In vivo confocal microscopy after DSAEK finds corneal abnormalities

Researchers were able to identify subepithelial haze, donor-recipient interface haze, interface particles and needle-shaped materials in the stroma.

ByAndrew Kelly

In vivo laser confocal microscopy can serve as an important tool in identifying subclinical corneal abnormalities in patients who have undergone Descemet’s stripping automated endothelial keratoplasty, according to a study.

Akira Kobayashi

Akira Kobayashi, MD, PhD, and colleagues at Kanazawa University Graduate School of Medical Science, Kanazawa, Japan, conducted the study on seven patients who were undergoing Descemet’s stripping automated endothelial keratoplasty (DSAEK) for bullous keratopathy.

Two men and five women with a mean age of 68.9 years were examined via in vivo confocal microscopy using the Rostock Cornea Module of the Heidelberg Retina Tomograph II (Heidelberg Engineering) before and after DSAEK and at 1, 3 and 6 months postoperatively.

“In this study, I used in vivo laser confocal microscopy for the first time to investigate corneas before and after DSAEK prospectively and quantitatively. As a result, I identified several subclinical corneal microstructural abnormalities, such as subepithelial haze, donor-recipient interface haze, interface particles and tiny needle-shaped materials in the stroma,” Dr. Kobayashi said. “The most important impact of this study is that in vivo confocal microscopy is proven [to be a] powerful tool to understand the science behind this surgery.”

Results

According to the study, all seven patients attained better than 20/63 best corrected visual acuity within 6 months, with five attaining better than 20/40 and one achieving 20/20.

Regarding in vivo confocal microscopy results, corneal epithelial edema, subepithelial haze and keratocytes forming a honeycomb pattern were consistently seen preoperatively. Postoperatively, normal epithelium, subepithelial nerves and normal keratocyte nuclei in the mid-stroma were observed in all cases.

Dr. Kobayashi and colleagues found that subepithelial haze and donor-recipient interface haze persisted after DSAEK but decreased over the course of the study. However, the researchers noted that haze persisted at the 6-month follow-up. They said this may explain why DSAEK patients have difficulty in attaining BCVA better than 20/20.

Future studies

“Further studies in a large number of patients and long-term follow-up — more than 6 months after DSAEK — using this device are under way to fully understand long-term corneal stromal changes after DSAEK,” Dr. Kobayashi said.

The postoperative subepithelial or interface haze after DSAEK may influence visual acuity. However, a much larger participant pool will be necessary to prove this, he said.

“In vivo laser confocal microscopy analysis after DSAEK is capable of providing several new insights into its in vivo histology. This information will deepen our understanding of DSAEK and may help to develop and evaluate a new type of endothelial keratoplasty that could reduce postoperative subepithelial and interface haze,” Dr. Kobayashi said.

For more information:

Akira Kobayashi, MD, PhD, can be reached at Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa-city, Ishikawa, 920-8641, Japan; +81-76-265-2403; fax: +81-76-222-9660; e-mail: kobaya@kenroku.kanazawa-u.ac.jp. Dr. Kobayashi has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.

Reference:

Kobayashi A, Mawatari Y, Yokogawa H, Sugiyama K. In vivo laser confocal microscopy after descemet stripping with automated endothelial keratoplasty. Am J Ophthalmol. 2008;145:977-985. Epub 2008 Apr 9.

Andrew Kelly is an OSN Correspondent based in Philadelphia, Pa.