PURPOSE Astigmatic changes induced by the pterygium and their relation to its size and morphology were analysed to establish the critical size for surgery before significant astigmatism occurs. MATERIALS AND METHODS We evaluated the refraction in 148 eyes of 108 adult patients with primary pterygia. We grouped the astigmatic values according to the keratometric results correlating with the ma...

Here we demonstrate that an astigmatic detection system (ADS), constructed with a modified digital-versatile-disk (DVD) optical head, can achieve real-time measurement of a linear displacement and two-dimensional (2D) tilt angles with a high sensitivity. An atomic force microscope (AFM), using our detection system to sense the deflection of microfabricated cantilevers, can resolve single atomic...

A retinitis pigmentosa (RP) population (268 eyes) had predominantly myopic refractive errors. Whereas 12% of a normal population have myopic refractions, myopia was found in 75% of 268 eyes of RP patients and in 95% of 41 eyes of X-linked RP patients. The spherical errors describe a single-peaked, skewed distribution, with a mean of -1.86 dioptres that is significantly (P less than 0.001) more ...

Small Incision Lenticule Extraction (SMILE) is a flap-free intrastromal technique for the correction of myopia and myopic astigmatism. To date, this technique lacks automated centration and cyclotorsion control, so several concerns have been raised regarding its capability to correct moderate or high levels of astigmatism. The objective of this paper is to review the reported SMILE outcomes for...

Report of a Case. A 41-year-old man had successful bilateral 8-incision RKs done elsewhere in 1992, resulting in 20/20 OU uncorrected visual acuity. As he was trimming a bush in September 1998, a branch (Figure 1) struck him in the right eye. There was immediate pain, blurriness, and tearing. He was seen immediately at a local hospital emergency department by an ophthalmologist and was referred...

We have developed a structured beams theory, computer simulation and experiment that lost rotational symmetry propagate in medium with general astigmatism. It transpires the astigmatic brings to light such hidden properties of as sharp growing orbital angular momentum exceeding sum radial azimuth numbers, well effect beam structure following cylindrical lens rotation.

PURPOSE To describe the laboratory findings in patients with infectious keratitis, who underwent refractive surgery, correlating the surgical procedure and the time of infection manifestation, and the results of culture and smears. METHODS The previous samples were obtained from patients submitted to radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in situ keratomileusis (L...