In this paper, we give a review of the tensor method for treating the propagation of scalar and electromagnetic Gaussian Schell-model (GSM) beams. Partially coherent complex curvature tensor is introduced to describe a scalar astigmatic partially coherent GSM beam with twisted phase (i.e., twisted anisotropic GSM beam). A tensor ABCD law for treating the propagation of scalar twisted anisotropi...

By Eric D. DonnEnfElD, MD Astigmatic management is the step that most often keeps patients from achieving optimal visual quality after refractive cataract surgery. Residual astigmatism of 0.50 D and sometimes less may result in glare, symptomatic blur, ghosting, and halos. A recent study of 4,540 eyes of 2,415 patients showed that corneal astigmatism was present in the majority of patients unde...

Adapting to blurred or sharpened images alters the perceived focus of subsequently viewed images. We examined whether these adaptation effects could arise from actual sphero-cylindrical refractive errors, by testing aftereffects in images simulating second-order astigmatism. Image blur was varied from negative (vertical) through isotropic to positive (horizontal) astigmatism while maintaining c...

AIMS To create a clinically useful classification for post-keratoplasty corneas based on corneal topography. METHODS A total of 360 topographic maps obtained with the TMS-1, from 95 eyes that had undergone penetrating keratoplasty (PKP), were reviewed independently by two examiners in a masked fashion, and were categorised according to a proposed classification scheme. RESULTS A high intero...

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...

PURPOSE The paraxial propagation of astigmatic wavefronts through astigmatic optical systems can be described by the augmented step-along method (ASAM). Its equivalence to the linear ray optics approach is considered in detail. METHODS The ASAM is exploited to derive paraxial ray paths through a general coaxial astigmatic system. RESULTS Starting from the information inherent in the ASAM al...

AIM To determine the effects of pupil size on uncorrected visual acuity (UCVA) in astigmatic eyes. METHODS The authors examined 20 normal eyes of 20 healthy volunteers (age 26.7±4.9 years (mean±SD); 8 men, 12 women). After fully correcting cycloplegic refraction, the authors created with-the-rule and against-the-rule astigmatism of 1, 2, and 3 dioptres (D) in each eye, and then assessed UCVA ...

PURPOSE Whether either natural emmetropization or compensation for imposed spectacle lenses requires the visual system to distinguish myopic from hyperopic blur is controversial. Some have argued that the visual system need only respond to the magnitude of the blur. This study was undertaken to test whether adding large amounts of astigmatic image blur would cause myopia and interfere with comp...

To understand the role that orientation-tuned disparity-sensitive mechanisms play in the perception of stereoscopic depth, we measured stereothresholds using two sets of random-dot stimuli that produce identical stimulation of disparity mechanisms tuned to vertical orientation but dissimilar stimulation of disparity mechanisms tuned to non-vertical orientations. Either 1 or 1.5D of astigmatic b...