Ординатура / Офтальмология / Английские материалы / Master Techniques in Cataract and Refractive Surgery_Hampton Roy, Arzabe_2004

37.Pallikaris IG, Papatzanaki ME, Stathi EZ, et al. Laser in situ keratomileusis. Lasers Surg Med. 1990;10(5):463-8.

38.Krueger RR, Parolini B, Gordon EI, et al. Nonmechanical microkeratomes using laser and waterjet technology. In: Pallikaris IR, Siganos DS, eds. LASIK. Thorofare, NJ: SLACK Incorporated; 1998:81-105.

39.Ratkay-Traub I, Juhasz T, Horvath C, et al. Ultra-short pulse (femtosecond) laser surgery. Initial use in LASIK flap creation.

Ophthalmol Clin North Am. 2001;14(2):347-55.

40.Moreno-Barriuso E, Lloves JM, Marcos S, et al. Ocular aberrations before and after myopic corneal refractive surgery: LASIK-induced changes measured with laser ray tracing.

Invest Ophthalmol Vis Sci. 2001;42(6):1396-403.

41.Mrochen M, Krueger RR, Bueeler M, et al. Aberration-sens- ing and wavefront-guided laser in situ keratomileusis: management of decentered ablation. J Refract Surg. 2002;18(4): 418-29.

42.Davis EA, Hardten DR, Lindstrom RL. LASIK complications. Int Ophthalmol Clin. 2000;40(3):67-75.

43.Lin RT, Maloney RK. Flap complications associated with lamellar refractive surgery. Am J Ophthalmol. 1999;127(2): 129-36.

44.Wilson SE, Ambrosio R. Laser in situ keratomileusis-induced neurotrophic epitheliopathy. Am J Ophthalmol. 2001;132(3): 405-6.

45.Nng RT, Dartt DA, Tsubota K. Dry eye after refractive surgery. Curr Opin Ophthalmol. 2001;12(4):318-22.

46.Kaufman SC. Post-LASIK interface keratitis, Sands of the Sahara syndrome, and microkeratome blades. J Cataract Refract Surg. 1999;25:603-4.

47.Kaufman SC, Maitchouk DY, Chiou AG, Beuerman RW. Interface inflammation after laser in situ keratomileusis. Sands of the Sahara syndrome. J Cataract Refract Surg. 1998;24: 1589-93.

48.Chao CW, Azar DT. Lamellar keratitis following laser-assisted in situ keratomileusis. Ophthalmol Clin North Am. 2002; 15(1):35-40.

49.Shah MN, Misra M, Wihelmus KR, Koch DD. Diffuse lamellar keratitis associated with epithelial defects after laser in situ keratomileusis. J Cataract Refract Surg. 2000;26(9):1312-8.

50.Linebarger EJ, Hardten DR, Lindstrom RL. Diffuse lamellar keratitis: diagnosis and management. J Cataract Refract Surg. 2000;26:1072-7.

51.Linebarger EJ, Hardten DR, Lindstrom RL. Diffuse lamellar keratitis: identification and management. Int Ophthalmol Clin. 2000;40:77-86.

52.Wang MY, Maloney RK. Epithelial ingrowth after laser in situ keratomileusis. Am J Ophthalmol. 2000;129(6):746-51.

53.Ruiz LA, Slade SG, Updegraff SA, Doane JF, Moreno ML, Murcia A. A single center study to evaluate the efficacy, safety and stability of laser in situ keratomileusis for low, moderate, and high myopia with and without astigmatism. In: Yanoff M, Duker JS. Ophthalmology. 1st ed. London: Mosby International; 1999.

54.Lindstrom RL, Hardten DR, Chu YR. Laser in situ keratomileusis (LASIK) for the treatment of low, moderated and high myopia. Trans Am Ophthalmol Soc. 1997;95:285-96; discussion 296-306.

55.Perez-Santonja JJ, Bellot J, Claramonte P, et al. Laser in situ keratomileusis to correct high myopia. J Cataract Refract Surg. 1997;23(3):372-85.

56.Lyle WA, Jin GJ. Laser in situ keratomileusis with the VISX Star laser for myopia over -10.0 diopters. J Cataract Refract Surg. 2001;27(11):1812-22.

