Macular telangiectasia (MacTel) type 2 is a bilateral, neurodegenerative disease that can result in significant visual impairment. In patients with MacTel, Müller glial cells, which provide nutrients to retinal neurons and help maintain the blood-retinal barrier, become dysfunctional, causing photoreceptor atrophy and visual loss.
Patients with MacTel often experience central visual field defects and near-vision issues that can cause functional difficulties, such as impaired reading ability.1 Although MacTel rarely leads to total blindness, it can substantially affect patients’ sense of well-being and facility with activities of daily living.
Accordingly, patients with MacTel report lower health-related quality of life across areas such as mental health, general health, and social functioning than do healthy controls.2 MacTel typically affects patients in their 40s and 50s, when they may present with nonspecific visual complaints such as metamorphopsia or paracentral scotomas.3
As such, differentially diagnosing MacTel from more common conditions, like age-related macular degeneration, can be a significant challenge. Nonspecific early symptoms and limited awareness of MacTel may contribute to its underdiagnosis.4
Diagnosing and monitoring MacTel with clinical imaging
The gold standard for diagnosing MacTel is measurement of ellipsoid zone (EZ) loss on optical coherence tomography (OCT).5 EZ loss is visible on OCT as a break in the photoreceptor inner segment/outer segment junction layer and hyporeflective cavities in the inner and outer retina; these changes often begin temporal to the foveal center, then progress as the disease advances toward the fovea and, later, to the nasal macula.6
The location of EZ loss can be an indicator of vision changes. Typically, patients with central EZ loss are more likely to experience vision loss, as measured by best-corrected visual acuity (BCVA). However, other retinal functional losses may be detectable on microperimetry before the break reaches the foveal center.6,7
Figure 1: Fundus (A) and corresponding OCT imaging (B and C) showing pronounced crystalline deposits, blunted retinal venules, and pigment proliferation. OCT shows loss of outer-retinal layers with inner and outer retinal hyporeflective cavities. Back shadowing beneath a hyperreflective region corresponds to pigmentary changes on the fundus photo.
Figure 1: MacTel type 2©Courtesy of Kiran Chandra Kedarisetti et al. Image used under CC BY-NC 3.0.
Figure 2: OCT of MacTel patient showing cystoid degenerative changes with loss of photoreceptors temporal to the fovea.
Figure 2: Courtesy of Roger A Goldberg, MD, MBA.
Many patients with MacTel report significant impairment in their ability to perform visual tasks, such as reading, despite minimal or no decrease in BCVA, which may be due to the presence of central field defects, which are easier to compensate for in the examination room.1 Findings like these highlight the importance of patient interviews or survey tools in understanding the impact and progression of vision loss in MacTel.
On fluorescein angiography, typical findings in a patient with MacTel include vascular abnormalities, such as telangiectatic capillaries in the deep plexus or blunted, right-angled venules, and fluorescein leakage in the absence of retinal edema, which may be among the first visible angiographic changes. On fundus photography, retinal graying may be seen, and in roughly half of patients with MacTel, small crystals on the inner retinal surface are noted.1
Figure 3: Fluorescein angiography of a MacTel patient showing characteristic juxtafoveal leakage.
Figure 3: Courtesy of Roger A Goldberg, MD, MBA.
One concern when examining a patient with MacTel is the possibility of subretinal neovascularization (SNV), also known as proliferative MacTel, which can be observed on fundus photography. This occurs in a minority of patients with advanced MacTel, is slightly more common in female patients, and can present at any stage of the disease.8
When SNV occurs, it can pose a serious threat to patients’ vision through subretinal hemorrhage, cystoid macular edema, and disciform scarring. The presence of SNV in one eye indicates a heightened risk of its development in the fellow eye. SNV can be treated with anti-vascular endothelial growth factor (VEGF) therapies, but anti-VEGFs have not been demonstrably effective in treating non-proliferative MacTel.1
Managing patients with MacTel
In the past, even if we were able to diagnose MacTel in its early stages, there were no approved treatments available to us; as such, the most we could do was monitor our patients with non-proliferative MacTel, which I would typically do every 6 months with exam and imaging to rule out new SNV.
Patients were instructed to monitor metamorphopsia at home using an Amsler grid and return to care for any latest changes.
Recent FDA approval of ENCELTO
In addition to anti-VEGF drugs, the FDA recently approved ENCELTO (revakinagene taroretcel-lwey) on March 6th, 2025, indicated for the treatment of adults with MacTel type 2.9 ENCELTO is an encapsulated cell therapy comprising a small capsule implanted and anchored to the sclera.
The capsule is made of a semi-permeable membrane containing genetically modified RPE cells engineered to produce ciliary neurotrophic factor (CNTF).9 In prior studies, CNTF has been shown to have a neuroprotective effect by promoting photoreceptor survival.10
To learn more about how ENCELTO performed in clinical trials, risks, and contraindications, check out Functional and Structural Outcomes in MacTel!
Conclusion
Our approach to managing patients with MacTel must be individualized, taking into account each patient's progression and including thoughtful counseling.
There is a clear need for us, as eyecare providers, to be aware of MacTel’s subtle presentations and imaging strategies to ensure early recognition and timely intervention.
