We know that the expression emmetropia is a conventional one and that in fact all normal human eyes have mild degrees of spherocylindrical errors (Shilo, 1997) or consist of a bitoric optical system, i.e. have principal meridians of relatively higher and lower powers at right angles. It is generally accepted that genetic factors have a significant role in determining ocular refractive status as...

INTRODUCTION this small study relates our early experiences with the Limbal Relaxing Incision (LRI) for management of astigmatism in patients undergoing cataract surgery. AIMS to evaluate the efficacy of LRI in the management of primary astigmatism when combined with phacoemulsification. SUBJECTS AND METHODS limbal relaxing incisions were performed to correct primary astigmatism in 12 eyes ...

In this study we investigated the impact of accommodation on axial and oblique astigmatism along 12 meridians of the central 30° of visual field and explored the compensation of corneal first-surface astigmatism by the remainder of the eye's optical system. Our experimental evidence revealed no systematic effect of accommodation on either axial or oblique astigmatism for two adult populations (...

For more than 100 years, eye scientists and clinicians have recognized that there is a difference between the refractive and anterior corneal astigmatism of the human eye. Javal postulated an approximately linear relationship between corneal astigmatism and refractive astigmatism, which became known as Javal’s rule: refractive astigmatism 1⁄4 1.25 (keratometric astigmatism) 0.50 90. For most ey...

OBJECTIVES To describe the refractive outcome of toric intraocular lens (IOL) implantation by comparing the postoperative refractive astigmatism with the preoperative keratometric astigmatism target. METHOD In a university department of a publicly funded hospital, 38 eyes of 29 patients underwent routine cataract surgery with insertion of a toric implant (SN60TT AcrySof Toric). Surgically ind...

BACKGROUND Previous studies have reported a greater prevalence of high astigmatism and vision disorders among Native Americans than occurs in the general U.S. population. The majority of these studies, however, have focused on Native American schoolchildren. This study assessed the distribution of astigmatism in a general clinic population at the Rosebud Indian Reservation in South Dakota. ME...

Pterygium is known to affect refractive astigmatism, which can have a significant impact on vision. This study was undertaken to evaluate the effect of pterygium excision on refractive astigmatism. Thirty-six eyes with primary pterygium with astigmatism of 2D or more were analysed before and after pterygium excision. Astigmatism increased with the increase in the grade of pterygium (P = 0.00000...

Contrast thresholds for different spatial frequencies were measured for four individuals with optimum optical correction and with 2 D of astigmatism induced at various meridians. Sensitivity for sine waves of low spatial frequencies was unaffected by the astigmatism; however, gross changes were found at high spatial frequencies when the astigmatism was induced with the power meridian perpendicu...

purpose: to evaluate changes in graft steepness after graft refractive surgery (grs) and to discover influential factors and a coefficient to predict the amount of postoperative shift. methods: keratoconic patients with history of penetrating keratoplasty (pkp) who underwent grs due to high post-pkp astigmatism were included. changes in mean keratometry after grs were evaluated to find possible...

Changes in astigmatism during development were studied in 299 infants with astigmatism as they grew from 1 to 4 years of age. All consecutive cases of 1-year-old infants with an astigmatism of 1.0 D or more in at least one eye found at an ophthalmic screening survey were selected for follow-up. The cycloplegic refraction was longitudinally followed at yearly intervals. During development there ...