PURPOSE To describe the treatment of highly aberrated eyes due to previous excimer laser surgery or trauma. METHODS Three eyes (three patients) with reduced visual quality due to previous decentration or corneal laceration (one eye) underwent topography-guided ablation using the CXIII excimer laser (NIDEK Co Ltd) to correct residual refractive error and/or wavefront aberrations. RESULTS Pos...

PURPOSE To determine preoperative patient characteristics that may predict topography and visual acuity outcomes of corneal collagen crosslinking (CXL). SETTING Cornea and refractive surgery practice. DESIGN Cohort study. METHODS Crosslinking was performed in eyes with keratoconus or corneal ectasia. Multiple regression and odds ratio analyses were performed to determine independent predi...

A modified Hartmann test is proposed for measuring corneal topography. The plane screen with holes used in the typical Hartmann test is replaced with a curved object surface. This object surface yields a plane image for a spherical mirror surface. We show that the object surface is an oval of revolution that can be modeled by an ellipsoid. The plane image will be formed by a square array of cir...

purpose: to evaluate the effect of location and size of chalazia on refractive error, corneal topography and visual acuity. methods: this randomized non-controlled clinical trial was conducted on patients with chalazion aged more than 3 years with minimum duration of one month. all patients underwent chalazion excision by the internal or external approach. results: two-hundred and fifty-three e...

This study investigated differences in geometrical properties and optical aberrations between a group of hyperopes and myopes (age-matched 30.3+/-5.2 and 30.5+/-3.8 years old, respectively, and with similar absolute refractive error 3.0+/-2.0 and -3.3+/-2.0, respectively). Axial length (AL) was measured by means of optical biometry, and corneal apical radius of curvature (CR) and asphericity (Q...

A videokeratograph quantifies one or more aspects of corneal shape by the computer analysis of a digital image. The image is the reflection formed by illuminating the cornea with a known source pattern. The type of shape information recovered and the accuracy of this information depend upon properties of the computer algorithm used in the analysis. We present a new algorithm that recovers a pol...