With its widespread availability and versatile capabilities, OCT has found a home in many facets of optometry, including diabetic retinopathy (DR) care. Carolyn Majcher, OD, FAAO, delved into the many applications of OCT and OCT angiography (OCT-A) for diabetic patients during her October 13 afternoon session, “Contemporary DR Care Utilizing OCT.”

Dr. Majcher began by emphasizing that diabetes is a worldwide epidemic impacting 10.5% of Americans, and is expected to affect nearly one billion people by 2050. Thus, the demand for DR care will only continue to rise, especially as it is now considered the leading cause of new cases of blindness among working-aged Americans. DR affects just under 30% of diabetes patients over the age of 40 in the United States, and the number of cases is forecasted to almost triple by 2050. This is where multimodal imaging comes into play, as it provides a more accurate and efficient option to stage DR in more patients in less time while still providing the highest quality of care.

The multimodal imaging capabilities of OCT helps clinicians stage DR by rendering the patient’s anatomical status in vivid detail.

The top two risk factors for DR include extended, sustained duration of diabetes and poor glycemic control. DR can be classified into proliferative and nonproliferative forms, depending on the presence of neovascularization (NV) and whether the pathology is confined to the retina.

Dr. Majcher divided her coverage of the role multimodal imaging plays in DR care into four parts: diabetic macular edema (DME), mild to moderate non-proliferative DR (NPDR), severe NPDR to low-risk proliferative DR (PDR) and high-risk PDR.

DME is defined as retinal thickening within 500μm of the center of the fovea. DME can be further broken down into center-involved (CI-DME) and non-center-involved (NCI-DME). Dr. Majcher recommends observing CI-DME and NCI-DME patients with visual acuity (VA) of 20/25 or better and referring for treatment if VA worsens to at least 20/30. OCT and OCT-A can aid in distinguishing CI-DME from NCI-DME, detecting subclinical DME (macular fluid that can’t be visualized with ophthalmoscopy alone) and macular ischemia and identifying potential sources of DME.

In the case of mild to moderate NPDR, Dr. Majcher notes that OCT-A is able to highlight subtle vascular abnormalities, providing more accurate DR staging. She also suggests that OCT-A is more telling than fundus examination alone, especially in detecting subclinical, or early, DR.

Dr. Majcher stresses the importance of referring all cases of severe NPDR to low-risk PDR, regardless of DME status. Treatment could include either panretinal photocoagulation (PRP) or anti-VEGF injection. Both Lucentis (ranibizumab, Genentech) and Eyelea (aflibercept, Regeneron) are FDA-approved even if DME is not present.

The “Take Home” Message

OCT Clinical Applications in DR:

  • Detect, classify and monitor DME
  • Determine PVD status
  • Detect preretinal tissue suggestive of neovascularization
  • Detect and monitor vitreoretinal traction/TRD

OCT-A Clinical Applications in DR:

  • Detection of subclinical DR
  • Highlight vascular abnormalities, allowing more accurate staging
  • Detection and quantification of nonperfusion, both peripheral and macular
  • Early detection of PDR
  • Monitor PDR regression with treatment

On examination, OCT is able to detect NV and determine posterior vitreous detachment status, while OCT-A differentiates between severe NPDR and early PDR.

As DR progresses to high-risk PDR, Dr. Majcher highlights the need to refer and treat all cases to prevent irreversible ocular damage. Treatment largely comes down to patient compliance, as anti-VEGF requires more office visits and injections, and whether or not there is concurrent DME present, as PRP exacerbates DME.

At this level, OCT and OCT-A are employed to detect subtle vitreous hemorrhage, monitor NV, monitor vitreoretinal traction, determine the status of the macula and detect retinal breaks.

“I believe that contemporary management of DR requires incorporation of multiple imaging modalities, particularly OCT with its now widespread ability and the advent of OCT-A,” Dr. Majcher leaves attendees with to conclude the course.