Refractive Lens Surgery

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12 CORE MESSAGES Synchrony IOL H. Burkhard Dick, Mana Tehrani, Luis G. Vargas, Stephen D. McLeod 2 The Synchrony IOL (Visiogen, Irvine, California) is a dual-optic, silicone,single-piece,foldable,accommodating IOL.The IOL features a 5.5-mm high-powered anterior optic connected to a 6.0-mm negative power optic by haptics. 2 The mechanism of accommodation potential is based on a lens complex formed by two optics linked by a spring system. 2 With accommodative effort, the zonules relax, releasing the tension on the capsular bag, thus allowing release of the strain energy stored in the interoptic articulations and anterior displacement of the anterior optic. 2 The Synchrony IOL has been implanted in more than 70 human eyes in different centers around the world. The lens has been safely implanted in the capsular bag after conventional phacoemulsification, with no major complications in the intra- and postoperative period. 2 The Synchrony dual-optic system represents a promising surgical option for cataract surgery and may enable an extended accommodative range. Accommodation in the youthful, phakic human eye is accomplished by contraction of the ciliary body and subsequent release in the resting tension of the zonular fibers by which the crystalline lens is suspended, resulting in increased lens curvature [1–3]. Presbyopia is defined as the progressive loss of accommodation amplitude producing compromised near function, and has been attributed to mechanical changes in the lens and capsule including changes in elastic property [1] and progressive circumferential enlargement of the crystalline lens [2, 3], weakening of the ciliary muscle [4], and loss of zonular and ciliary body effectiveness and elasticity [5, 6]. An excellent review of the variety of proposed mechanisms has been presented by Atchison [7].
114 H.B. Dick · M.Tehrani · L.G.Vargas, et al. 12.1 Surgical Restoration of Accommodation Although the mechanism of presbyopia remains incompletely understood, the weight of current evidence seems to suggest that, although some loss of ciliary body action might contribute to reduced accommodation [8], significant ciliary body function persists into advanced maturity, and that loss of lens and capsule elasticity in concert with changes in the geometry of zonular attachments are probably most culpable in producing the distress of presbyopia [9]. If so, then replacement of the crystalline lens with a lens that responds to ciliary body contraction should restore accommodative function. Attempts have been made to replace the crystalline lens by refilling the capsular bag with appropriately deformable gels [8, 10, 11]. However, this approach is limited by the intrinsic mechanical instability of such materials that at the moment cannot be expected to retain a specific shape (and thus optical power) over time while sustaining a rapid, constant, and predictable response to equatorial tension as demanded by the dynamics of accommodation. 12.2 Axial <strong>Lens</strong> Movement The principle of axial lens movement has been adopted by more recent accommodating intraocular lens (IOL) designs. For example, the AT-45 (Crysta<strong>Lens</strong>, Eyeonics Inc., Aliso Viejo, CA, USA) is a hinged single-optic IOL that is intended to be implanted with posterior vault. Cummings et al. reported the results of early clinical trials with this IOL design, in which varying degrees of near function were described in subjects following implantation [10]. Near function was ascribed to anterior axial displacement of approximately 0.7 mm (Cumming; unpublished data, 1989) and corresponding conjugation power change postulated by the authors to result from increased vitreous pressure. Küchle and co-workers [11] have recently reported clinical results of a more anteriorly positioned posterior chamber lens, the accommodative 1CU (HumanOptics, AG, Erlangen, Germany), also designed to undergo anterior axial displacement with accommodative effort. A mean retinoscopic accommodative range of 1.2 D (SD: 0.4) was achieved in these patients, and pharmacologically induced accommodation by instillation of pilocarpine produced a mean change of 0.63 mm (SD: 0.16) in anterior chamber depth. If these measurements are correct, the amount of excursion generated (usually between 0.4 and 0.7 mm) limits the accommodative range of a single-optic design. 