Keratoconus.

Not too long ago, the options for treatment of keratoconus were limited to contact lens wear or penetrating keratoplasty. Times have changed, which is reflected in 4 articles in this issue that have some bearing on current investigation and treatment options. One hundred fifty years ago, Dr. John Nottingham provided the first detailed description of keratoconus, with further observations by his contemporary Sir William Bowman. It was then more than 120 years before clinical and laboratory research provided deeper understanding of the disorder. Keratoconus is a noninflammatory condition that results in corneal thinning in central and paracentral areas of affected corneas. As the condition progresses, the inevitable astigmatism invariably changes from regular to irregular. The ultimate degradation is scarring and hydrops. However, modern technology offers therapeutic solutions to stop or at least slow the thinning process by corneal collagen crosslinking (CXL) (not yet approved in the United States despite 10 years of research proving its effectiveness in stiffening the cornea in keratoconic and ectatic eyes). Irregularity may be neutralized at least in part by corneal ring insertions, toric phakic intraocular lens (pIOL) implantation, or both. It seemed counterintuitive to apply corneal excimer ablation technology to the treatment ofmild degrees of keratoconus and to eyes believed to be exhibiting forme fruste of the disorder when significant diagnostic efforts were being made to avoid treating such eyes with that technology for fear of causing ectasia. By stiffening the biomechanics of the cornea through collagen fiber crosslinking, a much stronger argument can be posed for pursuit of that stratagem. Corneal CXL is now widely performed internationally, with evidence of its effectiveness in stabilizing the progressive nature of keratoconus. Touboul et al. (pages 1049–1055) continues the discussion by posing the question, Is topography-guided custom photoablation predictable in keratoconic eyes or those with irregular astigmatism? In their study, Placido topography is used to characterize the role of the corneal epithelium in living human keratoconic eyes after epithelial removal. This is based on the potential for corneal epithelial remodeling after photoablation. Their rationale is the increased interest in keratoconus management by photorefractive keratectomy now that corneal CXL is available internationally, as surgeons continue to look for ways to improve the predictability of visual outcomes. Photorefractive keratectomy removes Bowman membrane centrally