Ms. Habib et al., ULTRASOUND BIOMICROSCOPY OF INTRASTROMAL PHOTOREFRACTIVE KERATECTOMY WITH THE ND-YLF PICOSECOND LASER, Journal of refractive surgery, 11(6), 1995, pp. 448-452
PURPOSE: To evaluate corneal morphology in vivo following intrastromal
photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser,
using the ultrasound biomicroscope. MATERIALS AND METHODS: Myopic intr
astromal PRK was performed in the anterior stroma of cat corneas with
the neodymium:yttrium lithium fluoride (Nd:YLF) picosecond laser. Peri
odic examination of the treated corneas up to 6 months postoperative w
as performed with high resolution ultrasound biomicroscopy. Corneal th
ickness, depth of the laser patterns from the corneal surface, alignme
nt of the laser treatment, extent of stromal opacification until resol
ution, and contour of the corneal surface were measured with the ultra
sound biomicroscope throughout follow up. RESULTS: The treated corneas
were thickened on ultrasonic biomicroscopy measurement immediately af
ter intrastromal PRK and revealed a densely echogenic shadow parallel
to the corneal surface at the treatment site. There was increased stro
mal echogenicity denoting mild edema. The echoes decreased over time a
nd appeared thinner at 2 months compared to the preoperative and immed
iate postoperative measurements. At 6-month follow up, the treated cor
neas were echolucent on ultrasonic biomicroscopy. CONCLUSION: The ultr
asound biomicroscope might become a helpful tool in assessing accuracy
of treatment parameters of intrastromal PRK as well as in monitoring
the response of the cornea to treatment.