The transition from incisional methods such as radial keratotomy (RK) to excimer laser surgery, eg, photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) has dramatically increased the volume of corneal refractive surgery performed worldwide in recent years. As the current younger generation of patients who have undergone refractive surgery ages, we can assume that the presently small number of postrefractive patients requiring cataract surgery and intraocular lens implantation will increase correspondingly. This article addresses the problems encountered with calculating intraocular lens power after corneal refractive procedures. Starting with a description of keratometry in normal eyes, the causes of evident mismeasurements and miscalculation of the corneal power after keratorefractive surgery will be discussed, and different approaches to improving IOL power prediction will be described.
IVCM findings of the cornea in patients with severe ocular cGvHD include a rarefaction of the sub basal corneal nerve plexus and dense accumulation of hyper-reflective extracellular matrix in the anterior stroma.
The wound-healing response is generally poor after LASIK, which may result in significant weakening of the tensile strength of the cornea after myopic LASIK, probably due to biomechanically ineffective superficial lamella. After LASIK in patients with high hyperopia, compensatory epithelial thickening in the annular midperipheral ablation zone might be partly responsible for regression.
Corneal ectasia can occur after LASIK even in low degrees of myopia of less than ten diopters. Recently, -12 D has been specified as the upper limit for this technique. It is especially important to rule out an early keratoconus or a forme fruste of keratoconus preoperatively since keratectasia with particularly rapid progression can occur in such cases: we would like to designate this as "malignant keratoconus".
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.