PURPOSE To determine the effect of axis orientation on visual performance in astigmatic eyes. SETTING Department of Ophthalmology, Kitasato University, Kanagawa, Japan. DESIGN Investigational simulation. METHODS Healthy volunteers with no ophthalmic disease other than refractive errors were enrolled. After cycloplegic refraction was fully corrected with a 3.0 mm artificial pupil, with-the...

PURPOSE To evaluate the astigmatic outcomes of wavefront-guided sub-Bowman keratomileusis (WFG-SBK) for low to moderate myopic astigmatism. METHODS This study enrolled 100 right eyes from 100 patients who underwent WFG-SBK for the correction of myopia and astigmatism. The polar value method was performed with anterior and posterior corneal astigmatism measured with Scheimpflug camera combined...

Review of the cycloplegic refractions of all children who were first examined at Children's Hospital Medical Center in Boston between 1968 and 1978 revealed that 281 children between the ages of 0 and 9.5 years had astigmatism of 1 diopter (D) or greater but no other ophthalmological or neurological problems. In the 85 children under 3.5 years of age, against-the-rule astigmatism was 2.5 times ...

PURPOSE To demonstrate how higher-order corneal aberrations can cancel out, modify, or induce lower-order corneal astigmatism. PATIENTS AND METHODS Six representative eyes are presented that show different scenarios in which higher-order aberrations interacting with corneal astigmatism can affect the manifest refraction. WaveLight® Contoura ablation maps showing the higher-order aberrations a...

PURPOSE To define measures of assessing success and subsequent ways to improve excimer laser treatment of astigmatism. METHODS We studied 97 eyes of 79 patients, followed for 12 months, that underwent photorefractive keratectomy (PRK) for myopia and astigmatism with a VISX 20/20 excimer laser. Preoperative spherical equivalent refraction at the corneal plane was between -1.00 and -15.00 D. Me...

Until recently, the pursuit of emmetropia in patients with astigmatism (around 30% of the population) was infeasible since the only intraocular lenses available on the market were designed to correct myopia or hyperopia. However, with the new toric lens designs now available, a patient’s cataract, myopia, hyperopia and astigmatism can all be corrected by means of a simple, safe operation follow...

Naturally occurring (idiopathic) astigmatism is frequent, with up to 95% of eyes having detectable astigmatism. It is estimated that approximately 70% of the general cataract population has at least 1.00 D of astigmatism, and approximately 33% of patients undergoing cataract surgery are eligible for treatment of preexisting astigmatism.1,2 Today, cataract surgery is regarded as a refractive sur...

Primate eyes display considerable oblique off-axis astigmatism which could provide information on the sign of defocus that is needed for emmetropization. The pattern of peripheral astigmatism is not known in the chicken eye, a common model of myopia. Peripheral astigmatism was mapped out over the horizontal visual field in three chickens, 43 days old, and in three near emmetropic human subjects...

BACKGROUND To evaluate the torsional and flattening effect of steep meridian incisions and influence of posterior corneal astigmatism (PCA) on total corneal astigmatism (TCA) after cataract surgery. METHODS One hundred thirty-two eyes underwent cataract surgery with steep meridian 2.2 mm microcoaxial and 2.85 mm conventional clear corneal incisions. Eyes were divided into with-the-rule (WTR) ...

PURPOSE To describe the prevalence of high astigmatism in infants and young children who are members of a Native American tribe with a high prevalence of astigmatism. METHODS SureSight autorefraction measurements were obtained for 1461 Tohono O'odham children aged 6 months to 8 years. RESULTS The prevalence of astigmatism >2.00 diopters was 30% in Tohono O'odham children during infancy (6 m...