Disc hemorrhages (DHs) occur in up to 1.4% in individuals without glaucoma, but they are more common (up to almost 18%) in glaucoma patients.1 They can also be associated with various other conditions (e.g., posterior vitreous detachment, hypertension, diabetes, and use of certain systemic medications). Thus, DHs are not specific for open-angle glaucoma. But do they represent a feature that justifies a comprehensive glaucoma assessment? This question was investigated by Hogan et al., who calculated the positive predictive value (PPV) of a DH for open-angle glaucoma in a retrospective study of 618 consecutive patients referred by community optometrists to the glaucoma service in Edinburgh. Fifty-five patients (8.7%) had a DH (with or without other features suggesting glaucoma); in 21 patients a DH was the only reason of the referral. Twenty-nine of the DH patients were diagnosed with open-angle glaucoma (PPV 53.7%).
An almost 24% PPV may represent an acceptable cut-off in the well-organized Scottish healthcare setting
However, the PPV was only 23.8% when patients presenting with a DH as the only feature of glaucoma were considered. For the category of DH and one additional feature of glaucoma the PPV was 55%; for DH and two additional features the PPV increased to 92.3%. The presence of a disc hemorrhage did not increase the odds of glaucoma at the first visit. Patients with a disc hemorrhage were significantly (P < 0.001) older, more frequently females, had lower IOP and less features suggesting glaucoma than those without a DH.
As discussed by the authors, the translation of the results to the general clinical practice is difficult. It depends on the incidence of glaucoma in a population and the conditions offered by a health care system. They conclude that an almost 24% PPV may represent an acceptable cut-off in the well-organized Scottish healthcare setting. However, one may speculate that referring patients for glaucoma assessment because of an isolated disc hemorrhage would not be welcomed by most community health care systems in other parts of the World.