Dellen Associated with Filtering Blebs

I read with interest the article by Soong and Quigley in the March Archives (1983;101:385-387). The authors described the occurrence of nine cases of dellen of the cornea encountered in a series of 97 consecutive trabeculectomies. They observed that most dellen occurred in eyes with large blebs and noted “localized disruption of the precorneal tear film,” presumably due to the elevation of the bleb at the limbus. I am in full agreement with the authors’ views that dellen are associated with elevations of the bleb at the limbus, which prevents the upper eyelid from spreading the tear film in a normal fashion in that area. The logical approach to this problem is to fashion a bleb that is diffuse and less elevated and to direct the draining aqueous away from the limbus so that elevation of the bleb occurs posteriorly, keeping the limbal area flat. This.