PURPOSE Central corneal curvature is known to vary with refractive error, but the relation between corneal topography and ametropia is less clear. The current study was conducted to determine whether a relation exists between corneal asphericity and myopia. Associations between corneal asphericity and each of the components of refraction also were examined. METHODS Corneal asphericity and api...

PURPOSE To obtain an accurate algorithm for calculating the keratometric index that minimizes the errors in the calculation of corneal power assuming only a single corneal surface in the range of corneal curvatures of the normal population. METHODS Corneal power was calculated by using the classical keratometric index and also by using the Gaussian equation. Differences between types of calcu...

PURPOSE To examine the extent to which the two major determinants of refractive error, corneal curvature and axial length, are scaled relative to one another by shared genetic variants, along with their relationship to the genetic scaling of height. METHODS Corneal curvature, axial length, and height were measured in unrelated 14- to 17-year-old white European participants of the Avon Longitu...

In a prospective study we measured the intraocular pressure (IOP), the central corneal thickness (CCT) and the central corneal curvature in 172 myopic eyes before and after LASIK treatment. We find a significant decrease in intraocular pressure. Statistical evaluation reveals a linear correlation between the IOP decrease and the amount of stromal ablation. The IOP and corneal curvature are meas...

Evidence is presented for an active corneal component of accommodation in chicks. Using anesthetized chicks, consistent increases in corneal curvature were observed during accommodation produced either by electrical stimulation of the Edinger-Westphal nucleus or by topical application of 0.4% nicotine sulfate to the cornea. Electrical stimulation produced a mean accommodative amplitude of 9.2 d...

BACKGROUND To determine the relationship between central corneal thickness (CCT), refractive error, corneal curvature, anterior chamber depth and axial length in normal Taiwanese Chinese adults. METHODS Five hundred normal Taiwanese Chinese patients aged 40-80 years were recruited for the study. Measurement procedures included CCT, refractive error, corneal curvature, anterior chamber depth a...

background and objective: evaluation of the results, safety, and stability of ferrara intracorneal ring segment (ficrs) implantation for keratoconus correction (age range was 24.39±8.32 years).   materials and methods: in this clinical trial study, 64 eyes of 57 patients with keratoconus and clear cornea that had ficrs implantation were studied. uncorrected visual acuity (ucva), best-spectacle ...

PURPOSE To compare posterior corneal curvature in the fellow eye of the same patients after Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS This retrospective, case series comparative study included consecutive patients who underwent DSAEK in one eye and DMEK in the fellow eye. Each eye underwent corneal evaluation w...

PURPOSE To evaluate with the use of corneal topographic data the differences between total corneal power calculated using ray tracing (TCP) and the Gaussian formula (GEP) in normal eyes, eyes that previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK), and theoretical models. METHODS TCP and GEP using mean instantaneous curvature were calculated over the cen...