VITREOMACULAR TRACTION (VMT)

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What is vitreomacular traction?

Cross-sectional diagram of a human eye, labeling the macula, vitreous gel, fovea, optic nerve, retina, iris, cornea, pupil, and lens.

Image source: ASRS

To understand what vitreomacular traction is, it is important to do a quick anatomy review. The inside of the eye is basically a gel sack called the vitreous, and it is attached to the tissue that lines the back of the eye (the retina). This attachment between the vitreous and the retina is especially strong at a few key points, one of which is the macula (the part of the retina responsible for your central, sharpest vision). As we age, the vitreous changes and becomes more liquid. When it becomes more liquid, it shrinks away from the retina and detaches from it. This is normal- it’s called a posterior vitreous detachment (PVD). This detachment occurs most often as a natural aging process, but it can also occur as a result of trauma or disease.

Diagram of the four stages of a posterior vitreous detachment, or PVD.

A visual of the vitreous (gray mass in the middle) detaching from the retina
Image source: Eye

There are some cases where this detachment is incomplete, and the vitreous remains strongly attached to the retina. When this strong attachment occurs at the macula and DOES NOT damage or distort the underlying tissue, it is called vitreomacular adhesion (VMA). When this strong attachment occurs at the macula and DOES damage or distort the underlying tissue, it is called vitreomacular traction (VMT).

What does VMT do to the eye and vision?

The strong attachment between the vitreous and the macula often results in the vitreous tugging on and distorting the inner layers of the retina.

The symptoms will depend on the severity of the condition. Patients with mild VMT may have no/minimal symptoms, while many experience reduced sharpness and/or distortion of central vision. Flashes of light in vision may also be reported. In more severe cases, the tugging can cause significant changes to the anatomy of the macula, resulting in a dark spot in central vision.

What are the risk factors for VMT?

As discussed above, the age-related changes in the vitreous are the cause of VMT, so age is obviously the biggest risk factor. Other factors found to be associated with a higher incidence of VMT are high amounts of nearsightedness (myopia) and diseases that involve macular edema such as wet macular degeneration, diabetic retinopathy, and retinal vein occlusions (1, 2).

How is VMT diagnosed?

Optical coherence tomography (OCT) of the macula is very helpful in diagnosing and managing VMT. OCT uses light waves to produce cross-sectional views of the tissue in the back of the eye. This allows your eye doctor to visualize the adhesion and the resulting changes in the anatomy of the macula (as seen below).

A macula OCT showing vitreomacular traction, or VMT.

Macula OCT, with the red arrow pointing at the area of VMT

If swelling in the macula is suspected, a fluorescein angiography (FA) may be recommended.

What is the treatment for VMT?

For mild cases of VMT, many eye doctors will observe and monitor via OCT. The patient is often given an Amsler grid to take home and monitor for any changes to their central vision. In some cases, VMT releases on its own and the retina goes back to its normal contour (as seen in the case below). On average, about 1/3rd of cases resolve on their own, though the data is variable (3).

A series of four macula OCTs showing the progression and resolution of vitreomacular traction or VMT.

OCTs showing VMT progression and resolution over an 11 month period

However, more severe cases of VMT can result is swelling of the macula (cystoid macular edema), epiretinal membrane formation, or a macular hole. In those more severe cases, intervention may be indicated. A pars plana vitrectomy (PPV) is a procedure in which the vitreous is surgically removed, and it has been considered the “gold standard” in VMT treatment for many years. A newer option is an injection of ocriplasmin (Jetrea®) into the eye. This drug degrades the adhesion molecules (specifically fibronectin and laminin) that connect the vitreous to the macula, thus inducing a vitreous detachment and resolving the VMT (4). More on those options here. Pneumatic vitreolysis is a similar option that instead uses an expansive gas injection into the vitreous to induce a vitreous detachment and resolve VMT (5).

CLIFFSNOTES: Vitreomacular traction occurs when a strong adhesion between the vitreous and the macula results in the vitreous tugging on the underlying tissue and causing damage/distortion. Treatment options include observation, surgery, or injections in the eye; the appropriate treatment is determined by considering the symptoms and the extent of the damage/distortion. See your optometrist if you are noticing changes in your vision!