57.Koch D. Six-month results of the multi-center wavefront LASIK trial. Paper presented at: American Society of Cataract and Refractive Surgery Annual Symposium and Congress; June 1-5, 2002; Philadelphia, PA.

58.Claringbold II TV. Laser-assisted subepithelial keratectomy for the correction of myopia. J Cataract Refract Surg. 2002; 28(1):18-22.

59.Azar DT, Ang RT, Lee JB, et al. Laser subepithelial keratomileusis: electron microscopy and visual outcomes of flap photorefractive keratectomy. Curr Opin Ophthalmol. 2001;12(4):323-8.

60.Chen CC, Chang JH, Lee JB, et al. Human corneal epithelial cell viability and morphology after dilute alcohol exposure.

Invest Ophthalmol Vis Sci. 2002;43(8):2593-602.

61.Dreiss AK, Winkler Von Mohrenfels C, Gabler B, et al. Laser epithelial keratomileusis (LASEK): histological investigation for vitality of corneal epithelial cells after alcohol exposure. Klin Monatsbl Augenheilkd. [Abstract]. 2002;219(5):365-9.

62.Lee JB, Seong GJ, Lee JH, et al. Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia. J Cataract Refract Surg. 2001;27(4):565-70.

63.Camellin M, Cimberle M. LASEK technique promising after 1 year of experience. Ocular Surgery News. 2000;18(1)14-17.

INTRODUCTION

Presbyopia remains one of the great unsolved challenges in ophthalmology. Ever since von Helmholtz, much research has been conducted concerning mechanisms of accommodation, presbyopia, and potential solutions.

Despite excellent restoration of visual acuity and good biocompatibility of presently used posterior chamber intraocular lenses (PCIOL), there is no accommodation in pseudophakic eyes so that patients usually remain presbyopic after cataract surgery. This problem has only partly been solved by the introduction of diffractive and bifocal PCIOL. Thus, efforts are being undertaken to develop PCIOL that restore accommodation. A new accommodative PCIOL (1 CU, HumanOptics, Erlangen, Germany) has been designed after principles elaborated by Hanna. As of October 2002, this PCIOL has been implanted in over 100 human eyes in our department.

DEFINITIONS

In the literature, various terms such as accommodation, pseudoaccommodation and apparent accommodation are being used interchangeably with regard to pseudophakic eyes. We define pseudophakic accommodation as dynamic change of the refractive state of the pseudophakic eye caused

by interactions between the contracting ciliary muscle and the zonules—capsular bag—IOL, resulting in change of refraction at near fixation. Furthermore, we define pseudophakic pseudoaccommodation (apparent accommodation) as static optical properties of the pseudophakic eye independent of the ciliary muscle, resulting in improved uncorrected near vision.

ANATOMY AND DESCRIPTION

OF THE 1 CU ACCOMMODATIVE

INTRAOCULAR LENS

Several studies using impedance cyclography, ultrasound biomicroscopy, and magnetic resonance imaging have shown that the ciliary body retains much of its contractility in older patients. Furthermore, modern technology allows refined finite element computer methods to simulate the changes of the ciliary body-zonular lens apparatus during accommodation. Based on concepts by Hanna and on finite element computer simulation models, a new acrylic hydrophilic foldable single-piece PCIOL has been designed and manufactured (1 CU) (Figure 13-1). The 1 CU PCIOL is designed to allow transmission of the contracting forces of the ciliary body into anterior movement of the lens optic to achieve pseudophakic accommodation. This optic shift principle

Figure 13-1. Schematic drawing of the 1 CU accommodative IOL.

should allow a defined amount of accommodation, theoretically 1.6 D to 1.9 D per 1 mm anterior movement of the PCIOL optic (Figures 13-2 and 13-3). The spherical optic has a diameter of 5.5 mm, with a total diameter of the PCIOL of 9.7 mm. The lens haptics are modified with transmission elements at their fusion with the lens optic. In earlier laboratory studies in porcine eyes and human donor eyes not suitable for corneal transplantation, we have refined methods for intraocular implantation of this PCIOL. The 1 CU PCIOL is CE-approved.

Figure 13-2. Localization of the 1 CU accommodative IOL in the capsular bag.

