Case study

ERG Alters Follow-up Schedule and Education for Patient with Diabetes

by Nate Lighthizer, OD, FAAO
Northeastern State University (Tahlequah, OK)

Patient History

A 33-year-old Native American female presented because she lost her glasses a year prior. From a visual standpoint, she was doing well. She didn’t report any changes in her vision and was corrected to 20/20 in both eyes (-1.25 OD, -1.00 OS). Her last A1c was 10.0, which is certainly higher than we would like to see.

The fundus photos (Figure 1 and Figure 2) show increased hemorrhaging in both eyes when comparing the most current exam to an exam performed a year prior.

Figure 1: Fundus image (OD)

Figure 2: Fundus image (OS)

The photos show some progression, so we ran an OCT (Figure 3), which looks good overall, with no macular edema, no major macular ischemia or thinning.

Figure 3: OCT

Given the history, systemic and structural findings, I would classify this case as mild NPDR in a young patient with uncontrolled A1C. Based on this, I would say the patient needs to return for follow-up in one year. However, we now have access to a DR Score with the RETeval^®, which can provide additional information.

Why Was the ERG Test Performed?

When managing patients with diabetes, especially when you see progression, but disease is still mild, RETeval can offer a higher level of confidence to determine when a patient needs to be seen again.

My practice protocol is to perform ERG on all patients with diabetes if I see any degree of structural change, if the patient is uncontrolled, if there are recent vision changes, or if the patient has had diabetes for more than 5 years. Two of the four conditions applied here, so I didn’t think twice about the need to perform this test.

Patients also appreciate knowing their diabetic retinopathy score because it provides the feedback they need to feel more in control of their health outcomes. Patients come back visit after visit wanting to compare their scores. We explain that anything above 23.4 is abnormal, so the lower they can get the score, the better.

What Were the ERG Findings?

Although I would still classify this patient as having mild NPDR, the DR Score was abnormal at 24.4 (Figure 4), which indicates that this patient is more likely to progress to needing treatment.

Figure 4: ERG report with the DR Assessment protocol test results

How Did the ERG Impact Next Steps?

Due to the elevated DR Score indicating a higher risk of progression, I no longer feel comfortable waiting 12 months to see this patient back. Instead, I want to set the next follow-up to four-months and then potentially move to six months. This will give me an opportunity to have more of a show-and-tell education session with the patient. The DR Score helps me educate and empower patients in their journey to manage their disease with better diet, A1C control, exercise and nutritional supplementation.

In short, the functional ERG findings pair with structure. They don’t replace it, but they do help you get a better understanding of which patients are more likely to be stable and which are at greater risk of progressing.