Corneal specular microscopy in infectious and noninfectious uveitis

Involvement of the cornea endothelium during uveitis has not been extensively studied even though it might participate in or constitute a target of ocular inflammation. Formation of keratic precipitates (KP) is a characteristic finding in several forms of uveitis. The aim of this prospective study was to examine the vicinity of keratic precipitates in infectious and noninfectious uveitis by specular microscopy.

Patients with infectious and noninfectious uveitis in any activity level and presence of keratic precipitates were enrolled. The mean age was 40.5 years (+/-14.2 years). A Topcon SP-2000P noncontact specular microscope was used to capture endothelial images in the vicinity of keratic precipitates. Automated morphometric analysis was done for cell size, cell density and cells coefficient of variation. Statistical comparisons were made between the infectious and noninfectious groups.

From the 25 patients enrolled in this study, 16 (44%) eyes presented infectious uveitis, 19 (53%) noninfectious uveitis and 1 (3%) eye was excluded due to the impossibility to obtain a specular image. The mean cell density estimated was 2,628+/-204 cells/mm2 in infectious group and 2,622+/-357 cells/mm2 in noninfectious group. The mean cellular area in infectious and noninfectious group was respectively 385+/-31 microm2 and 390+/-60 microm2. The coefficient of variation (%) of the cellular area in the vicinity of keratic precipitates was 26.36+/-3.44 in infectious and 27.69+/-4.61 in noninfectious group. The differences between the groups were not statistically significant (P<0.005/Mann-Whitney test) for the three morphologic variables.

The clinical applicability of specular microscopy in patients with uveitis can be an useful tool to evaluate the corneal endothelium in the presence of keratic precipitates, however the handicap of the specular image formation might not be discarded in some cases. The differences found were not clinically meaningful between the infectious and noninfectious groups, however the uveitis in various degrees of intraocular inflammation and the relatively small number of patients in each clinical category of this study, indicates that further studies can be required to evaluate better the morphology of the endothelium.