Abstract
Purpose: :
To report the confocal microscopy findings in a case of unusual Nd:YAG Laser treatment of corneal haze following LASIK.
Methods: :
A 30-year-old young male with high myopia in UO (-10 D) was submitted to LASIK on April 2006. One month after surgery a corneal haze in LE occurred. On May and June 2006, two Nd:YAG laser treatments were performed, and on September 2006 a PTK was performed for residual opacity. On December 2006, he underwent a complete ophthalmic screening in our ophthalmic Department, including digital slit lamp examination, best-spectacle corrected visual acuity (BSCVA), computerized corneal topography (CSO, Florence, Italy), Orbscan (Orbscan IIz, Bausch & Lomb, US), corneal pachometry (Pachmate, DGH Technology Inc. Exton, PA, USA), endothelial microscopy (Konan Specular Microscope, Japan) and Confoscan 4 confocal microscopy (Nidek Technologies, Tokyo, Japan).
Results: :
Digital slit lamp examination showed a linear opacity at the interface level in the inferior cornea of RE, and a reticular central haze (stage 3) at the interface in LE associated with small intra-stromal scars confined to the infero-temporal corneal zone. Minimum corneal pachometry in LE was 298µm. In the central and paracentral corneal scans of LE, confocal microscopy examination of the anterior stroma showed an increased reflectivity due to a sub-epithelial keratinocities reactivity and scar formation (74-106µm thick). At the level of the Nd:Yag laser spots, the scans showed umbilicate, well demarcated, high reflective, circular lesions having a diameter of about 50µm, surrounded by hyporeflective bands, positioned at maximum of 50µm over the endothelium. None keratinocities or normal stromal structures were evident at the level of these alterations. Such corneal findings are similar to histological changes seen with optical microscopic evaluation, as reported in literature, and related to stromal coagulative necrosis.
Conclusions: :
Even if this laser has actually a large employment in Ophthalmology, to our knowledge this is the first case of Nd:YAG laser treatment of haze following refractive surgery. In this patient corneal scars, subsequent to the excimer laser ablation, caused a significant visual impairment in the LE and the Nd:Yag laser applications showed no influence in limiting haze development. In vivo and no invasive evaluation with corneal confocal microscopy showed the correspondence with histological findings.
Keywords: wound healing • microscopy: confocal/tunneling • refractive surgery: LASIK