This study evaluated the effect and safety of photodynamic therapy (PDT) with verteporfin retreatment on patients with corneal neovascularization.

Corneal neovascularization was induced with a silk suture of the corneal stroma in 24 white rabbits (48 eyes). Four rabbits were examined histologically before performing PDT. Ten rabbits were chosen randomly, one eye from each rabbit was treated with PDT at 50 J/cm2, and the other eye was used as a control. Both eyes of the remaining 10 rabbits were treated with PDT at 150 J/cm2. One week later, one eye was further retreated with PDT at the same intensity. The area of corneal neovascularization was measured and evaluated histologically using light and electron microscopies.

The least neovascularized area was observed in the retreated group (P=0.04). The histologic examination revealed fewer new corneal vessels in the retreated group, but the corneal epithelium, stroma, and endothelium showed a normal appearance. Results from electron microscopic examination demonstrated thrombi as well as destruction and nuclear fragmentation of the vascular endothelial cells. However, there were no other changes in the cornea except for vascular endothelial cells, even in the retreated group.

In conclusion, these results suggest that PDT with verteporfin retreatment appears to be safe and significantly more effective in patients with regression of corneal neovascularization.