Abstract
Glaucoma filtering surgery has evolved over the years from full-thickness fistulas, the standard practice in the 1950s, to partial-thickness fistulas or trabeculectomy, made popular in the 1960s. The newer procedures of deep sclerectomy and viscocanaliculostomy are nonpenetrating procedures, more difficult technically and require advanced subspecialty training, but are claimed to be associated with less complications. Gilbert Ozuzu, consultant ophthalmologist, and his colleagues describe an audit of their practice across Morecambe Bay.