Macular telangiectasia type 2 (MacTel 2) is a slowly progressive condition affecting the center of the retina, called the macula. The macula is responsible for detailed central vision, including reading and recognizing faces. MacTel usually affects both eyes.
What causes MacTel?
Although the name refers to abnormal retinal blood vessels, MacTel is primarily a degenerative disease of the retina.
Supporting cells in the retina called Müller cells become dysfunctional. Over time, this is associated with damage and loss of the photoreceptor cells that detect light and allow us to see fine detail.
What happens over time?
MacTel usually progresses slowly over many years. Early in the disease, central visual acuity may remain quite good even while changes are developing in the retina.
As the disease progresses, patients may notice:
- Difficulty reading
- Distortion or waviness
- Small missing or blurry areas near the center of vision
- Gradually decreasing central vision
On OCT imaging, we can often see progressive loss of the ellipsoid zone, which represents damage to the photoreceptors. This allows us to measure the disease over time.
A smaller number of patients can develop abnormal new blood vessels underneath the retina, called choroidal neovascularization (CNV). CNV can cause a more sudden change in vision and is treated differently.
How is MacTel treated?
Observation and monitoring
For many patients, the most appropriate approach is regular monitoring with retinal examinations and OCT imaging. If the disease is stable or progressing very slowly, treatment may not be necessary.
Treatment if abnormal blood vessels develop
If MacTel develops CNV, we can treat the abnormal blood vessels with anti-VEGF injections. These injections are used to control abnormal blood vessel growth, bleeding, and leakage.
ENCELTO for progressive MacTel
ENCELTO is an FDA-approved implant designed to protect the remaining photoreceptors and slow progression of MacTel. It continuously releases a protein called ciliary neurotrophic factor (CNTF), which helps support retinal cells.
In the two Phase 3 clinical trials, ENCELTO reduced the rate of photoreceptor loss by approximately:
55%
reduction in one study
31%
reduction in the second study
These studies measured progression by following enlargement of the area of photoreceptor loss on OCT over two years.
ENCELTO is intended to slow further degeneration. It does not restore photoreceptors that have already been lost. For that reason, it may be most relevant for selected patients who still have useful photoreceptors at risk and who show meaningful progression over time.
What should I do?
The most important step is regular follow-up. OCT imaging allows us to compare your retina over time and determine whether MacTel is stable, slowly changing, or progressing enough that treatment should be considered.
Please contact us promptly if you notice a sudden change in central vision, new distortion, or a new dark or blurry spot, as this can sometimes indicate the development of abnormal blood vessels.