INDICATIONS AND

CONTRAINDICATIONS

At present, only patients with cataract (ie, clinically manifest and visually disturbing lens opacities) are candidates for lens exchange with implantation of the 1 CU accommodative IOL. Up to now, only patients older than 30 years have undergone this surgical option. In our opinion, there is no upper age limit.

Up to now and until there is more experience with 1 CU PCIOL and longer follow-up, we carefully observe exclusion criteria including manifest diabetic retinopathy, previous intraocular surgery, previous severe ocular trauma involving the lens, the zonules or the ciliary body, visible zonulolysis, phacodonesis, pseudoexfoliation syndrome, glaucoma, uveitis, high myopia, and high hypermetropia.

Furthermore, this kind of surgery will not result in satisfying clinical results in patients with severe ARMD or marked glaucomatous optic atrophy.

In case of problems during cataract surgery such as radial tears of the capsulorrhexis, diameter of capsulorrhexis >5.5 mm, zonulolysis, rupture of the posterior capsule, or vitreous loss, the 1 CU accommodative IOL should not be implanted and surgery should be converted to implantation of a conventional PCIOL.

Figure 13-3. Localization of the 1 CU accommodative IOL in the capsular bag.

SURGICAL TECHNIQUES

Generally, any of the modern small-incision phacoemulsification techniques may be used to remove the lens nucleus and lens cortex before the 1 CU accommodative intraocular lens is to be implanted.

Anesthesia

Surgery may be safely performed under local or topical anesthesia. The surgeon may choose the methods that he is most comfortable with for cataract surgery. No specific modifications of anesthesia are necessary for implantation of the 1 CU accommodative IOL.

Figure 13-5. Cartridge used for implantation of the 1 CU accommodative IOL.

Procedure (General)

Phacoemulsification of the lens nucleus and cortical cleaning is not much different from routine cataract surgery. The surgeon may choose the incision and phacoemulsification technique that he routinely uses for cataract surgery. Either a clear cornea or a sclerocorneal incision may be used. If possible, the incision should be placed in the steepest corneal meridian to reduce any preexisting corneal astigmatism. The capsulorrhexis is of great importance; it should be small enough (maximum 5.0 mm) to safely and circularly cover the peripheral optic of the IOL (diameter 5.5 mm). In addition, the capsulorrhexis should be round and well centered to allow for the elastic forces of the zonules and lens capsule to be equally distributed. Meticulous removal of all lens cortex and polishing of the posterior lens capsule is important to reduce the risk of capsular fibrosis and posterior capsular opacification. Any of the commercially available viscoelastic agents may be used.

Procedure (Specifics)

Implantation and placement of the 1 CU accommodative IOL is the main step of the surgical procedure. It differs in

Figure 13-4. Injector used for implantation of the 1 CU accommodative IOL.

some aspects from implantation of standard IOLs but is relatively easily accomplished. IOL implantation is best performed with a cartridge and an injector (Figures 13-4 and 13-5). Folding and implantation with a forceps is also possible but may be associated with an increased risk of damaging the thin and delicate lens haptics. An incision width of 3.2 mm is usually sufficient. The 1 CU accommodative IOL is placed into the cartridge with the edges of the haptics pointing upward/anterior. When folding the lens inside the cartridge, care should be taken to avoid damage to the haptics. After completely filling the anterior chamber and the capsular bag with a viscoelastic agent, the lens is then implanted into the anterior chamber or directly into the capsular bag. In case the lens optic is placed in front of the capsular bag, it may be easily pressed down into the capsular bag with a cannula or a spatula. Then the 4 lens haptics are unfolded inside the capsular bag with a push-pull hook or an iris spatula. The viscoelastic agent should be completely removed also from behind the lens to prevent development of capsular block or capsular distension syndrome that might theoretically develop otherwise because of the relatively small size of the capsulorrhexis. The lens haptics should be placed at the 12-, 3, 6-, or 9-o’clock positions.

Postoperative

Postoperative care and medications are similar to that of routine cataract surgery. Postoperative medication usually includes topical antibiotics, topical corticosteroids, and topical short-acting mydriatics such as tropicamide.

