PURPOSE To analyze corneal curvature and visual acuity after asymmetric intrastromal corneal rings implantation, not following the nomogram proposed by the manufacturer. METHODS Seven eyes of seven keratoconus patients which had asymmetric corneal rings implanted in their corneal stroma were studied. RESULTS A flattening of the average corneal keratometry was noted in all patients, as well ...

PURPOSE Corneal curvature is a key determinant of the refractive power of the eye. Variants in two genes, FKBP12-rapamycin complex-associated protein 1 (FRAP1) on chromosome 1p36.2 and platelet-derived growth factor receptor alpha (PDGFRA) on chromosome 4q12, have shown genome-wide significant association with normal variation in corneal curvature in a study of subjects of Asian origin. Variant...

BACKGROUND To asses the effect of menopause on the corneal curvature changes using corneal computerized videokeratography (CVK) in premenopausal and postmenopausal healthy women. METHODS Thirty-six postmenopausal women with mean ages of 49.2 (range 39 to 57) were enrolled in this randomized, prospective study, comparing with 26 healthy controls with mean ages of 38.5 +/- 4.9 (range 32 to 49)....

AIMS To investigate the effect of central corneal thickness and corneal curvature on intraocular pressure measurements using the pulsatile ocular blood flow tonograph and the Goldmann applanation tonometer, and to assess the agreement between the pulsatile ocular blood flow tonograph and the Goldmann applanation tonometer in intraocular pressure measurement. METHODS 479 subjects underwent int...

The purpose of the study was to investigate the correlation between Corneal Visualization Scheimpflug Technology (Corvis ST tonometry: CST) parameters and various other ocular parameters, including intraocular pressure (IOP) with Goldmann applanation tonometry. IOP with Goldmann applanation tonometry (IOP-G), central corneal thickness (CCT), axial length (AL), corneal curvature, and CST paramet...

In astigmatism variations in the curvature of the cornea or lens along different meridians prevent the light rays from focusing onto a single point. Corneal refraction depends on the corneal curvature. If the cornea is more curved, the power of refraction is higher and vice versa. Corneal and lenticular astigmatism can complement or cancel each other. Their summation represents the so called “t...

In the optical system of the human eye, total refractive power consists mainly of corneal and lenticular components. Approximately two-thirds of the eye's converging power is at the air–cornea (tear film) interface; one-third is in the lens. Total corneal power is determined by corneal anterior and posterior curvature, corneal thickness, and the corneal refractive indices. Traditionally, anteri...

In recent papers (Lowe, I968, I969a) it was shown that in normal eyes, lens position and thickness were coordinated with axial length and radius of corneal curvature, whereas in eyes with primary angle-closure glaucoma these correlations were lacking. Throughout adult life, lenses increase in thickness at the same rate in normal eyes and those with angle-closure glaucoma, but no change could be...

AIMS To further understand the effect of refractive error on the corneal dimensions and function. METHODS Corneal curvature, corneal thickness, and axial length measurements were performed, as well as specular microscopy and fluorophotometry, on patients with various refractive statuses. 216 subjects, mean age 22.2 (SD 4.2) years, were examined. Patients with previous contact lens wear histor...

Aim: The primary aim of this study was to find if there is any correlation between the corneal radius of curvature and its eccentricity. Method: 45 subjects participated in this study, 24 emmetropes, 18 myopes and three hyperopes. All subjects were free of ocular abnormalities and had no media opacities. All the subjects had normal ocular health and good visual acuity of 1.0 or better for both ...