Comparison of yellow dye, continuous wave Nd:YAG, and argon green laser on experimentally induced corneal neovascularization.

BACKGROUND

Corneal neovascularization is generally undesirable because it can lead to corneal scarring, lipid deposits, and corneal graft failure. To eliminate these vessels, several techniques are available including laser photocoagulation.

METHODS

This prospective study was designed to compare the effectiveness of three laser wavelengths (continuous wave Nd:YAG, 1064 nm; argon green 514 nm; and yellow dye, 570 nm) to obliterate experimentally induced corneal neovascularization in the rabbit. Corneal vascularization was created in 12 rabbits by placing 7-0 silk sutures through two quadrants of the cornea. Once neovascularization was complete, the suture was removed and one of the three lasers was applied to occlude vessels at one of the neovascular sites. The other site was used as a control.

RESULTS

The yellow wavelength, when compared with the green required fewer exposures to occlude corneal vessels. At no time during observation was any laser more effective than the control. In the continuous wave Nd:YAG group, tissue necrosis was needed to achieve closure of vessels.

CONCLUSIONS

Yellow and green laser light are equally effective in eliminating the corneal vessels. Continuous wave Nd:YAG, as used here, appears to be a poor choice.