Ocular Microbiology and Immunology Group
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2013 OMIG Abstract 22

Patients with Infectious Keratitis Demonstrate Persistent and Long-term Increase in Immune cells and Diminished Subbasal Corneal Nerves After Cessation of
Anti-Microbial Therapy— A Laser In Vivo Confocal Microscopy Study
Rodrigo Müller^1,2, Andrea Cruzat^1,2, Bernardo Cavalcanti^1,2, Arsia Jamali¹, Roxanna Pourmirzaie¹,
Emma Brown¹, Joseph B. Ciolino², Ula V. Jurkunas², James Chodosh², Reza Dana²,
Deborah Pavan-Langston², Pedram Hamrah^1,2
1Ocular Surface Imaging Center, ²Cornea Service, Department of Ophthalmology,
Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA

Purpose: The purpose of this study is to investigate the long-term changes in dendritiform cell (DC) density and subbasal corneal nerves in patients with infectious keratitis (IK) by laser in vivo confocal microscopy (IVCM) after resolution of infection and cessation of anti-microbial therapy.

Methods: A prospective study was performed in 49 patients with acute IK, including bacterial, fungal and Acanthamoeba keratitis, as well as in 62 age-matched normal controls. IVCM with the HRT3/RCM was performed in the acute phase of the infection, at cessation of anti-microbial therapy, 1 to 2 months, and 3 to 6 months thereafter, to evaluate central corneal nerve density, nerve numbers, branching and corneal DC density in a masked fashion.

Results: Compared to normal controls, the eyes with IK demonstrated significant decrease in corneal nerves (p<0.001 for all paramaters), and showed further diminishment at cessation of therapy for nerve density (24321±3878 vs. 4063±4839 µm/mm²), total number of nerves (27.5±6.9 vs. 2.5±3.0  nerves/frame) and main nerve trunks (4.4±0.8 vs. 0.75±1.0 nerves/frame) on the day that the anti-microbial therapy was stopped (p<0.001 for all parameters). Although nerves began to regenerate, they did not reach the level of controls even 3 to 6 months after cessation of therapy (total number of nerves 7.6±5.0 nerves/frame). DC density in the affected eyes was significantly increased during acute IK as compared to controls (384.4±257 vs. 24.6±24.9 cells/mm², p<0.001). After cessation of anti-microbial therapy, DC density remained high when as compared to controls (210.1±174.0, p<0.001). Surprisingly, DC density remained high (106.2±104.7, p<0.001) and did not return to normal levels during the first 6 months of follow-up post resolution.

Conclusion: IVCM showed that both diminishment of the subbasal corneal nerves, and increase in DC density in the affected eyes of IK patients may be persistent at least remain until 6 months after resolution. These findings may have significant clinical and surgical implications, such as in contact lens wear and surgical planning.

Funding: Support: NIH K08-EY020575 (PH), Research to Prevent Blindness Career Development Award (PH), Falk Medical Research Trust (PH), MEEI Foundation (PH)
C,S

2013 Agenda and Abstracts | < Previous | Next >