2009 OMIG, Abstract 7

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In Vivo Confocal Microscopy of Corneal Nerve Alterations in Acute Acanthamoeba and Fungal Keratitis.
K. Kurbanyan, L.M. Hoesl, W.A. Schrems, P. Hamrah.
Cornea Service & Ocular Surface Imaging Center, Massachusetts Eye and Ear Infirmary, Harvard  Medical School, Boston, MA.
 
Purpose: To study sub-basal corneal nerve alterations in infectious keratitis, with focus on acanthamoeba and fungal keratitis, utilizing in vivo confocal microscopy (IVCM).
Methods: Retrospective analysis of IVCM scans of 8 corneas with acute Acanthamoeba keratitis (AK) and 4 corneas with acute fungal keratitis (FK), with comparison to 10 corneas of normal controls, was performed utilizing the Heidelberg Retina Tomograph 3 with the Rostock Cornea Module (HRT3/RCM) (Heidelberg Engineering GmbH, Dossenheim, Germany). Sub-basal corneal nerves were analyzed with respect to total number of nerves per image, number of main nerve trunks, branching pattern, total length of nerves per image, and tortuosity. For each variable, results for three frames were averaged, when available, and analyzed utilizing the Student’s t-test.
Results: Total corneal nerve length was significantly (p<0.0001) reduced in patients with AK (335.1 µm) and FK (258.5 µm) when compared to normal controls (3811.84 µm). In addition, total nerve counts in patients with AK (6.5) and FK (6.1) were significantly (p<0.0001 per sub-group) reduced in comparison to normals (24.7). Further, the number of main nerve trunks was decreased in both AK (p<0.0001) and FK (p<0.0002) sub-groups, and nerve branching was found to be diminished in AK (p<0.0024) and FK (p<0.0049) patients, when compared to controls. Tortuosity of nerves was increased in both keratitis groups, but results did not reach statistical significance.
Conclusions: Sub-basal corneal nerve density and nerve fiber length are significantly altered in eyes with AK and FK, as demonstrated by IVCM. These results are more profound than previously reported findings of a diminished nerve plexus in patients with herpetic keratitis. Further studies need to investigate whether these nerve changes are caused by severe corneal inflammation alone or are related to pathogens.

Financial Support: This work was supported by NIH/NEI K12-EY016335, and New England
Corneal Transplant Research Fund
Disclosures: none