practice.
■ Influences on visual performance of Crystalens 5.0 and HD. This study compared the effect of postop atropine, YAG capsulotomy, spherical aberration, defocus and pupil size on near visual performance with the Crystalens 5.0 and the Crystalens HD. The researcher summarized the results of four studies involving the two single-optic accommodating IOLs.
The atropine segment sought to ascertain whether immediate postop atropine enhanced long-term near or intermediate visual function for the Crystalens HD, examining 127 eyes implanted with the lens. Sixty-four eyes received atropine immediately postoperatively and 63 did not; follow-up was at six and at 12 months. At six months, the nondistance corrected data suggested an advantage for the atropine-treated eyes, especially with intermediate vision where the mean Jaeger values were significantly lower.
At 12 months, the percentage of patients achieving each J1 through J6 visual milestone for the distance-corrected near and intermediate vision was greater in the atropine eyes versus the non-atropine eyes. The 12 month mean Jaeger values for intermediate distance corrected vision was also significantly better for the atropine eyes. The data clearly supported superior long-term near and intermediate vision in eyes having received atropine.
The post-YAG capsulotomy study analyzed spherical shifts at least one month after YAG capsulotomies vs. immediate pre-YAG. For the Crystalens 5.0, 54 eyes were examined; for the HD, 60 eyes were examined. The mean spherical shift per eye for all patients with both IOLs was +0.23 D. Half-diopter shift analysis revealed a hyperopic shift in 43% and a myopic shift in 11.4% of patients, again for the 5.0 and HD combined. As for +0.75 D shifts, 22.8% of all eyes showed this, and 26.6% of the HD eyes did. In the category of +1.00 D shifts, 14% of all eyes resulted in this shift and 18.3% of HD eyes. Surgeons must be aware of the potential for a hyperopic shift following YAG when choosing their preoperative refractive targets, the researcher said, and delay the correction of residual refractive errors until after YAG laser capsulotomies are performed in patients implanted with a Crystalens IOL.
Examining the question of whether the HD optics provided "significantly greater" near and intermediate vision than the 5.0, the researcher studied 111 HD-implanted eyes and 86 Crystalens 5.0-implanted eyes, with follow-up at six and 12 months. "Our data does not support a consistent advantage for HD vs. 5.0 for near and intermediate beyond what was produced by half of the HD eyes that received atropine," Frank A. Bucci, Jr., MD, concluded.
Effects of Postoperative Atropine, YAG Capsulotomy, Spherical Aberration, Defocus and Pupil Size on Near Visual Performances of Models of Blended Hinged Accommodating IOLs. Bucci FA.
■ Visual function for the Crystalens and ReStor. The ongoing, nonrandomized, unmasked prospective study examined 98 eyes in 49 patients to describe the visual function and degree of spectacle independence of patients with bilateral accommodating IOLs and bilateral multifocal IOLs. Patients without previous ocular surgery or visually significant preoperative comorbidities received either the Crystalens HD or the ReStor D1. The key outcomes measure were responses to a questionnaire, with data collected at one month, three to six months, 12 months and 24 months postoperatively.
Thirty-eight eyes got the Crystalens HD; mean postoperative spherical equivalents were −0.69 ± 0.59; mean postop cylinder was 0.65 ± 0.54 D. Limbal relaxing incisions occurred in 50% of eyes; mean follow-up: 7.6 months.
Sixty eyes were implanted with the ReStor D1; mean post-operative spherical equivalents were −0.07 ± 0.40; postop cylinder was 0.50 ± 0.33 D and 40% of eyes required limbal relaxing incisions. Mean follow-up was 4.7 months. Patients rated their degree of spectacle independence.
Patients implanted with the Crystalens HD who answered "never" or "almost never" for the following activities: 79% for day driving, 68% for night driving, 83% for computer use and 83% for reading books. For ReStor D1 patients the scores were: 93% for day driving, 89% for night driving, 88% for computer use and 79% for reading books.
When asked how long they could comfortably use a computer, 11% of Crystalens HD patients replied less than 10 minutes, 89% said 10-30 minutes, 79% said more than one hour and 68% said more than two hours. The scores for ReStor D1 patients were 5%, 95%, 80% and 70%, respectively. For reading, 11% of Crystalens HD patients said less than 10 minutes, 89% said 10 to 30 minutes, 63% said more than one hour and 53% said more than two hours. None of the ReStor D1 patients said less than 10 minutes, while 100% said 10 to 30 minutes, 67% said more than one hour and 57% said more than two hours.
