PURPOSE: To assess morphological changes in the meibomian glands (MGs) pre- and post-hematopoietic stem cell transplantation (HSCT). METHODS: Participants yet to undergo HSCT were included in a pre-HSCT group. Meibography images of both lids were graded using Pult's meiboscale and analyzed using a semi-automatic software program. Meibography variables in the pre-HSCT group were compared with those in a control group of healthy participants. The follow-up group, a subset of the pre-HSCT group, comprised participants followed up for at least 6 months post-HSCT. Ocular Surface Disease Index (OSDI), tear break-up time, corneal fluorescein staining, and Schirmer test were performed. The differences in meibography variables and ocular surface tests pre- and post-HSCT were analyzed. RESULTS: Pre-HSCT and control groups comprised 181 and 24 participants, respectively. The pre-HSCT group had a higher meiboscale in the lower lid (2 vs. 1, p = 0.011) than controls. The follow-up group comprised 20 patients followed up for 12.75 months post-HSCT. After HSCT, the meiboscale of the upper lid was higher (2 vs. 1, p = 0.011), the MG area was lower in both lids (upper lid = 16.14 % vs. 21.49 %, p = 0.001
lower lid = 11.92 % vs. 17.59 %, p = 0.011), and the OSDI increased (15.2 vs. 26.85, p = 0.018) in the second visit compared to the first visit. CONCLUSIONS: Alterations in meibography were observed in patients pre- and post-HSCT. This may be attributed to the effect of treatments administered pre-HSCT, although an additive effect of conditioning regimen in the long-term cannot be discarded.