Refractive Lens Surgery

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62 S. Bylsma length),underwent full FDA clinical trial,leading to its approval in 1998. Data from the overall FDA study showed 76% of cases within 10 degrees, 88% within 20 degrees, and 95% within 30 degrees of the intended cylindrical axis. The uncorrected visual acuity (UCVA) of eyes with the STIOL was significantly improved compared to those that received the spherical IOL of similar design. Two years later, the FDA went on to designate the STIOL as a “new-technology” IOL due to its demonstrated improvement of UCVA in astigmatic patients when compared to a spherical IOL. Thereafter, the longer TL model was introduced in the lower diopter powers (£24 D) as a prophylactic against off-axis rotations in these larger myopic eyes. To date, both STIOL models have been widely evaluated [34–41]. These reports are quite consistent in demonstrating a predictable improvement in UCVA with the STIOL,yet they do differ widely in the occurrence of early off-axis rotation. In 2000, Sun and colleagues [35, 36] retrospectively compared 130 eyes that received the Staar AA-4203-TF to 51 eyes that received a spherical IOL with LRI. The STIOL was found to be superior to LRIs in producing UCVA of ≥20/40 (84% vs. 76%) as well as in reducing refractive cylinder to £0.75 D (55% vs. 22%) and to £1.25 D (85% vs. 49%). Twelve eyes (9%) underwent STIOL repositioning for off-axis rotation. That same year, Ruhswurm used only the +2.0-D toric power STIOL in 37 eyes with a mean preoperative refractive cylinder of 2.7 D and found 48% to achieve UCVA of 20/40 or better, with a reduction of refractive cylinder to 0.84 D postoperatively [37]. No cases of STIOL rotation greater than 30 degrees were observed, although 19% rotated up to 25 degrees. One year later, Leyland’s group used vector analysis software to calculate the magnitude of expected correction produced by the STI- OL in 22 eyes [38]. The group achieved 73% of the planned reduction of astigmatism, including the 18% of cases that experienced off-axis rotation by more than 30 degrees. In a smaller study of four eyes, a digital overlay technique was used to measure precisely the STIOL axis postoperatively; 75% of eyes were determined to be within 5 degrees and clinical slit-lamp estimates of axis were found to be quite precise in all cases [39]. All these reports exclusively studied the shorter TF model, as it was the only design available to the investigators at the time of their studies. More recent studies include data on the longer TL model. Till reported on 100 eyes and found a magnitude of reduction of 1.62 D for the +2.0-D toric power and 2.86 D for the +3.5- D power in the 89% of eyes that were observed to be within 15 degrees of the intended axis [40]. No difference in rotation rate between STIOL models was observed. In contrast, Chang compared the 50 cases receiving the longer TL model against the 11 receiving the shorter TF model and found a significant difference in rotation rates specifically for the TF group in the lower diopter range [41]. No case of rotation of more than 10 degrees was observed in any of the 50 eyes with the TL or in the five eyes with the higher-power TF.However, three of six eyes with the lower-power TF model required repositioning. This strongly suggests that lengthening the original (short) TF model in the lower power range (£24 D) may prove to be very beneficial in discouraging early off-axis rotations of the STIOL. In summary, the STIOL has been widely studied, with the reports showing a consistent, predictable effect of reduction of preoperative refractive cylinder for the group of eyes studied. The variability in the magnitude of correction of the STIOL in these numerous studies is not surprising, as the amount of refractive (spectacle) astigmatism correction of a given IOL varies with the overall refractive error of each patient [42]; myopes will achieve greater spectacle correction of astigmatism than hyperopes due to vertex-distance issues. Regardless, the STIOL has been clearly shown to be highly predictable in the correction of astigmatism at the time of refractive lens surgery.
