To investigate the effect of low-dose systemic cyclosporine A (CsA) in preventing graft failure after high-risk penetrating keratoplasty (PKP).

In this retrospective study, 36 eyes of 25 patients who underwent PKP were evaluated. At 24 months postoperatively, the failure rate in the CsA group (n = 19) was compared to the control group (n = 17). For subgroup analysis, the failure rate in the CsA group (n = 9) and control group (n = 9) was compared in patients who underwent a repeat PKP. The patients' side-effect profile was also collected.

The median follow-up in the CsA group was 32.8 months and 28.9 months in the control group. Graft failure occurred in 31.6% CsA patients and in 68.4% control patients ( p = 0.311). In patients with repeat PKP, the failure rate in the CsA group was significantly lower than the control group (22.2% vs. 77.8%, p = 0.018). In one case (5.26%), CsA was discontinued due to gastroinstestinal discomfort.

Low-dose CsA was not beneficial compared to conventional therapy in high-risk PKP patients. However, in the repeat PKP subgroup, the incidence of graft failure was lower with low-dose CsA than with conventional therapy. Although further study is necessary, adding low-dose CsA might be beneficial for repeat PKP patients.