Contributed by: Dr. Bryon McKay, MD PhD 2020
Patient Presentation: A 56-year-old male was referred to clinic for suspected diabetic macular edema. His past ocular history was unremarkable, and his past medical history is significant for type 2 diabetes that is controlled by diet only. He is otherwise healthy. On exam, vision is 20/50 OD, and 20/20 OS. Pupils were equal and reactive, with no relative afferent pupillary defect and IOP was 15mmHg in both eyes. Slit lamp examination was normal. The fundus photo of the right eye is below:
Question: What is the most notable abnormality in the fundus photograph?
An intravenous fluorescein angiogram was obtained next:
Pattern of IVFA consistent with perifoveal hyper-fluoresence (leakage pattern). Next, an OCT macula was performed as shown below:
Question: What layers of the retina are involved in this pathological process as shown in the OCT?
Question: What features on this OCT are atypical for DME?
Question: What is the diagnosis?
Now that we know the diagnosis, let’s re-visit the clinical images from this case.
In the fundus photo, there is a grayish discoloration in the peri-foveal area, which is characteristic of macular telangiectasia type 2.
In the IVFA, we can see ectatic, telangiectatic vessels in the temporal fovea that are classically seen in macular telangiectasia. These vessels (red arrow) often dive into the deeper retinal layers at a 90-degree angle.
For more information about macular telangiectasia, a helpful review article by Issa et al. (2014) is available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638089/.
The OCT features of macular telangiectasia are covered in their article: Issa PC, Gillies MC, Chew EY, Bird AC, Heeren TF, Peto T, Holz FG, Scholl HP. Macular telangiectasia type 2. Progress in retinal and eye research. 2013 May 1;34:49-77.
Question: The OCT to the left demonstrates another patient with macular telangiectasia type 2. What additional OCT findings are present here that indicate a later stage of disease?
1. Macular telangiectasia type 2 presents bilaterally and is characterized by abnormalities in the retinal capillary network.
2. On OCT, it is frequently characterized by focal disruption in the outer retinal layers and hypo-reflective cavities in the inner retina with a characteristic draping of the ILM. The foveal contour is typically preserved.