October 13, 2016

A failure to diagnose is one of the most reasons that patients file malpractice cases against optometrists. And, without question, glaucoma is the most frequently missed diagnosis I’ve observed as an expert witness.

Patient exhibits evidence of Krukenberg’s spindle. Courtesy: Ben Gaddie, OD

The case in question involved a 35–year–old male with moderate myopia. He was evaluated five times during a seven–year period; his intraocular pressure (IOP) was measured at three of those appointments.

At the initial visit, his IOP measured 18mm Hg OD and 19mm Hg OS. Optic nerve evaluation and fundoscopy revealed optic nerve asymmetry, with a cup-to-disc ratio of 0.3 OD and 0.4 OS.

His pressures were not documented at the second or third visits. However, his IOP measured 23mm Hg OD and 26mm Hg OS at the fourth visit, and 26mm Hg OD and 38mm Hg OS at the fifth visit. Following the fifth visit, he was referred to a glaucoma specialist.

Seven years after the patient’s initial visit, his cup–to–disc ratio was 0.6 OD and 0.9 OS. The referral consultation confirmed glaucoma OU, with advanced disease OS. What steps could have been taken earlier to identify the underlying cause of the patient’s escalating pressures?

The final diagnosis in this case was pigmentary glaucoma. It is important to note that many overlooked glaucoma diagnoses occur in patients with such secondary disease forms. One of the key insights we can garner from this case is the importance of identifying pigment dispersion syndrome (PDS) so we can monitor for the potential of pigmentary glaucoma.

Clinical signs of PDS include a vertical line of pigment located on the central corneal endothelium (i.e., Krukenberg’s spindle), iris transillumination and pigment in the trabecular mesh-work on gonioscopy. There is also a fourth sign known as Scheie’s line, which manifests as pig-mentary deposits along the peripheral posterior lens capsule (visible upon pupillary dilation). In most instances, such PDS findings tend to appear bilaterally and usually affect younger to middle-aged males.

It is essential that clinicians look for the aforementioned clinical signs associated with PDS to prevent progression to pigmentary glaucoma. Always be sure to monitor IOP and regularly document optic nerve findings.

"No one is in control of your happiness but you; therefore, you have the power to change anything about yourself or your life that you want to change."
    –Angelis, Barbara De

Review of Optometry® is published by the Review Group, a Division of Jobson Medical Information LLC (JMI), 11 Campus Boulevard, Newtown Square, PA 19073.

To subscribe to other JMI newsletters or to manage your subscription, click here.

To change your email address, reply to this email. Write "change of address" in the subject line. Make sure to provide us with your old and new address.

To ensure delivery, please be sure to add to your address book or safe senders list.

Click here if you do not want to receive future emails from Review of Optometry.