Correlation Between Clinical and Cytological Evaluation of Patients Affected by Limbal Deficiency (LD): Is the Goblet Cells Identification on Corneal Impression Cytology the Hallmark of Limbal Deficiency?

Abstract

Abstract: : Purpose: To investigate the relatioship between clinical signs and symptoms and cytologic features of the corneal epithelium in patients with limbal stem cell deficiency. Methods: Twenty patients (31 eyes) with clinical evidence of limbal deficiency were evaluated for signs (conjunctival hyperemia, corneal epithelium changes, superficial neovascularization, stromal opacity and neovascularization), symptoms (pain, burning, photophobia, foreign body sensation), corneal esthesiometry, BUT, and Schirmer test. All the corneal signs and the evaluation of corneal impression cytology were recorded and graded for 5 different corneal sectors (superior, temporal, inferior, nasal, central). Corneal impression cytology was performed to identify goblet cells (PAS staining) and to identify specific cytokeratins ( K3 and K19). Correlation between clinical signs and cytologic features was performed by Spearman Rho test. Results: Goblet cells were present in 22/31 (71%) while K19 positive cells were present in 30/31 (97%) of the evaluated corneal impression cytologies. The goblet cells present on the corneal surface significantly correlated with corneal epithelial changes (p=0; Rho=0.354 and p=0; Rho=0.302 respectively), superficial neovascularization (p=0.001; Rho=0.291 and p=0; Rho=0.341 respectively), and esthesiometry (p=0.005; Rho=-0.265 and p=0.014; Rho=-0.234 respectively), but not with all the other clinical parameters. A significant correlation was observed between the K19 positive cells on the corneal surface and corneal epithelial changes (p=0; Rho=0.602), superficial neovascularization (p=0; Rho=0.380), and estesiometry (p=0; Rho=-0.372). Conclusion: Limbal deficiency is characterized by non-specific corneal signs and symptoms. The diagnosis of this disease should be confirmed by cytologic evaluation of the corneal epithelium. Our data confirm a good correlation between clinical and cytologic findings. However, in 29% of the eyes the clinical diagnosis was not confirmed by the PAS staining, while the immunohistochemistry revealed the presence of K19 in all the samples but one. These results suggest to perform a K19 evaluation in absence of goblet cells before to decide the therapeutic approach. Indeed, the study highlights a potential role of corneal sensitivity in the pathogenesis of the disease.

Keywords: 372 cornea: epithelium • 381 cytology • 359 clinical research methodology