The deposits of cornea guttata, which often precede Fuchs' endothelial dystrophy, represent a risk factor in patients undergoing intraocular surgery, rendering a cornea unsuitable for use as donor material. These corneal guttae clinically resemble subendothelial blebs that accompany various corneal and anterior segment inflammatory conditions so that confusion between the two groups is possible. In differentiating the two groups it is noted that (a) guttae are more elevated and usually appear in the relief mode; (b) the endothelial mosaic, if present, is usually relatively normal around the guttae; (c) both guttae and blebs may be contiguous and even confluent; (d) guttae are more regular and endothelial cells are often arranged regularly around them; (e) although small guttae may occur, if guttae are at all numerous, large ones are also usually present; and (f) inflammatory cells are rarely present in the relief mode with guttae but are always present with blebs associated with uveitis.