Our current postoperative regime includes combined antibiotic and corticosteroid eye drops (dexamethasone sodium phosphate 0.03% and gentamicin sulfate 0.3%) twice daily and tropicamide 0.5% twice daily. After 5 days, the combined antibiotic/steroidal eye drops are discontinued and changed to prednisolone acetate 1% eye drops 5 times a day for 4 weeks. The tropicamide eye drops are also discontinued after 4 weeks. No atropine is used.

Figure 13-6. Cartridge and injector used for implantation of the 1 CU accommodative IOL.

OUTCOMES

Safety

Pilot studies have shown that the 1 CU PCIOL is safe for at least up to 2 years. We observed very little postoperative breakdown of the blood-aqueous barrier. No lens-specific complications were seen. No signs of decentration or dislocation were detected (Figure 13-6). The rate of posterior capsular opacification appears to be low (ie, not higher than in other types of PCIOL made of hydrophilic acrylate).

Stability

Prospective studies that followed patients with the 1 CU PCIOL showed that refraction, anterior chamber depth, and accommodative range all remained stable without signs indicating a systemic trend toward myopia, hypermetropia, PCIOL dislocation, or regression of accommodative properties. Thus, the 1 CU accommodative PCIOL provides stable refraction, accommodation, and PCIOL position also for longer time periods for at least up to 1 year (Figure 13-7).

Accommodation

We used several objective and subjective methods to measure pseudophakic accommodation after implantation of the 1 CU PCIOL.

1.Measurement of movement of the 1 CU lens optic with the IOL Master (Zeiss, Germany) after stimulation or relaxation of the ciliary muscle with eye drops. After pilocarine eye drops, a mean anterior movement of the lens optic of 0.63 ±0.16 mm in contrast to 0.15

Figure 13-7. Transillumination photograph of 1 CU localized in the capsular bag 1 year after implantation.

±0.05 mm in conventional control PCIOL was measured. Following relaxation of the ciliary muscle with cyclopentolate eye drops, a mean posterior movement of the 1 CU optic of 0.42 ±0.18 mm was determined versus 0.11 ±0.06 mm in control PCIOL. These findings indicate the proof of concept of the optic shift principle of this accommodative PCIOL.

2.Determination of accommodative range. We used several methods to measure pseudophakic accommodation. These methods included near point determination with an accommodometer (a), defocusing with minus lenses (b), and retinoscopy during near and distance fixation (c). Six-month results with the 1 CU PCIOL showed mean accommodative ranges of 1.83 D (a), 1.85 D (b), and 0.98 D (c). In comparison with a control group with conventional PCIOL, accommodative range was significantly greater in the 1 CU group, the difference being 0.67 D (a), 1.21 D (b), and 0.81 D (c).

3.Near visual acuity. Uncorrected or distance-corrected near visual acuity alone as the main outcome measure is problematic. Near visual acuity is severely influenced by a large number of factors. Determination of near visual acuity is troubled by inadequate bedside screening charts such as the Rosenbaum chart and the availability of several versions of inaccurate near reading charts. On most of these near reading charts, the optotypes are not scaled properly to the Snellen system, resulting in overestimation of near visual acuity by the Jaeger system. We use for standardized testing Birkhäuser reading charts in 35 cm and best distance correction. With this method, median near visual acuity with the 1 CU PCIOL was 0.4 versus 0.2 in control PCIOL.

Future Research

After very encouraging results of pilot studies, presently a prospective multicentric randomized masked study is being conducted comparing accommodative and near vision results of the 1 CU PCIOL with those of a control PCIOL (Rayner RaySoft, East Sussex, United Kingdom).

Future research should be directed to further improving the optical and accommodative results of this new generation of accommodative PCIOL.

BIBLIOGRAPHY

Bacskulin A, Gast R, Bergmann U, Guthoff R. Ultraschall-bio-

mikroskopische Darstellung der akkommodativen Konfig-

urationsänderungen des presbyopen Ziliarkörpers.

Ophthalmologe. 1996;93:199-203.

Glasser A, Kaufman PL. The mechanism of accommodation in primates. Ophthalmology. 1999;106:863-72.

Horton JC, Jones MR. Warning on inaccurate Rosenbaum charts for testing near vision. Surv Ophthalmol. 1997;42:169-74.

