[In vivo confocal microscopic characteristics of limbal stem cell deficiency]

Objective: To investigate the cellular changes and quantitative analysis of basal cell density (BCD) and corneal epithelial thickness (CET) in limbal stem cell deficiency (LSCD) by in vivo confocal microscopy (IVCM). Methods: Prospective case-control study. A total of 35 eyes of 23 patients diagnosed with LSCD and 25 eyes from normal subjects were included in this study. Based on slit-lamp presentation and the global consensus on classification, the LSCD patients were classified into LSCD Ⅰ, LSCD Ⅱ and LSCD Ⅲ. Confocal images of the central cornea, and the superior, inferior, nasal and temporal limbus were inspected by IVCM. Morphologic characteristics of LSCD were summarized. The BCD and CET in all locations were measured. ANVOA or Kruskal-Wallis test was used for analysis when appropriate. A receiver operating characteristic was used to detect the diagnosis efficiency of BCD and CET. Results: The characteristics in the corneal epithelium of LSCD on IVCM included nested corneal epithelial cells, goblet cells with hyper-reflective spots, irregular basal cells and decreasing subbasal nerve density. The mean BCD of the LSCD group was (8 976±1 096) cells/mm² in the central cornea. Compared to the control group, the BCD in the central cornea, superior, inferior, nasal and temporal limbus decreased by 30.2%, 26.0%, 28.7%, 29.3% and 30.2%, respectively (all P<0.007). The CET in the central cornea was (47.3±8.1) μm. The CET in the central cornea, superior, inferior, nasal and temporal limbus decreased by 27.9%, 23.7%, 20.6%, 26.9% and 23.1%, respectively, compared to the control group (all P<0.007). There was a decline of BCD and CET in more serious LSCD. Additionally, the decline of BCD and CET was shown in the unaffected region. The receiver operating characteristic showed the diagnosis efficiency of BCD in the corneal center and limbus (0.931 and 0.916) was superior to CET (0.853 and 0.817). Conclusions: There was a series of characteristic cellular changes in LSCD on IVCM. Both BCD and CET decreased significantly in LSCD. The BCD had higher diagnostic efficiency for LSCD.(Chin J Ophthalmol, 2020, 56:447-455).