Intrastromal stem cell implant moderately effective for advanced keratoconus

This study evaluates the 1-year safety and efficacy of an adipose-derived adult stem cell (ADASc) implant, applied with or without sheets of decellularized donor human corneal stroma, in patients with advanced keratoconus.

Study design

The authors performed a prospective interventional non-randomized study of 14 consecutive patients with advanced keratoconus. Each underwent implantation with either 1) autologous ADASc, 2) decellularized 120-μm thick corneal stroma lamina from a donor or 3) donor lamina recellularized with 1x10⁶ autologous ADASc with an additional  1x10⁶ cells at the time of surgery. Autologous ADASc were obtained by elective liposuction. Implantation was performed into the corneal stroma through a femtosecond-assisted 9.5-mm diameter lamellar dissection under topical anesthesia.

Outcomes

Twelve months after implantation, the average corrected distance visual acuity improved by 0.231, 0.264 and 0.094 Snellen lines in groups 1, 2 and 3, respectively. In group 1, refractive parameters showed an overall stability, while sphere improved by 2.35D and 0.625D in groups 2 and 3, respectively. Anterior keratometry remained stable in group 1 and improved in groups 2 and 3 by an average of 2 D.  No adverse events or complications were noted.

Limitations

The study was limited by a small sample size with only 1 year of follow-up data.

Clinical significance

These findings introduce a new potential treatment for patients who have a high risk of perforation with deep anterior lamellar keratoplasty (DALK) or who may not fare well with a full-thickness transplant. The procedure appears to carry a low level of risk, though the study should be repeated in a larger population with longer follow-up times. It is noted, however, that vision did not improve enough to match the results of DALK or penetrating keratoplasty.