Glaucoma-a diagnostic dilemma

September 1, 2007

A challenging decision for ophthalmologists is deciding when a patient transitions from suspected glaucoma to having early glaucoma. Years ago, clinical decisions were more closely linked to elevated IOP, but now the disease-defining characteristics of retinal nerve fiber layer loss and optic nerve cupping with or without functional visual field loss are measurable making the diagnosis of glaucoma more complex. Clinicians confront questions regarding what constitutes glaucomatous optic nerve damage and at what point normal aging-related axonal loss becomes glaucomatous axonal loss.

Key Points

Twenty years ago, clinical decisions were more closely linked to elevated IOP, but with tools now available to measure the disease-defining characteristics of retinal nerve fiber layer loss and optic nerve cupping with or without functional visual field loss, the diagnosis of glaucoma has become far more complex. Clinicians find themselves confronted with questions regarding what constitutes glaucomatous optic nerve damage and at what point normal aging-related axonal loss becomes glaucomatous axonal loss.

Such diagnostic dilemmas are not unique to the management of glaucoma. Even in seemingly straightforward medical settings such as those involving infectious diseases, at what point is a patient infected? Should a clinical threshold be based on measurable levels of infectious markers in the bloodstream or when there is a host inflammatory reaction? Regarding glaucoma, does it make a difference in health outcomes to diagnose the disease earlier, prior to visual field loss? Or is it better to wait for definite visual field loss?

I see no alternative to physicians acting on their informed clinical judgments even in the face of the risk that a chronic disease diagnosis would be perceived by patients as a setback. Still, given the complexity of diagnosing glaucoma and inherent uncertainty surrounding individual cases of early glaucoma, it is important to pay close attention to the components of our doctor-patient communication. Beyond the basic underpinnings of good communication, there is room for research on varying degrees of patient involvement in clinical decision-making. We should not automatically assume that more patient involvement is better, but as health professionals who have genuine expertise, neither should we be shy about sharing that expertise nor be afraid to engage patients in the decisions that have real implications in their lives.

Ultimately, the diagnosis rests on our knowledge, and the acceptance of the diagnosis and engagement of a patient in the treatment plan depends on our skills as communicators and educators.

Anne Louise Coleman, MD, PhD is the Frances and Ray Stark Professor of Ophthalmology and professor of epidemiology, Jules Stein Eye Institute, University of California, Los Angeles.