Researchers in Scotland recently looked at the potential diagnostic role of anterior segment OCT (AS-OCT) and realized clinicians should not use it to differentiate infective infiltrates from inflammatory keratic precipitates for patients presenting with postoperative inflammation.

Still, AS-OCT may be a good diagnostic and monitoring tool to assess response to treatment in cases where anterior segment inflammation of uncertain etiology is present, they noted. If AS-OCT only identifies endothelial deposits, clinicians should still suspect interface infection. The researchers could differentiate endothelial pigment deposits from keratic precipitates with smaller, poorly defined, hyporeflective deposits.

The case-based review included six patients with inflammatory keratic precipitates, one patient with infective interface keratitis following Descemet membrane endothelial keratoplasty and one patient with endothelial pigment. AS-OCT images in acute and active inflammation generally demonstrated hyperreflective keratic precipitant variants compared with other conditions with moderate or longstanding inflammation. The presence of hyperreflective precipitates on AS-OCT may help clinicians decide whether there may be active inflammation in the anterior chamber that requires treatment.

In the patient with infective interface keratitis, keratic precipitates were evident on the endothelial surface but no changes were identified at the graft-host interface. When patients first present with uveitis and keratic precipitates one week following surgery, AS-OCT did not demonstrate any morphological differences between the precipitates compared with the other non-infectious cases in this series. Therefore, the researchers noted that there were no significant differences between infective and inflammatory precipitates to help distinguish between the two.

The researchers noted that it could be possible that the presence of hyperreflective keratic precipitates on AS-OCT could be more suggestive of newly deposited precipitates and active inflammation as well as keratic precipitates of herpetic origin. This may be helpful if corneal edema or opacity otherwise prevents visualization of cells in the anterior chamber.

Shipton C, Hind J, Biagi J, Lyall D. Anterior segment optical coherence tomographic characterisation of keratic precipitates. Cont Lens Anterior Eye. January 13, 2020. [Epub ahead of print].