Ultrasound biomicroscopy in refractive surgery

The need for improved methods of assessing corneal topography arose from the advent of refractive surgery. Ultrasound biomicroscopy (UBM) is a high-resolution technique that uses high-frequency transducers to evaluate the cornea. We conducted a pilot study to assess the cornea after refractive surgery using UBM. Six patients who had prior epikeratophakia, radial keratotomy, or photorefractive keratectomy were examined with a 50 MHz transducer. Ultrasound biomicroscopy provided a striking image of the epigraft after epikeratophakia. Imaging after radial keratotomy and photorefractive keratectomy was less helpful. However, the corneal refractive power computed from the UBM data for the photorefractive keratectomy was close to the optical keratometry values. The study indicates UBM has some applications in analyzing the cornea after refractive surgery.