Abstract
Purpose: :
To analyze the preoperative features of the corneoescleral limbus by slit lamp examination (SLE) and in vivo confocal microscopy (CM) to identify the limbal stem cell (LSC) rich regions and to follow the wound healing process after harvesting limbal tissue for cultured LSC transplantation.
Methods: :
Five patients with unilateral LSC deficiency underwent evaluation for autologous cultured LSC transplantation. SLE and CM at 12, 3, 6, and 9 o’clock limbal meridians identified the most appropriate site for biopsy to harvest the LSC. After biopsy, similar evaluations were done at 24 hours, 1 week, 1, 3, and 6 months to assess the healing process and the possible limbal restoration.
Results: :
At initial assessment, SLE showed visible palisades of Vogt (POV) in only 3 patients, just at 12 and 6 o’clock meridians. By contrast, CM detected the POV in all 5 patients at 12 and 6 o’clock meridians; additionally, at 9 o’clock in 3 patients, and in 2 patients in all 4 meridians. POV were consistently better defined at 12 o’clock meridian, therefore, were selected for limbal biopsy. Mean depth of POV, was 80.4+19.8µm. Limbal biopsy (mean depth 136.8+19.12µm) extended significantly beyond the depth of the POV, harvesting LSC niche completely. The outgrowth rate of cultured biopsy-derived limbal explants was similar in all patients, regardless of the presence/absence of POV by SLE. At 1-week postsurgery, SLE showed complete re-epithelialization and peripheral scarring in all donor sites. In addition to these findings, CM detected scarring at the bottom of the donor limbus. Vascularization was observed at 1 month by CM and at 2 months by SLE. In months 3 and 6, CM showed fibrovascular tissue advancing from periphery and bottom to the center of the donor site.
Conclusions: :
In vivo CM allowed to accurately identifying limbal features which cannot be visualized by routine clinical evaluation methods, therefore making it a useful technique to identify the appropriate biopsy site for autologous cultured LSC transplantation. Additionally, it allows confirmation of an adequate depth of the limbal biopsies, assuring complete removal of the LSC niche. There was no restoration of the donor limbal structures after 6 months of follow up.
Keywords: comparative anatomy • cornea: clinical science • wound healing