Corneal wavefront–guided enhancement for high levels of corneal coma aberration after laser in situ keratomileusis

Abstract

Corneal wavefront-guided enhancements with the ORK-CAM system are a useful tool for the correction of the second order refractive errors and for the reduction of the corneal primary coma induced by previous keratorefractive procedures.

Corneal wavefront-guided photorefractive keratectomy in patients with irregular corneas after corneal refractive surgery

“…28 Specifically, corneal wavefront-guided ablation improves visual performance in very highly aberrated corneas because of the refractive importance of the anterior corneal surface and the more precise sampling analysis obtained using a corneal topographer. 1 With the topographic systems, more than 6000 points can be studied, after which an exhaustive analysis can be performed. 1 In addition, ocular wavefront sensors or aberrometers have limitations in the analysis of highly aberrated eyes.…”

“…1 With the topographic systems, more than 6000 points can be studied, after which an exhaustive analysis can be performed. 1 In addition, ocular wavefront sensors or aberrometers have limitations in the analysis of highly aberrated eyes. These include crowding or superimposing of the light spots or the assumption of a flat slope of each analyzed portion of the wavefront (HartmannShack devices).…”

“…[1][2][3]7,8 In these highly aberrated corneas, the first corneal surface is the most important source of optical errors. The aircornea interface is the main contributor to the total eye power as a result of the large difference in the refractive index between air and cornea.…”

“…These types of retreatments are safe and effective. [1][2][3]7,8 Another option is to create a new flap under the old cut; however, this newly created interface is another source of optical errors and limits effective refractive 9,10 and aberrometric 11 correction. In a cornea with high aberrations after unsuccessful LASIK, the main limitation is usually corneal thickness.…”

Higher order aberrations in amblyopic children and their role in refractory amblyopia

“…Studies have shown that lower order aberrations are responsible for about 90% of the quality of retinal images and that the remaining 10% is a combination of the effects of various higher order aberrations (9) . However, higher order aberrations do not interact with each other in a linear algebraic manner (10,11) ; in fact, the effects of the different aberrations tend to compensate for each other (4,12) . According to the work of Kelly et al, corneal optical aberrations are often compensated by internal ocular aberrations; therefore, the measurement of corneal wavefront aberrometry alone may produce inaccurate information about the retinal image quality (12) .…”