Although refractive errors are extremely common, their pathogenesis remains undetermined; both genetic and nongenetic factors appear to influence an individual's risk for myopia and the severity of the myopia. The pursuit of good visual acuity without corrective spectacles or contact lenses has spawned a large number of surgical procedures designed to correct myopia, hyperopia, and astigmatism,...

CASE REPORT We report the case of a 34 year-old man with progressive loss of visual acuity in his left eye, who was diagnosed with pigmentary glaucoma with an intraocular pressure of 32mmHg. Eight years previously, the patient had undergone refractive surgery (LASIK). Hypotensive treatment led to a significant refractive change accompanied by flattening of the corneal curvature. DISCUSSION We...

PURPOSE Early in life, the optical demand associated with the eye's effective refractive state regulates emmetropization in many species, including primates. However, the potential role of optical demand and/or defocus in the genesis of common refractive errors, like myopia, that normally develop much later in life is not known. The purpose of this study was to determine whether chronic optical...

We reviewed the SRK-II method and introduce a new equation to calculate the intraocular lens (IOL) power for eyes which underwent laser phototherapeutic keratectomy (PTK). The Gullstrand series was used to determine the power and the radius of curvature of planoconvex IOLs which alter the focal point from the cornea to reach the conjugate point on the retina. The radius of anterior corneal curv...

PURPOSE Peripheral refraction is commonly used to infer retinal shape. Because of the different prevalence of myopia in the white compared with East Asian populations, peripheral refraction along the horizontal meridian was compared in white and East Asian young adults with emmetropic, low myopic, and moderately myopic refractive errors. METHODS Thirty-five white and 37 East Asian subjects we...

Implantation of phakic refractive lenses PRL® (Phakic Refractive Lens; IOLTech/Carl Zeiss Meditec AG, Jena, Germany) is one of the options available for the correction of moderate to high myopia, although there are few reports on the outcomes. In those cases where a corneal laser-assisted surgical procedure is not indicated because of the great amount of tissue to be removed, small optical zone...

PURPOSE To assess the relationship between apparent accommodation in pseudophakic eyes, multifocal corneal effects, and wavefront aberrations of the cornea. METHODS In 102 eyes of 86 patients who had undergone phacoemulsification and posterior chamber intraocular lens implantation, the amount of apparent accommodation was measured with an accommodometer. The degree of corneal multifocality wa...

Purpose To compare two calculators for toric intraocular lens (IOL) calculation and to evaluate the prediction of refractive outcome. Methods Sixty-four eyes of forty-five patients underwent cataract surgery followed by implantation of a toric intraocular lens (Zeiss Torbi 709 M) calculated by a standard industry calculator using front keratometry values. Prediction error, median absolute err...

PURPOSE To present the prospective application of the Orbscan II central 2-mm total-mean corneal power obtained by quantitative area topography in intraocular lens (IOL) calculation after refractive surgery. METHODS Calculated and achieved refraction and the difference between them were studied in 77 eyes of 61 patients with previous radial keratotomy (RK), RK and additional surgeries, myopic...