Kommerell G. Strichskiaskopie: Optische Prinzipien und praktische Empfehlungen. Klin Monatsbl Augenheilkd. 1993;203:10- 8.

Küchle M, Gusek GC, Langenbucher A, Seitz B. First and preliminary results of a new posterior chamber intraocular lens. Online J Ophth. Available at http://www.onjoph.com/ deutsch/artikel/pciol.html. Retrieved November 12, 2003.

Küchle M, Gusek-Schneider GC, Langenbucher A, Seitz B, Hanna KD. Erste Ergebnisse der Implantation einer neuen, potenziell akkommodierbaren Hinterkammerlinse—eine prospektive Sicherheitsstudie. Klin Monatsbl Augenheilkd. 2001;218:603- 8.

Küchle M, Nguyen XN, Langenbucher A, Gusek-Schneider GC, Seitz B, Hanna KD. Implantation of a new accommodative posterior chamber intraocular lens. J Refract Surg. 2002;18: 208-16.

Küchle M, Nguyen NX, Langenbucher A, Gusek-Schneider GC, Seitz B. Erste Sechs-Monats-Ergebnisse der Implantation einer neuen akkommodativen Hinterkammerlinse (1 CU). Spektrum Augenheikd. 2001:15:260-6.

Küchle M, Nguyen NX, Langenbucher A, Gusek-Schneider GC, Huber S, Seitz B. Stabilität von Refraktion und Akkommodation während eines Jahres nach Implantation der akkommodativen Hinterkammerlinse 1 CU. Ophthalmologe. 2002;99(Suppl 1):S 184.

Langenbucher A, Huber S, Nguyen XN, et al. Measurement of accommodation after implantation of a new accommodative posterior chamber intraocular lens (1CU). J Cataract Refract Surg. 2002.

Ludwig K, Wegscheider E, Hoops JP, Kampik A. In vivo imaging of the human zonular apparatus with high-resolution ultrasound. Graefe’s Arch Clin Exp Ophthalmol. 1999;237:361-371.

Nguyen NX, Langenbucher A, Seitz B, Küchle M. Short-term blood-aqueous barrier breakdown after implantation of the 1 CU accommodative intraocular posterior chamber intraocular lens. J Cataract Refract Surg. 2002;28:1189-94.

Rohen J. Akkommodationsapparat. In: Velhagen K, ed. Der Augenarzt. Bd 1. Leipzig: Thieme, 1969:51-69.

Strenk SA, Semmlow JL, Strenk LM, Munoz P, Gronlund-Jacob J, DeMarco JK. Age-related changes in human ciliary muscle and lens: a magnetic resonance imaging study. Invest Ophthalmol Vis Sci. 1999;40:1162-1169.

Swegmark G. Studies with impedance cyclography on human ocular accommodation at different ages. Acta Ophthalmol. 1969; 47:1186-206.

von Helmholtz H. Über die Akkommodation des Auges. Graefe’s Arch Klin Exp Ophthalmol. 1855;1:1-74.

Weale R. Presbyopia toward the end of the 20th century. Surv Ophthalmol. 1989; 34:16-30.

INTRODUCTION

AND BACKGROUND

Modern cataract surgery has become a refractive procedure. Our patients expect the removal of the cataract and insertion of the lens without complications as a matter of course. They have recently come to expect a very specific refractive outcome—they want to be independent of their glasses. They must now be counseled that their expectations are probably unreasonable and may not be obtainable. The patient may be willing to live with reading glasses after their cataract surgery, but the surgeon who routinely leaves the patient with significant refractive error for distance vision will see a steady decrease in surgical volume.

Laser vision correction surgery is faced with unhappy patients who have distance vision of 20/20 or better without correction after their refractive surgery.1 Sometimes these patients have uncorrected or iatrogenic higher order aberrations. However, these patients were commonly low myopes and have developed symptomatic presbyopia because of surgical correction of their myopia. We all tell these patients they will need reading glasses after their corrective surgery. Some of the patients are still surprised and very upset by their loss of near vision in exchange for their distance vision.

