AIM To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism using wavefront-guided (WFG) and wavefront-optimized (WFO) ablation profiles. METHODS Prospective study included 221 eyes undergoing LASIK: 99 and 122 eyes with low and moderate myopic astigmatism (low and moderate myopia groups). Two subgrou...

PURPOSE To use powerful modeling techniques for predicting the optical performance of eyes implanted with different types of intraocular lenses (IOLs). This approach will allow performance of "virtual cataract surgery," with different IOL designs that can be used and physical parameters that may occur during actual surgery-in particular, in IOLs that correct spherical aberration. METHODS A co...

Background/Aim. Corneal cross-linking (CXL) treatment shows the best results in stabilizing cornea and stopping progress of ectatic process. The aim study was to assess impact CXL on keratoconus regarding higher-order aberrations (HOAs) potential improvement visual function. Methods. In 19 patients, a standard epithelium-off performed with an energy density three mW/cm2 for half hour. examined ...

Although the human eye has a relatively simple optical system, it is not perfect. It has been well known that the human eye suffers from the wavefront aberration that includes both lower (defocus and astigmatism) and higher order aberrations. The lower order aberration has been effectively corrected with conventional ophthalmic lenses such as spectacles and contact lenses. However, it is more c...

A geometric algebra of point sets in the complex plane is proposed, based on two fundamental operations: Minkowski sums and products. Although the (vector) Minkowski sum is widely known, the Minkowski product of two-dimensional sets (induced by the multiplication rule for complex numbers) has not previously attracted much attention. Many interesting applications, interpretations, and connection...

PURPOSE To review the early development of new technologies that are becoming available through customized corneal ablation techniques. METHODS The authors describe the early development of two diagnostic methods to perform customized corneal ablation as well as a variety of new treatment modalities in development. RESULTS AND CONCLUSION Results using the wavefront sensors indicate that the...

We analyze theoretically, by means of both computer simulations and laboratory experiments, the limitations of correcting aberrations with ideal customized contact lenses. Four experiments are presented: In the first one, we have analyzed the limitations of a static correction on the dynamic wavefront. In the second one, we studied the rotations of a contact lens on the eye using an optical met...

PURPOSE To compare the clinical outcomes of aberration-free ablation profiles based on the normal corneal vertex (CV) and the pupil center (PC) in relation to laser in situ keratomileusis. Aberration-free aspheric ablation treatments were performed in all cases. METHODS Two myopic astigmatism groups (CV centered using the offset between pupil center and normal corneal vertex and PC centered u...

PURPOSE To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality. METHODS Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 +/- 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measur...

We present a new method for subjectively evaluating intraocular lenses (IOLs) without implantation surgery. To illustrate the method, three types of single-piece IOL (equispherical monofocal, rotational symmetric aspheric monofocal, and diffractive bifocal) were assembled into a model eye and evaluated using an ocular adaptive optics system by a single subject. To separate the spherical aberrat...