Understanding corneal topography.

With the increase in corneal laser refractive surgery, there is a greater need for precise evaluation of the corneal surface. Articles published in the past year have reported possible use of confocal scanning laser technology-based devices to image the cornea. Other studies have compared existing instruments and software in an effort to determine if data from different instruments are comparable. Topographic evaluation also has served to highlight long-term complications of procedures like radial keratotomy and the promise of newer surgical procedures like the intrastromal corneal ring segments. Studies of the corneal surface have helped refine surgical procedures like photorefractive keratectomy, laser in situ keratomileusis, penetrating keratoplasty, and cataract surgery. Topographic measures that serve as direct correlates of ocular visual performance, however, still remain elusive. Studies in the past year have confirmed that corneal topographic evaluation may be a powerful tool in the search for a genetic basis of keratoconus. Important areas for future research include precise determination of the power of the postrefractive surgery cornea to allow precise estimation of intraocular lens power in these eyes. Detecting the presence of past corneal refractive surgery in donor eyes also is likely to be a challenge. Despite the numerous advances in the field of corneal topography in the past year, there is still a need to present the data in a standardized format that is universal to all instruments and technologies.