Güell JL (ed): Cataract. ESASO Course Series. Basel, Karger, 2013, vol 3, pp 100–115 DOI: 10.1159/000350912
Phakic Intraocular Lenses in Keratoconus Jose L. Güell · Daniel Elies · Paula Verdaguer · Oscar Gris · Felicidad Manero · Merce Morral
Abstract There are several circumstances where phakic intrao cular lenses (IOLs) might be considered in the manage ment of the keratoconic patient, obviously only in the case of a stable refractive situation, sometimes difficult to be defined in this setting. Taking into account that the IOLs will only correct the sphere and the regular com ponent of the astigmatism, sometimes they will be used in combination with other surgical strategies such as col lagen crosslinking and/or intracorneal ring segments. In this chapter, we will evaluate the conceptual possible indications for them and review the published data as well as our own experience during these last 15 years. Copyright © 2013 S. Karger AG, Basel
Keratoconus (KC), with a reported incidence of 1 per 2,000 in the general population, is a noninflammatory corneal disease that develops progressive thinning and anterior bulging of the cornea. Corneal ectasia frequently induces varied degrees of myopia and/or astigmatism [1]. In early stages, spectacles and contact lenses (CL) are the treatment of choice [2–4]. However, a considerable amount of patients with progressive KC have not only reduced visual acuity with spectacles due to irregular astigmatism [5, 6], but also reduced tolerance to CL [7–10].
Before the advent of modern refractive surgery techniques, penetrating keratoplasty or deep anterior lamellar keratoplasty was the treatment of choice when a patient with KC became CL intolerant or had poor best spectacle-corrected visual acuity. This is still true in advanced stages of the disease, where severe thinning and/or corneal scarring occurs. Because refractive anisometropia and high postoperative astigmatism are common pro blems after penetrating keratoplasty, visual rehabilitation and return to binocular function may be slow [11–15]. Moreover, complications related to corneal transplant surgery itself, such as endophthalmitis or rejection episodes, should also be taken into account [16–21]. Therefore, in the early stages of KC when the central cornea remains clear, other options should be considered to avoid or delay keratoplasty. With the exception of some anecdotal repor ts, corneal incisional (radial keratotomy, or arcuate keratotomy) and ablative refractive approaches such as photorefractive keratectomy (PRK) or LASIK are contraindicated in KC, as they increa se the risk of progressive, irreversible corneal ectasia [22–25]. Available refractive procedures include intrastromal corneal ring segments (ICRS), and toric phakic intraocular lenses (TPIOLs). The
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Instituto Microcirugía Ocular, Universidad Autónoma de Barcelona, Barcelona, Spain