PURPOSE To study the prevalence of and relation between refractive and corneal astigmatism in white school children in Northern Ireland and to describe the association between refractive astigmatism and refractive error. METHODS Stratified random clustering was used to recruit 1053 white children, 392 aged 6-7 years and 661 aged 12-13 years. Eye examinations included cycloplegic autorefractio...

PURPOSE To evaluate and investigate the distribution and repeatability of anterior corneal surface astigmatism measurements (axis and magnitude) using a novel corneal topographer. METHODS Anterior corneal surface astigmatism was investigated in a total of 195 eyes using a novel multicolored spot reflection topographer (Cassini; i-Optics). Two patient groups were studied, a younger-age group A...

Previous studies suggest that certain combinations of coma and astigmatism improve optical quality over astigmatism alone. We tested these theoretical predictions on 20 patients. Visual acuity (VA) was measured under best spherical correction for different conditions: low- and higher order aberrations corrected, in the presence of 0.5 D of induced astigmatism, and adding different amounts of co...

To the Editor: I read with interest the October editorial, “JRS Standard for Reporting Astigmatism Outcomes of Refractive Surgery”1 by Reinstein et al.; however, some clarification is required. I advocated common standards for reporting surgically induced astigmatism in 1997.2 In 2008, a comprehensive analysis of assessment methods and statistical analysis of surgically induced astigmatism was ...

Astigmatism’s defect has not yet been formulated in Physics and medical physics books theoretically. In this paper, we are trying to formulate the astigmatism’s defect. The results of formulation show that “the degree of astigmatism is negative reverse the distance that vision’s condition of astigmatism’s chart lines change conditions in dimness angle from dimness condition at infinite distance...

PURPOSE To determine the contribution of posterior corneal astigmatism to total corneal astigmatism and the error in estimating total corneal astigmatism from anterior corneal measurements only using a dual-Scheimpflug analyzer. SETTING Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. DESIGN Case series. METHODS Total corneal astigmatism was calculated using ray trac...

PURPOSE To report the use of circular keratotomy in eyes with stage I and II keratoconus to reduce astigmatism. METHODS A retrospective analysis was performed of all eyes operated from 1993 to 2006 by one surgeon using circular keratotomy for stage I and II keratoconus. Results were evaluated for reduction of corneal astigmatism, refractive stability, and change in best spectacle-corrected vi...

PURPOSE To evaluate the factors that affect postoperative astigmatism and post-suture removal astigmatism, and to evaluate the risk factors associated with astigmatism axis shift. METHODS We performed a retrospective chart review of 130 eyes that had undergone uneventful phacoemulsification cataract surgery. Preoperative astigmatism was divided into four groups (Groups I, II, III, and IV) acc...