When asked how they would rate satisfaction with their visual results on a scale of one to 10 (dissatisfied to extremely satisfied), Crystalens HD's score was 7.59 ± 2.12; ReStor D1's was 8.67 ± 2.23. When asked if the results of the procedure had met, exceeded or fallen short of the patient's expectations, 68% of Crystalens HD patients replied that it met or exceeded. For ReStor D1, 80% said the procedure met or exceeded expectations. Investigator Jonathan M. Davidorf, MD, concluded that the ReStor D1 appears more predictable at delivering a wide range of vision and that the planned slight myopic endpoint likely detracts from the distance vision results for the Crystalens HD.
Functional Vision with Presbyopic IOLs: Acrylic Aspheric Apodized Diffractive Multifocal IOL and Silicone-Blended Hinged Accommodating IOL. Davidorf JM.
■ Accommodation and the Synchrony. Subjective tests were performed on five Synchrony patients at one, two and three years. Researchers evaluated distance-corrected near visual acuity, push-down accommodative amplitude, and defocus curve (−3.0 D to +1.5 D in 0.5 D steps) with distance correction in place. Mean distance-corrected near VA was 20/20 or better at three years; push-down testing showed approximately 3D of accommodation.
Additionally, two different objective testing techniques were used to evaluate the accommodation of the Synchrony. High-definition UBM was able to show movement of the anterior optic with an accommodative stimulus opposite the fellow eye. At the two and three year follow-up intervals, wavefront aberrometry with the iTrace demonstrated an objective refractive change when a near target was given. The iTrace measurements were performed under lighting conditions that gave a 3-mm pupil diameter and cycloplegic measurements were compared to those taken with a near stimulus for each patient. Objective iTrace measurements of accommodation at both two years and three years was a mean of 2.94 D. This correlated with the mean subjective accommodative amplitude of 2.83D push-down test and 20/20 distance-corrected near visual acuity.
3-year Postop Objective Evidence for Accommodation with Synchrony Dual Optic IOL. Chang DF, Alarcon R, Bohorquez V.
■ Postoperative astigmatism and the Crystalens HD. An evaluation of the effect of postoperative astigmatism on visual acuity outcomes in patients implanted with the Crystalens HD studied results in 900 eyes. Unintended residual spherical error is a major cause of patient dissatisfaction and spectacle dependence with presbyopia-correcting implants, the researchers note. "Residual astigmatism occurs when surgeons do not perform limbal relaxing incisions or otherwise address corneal astigmatism ≥0.75 diopters," investigator John A. Hovanesian, MD, says.
For eyes with 0 to 0.5 D of cylinder, the mean distance UCVA was 20/22; the mean near UCVA was 20/38. For eyes with 0.75 to 1.00 D cylinder, however, mean distance UCVA was 20/33 and mean near UCVA 20/48. "Residual astigmatism ≥0.75 diopter causes an otherwise acceptable visual result to be unsatisfactory to the patient," says Dr. Hovanesian. Both researchers concluded that maintaining postoperative astigmatism below 0.75 D results in significantly better uncorrected visual acuity at all distances, and that surgeons implanting accommodating IOLs need a predictable method of reducing corneal astigmatism to this level in order to satisfy patients.
Effect of Astigmatism on Visual Acuity Outcomes in Eyes Implanted with a Presbyopia-Correcting IOL. Hovanesian JA, Kerzirian GM.
Also presented were data on the unique Calhoun Light Adjustable Lens, which just completed enrollment for US phase 2 clinical trials. In a study by Dr. Fritz Hengerer of Germany, 86% of eyes with the Light Adjustable Lens saw 20/20 one year after surgery.
"With standard IOLs and premium IOLs, only about 30 to 40% of eyes are 20/20," Dr. Maloney says.
IOLs to Use in Post-Refractive Eyes. Maloney RK.
■ Uncorrected distance and near vision for two presbyopiacorrecting IOLs. This interim analysis of an ongoing study evaluates patient satisfaction and uncorrected vision at distance and near. "I studied the lenses that were the ones most frequently used in 2009, the three-piece Tecnis multifocal and the Crystalens HD," Dr. Packer explains. He evaluated patients according to use of spectacle correction, a visionrelated quality of life questionnaire, manifest refraction, dark adaptation, photopic and mesopic pupillometry, uncorrected and best distance-corrected photopic visual acuity testing at distance, intermediate and near, and uncorrected and best distance-corrected mesopic visual acuity testing at distance, intermediate and near. Fifty subjects are included in the study; the interim analysis reported on 20 of them. Patients' mean post-op spherical equivalent was −0.07 D; mean cylinder was 0.36 D.
