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Progrès dans les méthodes diagnostiques du déficit en cellules souches limbiques. Apport de la microscopie confocale et de la tomographie en cohérence optique
摘要： The limbus is the anatomical and functional barrier between corneal and conjunctival epithelia. It is characterized by presence of the limbal stem cell niche which allows corneal homeostasis to be maintained. Limbal stem cell deficiency is characterized by a dual process: insufficient regeneration of corneal epithelium, which cannot therefore assure its function of physiological support, associated with corneal invasion by conjunctival proliferation. Diagnosis is currently made via routine clinical examination, corneal impression cytology and in vivo confocal microscopy (IVCM). Slit lamp examination shows abnormal limbal anatomy, thin and irregular epithelium with late fluorescein staining, and superficial vascularization. With its high resolution, IVCM allows identification of limbal and corneal epithelial changes at a cellular level in en face views, parallel to the corneal surface, but with a restricted viewing field of the corneal surface. It shows a poor transition between the corneal and conjunctival epithelia, associated with a loss of the normal corneal epithelial stratification, low basal cell and sub-basal nerve plexus densities, even with sub-epithelial fibrosis. Optical coherence tomography in central cornea and at the limbus, with scans in different orientations, allows a quick, global and non-invasive analysis of normal eyes and those with limbal stem cell deficiency. It shows a thin limbal epithelium, lacking normal thickening, featuring absence of stromal undulations and limbal crypts in cross-sections and sections parallel to the limbus, lack of visible limbal crypts in en face sections, loss of clear transition between the hyporeflective corneal epithelium and the hyperreflective conjunctival epithelium, and hyperreflective sub-epithelial fibrosis.
关键词： Limbal stem cell deficiency,Limbus,Optical coherence tomography,In vivo confocal microscopy
更新于2025-09-23 15:23:52
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Femtosecond Laser-Assisted Keratolimbal Allograft Transplantation for the Treatment of Total Limbal Stem Cell Deficiency
摘要： To investigate the surgical procedure and therapeutic efficacy of femtosecond (FS) laser-assisted keratolimbal allograft (KLAL) transplantation in the treatment of eyes with total limbal stem cell deficiency. Methods: Ten eyes from 10 patients who underwent FS laser-assisted KLAL transplantation were enrolled. The best-corrected visual acuity (BCVA), ocular surface stability, corneal transparency, and postoperative complications were recorded. Results: The keratolimbal grafts prepared using the FS laser were even in thickness and width. After the surgery, glucocorticoid and tacrolimus eye drops were administered locally to the eyes with concentration gradients, and a medium dose was prescribed for maintenance. Within the mean follow-up period of 16.8 6 7.3 months, 9 of 10 eyes (90.0%) maintained a stable ocular surface and showed significant transparency and improvements in corneal BCVA. Persistent corneal edema only occurred in one eye because of repeated epithelial defects, and the BCVA of this eye did not improve. Confocal microscopy revealed activated dendritic cells in the Bowman membrane at the limbus, but they were always low in density with small dendritic processes. No acute immune rejection, cataracts, or elevation of intraocular pressure were detected. Conclusions: The FS laser-assisted KLAL technique can produce ring-shaped grafts with an even depth and width, resulting in a stable ocular surface and good visual prognosis. After surgery, glucocorticoids and potent immunosuppressive eye drops were administered locally with concentration gradients and effectively inhibited acute immune rejection.
关键词： femtosecond laser,limbal stem cell deficiency,keratolimbal allograft
更新于2025-09-12 10:27:22
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Classification of Limbal Stem Cell Deficiency Using Clinical and Confocal Grading
摘要： To grade the severity of limbal stem cell deficiency (LSCD) based on the extent of clinical presentation and central corneal basal epithelial cell density (BCD). This is a retrospective observational comparative study of 48 eyes of 35 patients with LSCD and 9 eyes of 7 normal subjects (controls). Confocal images of the central cornea were acquired. A clinical scoring system was created based on the extent of limbal and corneal surface involvement. LSCD was graded as mild, moderate, and severe stages based on the clinical scores. The degree of BCD reduction was given a score of 0 to 3. Compared with BCD in controls, BCD decreased by 23.0%, 40.4%, and 69.5% in the mild, moderate, and severe stages of LSCD classified by the clinical scoring system, respectively. The degree of BCD reduction was positively correlated with larger limbal and corneal surface involvement and when the central visual axis was affected (all P # 0.0005). Mean corrected distance visual acuity logarithm of the minimum angle of resolution was 0.0 6 0.0 in control eyes, 0.2 6 0.5 in mild LSCD, 0.6 6 0.4 in moderate LSCD, and 1.6 6 1.1 in severe LSCD (P , 0.0001). There was a significant correlation between a higher clinical score and corrected distance visual acuity logarithm of the minimum angle of resolution (rho = 0.82; P , 0.0001) and a greater decrease in BCD (rho = 20.78; P , 0.0001). A clinical scoring system was developed to assess the extent of clinical presentation of LSCD. A classification system to grade the severity of LSCD can be established by combining the BCD score with the clinical score.
关键词： diagnosis,classification system,limbal stem cell,in vivo confocal microscopy,limbal stem cell deficiency
更新于2025-09-09 09:28:46