The corneal endothelial abnormalities after SLT shown in this study may be transient, and long-term effects are probably negligible in normal corneas or single treatments. However, in corneas with reduced transparency of the endothelium, such as compromised corneas and corneas with pigment deposits on the endothelium, there may be a risk of further corneal endothelial compromise, especially after repeated SLT. Larger and longer term studies with histopathologic evaluation would be useful to evaluate the effect of SLT on normal and subnormal corneal endothelium. Until further studies are done, it would be wise to minimize the number and energy of SLT laser shots.