Another consistent finding of these clinical studies is that, although each group of eyes studied shows good efficacy of mean cylinder reduction by the STIOL, a small percentage of individuals were found to experience an early significant off-axis rotation.The variability in these findings is likely multifactorial. First, earlier studies used the shorter STIOL exclusively (TF model), which is now thought to be of inadequate length for larger eyes [34–39]. Some later reports that included the TL model did not provide diopter-specific data on which TF cases underwent rotation [40]. Change provided the one study that detailed the diopter-specific results of each STIOL model, and the longer TL model in the lower diopter range showed no rotations [41], suggesting that recent design modifications of the STIOL may indeed improve future outcomes. Second, surgical technique varies among surgeons, including the completeness of viscoelastic removal between the STIOL and the posterior capsule. Third, the axis of implantation was marked on the eye preoperatively in the upright position by some investigators, while others used a Mendez gauge at the time of implantation; torsional rotation of the eye that occurs in the recumbent position may have produced mild misalignments in some cases. Next, a few cases of implantation on the improper axis were suspected in some reports, yet these eyes were included in the calculation of overall rate of STIOL malposition. Finally, and most obviously, there is clearly a tendency for the STIOL to rotate spontaneously within the capsule between the time of implantation and the first postoperative day examination. Regardless of the reasons for variability among rates of off-axis rotation, it is clear that occasional cases of off-axis alignments will be encountered. It is not known why some individuals experience spontaneous rotational malposition of the STIOL in the early postoperative period. Presumably there is a disparity in size between the capsule and the STIOL in some eyes. Larger capsules may be Chapter 7 Correction of Keratometric Astigmatism 63 found in myopic eyes as well as in cases of enlarged, hard, and more advanced 4+ nuclei [43, 44]. Other factors, including eye rubbing or digital compression, may play a role in some cases. Fortunately, these same clinical studies that document early malpositions also clearly demonstrate that repositioning of the off-axis STIOL after 1 or 2 weeks uniformly restores the desired effect, and late rotations are very rare. Other clinical studies have used the STIOL to correct excessive astigmatism with novel procedures. To correct excessive amounts of astigmatism, Gills combined LRIs with the STIOL or used multiple STIOLs in “piggyback” fashion [45–47]. Other suggestions that have not been well studied include placing a multifocal IOL in the sulcus as a piggyback over a bag-fixated toric IOL, or using toric IOLs to create pseudo-accommodation by leaving a residual refractive cylinder to aid in reading. In summary, these numerous clinical studies have clearly demonstrated the clinical results that can be expected when using the STIOL to produce improved UCVA in astigmatic eyes undergoing lens refractive surgery. We now turn our attention to the specific recommendations with which refractive lens surgeons must be familiar to achieve the best clinical outcomes for their patients. 7.4 Using the STIOL 7.4.1 Preoperative Issues One of the advantages of using the STIOL for the correction of astigmatism is that refractive lens surgeons must learn few new techniques or procedures. No significant changes to spherical IOL calculations are required,but a few specific steps must be taken to insure a successful outcome when using the STIOL. The first step is for surgeons to review recent cases and determine the keratometric changes that occur postoperatively in their
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Refractive Lens Surgery I. H. Fine
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Editors I. Howard Fine, MD Mark Pac
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Preface The first recorded time a h
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X Contents Chapter 14 AcrySof ReSTO
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Contributors Jorge L. Alio, MD, PhD
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1 The Crystalline Lens as a Target
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2 CORE MESSAGES Refractive Lens Exc
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na that have been observed with som
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piration through two separate incis
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6 R.S. Hoffman · I.H. Fine · M. P
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8 R.S. Hoffman · I.H. Fine · M. P
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10 R.S. Hoffman · I.H. Fine · M.
