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Scheimpflug camera measurement of anterior and posterior corneal curvature in eyes with previous radial keratotomy.
Camellin, Massimo; Savini, Giacomo; Hoffer, Kenneth J; Carbonelli, Michele; Barboni, Piero.
Afiliação
  • Camellin M; SEKAL Rovigo Microsurgery, Rovigo, Italy.
J Refract Surg ; 28(4): 275-9, 2012 Apr.
Article em En | MEDLINE | ID: mdl-22386371
PURPOSE: To compare the anterior and posterior corneal curvature in eyes with previous radial keratotomy (RK) to normal unoperated eyes. METHODS: In this retrospective observational case series, 29 eyes from 29 consecutive patients were analyzed and compared to a control group of 71 unoperated eyes. Corneal imaging was obtained by a rotating Scheimpflug camera (Pentacam, Oculus Optikgeräte GmbH). Anterior and posterior corneal curvature radii were measured at the 3-mm zone. RESULTS: The mean anterior and posterior corneal radii were 9.54 ± 0.89 and 8.54 ± 1.01 mm, respectively, both values being significantly higher than in the control group (7.81 ± 0.28 and 6.40 ± 0.24 mm, respectively, P<.0001). The mean anterior-to-posterior corneal curvature ratio was 1.12 ± 0.07, a value significantly lower than in the control group (1.22 ± 0.03, P<.0001). Mean corneal flattening was more evident in the posterior (33.44%) than in the anterior (22.15%) corneal curvature. The mean keratometric index, as calculated with the Gullstrand equation for thick lenses, was 1.3319 ± 0.0026, a value significantly higher than in the control group (1.3281 ± 0.0011, P<.0001). Linear regression detected a significant and directly proportional relationship between the number of radial incisions and flattening of both corneal surfaces (P<.0001). CONCLUSIONS: After RK, both corneal surfaces flatten but do not deform in parallel as commonly accepted, as shown by the fact that the anterior-to-posterior corneal curvature ratio decreases. This finding invalidates the standard keratometric index and thus has relevant implications for intraocular lens power calculation in RK eyes.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Refração Ocular / Ceratotomia Radial / Fotografação / Córnea Tipo de estudo: Observational_studies Limite: Female / Humans / Male / Middle aged Idioma: En Ano de publicação: 2012 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Refração Ocular / Ceratotomia Radial / Fotografação / Córnea Tipo de estudo: Observational_studies Limite: Female / Humans / Male / Middle aged Idioma: En Ano de publicação: 2012 Tipo de documento: Article