This Vietnamese study aimed to identify the speed of corneal neovascularization (CNV) after penetrating keratoplasty (PK) and to evaluate the influence of surgery-related factors on postkeratoplasty CNV in keratoconus patients.

The prospective, longitudinal, observational case series study included 66 consecutive primary PKs performed for keratoconus by four experienced surgeons between January 1, 2000, and December 31, 2002, at one department. Standardized corneal photographs taken preoperatively, and investigators evaluated them at six weeks, three months, six months, 12 months, 18 months and 24 months postoperatively. They measured limbus suture distance (LSD), limbus graft distance (LGD), inner suture angle (ISA) and maximal extension of CNVs in digitized pictures with 100-fold magnification at each of the 16 suture turning points at every timepoint.

Forty-four out of 66 corneal grafts (67 percent) developed some degree of CNV after PK, most commonly from around the 12 o"clock position. The mean speed of CNV growth was 114 microns/month, with the fastest growth occurring during the first six weeks after PK. Results showed an inverse correlation between CNV and LSD, LGD and ISA. Ninety percent of all CNVs developed with LSD less than 406 microns and with LGD less than 1000 microns.

The authors identified small LSD, small LGD and narrow stitching with small ISA as potentially modifiable surgical risk factors for CNV after PK. Because the speed of CNV outgrowth was most pronounced in the first weeks after PK, the authors emphasize the importance of making early postoperative controls for CNV growth and initiation of antiangiogenic treatment.