12.3 Dual Optics Recognizing these limitations, Hara et al. proposed refilling the capsular bag with a rigid shell, described as two lenses 8 mm in diameter connected by a polypropylene coil spring [8]. This design was later replaced by a pair of inflexible polymethylmethacrylate optics, 6 mm in diameter, connected by four peripheral closed polyvinylidene fluoride flexible loops separating the optics by 3.0 mm. The posterior optic was assigned no optical power, and change in the conjugation power of the eye was achieved by anterior and posterior movement of the anterior lens to which was assigned the full optical power of the lens system [12]. Visiogen Inc. (Irvine, California) has developed a dual-optic, silicone, single-piece, foldable, accommodating lens called Synchrony. The IOL features a 5.5-mm high-powered anterior optic connected to a 6.0-mm negative power optic by haptics that have a spring-like action (Fig. 12.1). In order to respond to ciliary body action, energy must be stored and released in the system. The mechanism of action of this lens is based on a lens complex formed by two optics linked by a
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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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12 M. Packer · I.H. Fine · R.S. H
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22 J.T. Holladay 4.1 Introduction T
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24 J.T. Holladay but only seven pre
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26 J.T. Holladay from morning to ni
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28 J.T. Holladay 4.3.2.2.3 Corneal
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30 J.T. Holladay rienced this condi
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32 J.T. Holladay many of these pati
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34 J.T. Holladay IOL eRx V 1336 =
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36 J.T. Holladay raised. A more tho
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38 J.T. Holladay rior segment laser
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40 D.D. Koch · L.Wang corneal refr
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42 D.D. Koch · L.Wang Table 5.1. M
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44 D.D. Koch · L.Wang Fig. 5.4. Nu
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46 D.D. Koch · L.Wang Fig. 5.5. Ce
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48 D.D. Koch · L.Wang ∑ Double-K
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50 L.D. Nichamin surgeon the abilit
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52 L.D. Nichamin Table 6.1. The Nic
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54 L.D. Nichamin 3.2 mm, its neglig
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56 L.D. Nichamin Fig. 6.4. The Nich
Page 72 and 73: 58 L.D. Nichamin References 1. Anon
Page 74 and 75: 60 S. Bylsma aphakic state. In cont
Page 76 and 77: 62 S. Bylsma length),underwent full
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 92 and 93: 80 M. Packer · I.H. Fine · R.S. H
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
Page 104 and 105: Fig. 10.7. One- and 3-year data fro
Page 106 and 107: 10.6 Postoperative Considerations C
Page 108 and 109: 10. Dell SJ (2004) Objective eviden
Page 110 and 111: 100 N.X. Nguyen · A. Langenbucher
Page 124 and 125: Fig. 12.1. The single-piece silicon
Page 126 and 127: 12.5 Clinical Results Clinical tria
Page 128 and 129: Fig. 12.6. Retroillumination photog
Page 130 and 131: References 1. Fisher RF (1973) Pres
Page 132 and 133: 124 F.M. Sarfarazi 13.1 The Nature
Page 134 and 135: 126 F.M. Sarfarazi Fig. 13.4. Lens
Page 136 and 137: 128 F.M. Sarfarazi Fig. 13.5. Mecha
Page 138 and 139: 130 F.M. Sarfarazi Fig. 13.9. Secon
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Page 142 and 143: 134 F.M. Sarfarazi Fig. 13.18. Work
Page 144 and 145: 136 F.M. Sarfarazi References 1. Ma
Page 146 and 147: 138 A. Mirshahi · E.Terzi · T. Ko
Page 152 and 153: 15 The Tecnis Multifocal IOL Mark P
Page 154 and 155: Fig. 15.1. The Alcon AcrySof multif
Page 156 and 157: Fig. 15.4. Multifocal vs. monofocal
Page 158 and 159: 16 Blue-Light-Filtering Intraocular
Page 160 and 161: Fig. 16.2. Cultured human RPE cells
Page 162 and 163: tion to benefiting from less exposu
Page 164 and 165: 16.7 Blue-Light-Filtering IOLs and
Page 166 and 167: 15. Marshall J, Mellerio J, Palmer
Page 168 and 169: 17 CORE MESSAGES The Light-Adjustab
Page 170 and 171: 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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