A 45-year-old white female was referred to a retina specialty clinic for macular evaluation. She reported blurred and distorted vision in her OD of uncertain onset. She had no pertinent medical or ocular history. Her best corrected visual acuities were 20/30 OD and 20/20 OS. All other entrance testing and anterior segment findings were normal. The posterior examination was not particularly striking, but there was mild retinal whitening and pigmentary changes temporally OD>OS. 

With OCT imaging, it was clear why the patient had trouble with the OD vision. There was a loss of the photoreceptor integrity line (PIL) subfoveally and in the parafoveal temporal region along with cystic gaps in the retina. The OS however did not have such a dramatic OCT presentation. Instead, the OS looked fairly normal with possible mild thinning and disorganization of retina layers in the temporal parafoveal region.

The OD presentation was highly suspicious for macular telangiectasia type 2 (MT2). MT2 is a bilateral, neurodegenerative disease, that most heavily affects the temporal parafovea in patients over the age of 40, leading to clinical signs of temporal retinal whitening, crystalline deposits, pigmented plaques, and right-angle vessels. On OCT, findings such as loss of PIL, disorganized retinal layers, cystic spaces, and draping of the internal limiting membrane may be present. While the disease is bilateral, it can present asymmetrically. 

The patient was educated about the likelihood of MT2 and was scheduled for additional testing (FAF, multicolor imaging, OCTA, and IVFA) to confirm or rule out the diagnosis. 

FAF revealed bilateral parafoveal areas of hyper-autofluorescence  consistent with MT2. As the disease progresses with formation of pigmentary plaques and more extensive RPE atrophy, hypo-autofluorescence will be present as well.

Multicolor imaging suggested altered reflectivity in the temporal parafoveal region bilaterally.


OCTA demonstrated altered, telangiectatic vessels in the temporal parafoveal region OD>OS. This is particularly evident in the deep vascular plexus of the OD. 

IVFA confirmed presence of irregular telangiectatic vessels in the temporal parafoveal region OD that leaked in later stages. Additionally it showed that the irregular vasculature was present not only in the OD, but in the OS as well.

While the OCT findings clearly suggested a disease state present in the OD, it was unclear with this imaging modality alone if the OS was affected. Multimodal imaging revealed the OS to have altered anatomy also consistent with MT2, making the diagnosis much more definitive. While OCT remains the workhorse for retinal disease diagnosis and management, other tools must still be used as necessary to make an accurate diagnosis.   

MT2 is unfortunately a progressive degenerative disease of the retina that can lead to central vision loss, scotomas, and metamorphopsia through retinal atrophy. There is no current treatment for the disease itself, but patients must be monitored for development of choroidal neovascularization which can be treated with anti-VEGF injections. In addition, patients with loss of ADL function should be referred to a low vision specialist. 

References

  1. Charbel Issa P, Gillies MC, Chew EY, et al. Macular telangiectasia type 2. Prog Retin Eye Res. 2013;34:49-77. 
  2. Khodabande A, Roohipoor R, Zamani J, et al. Management of Idiopathic Macular Telangiectasia Type 2. Ophthalmol Ther. 2019;8(2):155-175. 
  3. Kedarisetti KC, Narayanan R, Stewart MW, Gurram NR, Khanani AM. Macular Telangiectasia Type 2: A Comprehensive Review. Clin Ophthalmol. 2022;16:3297.