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Page 36 and 37: 22 J.T. Holladay 4.1 Introduction T
Page 38 and 39: 24 J.T. Holladay but only seven pre
Page 40 and 41: 26 J.T. Holladay from morning to ni
Page 42 and 43: 28 J.T. Holladay 4.3.2.2.3 Corneal
Page 44 and 45: 30 J.T. Holladay rienced this condi
Page 46 and 47: 32 J.T. Holladay many of these pati
Page 48 and 49: 34 J.T. Holladay IOL eRx V 1336 =
Page 50 and 51: 36 J.T. Holladay raised. A more tho
Page 52 and 53: 38 J.T. Holladay rior segment laser
Page 54 and 55: 40 D.D. Koch · L.Wang corneal refr
Page 56 and 57: 42 D.D. Koch · L.Wang Table 5.1. M
Page 58 and 59: 44 D.D. Koch · L.Wang Fig. 5.4. Nu
Page 60 and 61: 46 D.D. Koch · L.Wang Fig. 5.5. Ce
Page 62 and 63: 48 D.D. Koch · L.Wang ∑ Double-K
Page 64 and 65: 50 L.D. Nichamin surgeon the abilit
Page 66 and 67: 52 L.D. Nichamin Table 6.1. The Nic
Page 68 and 69: 54 L.D. Nichamin 3.2 mm, its neglig
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Page 72 and 73: 58 L.D. Nichamin References 1. Anon
Page 74 and 75: 60 S. Bylsma aphakic state. In cont
Page 78 and 79: 64 S. Bylsma K-Astigmatism
Page 80 and 81: 66 S. Bylsma STIOL in the reversed
Page 82 and 83: 68 S. Bylsma about the dynamics at
Page 84 and 85: 8 Correction of Keratometric Astigm
Page 86 and 87: Fig. 8.2. AcrySof toric IOL implant
Page 88 and 89: Fig. 8.3. Mean absolute residual cy
Page 90 and 91: References 1. Hoffer KJ (1980) Biom
Page 98 and 99: 10 The Eyeonics Crystalens Steven J
Page 100 and 101: Fig. 10.3. Under binocular conditio
Page 102 and 103: Fig. 10.6. Anterior movement of the
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Page 106 and 107: 10.6 Postoperative Considerations C
Page 108 and 109: 10. Dell SJ (2004) Objective eviden
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Page 122 and 123: 12 CORE MESSAGES Synchrony IOL H. B
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12.5 Clinical Results Clinical tria
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Fig. 12.6. Retroillumination photog
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References 1. Fisher RF (1973) Pres
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124 F.M. Sarfarazi 13.1 The Nature
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126 F.M. Sarfarazi Fig. 13.4. Lens
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128 F.M. Sarfarazi Fig. 13.5. Mecha
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130 F.M. Sarfarazi Fig. 13.9. Secon
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132 F.M. Sarfarazi Fig. 13.14. Sche
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134 F.M. Sarfarazi Fig. 13.18. Work
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136 F.M. Sarfarazi References 1. Ma
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138 A. Mirshahi · E.Terzi · T. Ko
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15 The Tecnis Multifocal IOL Mark P
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Fig. 15.1. The Alcon AcrySof multif
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Fig. 15.4. Multifocal vs. monofocal
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16 Blue-Light-Filtering Intraocular
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Fig. 16.2. Cultured human RPE cells
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tion to benefiting from less exposu
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16.7 Blue-Light-Filtering IOLs and
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15. Marshall J, Mellerio J, Palmer
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17 CORE MESSAGES The Light-Adjustab
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Fig. 17.2 a-c. Cross-sectional sche
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17.4 Animal Studies Dr. Nick Mamali
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Fig. 17.8. A laser interferogram (l
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enhanced visual function that remai
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13. Mather R, Karenchak LM, Romanow
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174 S. Norrby Fig. 18.1. Small cale
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176 S. Norrby Fig. 18.3. Scheimpflu
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178 S. Norrby Fig. 18.4. Schematic
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180 S. Norrby there was fibrin form
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182 S. Norrby material had a Young
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184 S. Norrby Koopmans et al. [28]
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186 S. Norrby 40. De Groot JH, Zuru
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188 L. Nordan · M. Morris regular
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190 L. Nordan · M. Morris produce
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20 CORE MESSAGES Bimanual Ultrasoun
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for an irrigating manipulator or ch
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5. Tsuneoka H, Shiba T, Takahashi Y
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200 J.L. Alio · A. Galal · J.-L.R
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22 CORE MESSAGES The Infiniti Visio
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Fig. 22.3. The AquaLase handpiece u
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23 CORE MESSAGES The Millennium Ros
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Fig. 23.1. Bausch & Lomb’s new cu
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Fig. 23.2. Advanced flow system car
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Fig. 23.5. Pulse or burst mode with
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24 CORE MESSAGES The Staar Sonic Wa
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Fig. 24.2. The tip undergoes compre
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the sonic tip moves back and forth
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25 CORE MESSAGES AMO Sovereign with
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Fig. 25.3. Schematic diagram of cav
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the Sovereign Compact (see Fig. 25.
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234 M. Packer · R.S. Hoffman · I.
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27 Conclusion: The Future of Refrac
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240 Subject Index Contrast sensitiv
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242 Subject Index P Pachymetry 53,
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