Corneal topography six years after photorefractive keratectomy for myopia and myopic astigmatism.

Purpose: To analyze the 6-year response of corneal topography to photorefractive keratectomy (PRK) for myopia and myopic astigmatism.

Methods: Twenty patients (40 eyes) who had PRK using the Technolas Keracor 217C excimer laser platform were followed up to 6 years after surgery. The eyes were subdivided into three groups according to the preoperative spherical equivalent refraction and astigmatism component.

Relative contribution of central and peripheral aberrations to overall high order corneal wavefront aberration.

Purpose: To analyze the influence of specific combinations of corneal high order aberrations on the optical image quality of the cornea before and after photorefractive keratectomy (PRK) for low to high myopia and myopic astigmatism.

Methods: Corneal topography was obtained for 80 eyes that underwent PRK using a scanning-spot excimer laser. The eyes were subdivided into three groups according to the preoperative refraction.

Ultrasound of the horizontal rectus muscle insertion sites: implications in preoperative assessment of strabismus.

Purpose: To determine the reproducibility and accuracy of ultrasonographic (US) measurements of distances between the corneoscleral limbus and the insertion site of the medial (MR) or lateral rectus (LR) muscle compared with intraoperative measurements in patients with strabismus.

Methods: One eye in each of 17 patients with postoperative secondary strabismus caused by over- or undercorrected eso- and exotropia and one eye of each of 19 patients with previously untreated strabismus underwent five repeated measurements by high-resolution ultrasonography of the distance from the corneoscleral limbus to the muscle insertion and three actual intraoperative measurements. Reproducibility, expressed as the coefficient of variation, accuracy (relative error) of US measurements, and the agreement with intraoperative measurements were assessed.