Orbscan II and double-K method for IOL calculation after refractive surgery.
Graefes Arch Clin Exp Ophthalmol
; 250(7): 1029-34, 2012 Jul.
Article
en En
| MEDLINE
| ID: mdl-22456944
BACKGROUND: Precise IOL calculation in post-refractive surgery patients is still a challenge for the cataract surgeon. The purpose of this study is to test whether adding Orbscan II values into the double-K method improves IOL calculation in this group of patients. METHODS: A prospective study with 43 eyes previously submitted to refractive surgery that underwent cataract extraction. IOL calculation was performed with double-K method. Post-K value was derived from Orbscan total-mean power map. The average corneal curvature of the general population (43.8D) was used as the pre-K value. Refraction results 30 days after surgery were compared with refraction that would be obtained if we used: (1) post-K values from keratometry, (2) post-K values from topography, and (3) pre-K values from Orbscan total-mean power. Anterior chamber depth measures obtained with the IOL Master and Orbscan II were compared. RESULTS: Mean postoperative spherical equivalent (SE) was -0.25 ± 1.10 D in eyes submitted to radial keratotomy , -1.04 ± 1.42 D in eyes previously submitted to myopic Lasik, and +0.05 ± 1.76 D in those submitted to hyperopic surgeries. Had we inputted post-K values derived from keratometer and from topography, we would have obtained significantly higher postoperative refractive errors in eyes previously submitted to myopic refractive surgery (p < 0.05). Refractions using pre-K derived from the central 8 mm Orbscan instead of 43.8 D were similar in all studied groups (p > 0.05). Anterior chamber depth measured with IOL Master or Orbscan were similar. CONCLUSIONS: Orbscan measurements used as the post-K values into the double-K method provide a precise IOL calculation, especially in post myopic refractive surgery patients.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Extracción de Catarata
/
Topografía de la Córnea
/
Procedimientos Quirúrgicos Refractivos
/
Óptica y Fotónica
/
Lentes Intraoculares
Tipo de estudio:
Observational_studies
Límite:
Aged
/
Humans
/
Middle aged
Idioma:
En
Revista:
Graefes Arch Clin Exp Ophthalmol
Año:
2012
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Alemania