STRONG INDICATORS

Disc haemorrhages increase the risk of progression threefold in eyes with glaucoma, not because the lesions cause progression, but because they are a manifestation of a progressive neurodegenerative disease process, said Jeffrey Liebmann MD, New York University School of Medicine, New York, US.

“For research, that means we can consider using disc haemorrhage as an endpoint in our clinical trials. For practising clinicians it means that the disc has to be examined at every visit,” Dr Liebmann told the 11th Congress of the European Glaucoma Society in Nice and that the presence of a disc haemorrhage should alter physician behaviour, either with respect to management and/or surveillance.

Disc haemorrhage has reported prevalence rates of 12 per cent to 15 per cent in primary open-angle glaucoma and 15 per cent to 20 per cent in normal tension glaucoma. Moreover, research suggest that the progression rate in eyes with the lesion ranges can be as high as 80 per cent when one lesion is present and 100 per cent when there are two or more.

The cause of disc haemorrhage is unknown, and some investigators have suggested that it is primarily a vascular injury. However, there is a great deal of evidence that its occurrence is part of the process of glaucoma structural progression.

For example, the haemorrhages always occur at the edge of a nerve fibre layer defect or at the edge of an area of rim abnormality in the disc. They typically appear in areas where there is previous damage or at the edge of those damaged areas and indicate that the disease is worsening at that location.

“This implies that the notch and the nerve fibre layer loss are all part of the same degenerative process of the optic nerve head complex and the disc haemorrhage is just a transient manifestation of that ongoing process,” Dr Liebmann said.

Strong structure/function correlation

The area of the disc haemorrhage almost always corresponds closely to an area of visual field loss. Before the haemorrhage occurs, progressive visual field loss can already present in the area of the visual field corresponding to the haemorrhage.

Because disc haemorrhages are such strong indicators of glaucomatous progression, the treating physician must be vigilant. Other risk factors for glaucoma progression include higher intraocular pressure, older age, exfoliation syndrome, thinner cornea and a beta-zone parapapillary atrophy, he added.

“If you have a disc haemorrhage, I think you have to act. You may want to change the way you monitor the patient, perhaps initiate treatment, if you haven’t already, and consider whether advancing treatment might be in the patient’s best interest,” said Dr Liebmann.

Standard ophthalmoscopy through an undilated pupil is a useful part of every examination for glaucoma. “In spite of the fact that we have very expensive imaging devices, don’t throw away your ophthalmoscope or your indirect lens, and do look for disc haemorrhages at every visit,” he concluded.

Jeffrey Liebmann: jml18@earthlink.net