In terms of patient satisfaction, 62% of Tecnis patients reported that reading small print in dim light was "easy" or "very easy" vs. 0% for the Crystalens. When asked about working on a computer, 83% of Crystalens patients rated the task either "easy" or "very easy," vs. 69% for the Tecnis. As for seeing objects far away, 84% rated the Crystalens "easy" or "very easy," vs. 92% for the Tecnis.
At this point in the study, Dr. Packer reports finding no significant differences in satisfaction with vision, use of spectacles or contact lenses, or convenience. "Under both photopic and mesopic conditions, Tecnis may provide better visual acuity at near, while under mesopic conditions, Crystalens may provide better visual acuity at intermediate," Dr. Packer concludes.
Comparative Study of Visual Acuity, Spectacle Independence and Patient Satisfaction with the Aspheric Diffractive Multifocal IOL and Blended Aspheric Hinged Accommodating IOL. Packer M.
■ Presbyopia-correcting IOLs and image quality. Six FDA-approved presbyopia-correcting IOLs were studied for imaging properties by examining the image quality through a range of object vergences and through various pupil diameters. The IOL models were the ReStor +4, ReStor +4 Aspheric, ReStor +3 Aspheric, ReZoom, Tecnis MF acrylic and Crystalens HD.
The lenses were placed in an anatomically and optically accurate model eye at four pupil diameters: 2, 3, 4 and 5 mm. For each combination of IOL model, pupil diameter and object vergence setting, a USAF target was imaged through the model eye and captured digitally. The sharpness of each digital image was objectively scored using a two-dimensional gradient function, and then the image quality score vs. object vergence was plotted for each IOL model and pupil diameter.
"We looked at these sharpness metrics, which we took from photography," Dr. Pepose explains. Used in auto-focus cameras, the metrics determine when the image is in focus, doing a pixel-to-pixel comparison. "They come up with different mathematical algorithms and the best ones have only one solution," Dr. Pepose explains. "We found that each lens worked in a really different way in terms of sharpness metrics at different pupil sizes and object distances."
His findings for each IOL: Crystalens HD offered the best distance image quality for all pupil diameters and only one point of best focus (monofocal) with broad depth of field asymmetrically biased toward near; the Tecnis MF offered consistent performance for all pupil diameters, and worse distance but better near image quality than ReStor +4/+3 when pupil diameter is large (and lower near image quality when pupil is small); ReStor showed better distance and worse image quality as pupil diameter increases, and worse distance and near image quality for ReStor +3 than ReStor +4; the ReZoom showed good distance when the pupil is small, but poor when it is large, as well as worse near image quality than other multifocal models.
Comparison of Through-Focus Image Quality Across Six Presbyopia-Correcting IOLs. Pepose JS.
■ Crystalens AO performance. The study evaluated monocular and binocular uncorrected distance, intermediate and near visual acuity; monocular and binocular BCDVA; monocular and binocular distance-corrected intermediate and near VA, and postop refraction compared to intended target. For monocular UCDVA, 95% of eyes achieved 20/40 or better, 85% achieved 20/30 or better, 64% achieved 20/25 or better and 47% achieved 20/20 or better.
For monocular UCIVA, 100% of eyes achieved both 20/40 and 20/30 or better, and 95% achieved both 20/25 or 20/20 or better. Monocular UCNVA scores were 92% J3 or better, 87% J2 or better, and 54% J1 or better.
Binocular acuities at least one month postop in 53 eyes were 70% at 20/20 or better for distance, 94% for intermediate and 62% for near. At 20/25 or better, the numbers were 91% for distance, 98% for intermediate and 92% for near. One hundred percent of eyes achieved 20/30 or better acuity for both intermediate and near, while 96% achieved that for distance.
"The real surprise in clinical trials was the high rate of 20/25+ near vision in binocularly implanted patients," Dr. Whitman says. "This, combined with less fibrosis issues than previous models, makes this lens a great addition to the premium surgeon's armamentarium." OM
Crystalens AO. Whitman J. ASCRS 2010.
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