The modern ophthalmic surgeon tries to handle these challenging situations in various ways. Monovision is the

most common method of maintaining near acuity. Monovision essentially under-treats 1 eye to minimize the negative effects of a successful treatment of both eyes for distance vision. Monovision works well in most patients who try it. But a significant percentage of patients who try monovision will not accept it and will need surgery to reverse the monovision. Another aspect of monovision that is frequently overlooked is the need to have the distance eye perfect. Because only 1 eye is focused for distance, the patient is very unforgiving of any blur. The patient can effectively optimize the near eye by moving a near object farther or closer to improve its focus. This increases the enhancement rate for the distance eye while decreasing it for the near eye. Surgical monovision has also been implicated in the possible permanent reduction of stereoscopic vision.

Another option is pseudoaccommodative IOLs. A pseudoaccommodative IOL corrects the distance vision in the usual manner as a monofocal IOL. It also has some mechanisms to allow for additional focal points in the near range. These mechanisms include a multifocal IOL optical design such as the Array Multifocal IOL (Advanced Medical Optics, Santa Ana, Calif) or a mechanical anterior-posterior translation of the lens such as the Crystalens (Eyeonics, Aliso Viejo, Calif). Since the mid to late 1990s, most markets in the world have had at least 1 lens option to simulate accommodation while correcting distance refractive error. The

Figure 14-1. Array Silicone MIOL.

Array Multifocal IOL (Figure 14-1) was approved by the FDA in the fall of 1997 for use in cataract patients over the age of 60. It subsequently received the CE mark from the European Union for the indication of correcting presbyopia in November 2001. There are other pseudoaccommodative IOLs pursuing approval for cataract indications in the US and Europe, including the Eyeonics CrystaLens (Figure 14- 2), and the Alcon multifocal lens, the MA60D3 (Fort Worth, Tex). There are other pseudoaccommodative IOLs pursuing approval in the European Union, including the Human Optics 1CU Lens (Erlangen, Germany).

A safe, effective, and predictable treatment for presbyopia is the current “Holy Grail” of cataract and refractive surgery. All of the current options, including monovision and pseudoaccommodative IOLs, have significant risks and compromises that the surgeon and the patient need to understand to be successful.2-6 Monovision with laser vision correction can be used to give many patients good distance and near vision. However, lens surgery is not reversible. The advantage of lens surgery is that it can correct almost any lower amount of order aberrations7-9 and some of the higher order aberrations in 1 procedure. By removing the lens, you remove the higher order aberrations of the natural lens and replace them with the higher order aberrations of a manufactured lens. With lens surgery, you may also be preventing the development of cataracts and their associated morbidity later in life.

PRELEX stands for PREsbyopic Lens EXchange.2 It is the surgical removal of the natural lens, replacing it with an artificial lens that has a pseudoaccommodative mechanism such as a multifocal optic and/or an anterior posterior translation of the optic to simulate the natural process of accommoda-

Figure 14-2. Eyeonics Crystalens.

tion. In our view, PRELEX is a procedure that is independent of the presence or absence of a cataract. PRELEX is a procedure to treat presbyopia whether that presbyopia is surgically induced by the cataract surgeon or naturally occurring by the passage of time. While the PRELEX procedure has been performed with several different types of IOLs, our personal experience is mostly limited to the use of the Array Multifocal IOL. Therefore, unless otherwise indicated the remainder of this discussion will be devoted to PRELEX with a multifocal IOL.

PATIENT SELECTION

PRELEX patients want to be less dependent on glasses after their surgery. They understand they will still need to wear glasses for some things, perhaps for most of their daily chores, but these patients want us to make every effort to decrease their dependence on their glasses or contacts. This means that the typical PRELEX patient is from 40 to 80 years old. Few patients younger that 40 would need or consider lenticular surgery and few patients older than 80 feel the need to be less dependent on their glasses. The typical age for a refractive PRELEX patient who is having the surgery for mostly refractive surgery reasons is about 53 years old. The typical age for a cataract PRELEX patient who is having the surgery primarily to correct cataracts is 62 years old (unpublished data).

When discussing treatment options with potential PRELEX patients, we emphasize several points. The surgery is irreversible. While the IOL can be exchanged, the natural lens cannot be replaced. The patient has the risk of a poten-